ESO Garching Science Colloquia and Seminars 2012

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January 2012

10.01.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Tales about Supernovae"
Jason Spyromilio (ESO)
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"Tales about Supernovae"
Jason Spyromilio (ESO)

Abstract A review of the scientific evolution in the field of supernovae over the past 25 years with an emphasis on work that underpins the use of supernovae as standard candles. Some recent results from the work following on from the original Lambda discovery papers will also be discussed.
11.01.12 (Wednesday)
16:30, Cluster Building, seminar room, basement, Universe Cluster Colloquium
"When massive stars are born - triggered star formation and the destruction of molecular clouds"
James Dale (LMU)
17.01.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"Star making at low-metallicity: the mass accretion process"
Loredana Spezzi (ESO)
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"Star making at low-metallicity: the mass accretion process"

Loredana Spezzi (ESO)

Abstract The mass accretion rate (Macc) is a key parameter to constrain the models of both star and planet formation, for it affects both the disk structure and evolution as well as planet formation and migration. In particular, Macc studies in low-metallicity environments are particularly important because the probability of a star hosting a planet depends on stellar metallicity.

We have conducted a multi-wavelength study of four star forming regions, spanning the age 1-14 Myrs, located between the 30 Doradus complex and the supernova SN1987A in the Large Magellanic Cloud (LMC), where the metallicity is much lower than in our Galaxy. We reliably identify about 1000 pre-main sequence (PMS) star candidates actively undergoing mass accretion and estimate their stellar properties and mass accretion rate (Macc). Our measurements represent the largest Macc dataset of low-metallicity stars presented so far. As such, they offer a unique opportunity to study on a statistical basis the mass accretion process in the LMC and, more in general, the evolution of the mass accretion process around low-metallicity stars.

In this talk, I will review the main results of this study in comparison to similar study in the Milky Way and the Small Magellanic Cloud.
12:30, ESO room D30, Lunch Talk
"The radio sky at 12mm - latest science results from the AT20G survey"
Elaine Sadler (University of Sydney)
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"The radio sky at 12mm - latest science results from the AT20G survey"

Elaine Sadler (University of Sydney)

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The Australia Telescope 20 GHz (AT20G) survey is a sensitive imaging survey of the entire southern sky (south of declination 0 degrees, at Galactic latitude |b|> 1.5 deg) carried out with the Australia Telescope Compact Array in the 12 millimetre band. The kinds of radio sources seen at 12mm are significantly different from those in seen in lower-frequency radio catalogues like NVSS and FIRST. I will discuss some recent science results from AT20G, including the discovery of a large population of young and recently-restarted radio galaxies. I will also mention some scientific links to the large optical/IR sky surveys currently underway at ESO, the Planck (CMB) and Fermi (gamma-ray) missions, and future work with ALMA.
18.01.12 (Wednesday)
16:30, Cluster Building, seminar room, basement, Universe Cluster Colloquium
"Photospheric emission in Fermi Gamma Ray Bursts"
Sinead McGlynn (Cluster fellow)
19.01.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Galaxy Mergers through Cosmic Time"
Jennifer Lotz (STScI, Baltimore)
Download (FLV) | Watch video / abstract
31.01.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"The link between turbulence, cloud structure, and star-formation"
Nicola Schneider (CEA Saclay / Observatoire de Bordeaux)
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"The link between turbulence, cloud structure, and star-formation"

Nicola Schneider (CEA Saclay / Observatoire de Bordeaux)

Abstract

Interstellar turbulence plays a major role during the formation process of molecular clouds and stars. I will review observational signatures of turbulence (filamentary structure of molecular clouds, Delta-Variance, probability density functions) and its link to star-formation. Recent observational data (continuum and molecular lines) from Herschel, Spitzer, SOFIA, and ground-based submm-radiotelecopes will be presented

In particular the new Herschel FIR photometric maps (70-500 micron) of Galactic clouds obtained within several programs (HOBYS, Gould Belt, Hi-GAL) allow for the first time to derive a large set of precise column density and temperature maps that allow to trace the cloud structure and the content of Young Stellar Objects at the same time. Combining Herschel continuum data with (sub)-mm molecular line data is essential to study the velocity structure of the clouds and to compare with numerical models. Preliminary results for the Rosette Cloud indicate that star-formation is mainly determined by large-scale turbulence that defined a primordial density structure, and not by UV-radiation. A study of the Cygnus region shows that it is due to high accretion rates, provided by filaments, that explain cluster formation.
12:30, ESO room D29, Lunch Talk
"The Star Formation & Chemical Evolution Timescales of Two Nearby Dwarf Spheroidal Galaxies"
Thomas de Boer (Kapteyn Astronomical Institute, Groningen)
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"The Star Formation & Chemical Evolution Timescales of Two Nearby Dwarf Spheroidal Galaxies"

Thomas de Boer (Kapteyn Astronomical Institute, Groningen)

Abstract

We present the detailed Star Formation History of the nearby Sculptor and Fornax dwarf spheroidal galaxies, from wide-field photometry of resolved stars, going down to the oldest Main Sequence Turn-Off. The accurately flux calibrated, wide-field Colour-Magnitude Diagrams are used directly in combination with spectroscopic metallicities of individual RGB stars to constrain the ages of different stellar populations, and derive the Star Formation History with particular accuracy. The detailed Star Formation History shows the star formation at different ages and metallicities, at different positions in the galaxy, and shows that the known metallicity gradients are well matched to an age gradient. The obtained SFH is used to determine accurate age estimates for individual RGB stars, for which spectroscopic abundances (alpha-elements, r- and s-process elements) are known. In this way, we obtain the accurate age-metallicity relation of each galaxy, as well as the temporal evolution of alpha-element abundances. This allows us to study, for the first time, the timescale of chemical evolution in these two dwarf galaxies, and determine an accurate age of the "knee" in the alpha-element distribution. Finally, we compare the timescale of chemical evolution in both dwarf galaxies, and determine whether the chemical abundance patterns seen in galaxies with recent episodes of star formation are a direct continuation of those with only old populations.

February 2012

01.02.12 (Wednesday)
16:30, Cluster building, seminar room (basement), Universe Cluster Colloquium
"Dust in the wind - Grain growth and transport in protoplanetary disks"
Til Birnstiel (LMU)
02.02.12 (Thursday)
12:30, ESO Council Room, Lunch Talk
"An atmospheric piston simulator for LINC - NIRVANA"
Roman Follert (MPIA, Heidelberg)
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"An atmospheric piston simulator for LINC - NIRVANA"

Roman Follert (MPIA, Heidelberg)

Abstract

LINC - NIRVANA (LBT INterferometric Camera - Near-IR / Visible Adaptive iNterferometer for Astronomy, LN) will demonstrate image plane interferometry with a wide field of view. This will, for the first time, allow imaging with the spatial resolution of a telescope with a 23 m aperture. This ambitious goal imposes serious requirements on the AO and fringe tracking systems of LN. Therefore, dedicated testing and verification experiments during integration are mandatory. In that respect, it will be beneficial to mimic the environmental conditions at the observatory site (Mt. Graham, Arizona) as realistically as possible. For this purpose, I designed and assembled an atmospheric piston simulator. Due to its optical fiber based design, there are various interfaces for the integration into LN. Furthermore, the piston simulator is controlled such that piston sequences of arbitrary complexity are generated. The atmospheric piston simulator will be used in near future to verify the LN fringe tracking system. In this talk, I will introduce the design, the respective control schemes, and the results of the lab verification experiment of the atmospheric piston simulator.
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"The power of gravity-mode oscillations to probe the physics of stellar cores"
Conny Aerts (KU Leuven)
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08.02.12 (Wednesday)
16:30, Cluster building, seminar room (basement), Universe Cluster Colloquium
"Experimental studies of strong interaction in exotic atoms"
Oton Vazquez-Doce (TUM)
09.02.12 (Thursday)
10:00, ESO Council Room, Euclid Journal Club
"A Type Ia Supernova at Redshift 1.55 in Hubble Space Telescope InfraredObservations from CANDELS, by Rodney et al."
Bruno Leibundgut (ESO)
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"A Type Ia Supernova at Redshift 1.55 in Hubble Space Telescope Infrared Observations from CANDELS, by Rodney et al."

Bruno Leibundgut (ESO)

Abstract

This is a fairly short paper, but it is the first from the multi-cycle HST program to find the most distant supernovae. I will expand on that a little bit as well.
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Super-Earths and Neptune-mass planets from the HARPS surveys: a window to planetary-system diversity"
Stephane Udry (University of Geneva)
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"Super-Earths and Neptune-mass planets from the HARPS surveys: a window to planetary-system diversity"

Stephane Udry (University of Geneva)

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I will report on the results of an 8-year survey carried out at the La Silla Observatory with the HARPS spectrograph to detect and characterize planets in the super-Earth and Neptune-mass regime. The size of our star sample and the precision achieved with HARPS have led to the detection of a sufficiently large number of low-mass planets to study the statistical properties of their orbital elements, the correlation of host-star properties with the planet masses, as well as the occurrence rate of planetary systems around solar-type stars. These results will be discussed in comparison with equivalent results obtained in our M-dwarf survey and with the recent Kepler findings.
14.02.12 (Tuesday)
10:00, ESO room D29, Star and Planet Formation Seminar
"Surface photometry of nearby galaxies with VST"
Massimo Capaccioli (INAF-Capodimonte, Napoli)
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"Surface photometry of nearby galaxies with VST"

Massimo Capaccioli (INAF-Capodimonte, Napoli)

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The VST + OmegaCam wide-field facility has come into operation at Paranal and we have just started the analysis of the first images of the nearby elliptical galaxies selected for the VEGAS survey. In particular we have fully reduced, using the pipeline VST-tube developed at Naples, the images of the giant NGC 1399 in Fornax taken in g, r and i bands. In the talk I will shortly report on the quality of the material, on the difficulties met during the reduction, and on the solutions adopted to overcome them. I will show comparisons with previous studies both for the galaxy light distribution and for the luminous extended halo (ICL), with hints to color gradients, and I shall report on a comparison made with the GCs of the galaxy observed by HST.
15.02.12 (Wednesday)
16:30, Cluster building, seminar room (basement), Universe Cluster Colloquium
16:30 - 17:00: "Galaxy (and) cluster formation at redshift z=2"
Raphael Gobat (CEA Saclay)
17:00 - 17:30: "Spectral energy distribution of heavily obscured AGN beyond the local Universe"
Italo Balestra (INAF Trieste)
23.02.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"A gas cloud on its way towards the supermassive black hole at the Galactic Centre"
Stefan Gillessen (MPE)
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28.02.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"EX Lupi from quiescence to outburst - a study of the molecular gas MIR emission from disks affected by star variability"
Andrea Banzatti (ETH Zurich, Institut fuer Astronomie)
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"EX Lupi from quiescence to outburst - a study of the molecular gas MIR emission from disks affected by star variability"

Andrea Banzatti (ETH Zurich, Institut fuer Astronomie)

Abstract

In recent years the study of gas in young circumstellar disks has been rapidly growing, especially in relation with an increasing interest in disk evolution processes and in the presence of molecules relevant for life at disk radii where planets are expected to form. In this talk I will present an analysis of the MIR emission from molecular gas (in particular H2O, OH, HCN, C2H2, CO2) observed in the strongly variable T Tauri system EX Lupi. We compared archival Spitzer spectra taken before and during an exceptional outburst happened in 2008 to see if and how the gas in the inner few AUs of the circumstellar disk is affected by a sudden large increase in the stellar+accretion luminosity. I will describe the method we developed and highlight the main results, as well as discuss the limitations and the new perspectives provided by this analysis. In an attempt to address some of them, in the conclusion I will mention the further investigations that I am currently undertaking using the powerful modern instruments available at the ESO VLT.
12:30, ESO room D29, Lunch Talk
"Properties of the AGN wind of Mrk 509"
Katrien Steenbrugge (Universidad Catolica del Norte en Antofagasta, Chile)
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"Properties of the AGN wind of Mrk 509"

Katrien Steenbrugge (Universidad Catolica del Norte en Antofagasta, Chile)

Abstract

I will present the optical, UV and X-ray data obtained during a 3 month observational campaign of the Seyfert 1 galaxy Mrk 509, using 5 different satellites, and obtained with the goal to determine the mass, kinematic luminosity and feedback on the host galaxy of this outflow. I will focus on the 600 ks XMM-Newton RGS spectrum, which is the deepest high-resolution X-ray spectrum yet of a Seyfert 1 galaxy, and the high signal-to-noise HST-COS UV spectrum. The excellent statistics allow us to study in detail the ionization structure and relative abundances (X-rays) and kinematics (UV) of this gas. The ionization structure spans 3 orders of magnitude and is discrete and the abundance ratios are consistent with solar ratios. We detect absorption from an AGN wind which has 8 different kinematic components and is located at distances between 5 and 400 pc; the host galaxy and probably a high velocity cloud about 22 kpc from Mrk 509.

March 2012

01.03.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Thermonuclear supernovae from different progenitor systems"
Friedrich Roepke (Univ. Wuerzburg)
Download (FLV) | Watch video / abstract
06.03.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"The MIDI AGN Large Programme: A statistical sample of resolved AGN tori"
Leonard Burtscher (MPE)
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"The MIDI AGN Large Programme: A statistical sample of resolved AGN tori"
Leonard Burtscher (MPE)

Abstract Interferometric observations with MIDI/VLTI in the mid-infrared made studies of the central dusty tori of Active Galactic Nuclei (AGNs) possible and proved their existence in a number of nearby galaxies. Both type 2 and type 1 galaxies showed dust on the parsec-scale whose general properties were comparable -- consistent with (but not proving) the "unifying model" for radio-quiet galaxies. Existing studies were, however, mostly based on single or very few sources and therefore dominated by the characteristics of individual galaxies. For a more comprehensive approach, a larger sample is needed. This statistical basis is set up as a VLTI/MIDI Large Programme that comprises 14 AGNs for which torus properties are being determined. Observations and data reduction are finished and show resolved dust emission in almost all of the sources. They represent the largest sample of resolved AGN tori so far, allowing to ask a number of questions, ranging from unification to the physics of accreting galactic nuclei. In particular, the observations allow us to dissect the parsec-scale infrared emission and to determine the sizes and fluxes of the various components.
08.03.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Feedback from Accreting Black Holes: The Importance of Momentum Driving"
Jerry Ostriker (Princeton University)
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13.03.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Density waves in debris disks"
Mir Abbas Jalali (Sharif University of Technology)
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"Density waves in debris disks"
Mir Abbas Jalali (Sharif University of Technology)

Abstract I present some new results on the dynamics of collisionless near-Keplerian discs. Such systems are models for debris discs around stars. After a brief review of observed structures around debris discs, I introduce a finite-element method to solve the linearized collisionless Boltzmann equation and Poisson's equation for a wide range of disc masses and rms orbital eccentricities. It is shown that debris discs can support large-scale 'slow' modes, which exist for arbitrarily small disc mass so long as the self-gravity of the disc is the dominant source of apsidal precession. I illustrate how slow modes in debris discs are excited during a fly-by of a neighbouring star. Many of the non-axisymmetric structures observed in debris discs (clumps, eccentricity, spiral waves) that are commonly attributed to planets could instead arise from slow modes; the two hypotheses can be distinguished by long-term measurements of the pattern speed of the features.

Further reading: Jalali & Tremaine (http://arxiv.org/abs/1110.4551)
15.03.12 (Thursday)
16:15, MPE Large Seminar Room 1.1.18b, Munich Joint Astronomy Colloquium
"Using stellar mass black holes to understand AGN"
Chris Done (Durham University, Dept. of Physics)
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"Using stellar mass black holes to understand AGN"
Chris Done (Durham University, Dept. of Physics)
Abstract I will review the spectral and timing properties of x-ray binaries, especially the behaviour seen as the source makes a transition from the low/hard to high/soft state. The broad band spectral evolution is well modelled by a truncated disc/hot inner flow geometry, where the truncation radius moves progressively towards the last stable orbit during the transition. Here I show that this same geometry can also quantatitively match the power spectral evolution, where fluctuations propagating through the hot flow (stirred up by the MRI) make the broad band continuum power spectra, and Lense-Thirring precession of the hot flow makes the prominent low frequency QPO. I will then take some of the insights on accretion in stellar mass black holes and see how they can help in interpreting AGN spectra.
20.03.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"News from the merger remnant NGC 1316 (Fornax A)"
Tom Richtler (Universidad de Concepcion, Chile)
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"News from the merger remnant NGC 1316 (Fornax A)"
Tom Richtler (Universidad de Concepcion, Chile)

Abstract I shall present results from recent photometric and spectroscopic work on the merger remnant NGC 1316 and its globular clusters (GCs). Wide-field imaging in the Washington system reveals morphological details which previously have gone unnoticed. The distribution of GC colors indicates an extended period of star cluster formation. The kinematics of about 170 GCs show a complex behavior, complicating a dynamical analysis. Finally, I briefly present the remarkable object SH2 in NGC 1316 which may be an infalling dwarf galaxy.
22.03.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Three Freaks of the Solar System (And Why They Matter)"
Dave Jewitt (University of California)
Download (FLV) | Watch video / abstract
27.03.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"Warm gas atmospheres of the protoplanetary disks seen by Herschel: Gas rich and carbon poor?"
Simon Bruderer (MPE)
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"Warm gas atmospheres of the protoplanetary disks seen by Herschel: Gas rich and carbon poor?"
Simon Bruderer (MPE)

Abstract With the Herschel Space Observatory, lines of simple species ([CII], [OI] and high-J lines of CO) have been detected in the atmosphere of protoplanetary disks. When combined with ground-based data on [CI] all principle forms of carbon can now be studied. This allows to test model predictions for the main carbon bearing species to study the gas-phase carbon budget and the presence of a warm surface layer.

I present new thermo-chemical modeling of the well studied disk around the Herbig Be star HD 100546. Using this model, we can reproduce the CO ladder (J = 3 $B!](B 2 to 30 $B!](B 29) together with the atomic fine structure lines of [OI] (63 and 145 $B&L(Bm) and either [CII] (158 $B&L(Bm) or the upper limit of [CI] (370 $B&L(Bm). We find that the high-J lines of CO can only be reproduced by a warm atmosphere with a gas temperature much increased over the dust temperature. The low-J lines of CO, observed from the ground, are dominated by the outer disk with radius of several 100 AU while the high-J CO observable with Herschel-PACS are dominated from regions within some tens of AU. The profiles of high-J lines of CO are predicted to be broader than the low-J lines. We study the effect of several parameters including the size of the disk, the gas mass of the disk, the PAH abundance and distribution and the amount of carbon in the gas phase. The absence of neutral carbon [CI], which is predicted to be strong by thermo-chemical models, is discussed in the context of the gas-phase carbon budget.
12:30, ESO room D29, Lunch Talk
"Nuclear clusters in late-type dwarf galaxies in low-density environments"
Iskren Georgiev (AIfA, Bonn)
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" Nuclear clusters in late-type dwarf galaxies in low-density environments"
Iskren Georgiev (AIfA, Bonn)

Abstract Massive star clusters in the nuclear regions of dwarf (irregular) galaxies have been envisioned as possible progenitors of a sub-population of peculiar Galactic globular clusters, e.g. wCen, NGC 2419, M54. The latter is still associated with the nucleus of the dissolving Sagittarius dSph. It is however not well known, how the properties of massive nuclear clusters in such dwarf galaxies compare to those of these Galactic GCs. A common origin, i.e. in a deep potential, will result in a similar evolution of their stellar populations and structural properties. I will present such an analysis based on a large sample of nuclear clusters in dwarf irregular galaxies studied with HST imaging and VLT spectroscopy and supplemented by new (still in progress) analysis of B,V,I VIMOS imaging of 10 LMC mass dIrrs, located in the outskirts of Fornax and Eridanus galaxy clusters.
28.03.12 (Wednesday)
16:30, Cluster building, seminar room (basement), Universe Cluster Colloquium
"Twenty-first Century Lattice Gauge Theory: Consequences of the QCD Lagrangian"
Andreas Kronfeld (Fermilab, Cluster guest)
29.03.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"The Precision Array to Probe the Epoch of Reionization"
Chris Carilli (NRAO)
Download (FLV) | Watch video / abstract

April 2012

03.04.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Interstellar polarization: old models and new ideas"
Nikolai Voshchinnikov (St. Petersburg State University)
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"Interstellar polarization: old models and new ideas"
Nikolai Voshchinnikov (St. Petersburg State University)

Abstract Interstellar linear polarization is caused by the linear dichroism of the interstellar medium due to the presence of non-spherical oriented grains. The interpretation of polarimetric observations includes computations of the polarization cross sections and averaging of them for given particles size and orientation distributions.

Early models dealt with infinite cylindrical particles which were assumed to be perfectly aligned. Such models produce polarization much larger than the observed one.

We use the model of spheroidal grains with imperfect alignment. It allows one to estimate the properties of dust grains and the angle between the line of sight and the magnetic field direction, i.e., to find the space structure of magnetic field. The results for Taurus molecular cloud TMC-1 will be demonstrated.

The nature of polarizing grains can be established from the comparison of the degree of interstellar polarization P and polarization efficiency P/E(B-V) or P/A(V) with dust phase abundances. We detect an anticorrelation between P and the dust phase abundance of iron in non silicate-containing grains, a correlation between P and the abundance of Si, and no correlation between P/E(B-V) or P/A(V) and dust phase abundances. These findings can be explained if mainly the silicate grains aligned by the radiative mechanism are responsible for the observed interstellar linear polarization.
10.04.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"Structure of accretion and outflow on small scales in high-mass protostars"
Ciriaco Goddi (ESO)
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"Structure of accretion and outflow on small scales in high-mass protostars"
Ciriaco Goddi (ESO)

Abstract Very Long Baseline Interferometry observations of molecular masers has been proved to be a unique tool to study the 3D kinematics of molecular gas in the proximity of massive young stellar objects (YSOs), probing expansion in jets/outflows (H2O) and rotation/infall in disks/envelopes (CH3OH).
I will describe our findings towards two targets which revealed two different patterns:
I) an intermediate-mass (possibly pre-ZAMS) YSO drives a radio jet which excites H2O masers in a "collimated" bipolar flow; CH3OH masers show that gas accretion onto the YSO is still ongoing.
II) an O-type (ZAMS) YSO excites a hypercompact (HC) HII region, which lies at the center of an arc-like distribution of H2O masers and drives a "wide-angle" flow, while CH3OH masers probe gas outside the HII region that may no longer accrete onto the YSO.
I will briefly describe an observational program whose key goal is to assess if the different patterns of ejection/accretion we observed is a typical signature in the evolution of massive YSOs.
This may enable to address two key questions in massive star formation:
1) Does outflow collimation decrease with protostellar mass or age?
2) Can mass-accretion proceed once a HC HII region has formed?
12.04.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Feedback Processes in Rapidly Star-Forming Galaxies"
Todd Thompson (Ohio State University)
Download (FLV) | Watch video / abstract
17.04.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Type Ia Supernovae: Explosions and Progenitors"
Wolfgang Kerzendorf (University of Toronto)
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"Type Ia Supernovae: Explosions and Progenitors"
Wolfgang Kerzendorf (University of Toronto)

Abstract Type Ia supernovae are known as the precise distance indicators that allowed the remarkable discovery of the accelerated expansion of the universe. Despite this astounding feat, there still remain large uncertainties in many of the key issues surrounding these extremely energetic events. These uncertainties, while not being horribly detrimental to their use as distance indicators, hamper the understanding of the far reaching consequences these cosmic factories of heavy elements have on the chemical evolution of the Universe.

Type Ia Supernovae can be divided into three distinct phases. The pre-supernova evolution, the explosion itself and the expansion phase, which results in spectra and light curves. In this talk I will first presents our findings on the progenitor question (pre-supernova phase). In addition, I will discuss my work on automating spectral analysis and how it links with explosion physics and the progenitor question. Finally, I will briefly highlight Universities of Toronto's involvement in arctic astronomy and introduce our transient search with the telescope CATS.
19.04.12 (Thursday)
12:30, ESO Auditorium, Lunch Talk
"Diffuse mid-IR emission: A problem for SFR measures?"
Alison Crocker (University of Massachusetts)
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"Diffuse mid-IR emission: A problem for SFR measures?"
Alison Crocker (University of Massachusetts)

Abstract Emission in the mid-IR (3-30 micron) in star-forming galaxies is mostly due to emission from small dust grains and large molecules. The large molecules, PAHs, emit in several bright bands, while both the large molecules and small grains emit continuum emission, after being heated to high effective temperatures by one or few photons (stochastic heating). These small particles have higher absorption cross-sections in the UV than classical (large) dust grains, theoretically making them a better tracer of young stars than the big grains which are more easily heated by lower-energy photos produced by older stars. However, they might be a less ideal tracer than hoped for due to two factors (1) the small grains/large molecules are largely destroyed in the vicinity of hot, young stars and (2) despite the UV-biased cross-section, the small grains/large molecules may be excited by old stars as well as young stars, particularly when located far from star-forming regions. Here I present work on a few, nearby, star-forming galaxies. By spatially separating the star-forming and non-star-forming regions and taking into consideration both UV photons and stars themselves "leaking" from star-forming regions, the fraction of 8micron dust emission due to old stars is approximately 40%, a large enough fraction to worry about this contribution when considering its use as both a low-redshift (typically resolved) and a high-redshift (at z=2 is in the MIPS 24 micron band) SFR measure. I will also discuss the decline of the 8micron to Halpha emission ratio in both star-forming and diffuse regions, discussing some (metallicity-dependent) reasons for the trends we see.
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Dusty nature of quasars"
Bozena Czerny (Copernicus Astronomical Center, Warsaw)
Download (FLV) | Watch video / abstract
24.04.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"Evidence of a low star formation rate in the Central Molecular Zone despite recent star formation outbursts"
Katharina Immer (MPIfR)
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"Evidence of a low star formation rate in the Central Molecular Zone despite recent star formation outbursts"
Katharina Immer (MPIfR)

Abstract The Central Molecular Zone (CMZ) is a place with extreme conditions in our Galaxy, the temperature, velocity dispersion and pressure values are much higher than in the Galactic disk. From a statistical point of view, a star formation study in the CMZ can uncover if star formation in this region is enhanced or suppressed by these extreme conditions compared to other parts of the Galaxy.

I will present 5-40 micron Spitzer/IRS spectroscopic observations of a sample of 68 ISOGAL sources with unknown natures. These sources were selected to test ISO color selection criteria. Based on their spectral features and the slope of their spectra, the sources were classified as young or late-type evolved objects. We applied the color selection criteria to all ISOGAL sources in the CMZ, selecting 485 young object candidates, and added 656 MSX young object candidates with F_E/F_D > 2 to the CMZ sample. The bolometric luminosities and subsequently the masses of the sources in the CMZ sample were determined. Applying a Kroupa initial mass function, the total mass in young objects that has been formed over the last 1 Myr was derived, yielding an average star formation rate of 0.08 solar masses per year for the CMZ. This result shows that, despite recent star formation outbursts, the star formation rate in the CMZ is at least magnitude lower than the global star formation rate in the Milky Way.
12:30, ESO room D29, Lunch Talk
"Extragalactic molecular line surveys"
Rebeca Aladro (University College London)
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"Extragalactic molecular line surveys"
Rebeca Aladro (University College London)

Abstract Molecular line surveys are excellent tools to study the physical chemical properties of the extragalactic interstellar medium. Recent studies have demonstrated that molecular abundances in the nuclei of galaxies can be used to disentangle the deeply obscured nuclear power sources (AGN or starbursts), as well as to estimate the strength of the UV fields, X rays, and/or shocks affecting the gas. I will review the most important studies done on this field, and show how the physical properties of the ISM can be derived from this chemical studies.
25.04.12 (Wednesday)
16:30, Cluster building, seminar room (basement), Universe Cluster Colloquium
"Constraints on gravity, dark energy, cluster astrophysics, and neutrino properties from galaxy clusters"
David Rapetti (Dark Cosmology Institute, Denmark)


May 2012

02.05.12 (Wednesday)
16:30, ESO Auditorium, Universe Cluster Colloquium
"Understanding neutrinos? GERDA and the neutrinoless double beta-decay"
Bela Majorovits (MPP Freimann)
03.05.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"The Galaxy-Halo Connection Across Mass and Time"
Risa Wechsler (KIPAC/Stanford University)
Download (FLV) | Watch video / abstract
10.05.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Debris disks in the Herschel era"
Christoffel Waelkens
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24.05.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Matters of gravity: modified gravity and the Lisa Pathfinder mission"
Joao Magueijo (Imperial College London)
29.05.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Systematic Trends in Sloan Digital Sky Survey Photometric Data"
Daniel Bramich (ESO)
31.05.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Towards Imaging the Event Horizon in the Galactic Center"
Heino Falcke (Radboud Universiteit Nijmegen)
Download (FLV) | Watch video / abstract


June 2012

05.06.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Extra-Galactic Planetary Nebulae with Integral-Field Spectroscopy"
Marc Sarzi (University of Hertfordshire)
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"Extra-Galactic Planetary Nebulae with Integral-Field Spectroscopy"
Marc Sarzi (University of Hertfordshire)

Abstract Planetary Nebulae (PNe) in external galaxies are mostly regarded either as tracers of the gravitational potential or as indicators for the distance of their galactic hosts, with the latter advantage owing to the almost universal -- though not fully understood -- shape of the PNe luminosity function (PNLF, generally in the [OIII]5007 emission).

Yet extra-galactic PNe can also be used as probes of their parent stellar population and understanding in particular the origin of the PNLF is a puzzle that, once solved, promises to reveal new clues on the late stages of stellar evolution and on the formation of PNe themselves.

I will show how integral-field spectroscopy allows to detect PNe in the optical regions of galaxies to flux levels otherwise inaccessible to standard narrow-band photometry. This allows to trace the PNLF in the same galactic regions where the properties of stellar populations can be well characterised, thus making it possible to understand how the shape of PNLF relates to the parent stellar population of PNe.

I will present results based on the detailed analysis of SAURON data for M32 and M31, showing for the first time that the PNLF is in fact not universal, and preliminary work on galaxies as far as the Virgo cluster. I will also discuss the future prospect of this field with next generation integral-field units such as MUSE on VLT.
12.06.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Co-evolving black holes and galaxies"
James Mullaney (Durham University)
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"Co-evolving black holes and galaxies"
James Mullaney (Durham University)

Abstract It is generally accepted that today's massive galaxies contain a central, supermassive black hole with a mass closely related to that of the host. However, how this situation has come about is far from clear. At some level, the growth of black holes and their galaxies must be linked, whether by active (e.g., direct feedback) or passive (e.g., common fuel supply) regulation. In this lunchtalk, I will highlight recent observational results which are beginning to shed light on how black holes and their host galaxies co-evolve and what processes may regulate their growth.
13.06.12 (Wednesday)
16:30, Excellence Cluster Garching, seminar room basement, Universe Cluster Colloquium
"Dynamics of protoplanetary discs including dust and metal effects"
Martin Ilgner (LMU)
14.06.12 (Thursday)
16:15, MPE Large Seminar Room, Munich Joint Astronomy Colloquium
"A modern look at galactic abundance gradients"
Fabio Bresolin (IfA, Hawaii)
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"A modern look at galactic abundance gradients"
Fabio Bresolin (IfA, Hawaii)

Abstract The study of metallicity gradients in spiral disks has been a crucially important tool to understand the chemical evolution of galaxies. I will focus this talk on extragalactic gradients derived from young populations, and will briefly describe how observations of ionized nebulae (HII regions and PNe) and massive stars have shaped our understanding of the present-day radial distribution of metals in galaxies.

I will highlight some recent developments in this field, in particular the study of gradients in outer galaxy disks and in galaxies at high redshift. I will conclude by introducing ongoing investigations of azimuthal metallicity variations and of gradients in low surface brightness galaxies.
19.06.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Shedding light on CANDELS"
Audrey Galametz (Rome Observatory, INAF)
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"Shedding light on CANDELS"
Audrey Galametz (Rome Observatory, INAF)

Abstract The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS; PIs: H. Ferguson, S. Faber; Grogin et al. 2011; Koekemoer et al. 2011) is the largest project in the history of Hubble (902 orbits). It will document the first third of galactic evolution from z = 8 to 1.5 via deep imaging of ~250,000 galaxies with HST WFC3/IR and ACS. It will also permit to find the first Type Ia SNe beyond z > 1.5. CANDELS is currently observing 5 fields (selected for their existing multiwavelength data e.g. ground-based, Spitzer and spectroscopy), GOODS-N and GOODS-S, UDS, COSMOS and EGS at two distinct depths (a.k.a `CANDELS-Deep' and `CANDELS-Wide'). CANDELS is a collaboration of more than 100 scientists who will exploit the data to get insights on research topics as diverse as SN, Cosmic High Noon (2>z>3; e.g, census on galaxy properties evolution (i.e., mass, morphology), study of AGN at z~2 etc.), Cosmic Dawn (z>6; e.g., constrain properties of galaxies at the end of the reionization epoch) etc.
21.06.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Looking at the dark side: weak lensing by large scale structure"
Henk Hoekstra (Sterrewacht Leiden)
Download (FLV) | Watch video / abstract
26.06.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Interaction of free-floating planets with a star-planet pair"
Harry Varvoglis (University of Thessaloniki & University of Tübingen)
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"Interaction of free-floating planets with a star-planet pair"
Harry Varvoglis (University of Thessaloniki & University of Tübingen)

Abstract The recent discovery of free-floating planets in the Milky Way introduced an intriguing possibility. Namely, that some exoplanets are not condensed from the protoplanetary disk of their parent star. In this novel scenario a free-floating planet interacts with an already existing planetary system and is captured as a new planet. In the present work we study this interaction process by integrating trajectories of planet-sized bodies, which encounter a binary system consisting of a Jupiter-sized planet revolving around a Sun-like star. The possible final outcomes of this interaction are only four, namely flyby, planet exchange, capture or disruption. We show that the process is a classical scattering problem with fractal properties. We find that the probability of exchange or capture (in prograde as well as retrograde orbits) is non-negligible, a fact that might possibly explain observations of planetary systems with orbits that are either retrograde or tight and highly eccentric.
28.06.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"The Large Hadron Collider Project: status, highlight results and future prospects"
Siegfried Bethke (MPI f. Physik)
Download (FLV) | Watch video / abstract

July 2012

04.07.12 (Wednesday)
16:30, Cluster building, basement room, Universe Cluster Colloquium
"Planck and the Cosmic Microwave Background"
Torsten Ensslin (MPA)
10.07.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Exploring the phase space structure of the Milky Way halo with stellar orbits"
Monica Valluri (University of Michigan)
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"Exploring the phase space structure of the Milky Way halo with stellar orbits"
Monica Valluri (University of Michigan)

Abstract Resolved surveys of the Milky Way's stellar halo can obtain all 6 phase space coordinates of tens of thousands of individual stars, making it possible to compute their 3-dimensional orbits. The "orbital spectral analysis" technique can be applied to halo orbits to construct frequency maps which are a compact, yet informative representation of the halo phase space distribution function. Frequency maps visually represent the major types of orbit families that constitute the stellar halo and their relative importance. Analysis of simulations shows that even when halos are quite close to oblate, a large fraction of orbits have the characteristics of orbits in triaxial systems. The structure of the frequency maps, especially the resonant orbits, reflects the formation history and shape of the dark matter potential and its orientation relative to the Galactic disk. The application of frequency analysis to cosmological hydrodynamic simulations of disk galaxies shows that the orbital families occupied by halo stars and dark matter particles are very similar. An application of these methods to a sample of ~17,000 Milky Way halo stars from the SDSS-SEGUE-II survey yields a frequency map with strong evidence for resonant trapping of halo stars by the Milky Way disk. The observed resonances in frequency maps of SEGUE stars point to a fairly quiescent history for the Milky Way. The application of frequency analysis methods orbits of Milky Way halo stars (e.g. from the upcoming Gaia mission) will provide new insights into the formation history of the halo.
11.07.12 (Wednesday)
16:30, Cluster building, basement room, Universe Cluster Colloquium
"Why make such a fuss about the doubly magic nucleus Sn-100?"
Thomas Faestermann (TUM)
17.07.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"The GAMA mass-metallicity relationship"
Caroline Foster-Guanzon (ESO-Chile)
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"The GAMA mass-metallicity relationship"
Caroline Foster-Guanzon (ESO-Chile)

Abstract We present the mass-metallicity relationship (MMR) of star forming galaxies in the Galaxy And Mass Assembly (GAMA) survey. The dependence of the MMR on intrinsic and apparent selection criteria is explored. We find that the shape and absolute position of the MMR in mass-metallicity space can be significantly altered by varying commonly used selection criteria. Implications for comparative studies of various surveys and redshifts are discussed.
12:30, ESO room D29, Lunch Talk
"Physical properties of distant galaxies under the cosmic microscope"
Johan Richard (CRAL, Observatoire de Lyon)
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"Physical properties of distant galaxies under the cosmic microscope"
Johan Richard (CRAL, Observatoire de Lyon)

Abstract I will present recent observational results obtained on the physics of distant galaxies (~ 1<z<6) taking benefit of massive clusters used as natural instruments. Gravitational magnification enables us to resolve even the most distant objects, and to probe intrinsically fainter sources at high redshift. This allows us to do the kind of research that will only be achievable with the ELTs, but using ground-based 8-10 m class telescopes and their current or soon-forthcoming instruments. After introducing the topic and the use of massive clusters for their strong lensing effect, I will present our ongoing work on strongly lensed star-forming galaxies in the optical and near-infrared, where we probe the properties (kinematics, size, stellar masses and metallicities) of low mass galaxies.
18.07.12 (Wednesday)
16:30, Cluster building, basement room, Universe Cluster Colloquium
"Effective Theories: from Black Holes to Nucleons"
Sean Fleming (University of Arizona)
24.07.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"A near-infrared spectroscopic survey of star-forming galaxies and AGNs with Subaru/FMOS"
John Silverman (Kavli Institute for the Physics and Mathematics of the Universe)
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"A near-infrared spectroscopic survey of star-forming galaxies and AGNs with Subaru/FMOS"
John Silverman (Kavli Institute for the Physics and Mathematics of the Universe)

Abstract I will discuss a new 'intensive' survey of star-forming galaxies in COSMOS using the Fiber Multi-object Spectrograph (FMOS) on the Subaru Telescope. FMOS is a multi-fiber instrument capable of simultaneously obtaining near-infrared spectra (1-1.8um) of a few hundred galaxies thus enabling a large redshift survey across a previously challenging redshift regime (1.2 < z < 1.8). Our survey is designed to detect Halpha in emission in order to establish the evolution of the SFR-Mstar relation and any dependence on environment. I will also highlight galaxies detected by Herschel/PACS and AGNs selected by their X-ray emission.
25.07.12 (Wednesday)
16:30, Cluster building, basement room, Universe Cluster Colloquium
"ALPs in the sky: bounds and discovery opportunities"
Alessandro Mirizzi (Hamburg University / DESY)
31.07.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Exploring the Ursa Major Region"
Kathrin Wolfinger (Swinburne University, Australia)
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"Exploring the Ursa Major Region"
Kathrin Wolfinger (Swinburne University, Australia)

Abstract The Ursa Major region is an ideal target to study the effect of environment on the evolution of gas-rich galaxies as it is nearby and most of the known member galaxies are late-type galaxies that are rich in neutral hydrogen (HI). We investigate 480 deg^2 and a heliocentric velocity range of 300-1900 km/s using data from the HI Jodrell All Sky Survey (HIJASS). The region includes the Ursa Major cluster (17.1 Mpc; Tully et al. 2008), the Canes Venatici groups (4.1 Mpc; Karachentsev et al. 2003) and the less dense filament connecting the Ursa Major and Virgo cluster (16.7 Mpc; Kent et al. 2007).

I will present an overview of the region: (i) the peak-flux limited catalogue containing 155 HI sources, 13 of which are first time detections in HI including a candidate galaxy/tidal tail/HI bridge, (ii) intriguing objects such as HIJASS detections with HI extensions/plumes and (iii) candidate regions for galaxy-galaxy interactions. Furthermore I will show preliminary results from our study regarding substructures in the region and their dynamics.

August 2012

07.08.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Herschel, Planck and the High Redshift Universe"
David Clements (Imperial College London)
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"Herschel, Planck and the High Redshift Universe"
David Clements (Imperial College London)

Abstract The far-IR/submm band from 200 to 500 microns has been largely unexplored until very recently. Since their launch, in May 2009, Herschel and Planck have been exploring this waveband and providing new insights into a wide range of astrophysics. This talk focuses on the high redshift (z>1) universe and will discuss gravitational lenses, galaxy clusters and the search for the highest redshift dusty galaxies. It is still early days for the exploitation and followup of Herschel and Planck surveys, but it is already clear that these missions will have a major impact on our understanding of dusty galaxies at high redshift.
14.08.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"Triggered star formation and dispersal of molecular clouds by ionising radiation"
Stefanie Walch (MPA)
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"Triggered star formation and dispersal of molecular clouds by ionising radiation"
Stefanie Walch (MPA)

Abstract The role of feedback from massive stars is believed to be a key element in the evolution of molecular clouds. We use high-resolution 3D SPH simulations to explore the dynamical effects of a single O7 star located at the centre of a molecular cloud with mass 10^4M_sun and radius 6.4pc. The initial internal structure of the cloud is characterised by its fractal dimension, D=2.0 - 2.8, and its log-normal density PDF. (i) As regards star formation, in the short term ionising feedback is positive, in the sense that star formation occurs much more quickly in gas that is compressed by the high pressure of the ionised gas. However, in the long term ionising feedback is negative, in the sense that most of the cloud is dispersed with an outflow rate of up to ~0.01M_sun/yr, on a timescale comparable with the sound-crossing time for the ionised gas (~1-2Myr), and triggered star formation is therefore limited to a few percent of the cloud's mass. (ii) As regards the morphology of the ionisation fronts (IFs) bounding the HII region and the systematics of outflowing gas, we distinguish two regimes. For low D<=2.2, the initial cloud is dominated by large-scale structures, so the neutral gas tends to be swept up into a few extended coherent shells, and the ionised gas blows out through a few large holes between these shells; we term these HII regions "shell-dominated". Conversely, for high D>=2.6, the initial cloud is dominated by small-scale structures, and these are quickly overrun by the advancing IF, thereby producing neutral pillars whilst the ionised gas blows out through a large number of small holes between the pillars; we term these HII regions "pillar-dominated". (iii) As regards the injection of bulk kinetic energy, by ~1Myr, the expansion of the HII region has delivered a rms velocity of ~6km/s; this represents less than 0.1% of the total energy radiated by the O7 star. (iv) Last but not least, the distribution of triggered stars changes - from clustered to distributed - with increasing D.
28.08.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"The Clump Mass Function of the Dense Clouds in the Carina Nebula"
Stephanie Pekruhl (USM)
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"The Clump Mass Function of the Dense Clouds in the Carina Nebula"
Stephanie Pekruhl (USM)

Abstract
In the Carina Nebula the feedback of the numerous hot stars disperses the parental Giant Molecular Cloud but also triggers the formation of new generations of stars. We obtained wide-field maps with the LABOCA camera at the APEX telescope, which provide the first spatially complete survey of the dust clouds in the Carina Nebula Complex and used the three common clump-finding algorithms CLUMPFIND, GAUSSCLUMPS and SExtractor to sample the Clump Mass Function (ClMF) in this region. To investigate the influence of the cloud temperatures on the ClMF we also assumed individual cloud temperatures for the clumps, resulting from an empirical relation between cloud column densities and temperature. In general we find a power-law of dN/dM ∝ M^(−1 .95), which is in good agreement with ClMF slopes found in previous studies of the ClMFs of other regions, but also that the shape of the resulting ClMF is highly dependent on the used extraction methods. While the CLUMPFIND ClMF is clearly described by a power-law the ClMFs based on the extractions with GAUSSCLUMPS and SExtractor are better represented by a log-normal distribution. This implies that the interpretations of a log-normal ClMF shape as a signature of turbulent pre-stellar clouds versus power-law ClMFs as a signature of star forming clouds only from observational determinations can be misleading.

September 2012

11.09.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"The importance of the interactions between dust, comets and planets in planetary systems"
Amy Bonsor (Institute of Astronomy, Cambridge UK)
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"The importance of the interactions between dust, comets and planets in planetary systems"

Amy Bonsor (Institute of Astronomy, Cambridge UK)

Abstract

Dusty, debris discs are observed around hundreds of stars and there is an ever growing number of planet detections. In our Solar System it is clear that dynamical interactions between the planets, comets, asteroids and dust are important in sculpting its current structure and future evolution. It is clearly not possible to study the dynamics in such detail in exoplanetary systems, however, the evidence in support of the importance of such interactions is growing. In this talk I discuss two examples of observations that may be signatures of such interactions. Firstly, high levels of warm, exozodiacal dust, observed close to main-sequence stars. Such dust cannot have survived the star's lifetime in its current position and must originate from elsewhere in the planetary system. Secondly, observations of dust and metal pollution in white dwarfs, that are thought to be linked to evolved planetary systems.
12:30, ESO room D29, Lunch Talk
"Probing the early stages of planet formation with ALMA and other sub-mm interferometers"
Luca Ricci (California Institute of Technology)
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"Probing the early stages of planet formation with ALMA and other sub-mm interferometers"

Luca Ricci (California Institute of Technology)

Abstract

Observations of protoplanetary disks at sub-mm wavelengths trace mm-sized dust grains in the disk outer regions. Models of the early stages of planet formation, including growth and radial migration of dust grains in the disk, can therefore be tested by these data. I will outline the state-of-the-art of this field by presenting old and new data obtained with CARMA, PdBI, ATCA and EVLA interferometers for a large sample of young disks in nearby star forming regions. I will show how very-low mass disks are particularly suitable to test the model predictions and investigate the physics of solids evolution in disks. This is currently being investigated through undergoing observations with ALMA of four disks around brown dwarfs and very low-mass young stars. I will present the first results from this project and outline in which aspects future ALMA observations can play a key role in our understanding of planetesimal formation.
18.09.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Pre-main sequence stars in clusters: from Orion to the Magellanic Clouds"
Nicola Da Rio (ESTEC)
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"Pre-main sequence stars in clusters: from Orion to the Magellanic Clouds"

Nicola Da Rio (ESTEC)

Abstract

The study of low mass, pre-main sequence (PMS) stars in clusters is critical for our understanding of the star formation process, and the initial mass function. Specifically, since PMS stars slowly contract towards the main sequence, they are natural tracers of the duration of star formation. Moreover, these objects are brighter than more evolved stars for the same mass, enabling us to detect them more easily well below the H-burning limit. Unfortunately, this is not without problems, and the uncertainties still remain large. I will describe some of my recent results in the field, focusing on the young stellar population in the Orion Nebula Cluster and in young regions of the Magellanic Clouds. I will mostly focus on issues and results related to the IMF in the very low-mass and brown dwarf regime, the long standing problem of the age spreads in young clusters, and the understanding of the time evolution of mass accretion rates.
25.09.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"A History of Photosynthesis Research, 1840-1960"
Kärin Nickelsen (LMU Munich)
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"A History of Photosynthesis Research, 1840-1960"

Kärin Nickelsen (LMU Munich)

Abstract

Photosynthesis is known as the process by which green plants utilize the energy of sunlight to produce carbohydrates from carbon dioxide and water in the green parts of the plant. It is fundamental to life on earth, and the way organisms accomplish this task has intrigued scientists for centuries. The first tentative (and rather simplistic) ideas were developed by organic chemists around 1840, while by 1960 an elaborate photosynthesis model at a molecular level had been established, encompassing a set of light reactions, with two different photochemical systems, which was linked to a light-independent sequence of dark reactions via a cyclic pathway. The paper outlines important milestones of this development, while it pays particular attention to the factors that drove the research in one direction or other.
27.09.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"From the IMF to the S-Process in Early-Type Galaxies"
Charlie Conroy (UCO / Lick Observatory)
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"From the IMF to the S-Process in Early-Type Galaxies"

Charlie Conroy (UCO / Lick Observatory)

Abstract

Our understanding of the stellar populations of unresolved galaxies is fundamentally limited by our lack of knowledge of the stellar initial mass function (IMF), and its variation with environment and epoch. In this talk I will present a technique that provides direct measurements of the low-mass IMF (~0.1-1 Msun) in unresolved stellar systems. When this technique is applied to high-quality optical-NIR spectra of nearby early-type galaxies, evidence is found for an IMF that is substantially more "bottom-heavy" than the Galactic IMF. I will also discuss ongoing work aimed at measuring elemental abundances (including C, N, O, Na, Mg, Ca, Ti, Cr, Mn, Fe, Sr, and Ba) of these galaxies, with the goal of constraining their formation histories.

October 2012

02.10.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Deep 21-cm HI Observations with the Arecibo Telescope"
Laura Hoppmann (ICRAR and University of Western Australia)
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"Deep 21-cm HI Observations with the Arecibo Telescope"

Laura Hoppmann (ICRAR and University of Western Australia)

Abstract

The star formation rate (SFR) in galaxies, as measured by optical, UV and far-infrared observations, appears to increase by an order of magnitude over the redshift interval of z=0 to z≈1. However, little accurate information about the co-evolution of neutral hydrogen is available. Measurements are limited to sparse and model-dependent observations of damped Lyman-α systems at high redshifts or to observations of 21cm radio emission line at very low redshift. However, the unique sensitivity of the Arecibo telescope can be used to directly detect 21-cm HI emissions from galaxies at cosmological distances. Previous detections have involved optically pre-selected galaxies and are therefore biased in their selection criteria. Here we present results from the ongoing Arecibo Ultra Deep Survey (AUDS) which is a blind 21-cm survey with the Arecibo L-band Feed Array (ALFA). We use data from AUDS to accurately derive the HI mass function and constrain the cosmic HI density ΩHI at redshifts greater than zero for the first time.
04.10.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Quasars Probing Quasars: Circumgalactic Gas in Absorption and Emission" Joe Hennawi (MPIA Heidelberg)
Download (FLV) | Watch video / abstract
09.10.12 (Tuesday)
12:30, ESO Auditorium, Lunch Talk
"The SMC in space and time: star formation history of a prototype dwarf irregular galaxy"
Monica Tosi (INAF - Astron. Obs. Bologna)
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"The SMC in space and time: star formation history of a prototype dwarf irregular galaxy"

Monica Tosi (INAF - Astron. Obs. Bologna)

Abstract

The SMC is an excellent benchmark for galaxy evolution studies, both as the closest representative of galaxies of the most diffuse morphological type, dwarf irregulars, and as member of the closest triple galaxy system. I will present our recent studies of the SFH of several regions of the SMC. These results are currently based on HST photometry, to be soon complemented with a complete and deep photometric coverage of the galaxy performed with VST-GTO. They are part of a multi-fold project aimed at deriving information on the evolution of the SMC and of dwarf galaxies in general.
11.10.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Multiple populations in globular clusters"
Raffaele Gratton (INAF - Padova Observatory)
Download (FLV) | Watch video / abstract
12.10.12 (Friday)
12:30, ESO Auditorium, Lunch Talk
"Kinematic structure and metallicity distribution of the Carina dSph galaxy"
Michele Fabrizio (University of Rome "Tor Vergata")
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"Kinematic structure and metallicity distribution of the Carina dSph galaxy"

Michele Fabrizio (University of Rome "Tor Vergata")

Abstract

Dwarf galaxies are the crossroad of significant theoretical and observational efforts, but we still lack firm constraints concerning their formation and evolution. They are also fundamental laboratories to investigate the impact of the environment on chemical evolution in stellar systems with total masses between giant galaxies and globular clusters.

We present accurate iron abundance measurements for 44 red giants (RGs) in the Carina dwarf spheroidal galaxy using high-resolution spectra (R~38,000) collected with UVES at ESO/VLT. For the 27 stars for which we measured both [FeI/H] and [FeII/H] abundances, we found evidence of NLTE effects between neutral and singly-ionized iron abundances.

We also present recent results concerning the kinematics properties of the Carina dwarf spheroidal. We performed precise radial velocity (RV) measurements of two thousands of stars covering the entire body of the galaxy. The individual spectra (21,340) were collected using FORS2 (low-), GIRAFFE (medium- and high-) and UVES (high-resolution) at the VLT. The RV distribution of the ~1,370 candidate Carina stars indicates the occurrence of secondary features across the galactic center. These findings are reminiscent of a substructure with transition properties, already detected in dwarf ellipticals, and call for confirmation by independent investigations.
18.10.12 (Thursday)
16:15, MPE Large Seminar Room 1.1.18b, Munich Joint Astronomy Colloquium
"Stellar Archaeology: New Science with Old stars"
Anna Frebel (M.I.T.)
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"Stellar Archaeology: New Science with Old stars"

Anna Frebel (M.I.T.)

Abstract

The early chemical evolution of the Galaxy and the Universe is vital to our understanding of a host of astrophysical phenomena. Since the most metal-poor Galactic stars are relics from the high-redshift Universe, they probe the chemical and dynamical conditions as the Milky Way began to form, the origin and evolution of the elements, and the physics of nucleosynthesis. They also provide constraints on the nature of the first stars, their associated supernovae and initial mass function, and early star and galaxy formation. I will discuss examples of the most metal-poor Galactic stars with extreme and unusual abundance patterns that can help elucidate the supernovae responsible for their chemical signatures. Furthermore, stars displaying a strong overabundance of the heaviest elements, in particular uranium and thorium, can be radioactively dated, giving formation times ~13 Gyr ago, similar to the ~13.7 Gyr age of the Universe. I then transition to a description of recent discoveries of extremely metal-poor stars in dwarf satellites of the Milky Way. Their stellar chemical signatures support the concept that small systems analogous to the surviving dwarf galaxies were the building blocks of the Milky Way's low-metallicity halo. This opens a new window for studying galaxy formation through stellar chemistry.
23.10.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"CALYPSO: A dive into the small-scale physics and chemistry of young envelopes, disks and outflows"
Anaelle Maury (ESO)
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"CALYPSO: A dive into the small-scale physics and chemistry of young envelopes, disks and outflows"

Anaelle Maury (ESO)

Abstract

Despite some progress in the past two decades, the physics of the youngest protostars (Class 0 objects) remains poorly understood. The mere existence of accretion disks and protobinaries at the Class 0 stage is highly controversial. Likewise, the launching mechanism of protostellar jets and their net contribution to mass and angular momentum extraction during protostar formation is strongly debated. The complex velocity and density structure shaping the inner protostellar environment is also a great puzzle to star formation models. Solving these issues, which all have a strong bearing on the long-standing "angular momentum problem" of star formation, is of paramount importance. To this aim, we obtained a comprehensive, systematic study of the nearest low-luminosity Class 0 objects with the A & C arrays of PdBI, also supported by a parallel MHD simulation effort. The CaLYPSO (Continuum and Line Young ProtoStellar Object) survey, carried out with both the IRAM 30-m telescope and Plateau de Bure Interferometer, targets 17 nearby Class 0 protostars in 3 different spectral setups, at subarcsecond resolutions reaching ~50AU scales. It is the most complete high-resolution survey of Class 0 objects carried out so far. I will present our first completed set of observations, and I will discuss the complementarity of continuum observations and line tracers to draw a comprehensive picture of the small scale infall/accretion processes in Class 0 envelopes. I will also show how our observations allow us to put unprecedented constraints on inner (50-500 AU) envelope properties and chemistry, as well as the disk formation scenario.
25.10.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"The Clearing of Discs around Young Stars"
Cathie Clarke (IoA Cambridge)
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26.10.12 (Friday)
12:30, ESO room D29, Lunch Talk
"The interplay between molecular and ionized gas surrounding massive embedded stars"
Katharine Johnston (MPIA Heidelberg)
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"The interplay between molecular and ionized gas surrounding massive embedded stars"

Katharine Johnston (MPIA Heidelberg)

Abstract

Although there is much evidence that B-stars (~3-15 Msun) form similarly to their low-mass counterparts, the picture is not so clear for O-stars. In this talk I present studies of two highly luminous (>10^5 Lsun) embedded O-star precursors, AFGL2591 and AFGL4176. Our aims were to determine whether the properties of these forming stars, such as the circumstellar structure, outflow and jet could be described satisfactorily by the properties of low-mass protostars, and to understand how the formation of an HII region may interrupt accretion or outflow onto/from the forming star. To this end, we used a variety of cm and mm interferometric observations to trace both the molecular and ionized gas. In addition, I will present our current results from radiative transfer modelling of these two sources, which provide insight into the density and velocity structure of their circumstellar material.
30.10.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Star formation in nearby young clusters"
Catarina Alves de Oliveira (Herschel Science Centre/ESA)
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"Star formation in nearby young clusters"

Catarina Alves de Oliveira (Herschel Science Centre/ESA)

Abstract

The rapid advances in infrared detector technology over the past decades have impelled the development of wide-field instruments, and shaped our view of the cold universe. Large infrared and submillimeter surveys of nearby star-forming regions in our Galaxy can pierce the obscuring dust to reveal embedded young stars and protoplanetary disks, and also uncover the cold large-scale structure of molecular clouds. I will present results from two projects based on such datasets, namely, i) to constrain the formation scenarios of substellar objects, and ii) study the connection between filamentary structure and star formation activity. In the first project, we make use of a deep WIRCam/CFHT imaging survey of two young clusters (Rho Oph and IC348) to uncover candidate substellar members. Through an extensive spectroscopic follow-up (using SofI/NTT, NICS/TNG, ISAAC/VLT, Osiris/GTC, and GNIRS/Gemini) we derive a reliable census of their substellar population down to a few Jupiter masses, which is used to study the initial mass function, mass segregation, and the properties of brown dwarf disks using new PACS/Herschel observations. In the second project, we use Herschel observations of the Chamaeleon molecular cloud complex, which contains three dark clouds with a dramatically different star formation activity, to investigate the connection between the properties of its filamentary structure and the on-set of star formation.

November 2012

06.11.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"Dust evolution during the star-planet formation process"
Leonardo Testi (ESO)
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"Dust evolution during the star-planet formation process"

Leonardo Testi (ESO)

Abstract

I will discuss what we think we know of the evolution of solids in protoplanetary disks towards the formation of planetesimals. I will try to focus on which are the main questions that we still need to address to understand the evolution of solids in disks. As we figured out that significant grain growth seem to be occurring at earlier stages of evolution of the forming star, I will also try to expand the picture to discuss how we can try and probe the evolution of grains from the molecular cloud, to the core and protostellar stages of star formation.
13:00, ESO room D29, Lunch Talk
"The CO connection to the radio-FIR correlation in M51"
Gaelle Dumas (IRAM, France)
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"The CO connection to the radio-FIR correlation in M51"

Gaelle Dumas (IRAM, France)

Abstract

I will present first results of the PdBI Arcsecond Whirlpool Survey (PAWS, PI E. Schinnerer). PAWS has imaged the CO(1-0) emission in the central 8 kpc of the nearby galaxy M51. Our final data is a combination of the IRAM 30m single-dish and PdBI observations. It reaches a resolution of about 40pc and is sensitive to Giant Molecular Clouds (GMCs) above 10^5 Msun. This data allow us to study in great details the properties of the GMCs in this galaxy and in particular we investigate the relations of the molecular gas to other tracers of the ISM. In this talk I will present a study of the relation between the CO emission, the radio continuum and the IR emission as a function of galactic environment. I'll discuss these results in the context of cosmic ray electrons diffusion and its relation to the star formation processes.
08.11.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"The Event Horizon Telescope: Observing Black Holes with Schwarzschild Radius Resolution"
Shep Doeleman (MIT Haystack Observatory)
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13.11.12 (Tuesday)
12:30, ESO Auditorium, Lunch Talk
"On the discovery of a possible portrait of the young Galileo Galilei"
Paolo Molaro (INAF - Osservatorio Astronomico di Trieste)
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"On the discovery of a possible portrait of the young Galileo Galilei"

Paolo Molaro (INAF - Osservatorio Astronomico di Trieste)

Abstract

I describe the discovery of a possible new portrait of a relatively young Galileo Galilei. The painting is an oil on canvas but it is not signed and the identification of Galileo is mainly physiognomic. The face in the painting reveals a clear resemblance to that of Galileo in the portrait of Domenico Tintoretto and in the engraving of Giuseppe Calendi derived from a lost portrait by Santi di Tito. Along with the portraits by Tintoretto, Furini, Leoni, Passignano and Sustermans this could be another portrait of Galileo made "al naturale", but, unlike the others, it depicts the scientist before he reached fame. Galileo in the painting looks rather young, at age of about 20-25 years. His eyes are clear and the expression intense and appealing. The painter is also unknown and could be one of the many painters from the circle of Galileo's friends. From Galileo's correspondence we know of portraits made by his friend Ludovico Cigoli and by Bronzino. Rather interesting, though admittedly quite improbable, is the possibility of a self-portrait whose existence is mentioned in the first biography of Galileo written by Thomas Salusbury in 1664. We include also some considerations on the Moon watercolors made by Galileo and used as a preparatory work for the etchings published in the Sidereus Nuncius.
14.11.12 (Wednesday)
16:00, ESO Auditorium, Special Colloquium
"The Emerald Planet: How plants changed Earth’s atmosphere"
David Beerling (University of Sheffield, UK)
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15.11.12 (Thursday)
12:30, ESO Auditorium, Astronomy talk for non-astronomers
"Hubble in Orbit - Two Decades and Counting"
Bob Fosbury (ESO Astronomer Emeritus)
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"Hubble in Orbit - Two Decades and Counting"

Bob Fosbury (ESO Astronomer Emeritus)

Abstract

During May 2009, the Hubble Space Telescope was subject to the most intense overhaul of its life with astronauts from the Space Shuttle Atlantis performing engineering feats far beyond what was originally envisaged for orbital servicing. Instruments were repaired and replaced during the most complex human process that had yet been performed in space. The telescope is now some hundred times more powerful than when it was launched in 1990.

This is the story of Hubble, looking back on the revolution in astrophysics that it has achieved and forward to what it is achieving now in its probings of the early history of the universe to the study of the atmospheres of extrasolar planets.
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"A deep look into AGN: accretion and outflow of gas in Mrk 509"
Jelle Kaastra (SRON, Utrecht)
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19.11.12 (Monday)
10:00, ESO room D30, Star and Planet Formation Seminar
"Time-domain observations of young stars"
Aleks Scholz (Dublin Institute for Advanced Studies)
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"Time-domain observations of young stars"

Aleks Scholz (Dublin Institute for Advanced Studies)

Abstract

Variability in fluxes, colours, and emission lines is a key feature of young stellar objects and is found at all stellar masses from Herbig Ae/Be stars down to brown dwarfs. The study of YSO variability was and still is one of the major drivers for the development of our understanding of star and planet formation. In this talk I will discuss our ongoing projects to characterise YSOs in the time domain and to use variability to constrain stellar rotation, magnetic activity, accretion, and disk properties. In particular, I will present new results from the project LAMP (Long-term Accretion Monitoring Program) and from a systematic survey for extreme variables, including the discovery of two new potential FU Ori-type objects. I will argue that we are witnessing a renaissance of this field, triggered by new resoureces that will allow us for the first time to study YSO variability in a comprehensive way.
20.11.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"The role of the structure formation process in regulating the galaxy star formation activity"
Paola Popesso (MPE)
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"The role of the structure formation process in regulating the galaxy star formation activity"

Paola Popesso (MPE)

Abstract

Achieving an observational determination and a theoretical understanding of the Cosmic Star Formation History (CSFH) of the Universe is one of the biggest challenges in the study of galaxy formation and evolution. The most striking feature of the CSFH is a dramatic drop of the star formation rate, since z~1 to the present day, after a rather constant phase of high activity at z~1-2 or above. A quenching process is required to trigger such an abrupt decrease of the Star Formation (SF) activity. As a matter of fact, the progressive decline of the SF activity of the Universe since z~1 anti-correlates with the late-time increase of the number density of group-sized halos. It is, then, mandatory to follow this tantalizing lead and to ask if the very same process of assembly and growth of structures may be the main cause, or one of the major drivers, of the 1 order of magnitude decline in the CSFH. I will tackle this issue by showing that group galaxies evolve much faster than galaxies in low density regions. Star forming group galaxies, in particular, are perfectly on the Main Sequence (MS) at z~1 whereas at lower redshift they are quenched, thus, dropping off the MS quicker than field galaxies towards the region of SF quiescence. I will also show that the efficiency of the quenching process depends on the halo mass, being more efficient in the most massive halos, and thus, in most massive galaxies that tend to reside in such halos.
22.11.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Galaxy Nuclei, Galaxy Outskirts"
Jenny Greene (Princeton)
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27.11.12 (Tuesday)
12:30, ESO room D29, Lunch Talk
"Cosmic chronometers: a new approach to constrain the expansion history of the Universe"
Michele Moresco (University of Bologna)
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"Cosmic chronometers: a new approach to constrain the expansion history of the Universe"

Michele Moresco (University of Bologna)

Abstract

The determination of the expansion history of the Universe is one of the most crucial measurements for cosmology, since the rate at which it decelerates/accelerates directly depends on the energy components which characterize it (and, in particular, the "dark energy", in case of an accelerated expansion). It is therefore fundamental to measure it, i.e. the Hubble parameter H(z), very precisely. In this talk I will present an innovative method to obtain direct constraints on H(z) from the differential age evolution of cosmic chronometers. I will provide the basic theoretical background of this approach, and I will as well discuss its dependence on assumptions and systematics. The "cosmic chronometers" approach has been recently used to obtain new high-accuracy measurements of H(z) up to z~1.1 from the analysis of a large sample of massive and passive ETGs. I will present these results, focusing the attention in particular to their cosmological consequences, showing the potentiality of this technique to discriminate amongst different cosmologies. I will also demonstrate that this approach can be not only complementary, but also competitive with the other "standard" probes, i.e. SNe and BAO.
29.11.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"The universal dark matter density profile and its destruction"
Andrew Pontzen (Oxford University)
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December 2012

04.12.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"The young stellar population of the Carina Nebula"
Henrike Ohlendorf (LMU)
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"The young stellar population of the Carina Nebula"

Henrike Ohlendorf (LMU)

Abstract

Containing several thousands of young stars, the Carina Nebula region is a prime target for large-scale studies of young stars. With infrared data taken with Spitzer, Herschel, WISE and VISTA, we are able to study its young stellar population, both individually and on a large scale. What kinds of stars are there to be found? How are they distributed? Are they triggering each other? What kinds of features do they exhibit? In my talk I will summarise our ongoing infrared study of the Carina Nebula region and the inferences for the young stellar population that can be drawn from it.
12:30, ESO room D29, Lunch Talk
"Evolution in galaxy cluster cores since z=1"
Claire Burke (Liverpool John Moores University)
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"Evolution in galaxy cluster cores since z=1"

Claire Burke (Liverpool John Moores University)

Abstract

The central regions of galaxy clusters are usually dominated by a massive brightest cluster galaxy (BCG), which generally sits at the centre of mass of the cluster, and a diffuse halo of intracluster light which can be extend beyond the cluster limits. BCGs are the most massive, most luminous galaxies observed in the Universe and their unique positions at cluster centres make them ideal for studying the buildup of large scale structures. A significant fraction of the total baryonic mass and luminosity of galaxy clusters is thought to be contained within the intracluster light (ICL), and the study of the ICL can reveal details of the evolution histories and processes occurring within galaxy clusters. I will review the current theory on the formation and evolution of these most massive galaxies and present the results of our recent observational studies on the evolution of BCGs and the ICL between half way back to the big bang and the present. Our studies show that BCGs are almost fully assembled half way back to the big bang and show almost no evolution up to the present day, in stark contrast to the predictions of cosmological simulations which state that BCGs should double in mass over the this time. The ICL, however, shows substantial growth and evolution over this time. These results point to a rapid early assembly of massive galaxies in clusters followed by passive evolution, with interactions between galaxies in clusters mainly occurring by stripping to build up the ICL at later times.
06.12.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"What spectral Fingerprints of Exoplanets reveal"
Lisa Kaltenegger (MPI f. Astronomie, Heidelberg)
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13.12.12 (Thursday)
12:30, ESO Auditorium, Astronomy talk for non-astronomers
"Death from Space"
Gero Rupprecht (ESO Garching)
Abstract
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"Death from Space"

Gero Rupprecht (ESO Garching)

Abstract

The World will end on December 21, 2012. At least that’s what some people proclaim. But is it true? One thing is sure: Somewhere out there in the solar system a killer asteroid is heading for a deadly collision with our Blue Planet. Unfortunately we don’t know, which of the millions of asteroids it is and when it might strike… Interestingly the Universe has more in store for us than mere asteroids, dangers worth of a good night’s nightmare!
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"The Formation and Evolution of Accreting Binaries: Insight from Multiwavelength Observations of Galaxies Both Near and Far!"
Bret Lehmer (Johns Hopkins University, Baltimore)
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"The Formation and Evolution of Accreting Binaries: Insight from Multiwavelength Observations of Galaxies Both Near and Far!"

Bret Lehmer (Johns Hopkins University, Baltimore)

Abstract

X-ray emission from accreting binary systems (X-ray binaries) provides a unique signature of the binary phase of stellar evolution and compact object populations (neutron stars and black holes). Through detailed X-ray and multiwavelength observations (e.g., from Chandra, Hubble, Spitzer, and other telescopes) of both nearby and distant galaxies, I am working on obtaining a more complete picture of how stars and compact objects formed and evolved throughout the history of the Universe. I will present ongoing and planned observational efforts to characterize (1) how the formation of X-ray binary populations in nearby galaxies is linked to the physical properties of the galaxies themselves (e.g., galaxy morphology, star-formation activity, stellar mass, stellar age, and metallicity); and (2) how X-ray binary populations evolved over the last 12 billion years of cosmic history (since z ~ 4) in response to significant changes in the physical properties of their host galaxies. I will highlight how forthcoming and archival observations, future multiwavelength telescopes, and binary population synthesis modeling will provide a powerful blend of resources for improving our understanding of X-ray binaries and compact objects.
14.12.12 (Friday)
12:30, ESO Auditorium, Lunch Talk
"The physics of massive-star magnetism explored through the MiMeS and BinaMIcS large projects"
Gregg Wade (Royal Military College of Canada)
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"The physics of massive-star magnetism explored through the MiMeS and BinaMIcS large projects"

Gregg Wade (Royal Military College of Canada)

Abstract

Since 2008, the Magnetism in Massive Stars (MiMeS) large programs at ESO, TBL and CFHT have led to a transformation of our understanding of the phenomenon of magnetism in hot OB stars. Starting in 2013, the new Binarity, Magnetism and Interactions in Stars (BinaMIcS) project will bring a fundamental new ingredient to these investigations: the influence and importance of close binarity on massive-star magnetism, and the unique interactions that result thereby. In this presentation I will review the results of the MiMeS survey, discussing in particular the properties of newly-discovered magnetic O-type stars, and introduce the scope and objectives of the BinaMIcS project.
18.12.12 (Tuesday)
10:00, ESO room D30, Star and Planet Formation Seminar
"Shadows, gaps, and ring-like structures in proto-planetary disks"
Ralf Siebenmorgen (ESO)
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"Shadows, gaps, and ring-like structures in proto-planetary disks"

Ralf Siebenmorgen (ESO)

Abstract

We study the structure of passively heated disks around T Tauri and Herbig Ae stars (AA 539, 2012) and present a vectorized Monte Carlo dust radiative transfer model (ApJ 751, 2012). The vectorization provides a speed up factor of 100 when compared to a scalar version of the code. Proto-planetary disks are composed of either fluffy carbon and silicate grains of various sizes or dust of the diffuse ISM. The IR emission and the midplane temperature derived by the MC method differ from models where the radiative transfer is solved in slab geometry of small ring segments. Under the assumption of hydrostatic equilibrium we find that the disk in the inner rim puffs up, followed by a shadowed region. The shadow reduces the temperature of the midplane and decreases the height of the extinction layer of the disk. It can be seen as a gap in the disk unless the surface is again exposed to direct stellar radiation. There the disk puffs up a second time, a third time and so forth. Therefore several gaps and ring-like structures are present in the disk surface and appear in emission images. They result from shadows in the disks and are present without the need to postulate the existence of any companion or planet. As compared to Herbig Ae stars, such gaps and ring-like structures are more pronounced in regions of terrestrial planets around T Tauri stars. We present an accurate treatment of PAH molecules in the MC code. Particular attention is given to the photo-dissociation of the molecules by energetic photons. We consider beside PAH destruction also the survival of the molecules by vertical mixing within the disk (see Fig.). By applying typical X-ray luminosities the model accounts for the low PAH detection probability observed in T Tauri and the high PAH detection statistics found in Herbig Ae disks (AA 543, 2012). Spherical halos above the disks and mid-IR images are presented. We show that disks are easier to resolve when PAH emission dominates.
20.12.12 (Thursday)
16:15, ESO Auditorium, Munich Joint Astronomy Colloquium
"Galaxy Clusters: tools for cosmology and laboratories for astrophysics"
Stefano Borgani (INAF - Astronomical Observatory of Trieste)
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