|
|
Munich Joint Astronomy Colloquia 2002-2003 |
October 2002
10 - Emil Mottola [Los Alamos National Laboratory] (host - ESO)
"Two Problems of Some Gravity: Cosmological Dark Energy
and Black Holes"
ABSTRACT:
The diffuculties in reconciling gravity with quantum mechanics are nowhere better
illustrated than in the cosmological or vacuum dark energy that recent observations
suggest pervade the whole universe, causing its expansion to accelerate; and black
holes, the final state of complete gravitational collapse of matter into a singularity
of space and time. After reviewing the problems that arise when attempting to bring
these two phenomena into accordance with quantum principles, I will describe a new
solution for the endpoint of gravitational collapse, called a Gravitational Condensate Star
which involves both. This is a cold, compact object with an interior vacuum energy
of just the kind that causes the universe's expansion to accelerate, but with no
singularity,
no event horizon, and a global time. Unlike black holes, a collapsed star of this kind is
thermodynamically stable and has no quantum information paradox. Some possible
observational consequences of this hypothesis will be discussed.
17 - Richard Bower (host - MPE)
"Galaxy Ecology"
ABSTRACT:
24 - D. Kiselman (host - MPA)
"The Sun seen at 0.1 arcsec resolution"
ABSTRACT:
ADDITIONAL COLLOQIUM, note exceptional schedule: Friday,
11.00
25 - J. Ostriker, IoA, Cambridge (host - ESO)
"The Cold Dark Matter Paradigm for the Growth of Cosmic Structure:
Is it Correct?"
ABSTRACT:
31 - Lance Miller (host - ESO)
"Results for the 20,000 quasars in the 2dF survey"
ABSTRACT:
November 2002
7 - Scott Kenyon (host - MPA)
"Debris disks and planet formation"
ABSTRACT:
14 - John Barrow (host - MPA)
"Varying constants from alpha to Omega"
ABSTRACT:
21 - Jim Stone (host - MPA)
"Magnetised accretion onto black holes"
ABSTRACT:
28 - H.-W. Rix (host - MPE)
"The GEMS in COMBO-17:
Studying Galaxy Evolution with 2m Telescopes"
ABSTRACT:
December 2002
5 - Alvio Renzini (host - ESO)
"TBD"
ABSTRACT:
12 - Henk Spruit (host - MPA)
"TBD"
ABSTRACT:
19 - Grazyna Stasinska (host - MPE)
"Emission lines in galaxies"
ABSTRACT: Emission lines in galaxies are indicators of their chemical
composition and star formation rate. With the era of extensive
surveys, they are becoming a powerful tool to unravel the evolution
of galaxies. There are however pitfalls which are worth of attention.
We will present a brief overview of the use of emission lines both on
purely empirical grounds and in model dependent approaches. We will
argue that the study of local metal poor blue compact galaxies is a
necessary step to improve our understanding of the behaviour of
emission lines in any kind of galaxy. We will show that presently,
there are still important questions to be answered even in this most
simple case.
26 - No Colloqium
January 2003
2 - No Colloqium
9 - No Colloqium
16 - Sam Falle (Host - MPA)
"Multifluid Shock Structures"
ABSTRACT:
23 - Rafaelle Gratton (host ESO)
"Age of Globular Clusters"
ABSTRACT:
Globular clusters are among the oldest objects in our Galaxy for which accurate
ages can be determined. Dating globular clusters has a broad impact on both
galactic and extragalactic astronomy. Significant progresses have been made
in the last years, including introduction of new techniques to derive ages
of old systems (nucleocosmochronology, end of the white dwarf cooling sequence)
and refinement on known methods (turn-off luminosites). Accurate distances
are crucial in most of these determinations. We show that distances accurate
to a few per cent begin to be available for globular clusters using the
subdwarf fitting method, and similar accuracies will be likely achieved
routinely within a few years using distances based on dynamical methods. Also,
new data provide costraints on theoretical framework. The impact of these
achievements on the formation of the Galaxy is briefly outlined.
30 - Yasuo Tanaka (host MPA)
"Comparing X-ray properties between stellar-mass black holes and AGN"
ABSTRACT:
The Galactic black-hole binaries exhibit three distinct states in X-rays:
(1) a soft thermal spectrum with a hard tail at high accretion rates,
(2) a hard power-law spectrum at intermediate accretion rates, and
(3) a quiescent state at low accretion rates.
In comparison, most AGN closely resemble the black-hole binaries at
intermediate accretion rates. NLS1s have been suspected to be AGN analogues
of the black-hole binaries at high accretion rates. This view will be pursued
based on the XMM-Newton results of some NLS1s with respect to the spectrum
and the time variabilities, and the implications will be discussed.
February 2003
6 - talk by M. Shull has been cancelled
(host - MPE)
"NEW FUSE RESULTS ON THE INTERSTELLAR AND INTERGALACTIC MEDIUM"
ABSTRACT:
The Far Ultraviolet Spectroscopic Explorer (FUSE) was launched
in June 1999 to address a number of scientific questions, ranging
from cosmologically significant D/H measurements to studies of
hot gas (O VI), molecular hydrogen, elemental abundances, and
singly-ionized helium in the high-redshift intergalactic medium.
I will report on recent FUSE studies of the interstellar medium (ISM)
and intergalactic medium (IGM). Among the highlights are:
(1) widespread detection of molecular hydrogen in the LMC/SMC,
(2) confirmation of the helium reionization epoch (z = 2.8), and
(3) discovery of intergalactic O VI associated with the development
of large-scale structure of galaxies and shocked warm/hot IGM.
13 - Claes Fransson (host - MPA)
"SN-interaction with ISM"
ABSTRACT:
20 - Werner Weiss (host - MPA)
"Astroseismology"
ABSTRACT:
27 - Reinhardt Genzel (host - MPE)
"Inward Bound: The Galactic Center"
ABSTRACT:
March 2003
6 - John Bahcall (host - MPA)
"Solar neutrinos"
ABSTRACT:
Seven beautiful experiments (Homestake, Kamiokande, GALLEX, SAGE, GNO,
Super-Kamiokande, and SNO) have detected solar neutrinos, which have
fluxes and energies consistent with the predictions from standard solar
models. These experiments settle empirically the debate initiated in the
middle of the 19th century on how the sun shines. Moreover, the
measurements indicate that physics beyond the minimal standard
electroweak model is occurring. The inferences regarding new physics are
confirmed and refined by the recent KamLAND reactor neutrino experiment.
The combined solar and reactor neutrino experiments determine to high
accuracy, 6% (1 sigma), the rare 8B solar neutrino neutrino flux. The
measured value agrees to better than one standard deviation with the
most sensitive prediction of the standard solar model, namely, the
predicted flux of 8B neutrinos (which is proportional to the 24th power
of the central temperature). All of the solar and reactor neutrino
results are well described by simple models of neutrino oscillations.
I will summarize the current status of solar neutrino research and
review the prospects for making precise tests of the theory of stellar
evolution and of discriminating between different neutrino oscillation
scenarios with future experiments (
background material).
EXCEPTIONAL SCHEDULE - COLLOQIUM ON WEDNESDAY
12 - Scott Tremaine (host - MPA)
"The demography of nuclear black holes"
ABSTRACT:
20 - M. Franx (host - ESO)
"A significant population of red, infrared selected galaxies at high redshift"
ABSTRACT:
We have used the VLT take take very deep Near-IR imaging of
two fields, the Hubble Deep Field South, and the cluster
MS1054-03. The Near-IR imaging allows us to select high redshift
galaxies by their restframe optical light. We find a large population
of galaxies in both fields at redshifts higher than 2 with a simple
color criterion. Most of these galaxies would not be found by the
classical Ly-break selection technique, because they are too faint in
the observers optical. We discuss the properties of the galaxies, and
present evidence that the population is an important constituent of
the high redshift universe.
27 - Simon Garrington (host - ESO)
"High-resolution and high-sensitivity radio astronomy"
ABSTRACT:
April 2003
3 - Lars Bildsten (host - MPA)
"TBD"
ABSTRACT:
10 - Mark Mc Caughrean (host ESO)
"Star and planet formation: the impact of environment"
ABSTRACT:
The 1990s saw the start of a distinct shift in the emphasis of star and
planet formation studies, with the recognition that almost all stars are
born in close proximity to others, as binaries, dense groups, or
clusters,
and often in the presence of massive stars, with their intense ionising
flux
and strong winds. It is now realised that interactions between stars in
such
environments, both in the protostellar and pre-main sequence phases,
can have
an important impact on the key 'products' of star formation, including
the
stellar initial mass function and the fraction of stars with planetary
systems.
In my talk, I shall describe some of the important aspects of this
developing 'holistic' picture of the star and planet formation process,
using some of our recent work on dense stellar clusters, protoplanetary
disks, and jets and outflows for illustration. Key to this work has been
access to the VLT and HST, and I shall also outline how future advanced
ground-based instrumentation and the Next Generation Space Telescope
should lead to significant progress in our understanding of the origins
of stars and their planetary systems.
17 - No Colloqium (Maundy Thursday)
24 - talk by R. Cayrel has been cancelled
ABSTRACT:
May 2003
1 - Holiday
8 - Roberto Terlevich (host MPA)
"The ages of HII galaxies"
ABSTRACT:
15 - Antonella Natta (Arcetri) (host - MPA)
"The formation of brown dwarfs"
ABSTRACT:
22 - Jim Moran (host MPE)
"Water megamasers and black hole accretion disks"
ABSTRACT:
28 Special Colloqium by
Riccardo Giacconi
"The dawn of X-ray Astronomy"
29 - Holiday
June 2003
5 - George Miley (Sterrewacht Leiden) (host ESO)
"Distant Radio Galaxies: Probes of the First Protoclusters"
ABSTRACT:
Evidence will be presented that the most distant radio galaxies are unique
laboratories for studying the formation and evolution of massive galaxies
and clusters of galaxies. The emphasis in this talk will be about recent
VLT observations that have led to the discovery of several regions of
galaxy overdensity at redshifts > 2 and follow-up observations with
the Advanced Camera on the HST. The host radio galaxies have the
characteristics expected of forming central cluster galaxies. It is
therefore highly probable that the most luminous radio galaxies can
be used to pinpoint the ancestors of rich clusters of galaxies in
the early Universe. The implications of this will be discussed.
12 - Guillaume Hebrard (host ESO)
"TBD"
ABSTRACT:
19 - Holiday
26 -
"TBD"
ABSTRACT:
July 2003
3 - Mordecai-Mark MacLow (host MPE)
"The Control of Star Formation by Supersonic Turbulence"
ABSTRACT:
The mystery of star formation in our Galaxy is why it occurs so slowly.
The gravitational collapse time of star-forming gas clouds is only a
few million years, and yet star formation has lasted for billions of
years. A further mystery is the observation of strongly supersonic
motions in the star-forming clouds that ought to dissipate in a few
crossing times in the absence of driving. Magnetic fields have been
invoked to explain both of these mysteries, through magnetohydrostatic
support against collapse, and by transforming supersonic turbulence into
dissipation-free Alfven waves. In this talk I use direct numerical
simulation to show that magnetic fields do not markedly reduce the
energy dissipation rate of supersonic, trans-Alfvenic turbulence, and so
do not reduce the requirements for external driving to explain the
observed supersonic motions. However, those supersonic motions by
themselves can explain the observed low star formation rates. Our
numerical simulations also show that supersonic turbulence can globally
support a region against gravitational collapse. Local collapse at a
low rate still occurs for driving parameters typical of molecular
clouds, suggesting that global turbulent support leads to isolated local
star formation, while lack of turbulent support leads to
high-efficiency, clustered star formation. I will show why the most
likely driver for the turbulence, at least in disk galaxies, is likely
to be the ensemble of supernova explosions in star-forming regions of
the disk. Finally, I will show simulations of supernova-driven
interstellar turbulence and briefly discuss how it can provide a natural
description of the interstellar gas.
| Last update: Jan. 21, 2003 | Wolfram Freudling | Send Comments |
|---|