I will discuss a new, open-source astronomical image-fitting program, specialized for galaxies, which is fast, flexible, and highly extensible. A key characteristic is an object-oriented design which allows new types of image components (2D surface-brightness functions) to be easily written and added to the program. Image functions provided with the program include the usual suspects for galaxy decompositions (Sersic, exponential, Gaussian), along with Core-Sersic and broken-exponential profiles, elliptical rings, and components which perform line-of-sight integration through 3D luminosity-density models of disks and rings seen at arbitrary inclinations. Minimization can be done using  standard chi^{^2} or Poisson-based maximum-likelihood statistics, which are appropriate for Poisson data in low-count regimes; different minimization algorithms allow trade-offs between speed and decreased sensitivity to local minima in the fit landscape.  I will also show that fitting low-S/N galaxy images by minimizing chi^{^2} can lead to biases in fitted parameter values, which are avoided if a Poisson ML statistic is used.

I will present a comprehensive study of the mid-infrared spectral features in a sample
of almost 700 active galactic nuclei (AGN) with available spectra from the
Spitzer InfraRed Spectrograph (IRS). I will talk about the contribution of the
AGN and host galaxy components to the mid-infrared emission of the AGN, the strength and
peak wavelength of the silicate features at 9.7 and 18 micron and the implications on the
modelling of the dust in the torus, as well as the PAH features, present in many of the AGN
mid-infrared spectra.

IceCube has recently reported the discovery of high-energy neutrinos of astrophysical origin, opening up the PeV (10^15 eV) sky. These observations are challenging to interpret on the astronomical side and have triggered a fruitful collaboration across particle and astro-physics. I will first describe the IceCube experiment and then, by using positional and energetic diagnostics, discuss plausible astronomical counterparts to the neutrino events. These include extragalactic sources, namely BL Lacertae objects, a sub-class of blazars, and Galactic pulsar wind nebulae. I will conclude by addressing the implications of the results and possible ways forward.

I will present the results of an ultra-deep spectroscopic survey of the Hubble Deep Field South using MUSE. The data cube resulting from the 27 hours of integration covers one arcmin2 field of view at an unprecedented depth increasing the number of redshifts known in the region by an order of magnitude, up to 189 redshifts with 26 Ly-a emitting galaxies that are not even detected in the HST images down to magnitude 29.5. I will describe the overall sample properties and demonstrate the power of MUSE to perform deep field spectroscopy at comparable depth to the HST imaging deep-fields. I will discuss the promise of MUSE for future deep surveys of the Universe.

Quasars are the brightest (non-transient) objects observed at the highest redshifts, z>7. Such high redshift quasars are important as detailed analysis of quasar spectra provide unique information about the baryonic and physical condition of the Universe during the epoch of reionisation. Furthermore, the density of high redshift quasars puts powerful constraints on the mechanisms that are required to seed and grow >10^9 Msun supermassive black holes less than a Gyr after the Big Bang. Because these quasars are rare, surveys covering large areas on the sky are required to discover such objects. In this talk I will describe our on-going programme aimed at discovering quasars at the highest redshifts in optical and near-infrared surveys. I will present the results of our multi-wavelength follow-up observations, including mm observations with ALMA and the Plateau de Bure Interferometer of the quasar host galaxies, and discuss the implications for massive galaxy formation at high redshift.

Giant (100 kpc) and luminous Lyman-alpha nebulae are observed at high redshift around high-redshift radio galaxies (HZRGs), QSOs, and in a population known as Lyman-alpha blob (LABs). There is a growing body of evidence that all of these phenomenon are somehow related, although the mechanism powering their emission is poorly understood. I will present the first results of an ongoing narrow-band imaging survey for diffuse Ly-alpha emission around z ~ 2 quasars, including the discovery of two of the largest Ly-a nebulae known, with emission extending out to ~ 500 kpc into the cosmic web. Observations of high-ionization emission lines like HeII (1640A) and CIV (1549A) provide important diagnostics of physical conditions in these nebulae, and clues to the mechanism that power them. I will present sensitive observations of these emission lines, for a giant Ly-a nebula around a quasar, as well as from deep observations of a sample of 13 Ly-alpha blobs. I will show how photoionization models can be used to interpret such observations. Future deep observations with VLT/MUSE will revolutionize the study of such nebulae, allowing the detection of multiple diagnostic lines, which will provide important constraints on the physical nature of circum/inter-galactic gas.

Brightest group and cluster galaxies (BGGs/BCGs) are old giant ellipticals, which have been shown to be different from any other cluster galaxy. Despite of being easy detectable their formation and evolution is still poorly understood. I will present a statistical analysis of a large sample of 883 Brightest group and cluster galaxies (BGGs/BCGs) from the Galaxy and Mass Assembly Survey (GAMA). We analyse their stellar mass growth, position in the cluster, and the percentage of BGGs/BCGs that show H\alpha in emission. We find that BCGs grow steeply until z~0.5, and slow down at lower redshift.

BCGs have been predicted to have a more active accretion history than less massive galaxies. We further use IFU spectroscopy to study the spatially-resolved stellar populations of BCGs and their connection with galaxy’s angular momentum. We find that all the BCGs in our sample have gone through at least one major merger after z=1. Our stellar population analysis suggest that BCGs have a more active accretion history than early-type galaxies of similar mass.

Free-floating substellar objects are the link between stars and planets. They play a key role for our understanding of star and planet formation and of cool planetary-like atmospheres. After reviewing aspects of their physics, detection history, and formation, I will present observations of young brown dwarfs and free-floating planets. This includes a precise radial velocity survey for companions at the VLT, Herschel studies of disks, accretion studies, and spectro-astrometric detections of outflows. I will present our recent result that the coolest known object that is formed in a star-like mode is a free-floating planet. We discovered significant accretion (VLT/SINFONI) and a substantial disk (Herschel) of the young 12 Jupiter mass object OTS44 (M9.5). This demonstrates that the processes that characterize the canonical star-like mode of formation apply to isolated objects down to a few Jupiter masses. Our results suggest that the increasing number of young free-floating planets and ultra-cool field T and Y dwarfs are the low-mass extension of the stellar population.

Galaxies are thought to form within haloes of dark matter, whose gravity allows the galaxies to exist. The formation and evolution of galaxies is affected by a multitude of other processes besides gravity and computational modelling is the only way we can attempt to understand all these processes. In this work we present a new development of the GALFORM semi-analytical model of galaxy formation and evolution, which exploits a Millennium Simulation-class N-body run performed with the Wilkinson Microwave Anisotropy Probe 7 cosmology. We use this new model to study the impact of the choice of stellar population synthesis (SPS) model on the predicted evolution of the galaxy luminosity function. Besides this model, we have generated a new GALFORM flavour constructed from merger trees derived from EAGLE, a hydrodynamical simulation. We compare results from both GALFORM and EAGLE.

We present the AKARI far-infred (FIR) all-sky maps and describe its characteristics, calibration accuracy and scientific capabilities. The AKARI FIR survey has covered 97% of the whole sky in four photometric bands, which cover continuously 50--180 micron with band central wavelengths of 65, 90, 140, and 160 microns. The spatial resolution of the maps is ~60--90 arcsecs and the detection limit is ~1--12 [MJy/sr] with an absolute accuracy of ~20%.

The data for the first time reveal the whole sky distribution of interstellar matter with arcminute-scale spatial resolutions at the peak of dust continuum emission, enabling us to investigate large-scale distribution of interstellar medium in great detail. The filamentary structure covering the whole sky is well traced by the all-sky maps.

The data are currently under assessment by the AKARI science team members and to be publicly released later this year. The release schedule is also described in this presentation.

The talk starts with the introductory accounts of the astrochemistry, the cosmic rays and the hydrogen molecular ion H3+ to illustrate how the study of the one has immediate impacts on the other two. The Galactic Center is used as a laboratory to show that the three elements lively influence each other. The emphasis is put on how the spectroscopy of the H3+ has been used to develop our view of the interstellar medium in the Galactic Center in the past decade.

The metal content of a galaxy is one of the most important properties used to distinguish between viable evolutionary scenarios and strongly influences many of the physical processes in the ISM. An absolute and robust calibration of extragalactic metallicities is essential in constraining models of chemical enrichment, chemical evolution, and the cycle of baryons in the cosmos. Despite this strong dependence on abundance, the calibration of nebular abundances from nebular emission lines remains uncertain. Different calibrations of the abundance scale require different assumptions, which may or may not be valid, and measurements, not all of which are easily obtained. MODS on LBT and the late Herschel Space Observatory are allowing us to clarify this long standing calibration uncertainty. The sensitivity of MODS is enabling the detection of numerous temperature sensitive lines and features in nearby galaxies and Herschel observations of the [O III] 88 micron fine structure line in nearby galaxies are enabling the determination of nebular abundances that are nearly independent of temperature. I will discuss current efforts at constraining the abundance scale using these modern facilities.

Filamentary structures in interstellar molecular clouds have long been recognised as an important part of the star formation process. Recent studies have confirmed that dense cores in different stages of star formation are commonly located in the filaments. Therefore, it is important to study the structure and formation of the filaments and the cores, to understand the details of the early phases of star formation. The density structure of molecular clouds can be studied using many different methods and wavelengths. All techniques have their own drawbacks, and, therefore, it is crucial to compare the results obtained with different methods. Before making conclusions on observational data, the observational uncertainties and biases should be evaluated with simulations. In this presentation, I will give a short overview of star formation theory, observations, and simulations, and review the main results of my PhD thesis, concentrated on comparing simulations and observations of the early, prestellar phase of star formation.

On 6 August, Rosetta successfully rendezvoused with Comet 67P/Churyumov-Gerasimenko at a distance of more than 400 million km from Earth, marking the beginning of its main science mission. For the first time, Rosetta will escort and study a comet in great detail and at close proximity as it evolves from now until perihelion in August 2015 and beyond, and will deploy a smaller lander, Philae, to the comet's surface in November this year.

I'll give an overview of the scientific goals of this unique mission, the journey taken to reach 67P/C-G, and what to expect over the coming months as the landing site is selected and Philae is deployed. I'll also give a flavour of the early science results from the mission. Finally, I'll discuss some of the successes and pitfalls of our substantial communications and outreach campaign for the mission.

We have undertaken multi-molecular-line surveys of the G333 and Vela C molecular clouds, using the wide-band capabilities of the Mopra telescope. The data sets are being used to investigate the chemistry, kinematics and hierarchical structure of the interstellar medium. In this talk we discuss the probability density function distribution in a range of molecules tracing different critical densities. We show that the chemical and excitation differences between different molecules show up as differences in the PDF for each molecule. The interpretation of the differences in terms of the type of gas traced by different molecules, and how useful each is for tracing gravitationally bound gas and/or gas that is tracing the broader hierarchical structure is discussed.

The ionizing continuum emitted by AGN can photoionize gas in the host galaxies on scales of tens of parsecs to kiloparsecs. The AGN-ionized gas on these scales is called 'narrow-line region' (NLR), because the gas emission lines are narrow (typically ~200-500 km/s) compared to the lines emitted by the high-density, high-velocity 'broad-line' gas at ~0.1 pc from the AGN. Since the density in the NLR is sufficiently low, the spectrum shows prominent forbidden lines ranging from low to high ionization. Emission from the NLR can be used to probe the shape of the AGN ionizing continuum, gas conditions in the AGN environment, obscuration and AGN unification, as well as AGN feedback. I will give an overview of the picture that has emerged from observations of AGN NLRs. I will show recent results from our ongoing optical IFU studies of NLRs in Seyfert galaxies and discuss open questions.

Dust emission is a sensitive probe of the ISM in galaxies. Previous surveys have found galaxies were significantly dustier at earlier times, but the cause of this evolution, and the origin of the dust, are hotly debated topics in astrophysics. Using panchromatic data from the UV to the submillimetre, I will explore the physical properties and SEDs of a sample of ~250μm rest-frame selected submillimetre galaxies (SMGs). I then compare the SMGs to dusty galaxies at low redshift selected from one of the largest extragalactic Herschel surveys, H-ATLAS. From SED analysis it is found that a large fraction of the dust luminosity in SMGs originates from star-forming regions, whereas at lower redshifts the dust luminosity is dominated by the diffuse ISM. At the same dust mass the SMGs are offset towards a higher star-formation rate compared to the low redshift H-ATLAS galaxies. This is not only due to the higher gas fraction in SMGs but also because they are undergoing a more efficient mode of star formation. I will also present the results of chemical evolution modelling to understand the origin of dust in SMGs. Even after accounting for dust produced by low mass stars and supernovae the deficit in the dust mass budget provides support to the hypothesis that higher supernova yields, and/or substantial grain growth in the interstellar medium are required in order for the predicted dust mass to match observations of SMGs.

Young stellar clusters and associations are the direct output of the star formation process, and therefore can provide useful clues on how the conversion of gas into stars takes place in space and time, and on several details of the physics involved. The Orion Nebula Cluster, the densest cluster within a large star forming complex, due to its vicinity and abundant young population has always been target of observational studies. I will describe my research on this region, focusing on the first accurate constraint of its age spread - which therefore tracks the duration of star formation - the substellar IMF, the accretion lifetimes, the structure and kinematics. In particular I will describe the first conclusive evidence that the system is expanding due to early gas removal.

Quasar feedback on host galaxies in the form of powerful outflows is invoked as a key mechanism to quench star formation in massive galaxies, but direct observational evidences are still scarce and the debate on the physical origin of the observed outflows is still open. After reviewing the observational constraints we have so far on the existence and origin of this mechanism, I will present new X-shooter@VLT observations of a representative sample of 10 luminous, X-ray obscured QSOs at z~1.5 from the XMM-COSMOS survey, expected to be caught in the transitioning phase from starburst to AGN dominated systems. From the rest-frame optical spectra we could infer the presence of outflows in 6 out of 8 sources. This may be considered as a compelling indication that the color selection applied to our X-ray sample is effective in picking up objects in the outflowing phase. A comparison of the outflow energetic with the AGN luminosity and the kinetic energy associated to stellar processes, suggest that the AGN rather than the on-going star-formation may be the major driver for the presence of the observed broad and shifted components. In the two brightest sources we were also able to probe, via slit resolved spectroscopy, that the outflows extend up to 10 kpc scales. Most important, thanks to SINFONI data available for one of these 2 targets (XID2028) we were able to probe the presence of both negative and positive outflow-induced feedback in the host galaxy of the powerful QSO.

After a lengthy commissioning period, the SkyMapper telescope at Siding Springs Observatory in Australia has finally started its eponymous survey in March 2014. I will present the updated survey plans including its various components, an outlook to the science pursued including first results and the anticipated timeline for finishing the survey and worldwide access to the data.

Water vapor masers have been detected in over 150 galaxies. In at least 25% of these galaxies, the masers are arranged in thin, sub-parsec disks orbiting the central supermassive black holes in AGNs. Maser disks can be mapped with VLBI, and in fact they provide the only means of mapping gas in AGNs on such scales, directly. So far, twenty have been mapped. The masers trace Keplerian orbits about the nucleus, and provide gold-standard masses of the central black holes. In several cases, they can be used to measure the distance to the host galaxy, geometrically. The Megamaser Cosmology Project (MCP) focuses on discovering such maser disks and using them to measure galaxy distances, and hence the Hubble Constant. The MCP is playing a critical role in resolving the apparent discrepancy between standard-candle based measurements of H0 and the value predicted by Planck measurements of the CMB.

The abundance of most of the molecules observed in interstellar clouds can be explained by chemical reactions occurring in the gas phase; however some key species, like for instance H2 (the most important molecule in the Universe) and CO2 , cannot be formed efficiently enough by gas phase reactions. Their abundance can be understood when reactions occurring on the surface of interstellar grains (that act as catalysts) are taken into account. Furthermore several other species (like for instance water, formaldehyde, methanol and so on), for which gas phase formation routes do exist, are synthesized more efficiently on grain surfaces.

Surface reactions have been for long neglected or taken into account only on a theoretical ground, while due to intrinsic difficulties experimental investigations, in conditions and on solids that can be considered realistic analogues of interstellar grains, started to be tackled only rather recently.

In this talk I will present together with some well consolidated results on the formation of molecular hydrogen, that we started to study in the nineties, also some very recent and interesting results on other important species.

BICEP2 recently reported a detection of B-modes in the CMB polarization 
at degree angular scales. This B-mode pattern is widely interpreted as 
the likely signature from primordial gravitational waves, consistent 
with those predicted to arise in the first 10^-34 seconds of the history
 of the universe, stretched from quantum to classical scales by the 
exponential expansion of cosmic inflation.

BICEP2 is a CMB polarimeter that was specifically designed to search for
 the elusive signal from inflationary gravitational waves in the B-mode 
power spectra around l = 80. BICEP2 has accumulated 3 years of data from
 the South Pole from 2010 to 2012, integrating continuously on a 
low-foreground region of effective size 1% of the whole sky. I will 
describe the experimental strategy, tests for foreground and systematics
 contamination, and results in the map and power spectra. The reported 
B-mode spectrum is well fit by a lensed-LCDM plus tensor theoretical 
model with tensor/scalar ratio r = 0.20 +0.07 -0.05 with r = 0 is 
strongly disfavored.

With the selection of PLATO as ESA’s M3 mission, the situation for astronomical observations of exoplanets from space is going in the right direction. At the moment the global astronomical community can prepare for a number of missions - CHEOPS, TESS, JWST and PLATO - that will provide the next necessary step on the way to understand exoplanets, stars and eventually ourselves. A new science of truly comparative planetology is being born at the moment and will surely thrive fully in the 2020:ties.

PLATO, intended for a launch in the first quarter of the year 2024, will push the precision of transit photometry to the limit where it is possible to simultaneously detect the astroseismic p-modes from the host star as well as the high precision shape of the transit light curve. This will allow the determination of masses and radii of the star and planet to an accuracy of a few percent. The actual comparison between different types of planets then finally becomes possible. At the same time, it will be feasible to determine the age of exoplanetary systems to a precision of less than 10% (or typically 250 Myears), an order-of-magnitude improvement for main sequence solar type stars.

PLATO will also put strong requirements on the required ground based follow-up program, and the preparation for this will have to begin within the near future.

The line of sight toward the lensed blazar PKS1830-211 is remarkable for several reasons and offers the opportunity to address many astronomical interests. The 40+ molecules detected so far in the z=0.89 absorber in front of the blazar do not only tell us about the physico-chemical conditions of the molecular gas in a galaxy at a lookback time of more than half the current age of the Universe, but they can also be used as powerful cosmological probes. Based on recent radio observations, including ALMA cycle 0 data, I will present
1) a precise and accurate measurement of the cosmic microwave background temperature at z=0.89;
2) constraints of the cosmological variations of fundamental constants such as the proton-to-electron mass ratio;
3) measurements of isotopic ratios at z=0.89, and 4) I will argue that lensed blazars such as PKS1830-211 offer the unique opportunity to monitor the activity of a blazar black-hole down to unprecedented accuracy.

In my talk I will present the analysis of medium-resolution spectra of hot horizontal branch stars in the metal-poor globular cluster NGC 288. Equally important I will describe the pitfalls we encountered before arriving at our final results. In order not to spoil the talk no further details are given here.

I will talk about the distribution of HI and metal absorbers in cosmological simulations and compare the simulation results with observations. I will further discuss the implications for the relation between absorbers and galaxies.

Comparative studies of the restframe colours of active and inactive galaxies have shown no clear differences when the stellar mass-dependency of the AGN fraction is taken into account. This is in contrast to the observation of a lower frequency of AGN in quiescent galaxies, and specific star formation rates in AGN hosts that are comparable to those in star-forming galaxies at the same redshift. In this talk I will show recent results from the Survey for High-z Absorption Red and Dead Sources (SHARDS) that provide an interpretation of these two apparently contradictory observations.

The EAGLE (Evolution and Assembly of Galaxies and their Environments) project is a suite of hydrodynamic simulations of the Universe. The simulations take into account the full range of baryonic physics, including metal dependent gas cooling, star formation, supernovae and black hole formation. The resolution of the simulations is sufficient to resolve the onset of the Jeans instability in galactic disks, allowing us to study the formation of individual galaxies in detail. At the same time the largest calculation simulates a volume that is 100 Mpc on each side, exploring the full range of galaxy environments from the isolated dwarves to rich galaxy clusters.

A key philosophy of the simulations has been to use the simplest possible sub-grid models for star formation, black hole accretion and feedback from supernovae and AGN. Efficient feedback is achieved without hydrodynamic decoupling of particles. The small number of parameters in these models are calibrated by requiring that the simulations match key observed properties of local galaxies. Having set the parameters using the local Universe, I will show that the simulations reproduce the observed evolution of galaxy properties extremely well. The resulting universe provides us with deep insight into the formation of galaxies and black holes. In particular, we can use the simulations to understand the relationship between local galaxies and their progenitors at higher redshift and to understand the role of interactions between galaxies and the AGN that they host. I will present an overview of some of the most important results from the project.

At the end of 2010, a Very Large XMM programme - the XXL survey - was granted in order to map two regions of 25 deg2 each at medium sensitivity. This will lead to the detection of several hundreds of clusters of galaxies and of some 30 000 AGNs with well defined selection functions. Since 2012, an ESO Large Programme is performing the spectroscopic identification of the galaxy clusters. After reviewing the scientific motivations, we describe the some 540 XMM observations, the associated multi-wavelength follow-up and simulation programmes. We especially underline the cosmological goals of the project involving cluster number counts, large-scale studies with clusters and AGNs as well as the systematic search for very distant clusters in a multi-lambda space. This will be the occasion to review in some detail the still hotly debated question of the proper use of clusters of galaxies for cosmology, as recently revived by the tension between the cosmological constraints from the Planck CMB and the Planck clusters. We describe a new method for the cosmological analysis of cluster surveys that bypasses the traditional mass calculation step. We present the first scientific results.

Combining Herschel with data at other wavelengths enables us to study different physical processes that are at work. In my talk I will present results from two recent projects that I have (co-)led. The first project probes the co-evolution of black hole growth and star formation by studying the cross-correlation between optically selected type 1 SDSS quasars and the CIB. For the first time, we detect not only the sub-millimetre emission of the quasars themselves which dominates on small scales but also the correlated emission of dusty star-forming galaxies on larger scale. The correlated emission comes from satellite galaxies in the same halo as the quasar and galaxies which reside in separate halos correlated with the quasar-hosting halo. The second project looks at the cross-correlation between the CIB and the cosmic microwave background (CMB). Apart from the dusty star-forming galaxies which are present in both the CIB and CMB maps, we also detect the cross-correlation between the thermal Sunya'ev-Zeldovich (tSZ) signal and the CIB sourced by dusty star-forming galaxies. The tSZ-CIB cross-correlation signal not only provides constraints on the level of star-formation activity in massive systems, but also significantly improves constraints on the kinetic SZ which is of great interest for studying the duration of reionization.

We realized long ago that accretion onto compact objects was a more efficient engine than thermonuclear reactions. Relativistic jets, however, seem to carry more power than what accretion can provide. I will present the evidences for this statement by considering the jets of blazars, and finding robust results about their power.

I will present latest results from our work on multi-wavelength modelling of the evolution of galaxies. The work combines a theoretical model of galaxy formation based on Lambda-CDM with a radiative transfer calculation of the reprocessing of stellar emission by dust in galaxies. Our previous work implied the need for a top-heavy IMF in starbursts in order to explain the number counts and redshifts of sub-mm galaxies in this framework, once the observational constraints from the present-day galaxy luminosity function at optical and near-IR wavelengths were included. We have revisited this using an improved galaxy formation model, which includes a more realistic treatment of star formation, as well as feedback from AGN. In the new work, we also impose the constraint that the model reproduces the observed evolution of the galaxy luminosity function at near-IR wavelengths. We find that variations in the IMF still seem to be required when we try to match all of these observational constraints simultaneously.

The recently launched Gaia satellite mission will provide astronomers with an astrometric dataset comprising data on 1 billion stars of unprecedented precision. In order to fully exploit the capabilities of Gaia, the location and velocity vector of the space craft itself need to be known to a high degrees, more precisely than conventional means can deliver. For this reason a network of small to medium telescopes was set up to track the satellite astrometrically. The overall structure and strategy of this campaign will be described in this presentation. Since the launch of Gaia, the GBOT group had to enter a process of redefinition and reassessment of its strategy after the target turned out to be ~3 mags fainter than anticipated. The actions taken and the current status of the effort will be reviewed and commented on.

In the current era of precision astronomy, a complete sky background model is crucial, especially as the telescopes become even larger in the next decade. Such a model is needed for planning observations as well as understanding and correcting the data for the sky background. We have developed a sky model for this purpose, and it is the most complete and universal sky model that we know of to date (Noll et al. 2012). It covers a wide range of wavelengths from 0.3 to 30 microns up to a resolution of 1,000,000 and is instrument independent.

The brightest natural source of optical light at night is the Moon, and it is the major contributor to the astronomical sky background. We have an improved scattered moonlight model (Jones et al. 2013), where all of the components are computed with physical processes or observational data with less empirical parametrizations. This model is spectroscopic from 0.3 to 2.5 microns and was studied with a FORS1 (Patat et al. 2008) and dedicated X-Shooter data set. To our knowledge, this is the first spectroscopic model extending into the infrared.

I will introduce the sky background model and scattered moonlight model. Then I will go into more detail about the scattered moonlight model and present its current status as well as its performance in the optical and near-infrared.

AGN inhabit a wide range of dark-matter halo environments; from the centres of clusters, where radio galaxies reside, to average Milky-Way like haloes in which quasars are found. In my talk, I will demonstrate that the variety of AGN environments can be explained when more than one accretion modes are responsible for fuelling the growth of black holes. I will show this by means of semi-analytic modelling, combined with detailed SPH simulations of galaxies in a Λ cold dark matter universe with AGN feedback. With these tools, I will explain how the large scale environment of AGN depends on luminosity and AGN type, and I will demonstrate how AGN can be used, along with line-emitting galaxies, to pinpoint the location of galaxy protoclusters in the high-redshift Universe.

Nowadays, the development of the observational instruments is so high that became very sensitive to the details of stellar surface. The interpretation of the stellar surfaces images, the fundamental parameters, the stellar variability and the planet detection needs realist simulations of stellar convection. Three-­dimensional radiative hydrodynamics simulations of cool stars are essential to a proper and quantitative analysis of these observations. I will present how these simulations across the Hertzsprung-Russel diagram have been (and will be) crucial to prepare and interpret the spectrophotometric, interferometric, astrometric, and imaging observations.

HI recombination lines at optical/near-IR wavelengths are a powerful diagnostic tool for the study of Young Stellar Objects (YSOs). On the one hand these lines are commonly used as a tracer of the mass accretion process, on the other hand they can also be employed to probe the physical properties of the gas in the circumstellar structures of young sources. In this talk I will present two different applications of the analysis of HI lines.

In the first part I will talk about the POISSON project (Protostellar Optical-Infrared Spectral Survey On NTT), a large low-resolution spectral survey of 150 YSOs from five different star-forming regions. In this work we used the near-IR HI lines as a proxy for the mass accretion rate (using empirical relationships connecting line flux to the accretion luminosity), thus obtaining a large database of values, which allowed us to study in particular the time evolution of the accretion rate.

In the second part I will present the preliminary results of the analysis of the HI decrements (i.e. the flux ratio of the lines of a series relative to one used as reference) observed on X-Shooter spectra of a sample of YSOs in Lupus. X-Shooter, with its broad wavelength coverage and moderate spectral resolution, is the perfect instrument to study the HI decrements of the Balmer, Paschen, and Brackett series. I will discuss the potential and limitations of the decrement analysis to provide information on the properties of the emitting gas and of the central source. In particular, I will focus on the correlations between the decrement shape, the observed line profiles, and the (stellar and accretion) properties of the objects.

Massive clusters are important tracers of star formation in galaxies and
laboratories for the study of massive star formation and populations.  Because
they are rare and therefore distant, neither the population of these clusters
nor the details of their assembly are well understood.

I will discuss the importance of these clusters and some theoretical formation
mechanisms.  I will focus on two well-known regions, the massive forming
cluster W51 (not M51) and the potentially pre-star-forming cloud G0.253+0.016,
aka The Brick or The Lima Bean.  We have used formaldehyde as a probe of
physical conditions in these regions, mapping the gas density and examining
properties of the turbulence.  In The Brick, we find that the mean density is
very low, which explains the low observed star formation activity but raises
questions about the geometry and dust properties.  In W51, the density
structure is highly varied, from an n~100 cm^-3 infrared dark cloud to the
n~10^5 cm^-3 massive clump.  Overall, the gas seems to favor a more prolonged
formation scenario for massive clusters.

The OmegaCAM wide-field imager at the VST at ESO Paranal is over 2 years in science operations. Three public surveys are being observed in parallel: KiDS, ATLAS and VPHAS+. Together with the VISTA surveys they provide a view on the Southern Hemisphere from u to K at unprecedented depth and spatial resolution. In addition, the Dutch astronomical community has access to almost 1 year of guaranteed time in the coming ten years.
In this talk I focus on the science being pursued with OmegaCAM in the Netherlands. It includes the Galaxy (ultracompact binaries, stellar streams), galaxy evolution (Local Group, Fornax, Hercules Supercluster) and cosmology (dark matter, dark energy, quasars at extreme redshifts).

Gas in the central parsecs of our Galaxy is subject to a harsh environment, including the close proximity of a supermassive black hole, supernova remnants, and massive star clusters. By characterizing the molecular gas conditions in this region, we can quantify the effect that the resulting shocks, x-rays, and cosmic rays have on gas properties and eventually star formation in this region. I will present a combination of results from the APEX, VLA, and GBT telescopes which place new limits on the large densities, temperatures, and turbulent line widths found in the molecular gas in the central 100 parsecs. Close to the black hole, we use data from the APEX telescope, to study the gas density in the Circumnuclear disk (CND), finding that it is not stable against tidal disruption. Almost all clumps appear to be transient and unlikely to form stars. We additionally find that reprocessed dust radiation from the central star cluster appears to be contributing to radiative excitation of HCN in the CND, which may lower the gas densities inferred using this molecule. Farther from the black hole, I will present larger scale VLA and GBT surveys of gas temperatures and turbulence in Galactic center clouds, including new detections of a 400 K gas component which may be shock heated, and finally new hints of cooler and less turbulent clumps embedded within these clouds.

In this talk, I will present our surveys of multiple CS transitions (from J=1→0 to 7→6) in nearby active star-forming galaxies, with the JVLA, GBT 100m, IRAM 30m, SMT 10m, and APEX 12m. The sample includes normal spiral galaxies, starburst, and ULIRGs. We find linear correlations between the luminosities of dense gas (L_dense) and IR emission (L_IR) for all CS transitions. These correlations even extend over eight orders of luminosity magnitude down to Galactic dense cores, and are likely tenable for all densities > 10^4 cm−3 , which indicates that star formation is not related to free-fall time scale for the dense molecular gas. For the first time we prove that irrespective of the critical density of a specific transition, dense molecular gas is universally related to star forming activities for self-gravitational bound gas systems.