VIIth Marseille International Cosmology Conference

### Harvesting the Desert : the Universe Between Redshift 1 and 3June 29, July 3rd 2009, Marseille, France

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.
2 VIIth Marseille International Cosmology Conference : Star formation and dust obscuration at z~2: galaxies at the dawn of downsizing
Maurilio Pannella (NRAO)

I present first results of a study aimed to constrain the star formation rate and dust content of galaxies at z~2.  I use a sample of BzK-selected star-forming galaxies to perform a stacking analysis of their 1.4 GHz radio continuum as a function of different stellar population properties, after removing AGN contaminants from the sample. Dust unbiased star formation rates  are derived from radio fluxes assuming the local radio-IR correlation. The main results of this work are: i) specific star formation rates are constant over about 1 dex in stellar mass and up to the highest  stellar mass probed; ii) the dust attenuation is a strong function of galaxy stellar mass with more massive galaxies being more obscured than lower mass objects; ...

Durée: 14:20 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : The Spitzer View of Lensed Lyman Break Galaxies: Testing Star Formation Diagnostics at High Redshift
Brian Siana (Caltech)

The star formation rates (SFRs) of Lyman Break Galaxies (LBGs) are typically estimated based on their UV properties or mid-IR photometry using local relations that are assumed to be true at high redshift (eg. reddening laws, IR SEDs). Recently, several lensed LBGs have been discovered with large magnifications allowing detailed infrared studies of this otherwise unobservable population. I'll present the Spitzer mid-IR spectra and mid- to far-IR photometry of two lensed LBGs, cB58 and the "Cosmic Eye." With these data we can test whether or not these locally determined relations are valid for high redshift starbursts. The PAHs and far-IR SEDs are similar in shape to local starbursts and have similar PAH-to-IR luminosity ratios. However, in both ...

Durée: 16:45 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Redshift-2 Sub-Millimeter Galaxies in Spitzer wide surveys
Alain Omont & Nicolas Fiolet (Institut d'Astrophysique de Paris, CNRS and Université Pierre et Marie Curie), and the SWIMAMBO collaboration

Our recent millimetre observations at IRAM have confirmed the possibility of identifying a subclass of Sub-Millimeter Galaxies (SMGs, i.e. ULIRGs at z ~ 1.5-2) in Spitzer wide surveys, such as SWIRE, through their bright 24um intensity from redshifted PAH emission, and the characteristic 1.6um stellar maximum redshifted into the IRAC bands.  Mid-IR spectra and photometry, as well as deep, multi-lambda radio data, are powerful in identifying AGN or starburst dominated sources, or composite objects. Starburst dominated galaxies are generally more luminous in mm continuum and CO lines. We will discuss which clues may be ...

Durée: 31:29 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Star Formation in the E-CDFS: Observations Confront Models
Maaike Damen

I will present the latest results of SIMPLE: the Spitzer IRAC and Musyc Public Legacy Survey of the Extended-CDFS. We use the multiwavelength data (from the X-ray to the IR) to trace the star formation activity and stellar mass assembly of massive galaxies at z=1-3. The average specific star formation rates increase with redshift out to z~2, and the rate of incline does not seem to  be a strong function of galaxy mass. These results are confirmed and  extended to higher redshift using the deep FIREWORKS catalog  of the CDFS.
We also compare the observed star formation with semi-analytic galaxy  formation models that were implemented on the Millennium Simulation.
The models predict that the specific star formation rates ...

Durée: 15:58 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Mid-Infrared Spectroscopy of Submillimeter Galaxies: Extended Star Formation in Massive High Redshift Galaxies
Karín Menéndez-Delmestre (Observatories of the Carnegie Institution of Washington)

Ultra-luminous infrared galaxies (ULIRGs; L > 10^12 Lsun) are quite rare in the local universe, but appear to dominate the co-moving energy density at z>2. Many are optically-faint, dust-obscured galaxies that have been identified only relatively recently by the detection of their thermal dust emission redshifted into the submillimeter wavelengths. We used the Spitzer Infrared Spectrograph (IRS) to study the mid-IR properties and investigate the energetics of 24 such Submillimeter Galaxies (SMGs) in the redshift range of z~0.65-3.2. We detect in  >80% of our sample prominent emission features from Polycyclic Aromatic Hydrocarbons (PAHs), which are associated to intense ...

Durée: 16:58 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Infrared galaxies in the redshift desert
Guilaine Lagache (Institut d'Astrophysique Spatiale, Orsay)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 25:42 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : The impact of Helium reionisation on the HI Lyman-alpha forest
James Bolton (MPA-Garching)

Observations of the HeII Gunn-Peterson trough and patchy transmission in the HeII Lyman-alpha forest provide the most direct evidence for HeII reionisation occurring around z~3.  However, the epoch of HeII reionisation can also be probed, albeit indirectly, through the thermal history of the IGM inferred from the HI Lyman-alpha forest.
In this talk I shall present new numerical and semi-analytic modelling of the IGM during HeII reionisation, and discuss these results in the context of the HI Lyman-alpha forest observed in high resolution quasar spectra at z~3.  I shall highlight that rapid, strong photo-heating is difficult to achieve across the entire IGM during HeII reionisation, and demonstrate that radiative transfer effects will ...

Durée: 17:21 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : The Epoch of HeIium reionization
Steven Furlanetto (UCLA)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

OAMP

Durée: 34:54 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Observations of the Intergalactic Medium near Star-Forming Galaxies at z~2.3
Olivera Rakic (Leiden)

We study the intergalactic medium around star-forming galaxies by analyzing high resolution spectra of 15 QSOs with ~600 spectroscopic galaxy redshifts at z~2.3, using pixel optical depth correlation techniques. Most of the galaxies are within 2 Mpc (proper) from the lines of sight to the QSOs. We measure the distribution of HI, CIV, SiIV, OVI and NV absorption as a function of separation from galaxies and of galaxy properties. We find many very strong correlations that give us insight into the physical state of the intergalactic medium in the vicinity of starburst galaxies. Finally, we compare our findings with the results from the cosmological smoothed particle hydrodynamics simulations (OWLS).

Durée: 13:01 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Using Simulations of Galaxy Formation/Evolution to Interpret HIRES/UVES/COS Quasar Absorption Lines through Galaxy Halos: The Spatial, Kinematic, and Ionization Distributions of the Gas Revealed
Glenn Kacprzak

The technique of using background quasars to study absorption lines produced by gaseous halos of foreground galaxies provides a uniquely powerful tool to probe the gas-galaxy and IGM interface.  With absorption lines, we are capable of studying the kinematic, chemical, and ionization conditions of galactic halos over all redshifts out to projected galactocentric radii of several 100 kpc. We have recently begun to produce similar absorption line observations of galaxies and their gaseous halos in LCDM cosmological simulations in order to constrain the dynamic interaction of the galaxy/halo/cosmic web environment and the distribution of gas within halos. Here we study absorbing gas in many ionization phases, which have a range of temperatures and densities and ...

Durée: 16:49 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Real Galaxy Winds in LCDM Cosmological Simulations: LBGs at z=3, MgII Winds at z=1, and IGM Enrichment to 500 kpc and Beyond

Chris Churchill (NMSU)

The conference is  devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 28:55 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Harvesting IGM properties with the FLO method
Stefano Cristiani (INAF-Astronomical Observatory Trieste)

I will briefly introduce the FLO method (From Lines to Overdensities) applied by our group to recover the IGM density field from the measured column densities of HI Lyman-alpha lines. We have applied FLO to a sample of more than 20 high resolution, high signal-to-noise spectra of QSOs. I will describe the results already obtained on the Lyman Forest, the proximity effect and work in progress on metals in the IGM.

OAMP

Durée: 26:21 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Metals in the IGM as a star formation tracer
Joop Schaye (Leiden)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

OAMP

Durée: 31:00 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : DoubleBlind: A super deep Lyman-alpha and H-alpha survey at z=2.2
Matthew Hayes (Observatory of Geneva)

We have obtained the deepest z=2.2 narrowband H-alpha observations to date using VLT/HAWK-I in the GOODS-S field. We have subsequently cloned the bandpass, shifted it in wavelength, and manufactured a VLT/FORS filter for Lyman-alpha at the same z: hence a 'Double-Blind' survey for Ly-a and H-a. DoubleBlind presents and *unbiased* survey of the two emission lines in one snapshot. A - DoubleBlind allows the estimation of Lya escape fractions in individual targets without resorting to complex models of stellar physics. B - comparison of the observed Lya luminosity with the intrinsic one (derived from H-alpha) is not subject to cosmic variance -- exactly the save volume is probed.
I will present first results from this survey, including ...

Durée: 12:53 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Stellar and halo masses of z~2 star-forming galaxies well below L*: SFR dependence on stellar mass and the shut-down of star formation in the most massive halos
Marcin Sawicki (Saint Mary's University)

We use very deep multi-wavelength imaging to study the stellar and dark matter halo masses of UV-selected galaxies at z~2.  We probe deep into the z~2 galaxy population, reaching 3 mag below L* - i.e., pushing to galaxies with (dust corrected) star formation rates of only ~1Msun/yr.  Star formation rates and dust content, particularly of galaxies below the luminosity function knee at L*, show a strong correlation with stellar mass that hints at the underlying galaxy-formation physics.  The observed SFR-stellar mass relation is offset from that in z~5 LBGs, so that the specific star formation rates at z~2 are a factor of ~20 lower than at z~5.  These results also show that the bulk of the stellar mass at z~2 likely ...

Durée: 17:53 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : The Ultra-Deep VVDS sample, the star forming population of galaxies with 1.4
Olivier Le Fèvre (LAM)

The Vimos VLT Deep Survey Ultra-Deep sample consists of a magnitude limited sample of ~700 galaxies with 23<24.75 and a sample of  ~200 Lyman Alpha Emitters (LAE) identified serendipitouly in the slits of VVDS main targets. I will discuss the redshift distribution of this sample  which peaks at z~1.4 and extends to z=6.6, and will compare the galaxy counts  from this magnitude selected survey to samples at similar redshifts selected from  different techniques to derive a proper census of the star forming galaxy  population. The global properties of the sample will be presented  including luminosity function, correlation function and spectrophotometric  properties, with new constraints on the evolution of the ...

Durée: 26:54 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : On the Star Formation Rates of Redshift Desert Galaxies

Casey Papovich (Department of Physics, Texas A&M University)

Abstract:  Current studies from extragalactic surveys conclude that the global cosmic star-formation rate (SFR) density reached a global maximum between redshifts of 1.5 < z < 3.  However, these studies have relied nearly entirely on indicators using local SFR calibrations.  I will discuss recent work to test the accuracy of SFR tracers for galaxies in the redshift desert.  This work includes our study of the far-IR colors of Spitzer 24 micron-selected galaxies at these redshifts using data from the Extended Chandra Deep Field South.

I will also discuss the results of our program to measure the Paschen-alpha emission from direct spectroscopy using Spitzer for a sample of ...

Durée: 28:25 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Star Formation in Galaxy Population through Cosmic Time
Laurence Tresse (LAM)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

OAMP

Durée: 32:45 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : The variety of dust populations at 1 < z < 2.5
Stefan NOLL (LAM)

The properties of dust attenuation at rest-frame UV wavelengths are inferred from high-quality spectra of about 200 galaxies at 1<2.5 from the GMASS, FDF, K20, and GDDS surveys. The shape of the UV extinction curve is constrained by a parametric description of the rest-frame UV continuum. The UV bump is further characterised by fitting Lorentzian-like profiles.
Spectra exhibit a significant 2175A feature in at least 30% of the cases. Depending on the dust distribution in the galaxy, effective UV extinction curves in-between those of the SMC and LMC are most likely. On average, the UV-bump width is about 60% of the values typical of the LMC and Milky Way, which suggests the presence of dust similar to that found in the LMC2 supershell close to 30Dor. ...

Durée: 18:22 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : H-alpha emission detections of Damped Lyman-alpha Absorbers at z~1 with VLT/SINFONI
Celine Peroux (LAM)

Damped Lyman-alpha Absorbers (DLAs) appear to dominate the mass density of neutral gas in the Universe. What is the morphology of these objects? How do the stellar properties of the absorbing galaxy relate to the gas metallicity? How does the emission-line metallicity compare to the absorption-line metallicity? To answer these questions, one needs to image the stellar content of the absorbers in emission at z=1-2. However, only 18 identifications of DLA galaxies were known so far. For the first time, IFU VLT/SINFONI enables us to probe redshifted H-alpha in the inner few arcsecond radius regions around the bright background quasars without being contaminated by the quasar light. In this talk, we would like to report 2 secure SINFONI detections at z~1. The ...

Durée: 17:20 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Galaxy Metallicity in the Redshift Desert

Dawn Erb (University of Califormia Santa Barbara)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 34:30 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Linking galaxies from z=3 to z=0: upsizing and surface density dependent evolution

Marijn Franx (Leiden)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

OAMP

Durée: 30:59 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Controlling the fire: Evidence for feedback in high-redshift galaxies

Redshifts z=2-3 correspond to the epoch where the Universe formed most of its stars, and much of this star formation occurred in rapid, vigorous starbursts. We are only starting to understand the physical processes that regulated star formation in these galaxies, which seem to differ fundamentally from star-forming galaxies at low redshift. Studying the ionized gas in blue starburst galaxies at z=2-3 with rest-frame optical imaging spectroscopy, we find extreme gas pressures and star-formation intensitites similar to those in the nuclei of nearby starburst galaxies -- but extending across 10s of kiloparsecs. I will argue that the energy injected by the starburst may be sufficient to influence the large-scale gas kinematics and produce the

Durée: 23:55 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : A Complete Census of Galaxies at z=1-3 in the Subaru Deep Field
Chun Ly (UCLA)

Abstract:
Recent advances in photometric selection have helped populate the 'redshift desert' at z=1.5--3. With short-wavelength methods, LBGs and BXs are selected by requiring a relatively unreddened UV continuum from recently formed stars. In contrast, near-IR galaxy selections (e.g. DRGs) are more sensitive to massive evolved galaxies. Given the different galaxy types selected by different methods, reliable measurements of galaxy evolution across the redshift desert require combining UV and IR techniques, preferably in the same deep field.

We therefore made a large survey in the Subaru Deep Field by using all available photometric techniques to identify and study galaxies in the redshift desert. This includes 1) LBGs at z~2 found from ...

Durée: 15:53 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : A Model for Lya Blobs
Mark Dijkstra (Univ. Melbourne)

Since the discovery of two giant Lyman Alpha (Lya) 'blobs' by Steidel et al. in 2000, the number of these mysterious objects has grown substantially. Current observations show that Lya blobs are strongly clustered in overdense regions of our Universe, and that they are associated with a wide range of sources that include type I and type II AGN, submm sources, and regular LBGs. Sometimes there is no obvious counterpart to a blob at all. I will discuss a simple model that is consistent with all of these observations. This model may also shed some light on the observed range of Lya line widths + blob morphologies.

OAMP

Durée: 14:59 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : The Rest-Frame Mid-UV Spectra of Galaxies
Sara Heap (NASA’s Goddard Space Flight Center)

At redshifts, z>1, the rest-frame mid-UV is brought into view of large, ground-based telescopes. Here, we report on a study of the potential of the rest-frame UV spectrum for deriving the age since the last major episode of star formation in a galaxy. We base this investigation on wide-band (0.2-1.0 microns), low-resolution (R~1000) spectra of single stars in Hubble’s Next Generation Spectral Library (NGSL). We find that a combination of mid-UV spectral indices and colors can indeed yield the age of a stellar population, but only if light from the stellar population is unreddened.

OAMP

Durée: 19:34 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : The physical and morphological properties of high redshift Lyalpha emitting galaxies
Laura Pentericci (Astronomical Observatory, Roma)

Understanding the physical nature of Lyalpha emitters and Lyman break galaxies and the relation between the two samples, is important to assess the role they played in the early Universe and constrain the relative contribution e.g. to the total stellar mass density. Are the LAEs a subset of the LBG population or is there an evolutionary sequence from one sample to the other, as claimed by several authors?
To assess these issues we studied a large sample of color selected galaxies from z~2 to z~4 from the GOODS-S survey, that have spectroscopical
We then investigated their physical and morphological properties and their dependance on the nature of the Ly alpha emission/absorption characteristics, using the GOODS ...

Durée: 20:41 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : Dynamics and mass assembly of 1
Thierry Contini, and the MASSIV collaboration (www.ast.obs-mip.fr/massiv)

Abstract: A key question in the formation and evolution of galaxies is the epoch and mechanisms of mass assembly. I will present the first results of MASSIV (Mass Assembly Survey with SINFONI in VVDS), an on-going ESO Large Program, using the AO-assisted NIR 3D spectrograph SINFONI on VLT, aiming to measure the velocity field of a unique sample of ~100 star-forming galaxies in the redshift range 1-2 selected in the VIMOS VLT Deep Survey. This large sample, spanning a wide range of masses (logM=[9-12]), is statistically representative of the overall population and thus suitable to probe the evolution in masses, mass-to-light ratios, and metallicities of these galaxies, as well as the fraction of mass ...

Durée: 17:43 mn Date: 04 2010

2 VIIth Marseille International Cosmology Conference : The Gemini view of the redshift desert: nuggets & novelties.
Karl Glazebrook (Swinburne University of Technology)

Abstract:  the latest observations and interpretations of compact red galaxies discovered at 1<2 using Gemini and HST.

OAMP

Durée: 27:08 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Galaxy caracterization
Naveen Reddy (Hubble Fellow, NOAO)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 35:27 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : A major spectrocopic campaign targeting K-band selected galaxies in the UKIDSS Ultra-deep Survey A backward evolution model for infrared surveys: the role of AGN- and Color-L_TIR distributions
Elisabetta Valiante ( UBC - Dpt of Physics and Astr. )

Empirical 'backward' galaxy evolution models for infrared bright galaxies are constrained using multi-band infrared surveys. I developed a new  Monte-Carlo algorithm for this task, implementing luminosity dependent distribution functions for the galaxies' infrared SED and for the AGN  contribution, allowing for evolution of these quantities. A local infrared luminosity function is adopted and evolved using power law  parametrizations for possible luminosity and density evolutions. The adopted SEDs take into account the contributions of both starburst and AGN to  the total infrared luminosity, for the first time in a coherent treatment rather than separate AGN and star-forming populations. The ...

Durée: 16:33 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Probing the Limits of Nuclear Activity in the Redshift Desert
Chris Impey (Steward Observatory, University of Arizona)

The Cosmological Evolution Survey (COSMOS) is centered on the largest contiguous region of the sky ever imaged by HST. It was motivated by the study of galaxy evolution and morphology but the combination of depth, breadth and extensive multiwavelength data makes it the best region in the sky for a comprehensive study of the coevolution of AGN and galaxies. This contribution will concentrate on the properties of ~300 Type 1 AGN selected by X-ray emission, where obscured and rare populations can be recovered using bolometric selection and where the sensitivity reaches black hole masses below 10^8 and accretion rates below 0.01 L_edd through the redshift desert from 1 < z < 3.

Durée: 19:26 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : QSO Built up
Gordon Richards (Drexel University)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 28:32 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Evolution of the color magnitude relation and galaxy properties in clusters and groups at z~1

Simona Mei (Paris Observatory)

We applied detailed observations of the Color-Magnitude Relation (CMR)  with the ACS/HST to study galaxy evolution in eight clusters at z~1 (ACS GTO Intermediate Redshift Cluster survey; Mei et al. 2008). The early-type red sequence is well defined and elliptical and lenticular galaxies lie on similar CMRs. We analyzed CMR parameters - scatter, slope and zero-point - as a function of redshift, galaxy properties and cluster mass. While the bright S0 population consistently shows larger scatter than the ellipticals, the scatter of the latter increases in the peripheral cluster regions. We interpret these results in terms of galaxy age differences. We also analyzed the morphological fractions of red sequence galaxies. We find that, while in ...

Durée: 15:45 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Kiloparsec-Scale Kinematics in High Red shift Star-Forming Galaxies

David R. Law  (UCLA)

I discuss the results of a multi-year Keck/LGSAO survey of the internal kinematics of rapidly star-forming galaxies at redshift z ~ 2 - 3 as traced by nebular line emission on angular scales ~ 0.1''.  At most 5 of the 13 best-detected galaxies have spatially resolved velocity gradients consistent with rotation, while the remaining galaxies have relatively featureless or irregular velocity fields.  All of our galaxies exhibit high local velocity dispersions ~ 60 - 100 km/s, suggesting that even for those galaxies with clear velocity gradients rotation about a preferred kinematic axis may not be the dominant means of physical support.  The dynamical importance of cold gas appears to be the primary factor governing the observed ...

Durée: 6:27 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Suerdense massive galaxies : sizes and evolution since z - 3

Alonso Fernando Buitrago ( Univ. Nottingham)

Understanding the evolutionary pathway of massive galaxies (M ≥ 1011 M⊙)  is one of the greatest challenges of the present day Astronomy. To address this problem our group carried out using the HST NICMOS 3 camera the  GOODS NICMOS Survey which provides us with extremely deep (H  ∼26.8)  imaging of 81 these galaxies at 1.7 < z < 3. Our sample is almost one order  of magnitude larger than previous studies, and is the ﬁrst statistical study  of massive galaxies at these redshifts. The results (split between spheroid  and disk like ob jects according to their S´ersic index) show that these massive galaxies are extraordinarily compact, reaching densities comparable ...

Durée: 16:48 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Size evolution of early-type galaxies

Arjen van der Wel (Max-Planck-Institute for Astronomy, Heidelberg)

Abstract:
Several studies have revealed the presence of high-redshift (z~2) galaxies that are much like present-day early-type galaxies: they are compact, their star-formation rates are low, and they have evolved stellar populations. The main difference between these objects and equally massive local counterparts is that their sizes are 3-5 times smaller. The need to understand how these galaxies evolved between z~2 and the present goes beyond the need to satisfy our curiosity regarding the fate of these intriguing objects: their evolution must be intimately related to galaxy assembly over cosmic time in general. First I will summarize the observational evidence for strong size evolution of early-type ...

Durée: 20:40 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Weak velocity dispersion evolution of spheroid-like massive galaxies since z-2

Nacho Trujillo (IAC)

Abstract: Massive galaxies (M~10^11 Msun) at z>1.5 were structurally very different than their equally massive local counterparts. These galaxies were extremely compact, with effective radii <1.5 kpc and stellar densities as high as those that can be found in present-day globular clusters. In this contribution I will summarize the recent results that our group has found in relation to the evolution of these primordial objects. I will particularly focus on the first determination of the velocity dispersion of such galaxies at z~1.6 based on an averaged spectra with a total integration of 480 hours in the VLT.  By comparing with galaxies of similar stellar mass at lower redshifts, we find evidence for a weak evolution in velocity ...

Durée: 17:55 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Dynamics and Morphologies of z - 2 Star-forming Galaxies
N. M. Förster Schreiber (MPE)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 40:59 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : A major spectrocopic campaign targeting K-band selected galaxies in the UKIDSS Ultra-deep Survey

Henry Pearce ( Institute for Astronomy, University of Edinburgh)
Co-Authors: H. Pearce, R. McLure, M. Cirasuolo, O. Almaini

The UKIDSS Ultra-deep survey (UDS) is currently the deepest, wide-area, near-IR imaging survey in existence. The combination of deep near-IR data with optical imaging from Subaru and deep IRAC+MIPS imaging from Spitzer makes the UDS an ideal laboratory for studying the high-redshift evolution of massive galaxies. At present, the UDS data-set is being greatly enhanced by the addition of a large VIMOS+FORS2 spectroscopic follow-up campaign on the VLT, designed to provide redshifts for >4000 K-band selected galaxies at z>1. Here we present the first results from the on-going FORS2 spectroscopy campaign which has already provided robust ...

Durée: 09:38 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : The Stellar mass assembly type out to z=2 from the S-COSMOS survey

Olivier Ilbert (LAM)

How, when and at which rate, the different galaxy types assemble their stellar populations ? I will characterize the stellar mass assembly by type using the 2-deg2 S-COSMOS survey. Our study is based on 192,000 near-infrared selected galaxies with 1-2% accurate photometric redshifts computed with 30 deep bands. Using very deep SPITZER data, we trace the stellar mass evolution out to z=2. We split the sample in quiescent and star-forming galaxies based on a color-color criteria efficient to separate dusty star-forming and quiescent galaxies. I will show that the evolution of the quiescent and star-forming galaxies is strongly dependent on the considered stellar mass. We obtain that the most massive galaxies are already in place at z=1 while we observe ...

Durée: 15:11 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Probling Stellar Populations and Structural Evolution out to the densest environments at z-1.3: Star formation histories and sizes of massive aerly type galaxies in field, groups and clusters
Alessandro Rettura ( John Hopkins University - ACS Team)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 15:34 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : The strongly-clustered population of red galaxies at z-2

Recent surveys have made it possible to perform very precise measurements of the clustering of a diverse set of nearby galaxies.  Reliable measurements have been made up to z~1, where highly complete spectroscopic samples are available.  The ability to successfully model these observations using simple prescriptions for the expected galaxy clustering in the LCDM framework represents a significant triumph, from an observational as well as a theoretical perspective.  However, as we push the observations to higher redshift, the situation becomes less clear.  It is now becoming possible to measure the clustering of a variety of galaxy types at z~1-3 with good precision.  I will present results for the strongly-clustered massive red ...

Durée: 14:09 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : How do galaxies accrete their mass? Quiescent and star-forming massive galaxies at high redshift
Adriano Fontana (Osservatorio Astronomico di Roma)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 22:01 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : A major spectrocopic campaign targeting K-band selected galaxies in the UKIDSS Ultra-deep SurveyEvolution of the merger rate from spectroscopically confirmed galaxy pairs since z-2
Loic de Ravel (LAM) & the VVDS team

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 14:45 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : The Evolution of the Stellar Mass Function of Galaxies from z=4 and the First Comprehensive Analysis of its Uncertainties: Evidence for Mass-Dependent Evolution
Danilo Marchesini (Yale)

Abstract : I present the evolution of the stellar mass function (SMF) of galaxies from z=4.0 to z=1.3 measured from a sample constructed from the deep NIR MUSYC, the FIRES, and the GOODS-CDFS surveys, all having very high-quality optical to mid-infrared data. I provide, for the first time, a comprehensive analysis of random and systematic uncertainties affecting the derived SMFs. I find that the mass density evolves by a factor of ~17 since z=4.0, and a factor of ~4 from z=1.3. The evolution appears to be mostly driven by a change in the normalization Phi*, but I also find evidence for evolution in the shape of the SMF, with the low-mass end evolving more rapidly than the high-mass end. Taking these results at face value, I find that they are in ...

Durée: 16:35 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : The many Manifestation of Downsizing: Hierarchical Galaxy Formation Models confront Observations
Fabio Fontanot (INAF-OATs)

Several observations suggest that galaxy evolution follows a different trend with respect to the bottom-up assembly of Dark Matter structures. In this talk we discuss several observed trends for which the word downsizing'' (DS) has been used, and in particular the evolution with redshift of stellar mass (i.e. more massive galaxies assemble earlier than low-mass counterparts), of the star formation rate (i.e. the mass of typical star-forming galaxies declines with decreasing redshift) and the archaeological'' DS (i.e. more massive galaxies host the older stellar populations). We compare available data-sets in the redshift range 0 < z < 4, with the predictions of three different semi-analytical models of galaxy formation within the LCDM ...

Durée: 12:32 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : The relative contribution of environment and stellar mass in shaping galaxies
Lidia Tasca & zCosmos Team

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 18:32 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Theoretical view : Formation of massive galaxies
Gabriella De Lucia (INAF - Astronomical Observatory of Trieste)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 31:11 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Galaxy clusters at Z>1
Masayuki Tanaka (ESO)

We discuss properties of galaxies in clusters at z>1 based on three different data sets.

First, we present detailed spectral analyses of galaxies in the large-scale structures around the RDCSJ1252 cluster
at z=1.24.  We spectroscopically confirm prominent structures around such a high redshift clusters for the first time.
We then look into spectral properties of galaxies and find that
(1) there are some dusty star forming galaxies in groups and field, but the cluster hosts no such galaxies and
(2) group galaxies show systematically weaker Hd absorptions compared to field galaxies.
The groups are the environment in which we observe the on-going build-up of the red sequence and we suggest that galaxy-galaxy ...

Durée: 13:15 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Cluster galaxy populations 9 billion years ago
Veronica Strazzullo (NRAO)

Galaxy clusters beyond redshift one give us the chance to study environmental effects early on in cosmic times, allowing us to track galaxy evolution in overdense environments over more than 8 billion years.
I will present results from a study of galaxy populations in the X-ray luminous cluster XMMU J2235-2557 at z~1.4, among the most distant clusters discovered to date, and the most massive known at redshift z>1. An extensive high-quality multiwavelength dataset and a spectroscopic sample of 26 cluster members allow us to study luminosity functions, red sequence, and spectral energy distributions, for a sample of cluster galaxies living in an unusually overdense region in the 5Gyr old Universe.

Durée: 11:59 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : The role of group environment in the morphological transformation of galaxies
Katarina Kovac (ETH Zurich)
Katarina Kovac and the zCOSMOS collaboration

We  study the evolution  of the  morphological properties  of galaxies residing in group environments  using the data from the zCOSMOS-bright survey.  The  fraction of early-type galaxies in  groups selected from the luminosity complete samples is constantly increasing from redshift 1 to the  present, while for the mass complete  samples, this holds up only  for galaxies  of lower  masses (log(Mstellar/Msol)  < 11).  At a given redshift, the  fraction of early type galaxies  in the groups is higher  than in  the field  and the  fraction of  early  type isolated galaxies is ...

Durée: 17:41 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : The VIRMOS-VLT Deep Survey: the large scale structure emerging from the redshift desert
Agnieszka Pollo (Institute for Nuclear Research, Warsaw/Jagiellonian University, Cracow)

The VIRMOS-VLT Deep Survey (VVDS) has been a milestone in our understanding of the state of the large scale structure of the Universe back to z~2. We plan to discuss the evolution of clustering of galaxies seen by the VVDS. We investigate the evolution of the projected two-point correlation function for the global galaxy population and for particular galaxy classes, with different intrinsic luminosities, spectral types, colors and other properties. Particularly interesting is e.g. the difference between the clustering of the brightest galaxies (with L>L*) now and in the past; the shape of their correlation function deviated from the power-law much more strongly at z~1 than it is ...

Durée: 19:48 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Large Scale Structures in the GOODS-SOUTH Field up to z - 2.5
Marco Castellano (INAF - Osservatorio Astronomico di Roma)

We use the deep  multi–wavelength GOODS-MUSIC catalogue, provided with accurate photometric redshifts,  to compute an adaptive estimate of the 3D density field, through a specifically developed algorithm, in the redshift range 0.4<2.5.
We find several high density peaks embedded in larger structures up to z~2.3. We analyse their physical properties (mass profile, M200, \sigma_v, L_X, U − B vs. B diagram), and derive that most of them are groups of galaxies, while two (at z~0.7 and z~1.6) are poor clusters with masses of few times 10^14Msun. These two clusters have an X-ray emission (Chandra 2Ms data), significantly lower than expected from their optical properties, suggesting that the two ...

Durée: 14:24 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Lya forest simul vs observations

Martin Haehnelt (IOA University of Cambridge)

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 36:12 mn Date: 03 2010

2 VIIth Marseille International Cosmology Conference : Evolution of large scale structures and theoretical expectations

Risa Wechsler (SLAC National Accelerator Laboratory)

KIPAC / Stanford University

The conference is devoted to the last results from observational and theoretical programs studying the Universe between redshifts 1 and 3, the so called redshift desert. During this more than 3.5 Gyr long period, the first massive structures condensed, and part of the massive galaxies  formed through merging processes. The QSO Luminosity fonction peaked in intensity, allowing to study in detail the IGM  physics. A new generation of large observational programs proposes as well to investigate the fundamental cosmology in this period. We propose to browse all these subjects, with reviews, invited talks, and shorter contributions.

Durée: 42:34 mn Date: 03 2010