Galaxy evolution is fortunate to be a data-rich research field. But the constant stream of new results can bring with it some difficulties. When data are rare, there is at least time to become familiar with the competing theories before each new result is published. Conversely, when theories are regularly adapted in response to each new set of observations, it can be difficult to extract from literature the physical explanations that have, or have not, been ruled out. With this in mind, we review key issues arising from the latest high-redshift galaxy surveys, but focus on reexamining the observational samples in terms of the simple, physical limits from which our complex galaxy formation models are built:
- Could they even have formed according to standard cosmology, and natural cooling and infall thresholds?
- How would they continue to evolve under certain limiting cases of mass accretion?
- And what fraction of the familiar, low-redshift population might these
first glimpses of the early Universe really represent?

The tight links between supermassive black hole (SMBH) and galaxy spheroid mass observed in the local Universe strongly suggests they have grown concurrently. However, the large-scale mechanisms that drive SMBH and galaxy growth remain poorly understood, especially at high redshifts. While major-mergers between galaxies provide a natural route to intense star-formation and rapid SMBH growth, observations of the high redshift Universe have begun to question the importance of such dramatic events, instead suggesting that most stellar mass was put in place via slower, "secular" processes. In this talk, I will explore SMBH growth in terms of this secular vs. major-merger view of galaxy evolution in an attempt to determine how today's SMBHs acquired their mass.

La vie, est-elle arrivée sur Terre de l’espace ? Notre expérience spatiale représente un test (partial) de cette hypothèse [1]. Dans le cadre du projet EXPOSE de l’ESA nous avons exposé des graines d’Arabidopsis Thaliana (l’Arabette des Dames) et de Nicotiana tabacum (tabac)
à l’extérieure de l’ISS pendant 18 mois. Nous avons mesuré la capacité de ces graines de germer au retour sur Terre, graines ayant subis pendant 18 mois les effets du rayonnement solaire, rayons cosmiques, variations de température et vide spatial existant à 440 km d’altitude. Les effets de ces divers paramètres ont été évalués. Les résultats ont montré qu’une graine de plante, ou une entité biologique similaire, pourrait survivre un transfert directe de Mars à la Terre ayant lieu en une année, durée courte, mais statistiquement possible.

Ce travail, qui comporte également des expériences de simulation au laboratoire, a été effectué, en collaboration intense, par David Tepfer (D.R. INRA) et Andreja Zalar (Docteur de l’ Univ.Versailles), biologistes des plantes à l’INRA de Versailles, et avec l’aide de Norbert Champion (LERMA, Obs.Meudon) et Soeren Hoffmann (ASTRID Synchrotron, Aarhus, Danemark).

[1] D.Tepfer, S.Leach, « Plant Seeds as Model Vectors for the Transfer of Life Through Space », Astrophys.Space Sci. 306 (2006) 69.

In most domains of astrophysics, knowledge of the distances to the objects
being studied is crucial. This is the case for stars in our Galaxy, which
will be spectacularly addressed by the upcoming Gaia mission. Currently,
two satellites are observing the Milky Way's interstellar medium (ISM) :
Herschel and Planck. The views that we are getting of the dust and gas are
at higher resolution and sensitivity to anything previously available.
However, in the plane of our Galaxy, the emission comes from a large range
of distances and environments and is concentrated in a relatively thin strip.
Not only do we need distances to infer physical sizes, masses and other
parameters of sources being studied, but we need to separate the different
contributions to the observed signal if we hope to perform a robust analysis.
I will present work that I have undertaken to explore the third dimension in
Galaxy, using stellar observations as well as thermal dust emission and radio
emission from the ISM. I will also discuss the long awaited ESA mission Gaia,
and its implications for the study of the ISM.

Les grands relevés spectro-photométriques comme le VVDS permettent
de déterminer la distance de milliers de galaxies et d'apporter des
contraintes sur les modèles cosmologiques et l'évolution des propriétés
globales des galaxies (luminosité, masse, environnement, ...).
Mais les observations et notamment les spectres de ces galaxies
contiennent beaucoup plus d'informations permettant d'affiner plus
précisément les modèles d'évolution physique et chimique.
Je ferai le point sur quelques résultats récents et sur les perspectives
attendues avec les nouveaux instruments (MUSE, EMIR, Euclid, ...).

Within the hierarchical framework for galaxy formation, minor merging
and tidal interactions are expected to shape large galaxies to this
day. As part of a pilot survey, we have carried out ultra-deep,
wide-field imaging of some isolated spiral galaxies in the local
universe with data taken at small (0.1 to 0.5-meter diameter),
robotic telescopes that provide exquisite surface brightness
sensitivity. Our observational effort has led to the discovery of
previously undetected giant stellar structures in the halos of
these spiral galaxies, likely associated with debris from tidally
disrupted satellites. Our collection of galaxies presents an
assortment of tidal phenomena exhibiting strikingly diverse
morphological characteristics. Our preliminary comparison with
available stellar halo simulations set in a Lambda-Cold Dark Matter
cosmology suggests that this extraordinary variety of morphological
specimens detected in our survey could represent one of the first
comprehensive pieces of evidence to support that the hierarchical
formation scenarios predicted by these theoretical models apply
generally to galaxies similar to the Milky Way in the Local Volume.
Finally, I will also present the discovery of a tidal stream around
a nearby dwarf irregular galaxy with our small telescopes. Followup
observations with Subaru telescope show this stream completely
resolved into stars, providing observational evidence of a minuscule
merger in a LMC-type system in the local universe. This result
suggests that dwarf accretion could play an important role in the
star formation history and evolution of nearby dwarf galaxies.

The dark matter particle has not (yet?) been detected, and
its nature is still unknown. Lambda Cold Dark Matter (LambdaCDM) is
the currently favoured paradigm for structure formation in the
Universe: it is very successful in explaining the observations of
large scale structures in the Universe, but on galaxy scales there is
a discrepancy between observations and (dark matter only) LambdaCDM
predictions. I will introduce the dark matter problem in galaxies, I
will talk about advances that have been made in deriving the
distribution of dark matter in galaxies, and I will discuss future
projects that will enable us to shed more light on dark matter,
including the HALOGAS (Westerbork Hydrogen Accretion in LOcal
GAlaxieS) survey, the deepest HI survey of a sizeable sample of spiral
galaxies.

We discuss the effects of supermassive black hole (SMBH) outbursts on
the hot atmospheres of early type galaxies, galaxy groups, and galaxy
clusters whose atmospheres are only seen through X-ray
observations. The discussion is motivated by the need to understand
the separation of galaxies into their two fundamental classes - the red
and "dead" early type galaxies with little star formation and the
blue clound (spiral, actively star forming galaxies). We show the
detailed effects of the outbursts from the supermassive black hole in
M87 at the center of the Virgo cluster using Chandra and XMM-Newton
observations including buoyant bubbles of relativistic plasma produced
by the central SMBH, uplifted filaments of X-ray emitting gas, and the
Mach 1.2 shock. We present the results from a large survey of more
than 100 early type galaxies observed with Chandra. From the X-ray
images, we identify the sample of hot coronae that show gas cavities,
estimate cavity ages, and compute the mechanical power needed to
inflate the cavities. From the X-ray luminosities, we derive
Eddington ratios and briefly discuss the accretion mode for these
low-luminosity actice galactic nuclei. We compare the early-type
galaxy AGN to their more powerful counterparts in rich clusters.
Finally, we show the dramatic effects that SMBH outbursts can have on
galaxy-scale hot coronae.

The Plateau de Bure Arcsec Whirlpool Survey (PAWS, PI: E. Schinnerer) has imaged
the CO(1-0) emission in the central 8 kpc of the nearby spiral galaxy M51.
Our final data is a combination of the IRAM 30m single-dish and Plateau de Bure
interferometer observations, reaching a linear resolution about 45pc and with
sensitivity to giant molecular clouds (GMCs) above 10^5 Msun. Thanks to such
high quality data, we are able to study the structure of the molecular gas from
galactic scales (e.g. spiral arms) down to a single GMC. In particular we study
the correlations between the CO(1-0), IR and Radio Continuum emissions on
different spatial scales and investigate the physical processes behind these
observed correlations. In this talk, I will present the first results of such
an analysis and their consequences on star formation estimation within
the galactic disk. I will then review the other prospects of this ambitious
project, discussing in particular how high resolution mm observations (e.g.
with ALMA) will further the study of the interstellar medium
in nearby galaxies and its role in star formation.

We have performed axisymmetric hydrodynamic simulations black hole
fueling and feedback in a massive galaxy. The effects of the central
black hole on the temperature and momentum of galactic gas resulting
from both radiative and mechanical feedback (in the form of a
broad-line wind) are treated carefully using a detailed and physically
well-motivated prescription. The simulations cover a range of length
scales from ~1 pc to ~100 kpc. We carefully treat the forces on the
gas due to dust opacity in the UV, optical, and IR bands from photons
generated by both stars and the central AGN. We include a
prescription for angular momentum transport, allowing us to consider
galaxies with large specific angular momenta (disk galaxies) in the
axisymmetric code. We consider the case of including steady
cosmological infall of cold gas, as well as the case of the rapid
removal of the angular momentum of a cold gas disk to mimic the effect
of a galaxy merger. We find that the black hole accretion rate
depends strongly on the inner radius of the simulation, implying that
physical processes that operate on infalling gas between 1 and 100 pc
have an important effect on the true black hole accretion rate and the
resulting feedback processes.

Nearly 700 extrasolar planets have been detected so far and an intense
characterisation effort has been undertaken to unveil the atmospheric
properties of some of these distant worlds seen in transit accross
their stars. A large number of transiting exoplanets are found in extreme irradiation environments, very close to their stars, and the question arise
of whether the atmospheres of these planets remain stable or get blown away.
In particular, it is surmised that the recently detected rocky super-earths
(1-10 Earth masses) can be evaporation remnants of once more massive planets
completely eroded by the extreme stellar irradiation. Detecting the extended
atmospheres of exoplanets in different mass regimes and measuring their
mass loss rates and efficiencies are key steps towards the understanding of
the atmospheric dynamics and properties of low-mass exoplanets. I will review
the results we have obtained with HST on the atmospheric evaporation of
transiting exoplanets, on both observational and theoretical sides. Steping
back into the habitable zones, I will finally discuss the prospects about
atmospheric characterisation for Earth-size planets (such as Kepler-22b) and
how the upcoming transit of Venus in June 2012 could be a Rosetta stone to
interpret the future transmission spectra of Earth-like exoplanets that could
be obtained in the next decade."

It is established that stars form within molecular clouds via
gravitational collapse. I will present radiation-magneto-hydrodynamics
calculations of low-mass and massive dense core collapse, focusing on
the first collapse and the first hydrostatic core (first Larson core)
formation. The influence of magnetic field and initial mass on the
fragmentation properties will be investigated. In the first part,
I will briefly present the numerical method I use. In the second part
reporting low-mass dense core collapse calculations results,
synthetic observations of spectral energy distributions will be
derived, as well as classical observational quantities such as the
bolometric temperature and luminosity. I will show how the dust
continuum can help to target first hydrostatic cores and to state
about the nature of VeLLOs. Last, I will present synthetic
ALMA observation predictions of first hydrostatic cores which may
give an answer, if not definitive, to the fragmentation issue at
the early Class 0 stage.

In the third part, I will report the recent results of
radiation-magneto-hydrodynamics calculations in the context of
high mass star formation, using for the first time a self-consistent
model for photon emission (i.e. via thermal emission and in
radiative shocks) and with the high resolution necessary to resolve
properly magnetic braking effects and radiative shocks on scales
<100 AU (Commercon, Hennebelle & Henning ApJL 2011). In this study,
we investigate the combined effects of magnetic field, turbulence,
and radiative transfer on the early phases of the collapse and the
fragmentation of massive dense cores (M=100 Msun). We identify
a new mechanism that inhibits initial fragmentation of massive
dense cores, where magnetic field and radiative transfer interplay.
We show that this interplay becomes stronger as the magnetic field
strength increases. We speculate that highly magnetized massive
dense cores are good candidates for isolated massive star formation,
while moderately magnetized massive dense cores are more
appropriate to form OB associations or small star clusters.

I will present recent observational results obtained on the physics of
distant galaxies (~ 1<z<6) taking benefit of massive clusters used as
natural instruments. Gravitational magnification enables us to resolve
even the most distant objects, and to probe intrinsically fainter
sources at high redshift. This allows us to do the kind of research
that will only be achievable with the ELTs, but using
ground-based 8-10 m class telescopes and their current or
soon-forthcoming instruments. More precisely, after introducing
the topic and the use of massive clusters for their strong lensing
effect, I will present our ongoing work on strongly lensed LBGs in
the optical and near-infrared. In a second part, I will focus
on recent results obtained with Herschel, PdBI and SMA at
far-infrared / sub-mm and millimeter wavelengths, which enlarge
our panorama of the distant galaxy population.

After a spectacular birth, with the glow of the Big Bang fading away and the first atoms of hydrogen being formed, our Universe quickly became a dull place, with the first stars and galaxies yet to appear. How long these cosmic dark ages lasted and how they came to an end are questions of outmost importance in cosmology.
Based on recent theoretical and observational results, I will show that besides the ultraviolet radiation from primordial massive stars, X-rays and relativistic jets from their black hole fossils, must have played an important role at the dawn of the Universe. In this context, contrary to the prevailing view that the early Universe had a "Swiss-cheese"-like appearance that lasted several hundred million years, the dark ages may have had a smooth and fast end. These could be good news for the future probes of the dark ages by means of the redshifted 21 cm line of atomic hydrogen.

We currently have only a restricted picture of the star formation activity in
galaxies, partly because we don't have sufficient resolution to locate
properly sites of star formation beyond the Local Group. Interferometers such
as IRAM-PdBI, CARMA, SMA, and especillay ALMA now, are changing this picture.

In complement, I will show that we can actually improve our understanding of
the processes of star-formation in galaxies with single-dish telescopes, using
strategically key chemical tracers. More precisely, I will present work on the
determination of the ISM properties in local starburst, spirals, AGN-dominated
galaxies and early-type galaxies. Then, I will present some ISM properties in
'exotic' or more disturbed places such as in cosmic-ray dominated galaxies
and in cooling flows seen in the Perseus cluster.

I will also show some recent results acquired using interferometers enhancing
our knowledge to the finest scale possible today.

Using hydro-cosmological simulations and analytic modeling, we attempt solid
predictions for the formation of massive galaxies at high redshift within the
LCDM cosmology. The emerging picture highlights the formation of galaxies
at the nodes of the cosmic web. These galaxies are steadily fed by cold
streams along dark-matter filaments, which are observable in Lyman-alpha.
The streams, including a smooth component and merging galaxies, penetrate
through hot gas in dark-matter halos to form extended, turbulent, rotating
disks and bulges with central black holes. The streams transport angular
momentum from large distances into the disk that grows inside out, but a significant exchange of angular momentum occurs in the greater disk vicinity.
The intense gas input drives a self-regulated, violent gravitational disk
instability with transient features and giant clumps, where stars form rapidly.
The violent instability induces quick migration to the center, complementing
mergers as a mechanism for spheroid formation and for feeding AGN. We address
the implications of this developing picture on different aspects of galaxy
formation theory and its observable features.

La variété de galaxies dans le Groupe Local rend possible l'étude du milieu interstellaire et de la formation d'étoiles dans des conditions différentes de celles trouvées dans la Voie Lactée, tout en conservant une grande résolution spatiale grâce à leur proximité. Nous avons étudié le milieu interstellaire d galaxies du Groupe Local, M33 et NGC6822, dont les métallicités sont inférieur d'un facteur 2 à 3 à celle du soleil et qui sont respectivement dix fois et ce fois moins lumineuses que la Voie Lactée. Nos observations de la transition J=2- monoxyde de carbone, avec une résolution suffisante pour résoudre les nuages moléculaires géants, fournissent la première carte du milieu moléculaire de NG et la cartographie de M33 avec la meilleure combinaison de résolution et de sensibilité. Nous présentons également une cartographie haute résolution du mi atomique de M33 à partir d'une mosaïque intérférométrique dans la raie à 21cm l'ensemble du disque de la galaxie. Combinées avec des données allant de l'ultraviolet à l'infrarouge lointain, ces observations permettent l'étude du interstellaire et de la formation d'étoiles à des échelles allant du nuage individuel à la galaxie dans son ensemble. Ces deux objets, chimiquement jeun semblent convertir l'hydrogène moléculaire en étoiles plus rapidement que les grandes galaxies spirales comme la Voie Lactée. Est-ce à rapprocher du taux é de formation d'étoiles dans les galaxies de l'univers plus jeune (z~0.5-1), également riches en gaz et bleues comme M33 et NGC6822 ? Un soin particulier apporté pour tenter de mesurer la masse de dihydrogène, difficile dans ce type d'objet, à l'échelle de la galaxie ainsi qu'à l'échelle du nuage. Une méthode d'identification automatique et de mesure des propriétés physiques des nuages moléculaires géants a permis d'obtenir, dans le cas de M33, le plus grand cata de nuage moléculaires dans une galaxie extérieure. Il en résulte que les nuage M33 et de NGC 6822 ont, en moyenne, une largeur de raie plus faible, pour une donnée, que les nuages de la Voie Lactée. Dans M33, la fraction de petits nua augmente significativement avec le rayon galactocentrique. Au moins un sixièm nuages moléculaires géants ne sont pas associés à de la formation stellaire (détectée) mais nous n'avons pas identifié de caractéristiques physiques particulières pour ces nuages.

High spectral resolution allows us to discern the number of clouds along the line of
sight, their kinematics, the relative importance of turbulent motions, and chemical
signatures, including isotope ratios. Three recently completed projects will be
described. Absorption from atomic and molecular gas toward stars in the Pleiades
provided details of the interaction between the cluster and interstellar material.
It appears that the UV radiation from the stars has heated the gas sufficiently that
CH+ was formed in observable quantitites. In another study based on UV measuerments
with HST on CO and with FUSE on H2, the trends between CO abundance and H2 were
examined, as was the fractionation between 12C16O and 13C16O. The third study
involved 12 and 13 isotopoloques of CH+ and CN and the rotational temperatures of
12C14N and 13C14N. Here, we found that the 12CH+/13CH+ ratio appears to be
essentially constant within about a kpc of the Sun and that CN excitation
predomiantly arises from the Cosmic Background.

I will briefly describe the goals and strategy of the Atlas3D project
which targeted a complete volume-limited sample of 260 nearby early-type
galaxies. I will summarise the main (mostly published) results, and then
update the audience with the most recent advances obtained within the
context of that project: this leads us to a significantly revised view
of the nearby population of galaxies.

Since the appearance of General Relativity, its intrinsic general covariance has been very often misinterpreted as implying that physically meaningful quantities (and conclusions extracted from the theory) have to be absolutely independent on observers. This incorrect point of view is sometimes expressed by discarding the very concept of observer in the structure and applications of the theory. As we shall stress in this seminar, through some examples, the concept of observer is as essential to General Relativity as it is to any physical theory.

We studied the formation of water on dust grain analogs using isotopically labeled atomic hydrogen and oxygen beams. We detect the formation of water and intermediate products. As dust analogs, we used amorphous silicate films; for comparison, experiments done on a single crystal silicate were also carried out. The samples were characterized by in-situ infrared spectroscopy and ex-site atom force microscopy. Implications of these results on the formation of water in ISM environments will be discussed.

The Interstellar Medium is both the medium between the stars and the place of birth of the stars. At the Galactic scale, the ISM is best understood as a turbulent place. On smaller scales, the cold ISM, where stars form, is likely also turbulent. Words of caution arise from the lack of a definitive proof for the turbulent nature of the ISM which itself amounts to the lack of a complete theory of turbulence. Not only is the ISM turbulent: magnetic fields are now estimated strong enough to imprint their configuration on the cold matter distribution. If a theory of turbulence is still lacking, a theory of compressible, magnetized turbulence may seem unachievable. Even though, understanding turbulence in the cold ISM is required for a proper understanding of the cycle of matter in the ISM. The last decade has fostered direct numerical simulations of the physics of the ISM. Comparisons between theoretical predictions, numerical results, and observational constraints is becoming a tool to study the complex interplay of physics and chemistry in the ISM. I will review the general arguments that support a turbulent view of the ISM, with special emphasis towards the cold molecular ISM. Some consequences of turbulence in the ISM will be presented in the view of recent Herschel satellite results, whereas the Planck mission will provide constraints to the interplay between turbulence and magnetic fields. The soon-opening (extremely) high angular resolution era will certainly bring new constraints on fundamental questions regarding the nature of the interstellar turbulence and the structure of the ISM.

The last years impressively showed that to understand the assembly and formation of massive galaxies, it is critical to study Submillimeter Galaxies (SMGs). Since their first detection more than ten years ago, several hundred dust-enshrouded high-z sources have been selected through ground-based submm/mm imaging with bolometer cameras like SCUBA, LABOCA, AzTEC or MAMBO, opening a new exciting era in observational cosmology and giving an important route to investigate star formation and the formation of spheroids in the distant universe. One of the current key topics in galaxy formation and assembly is to obtain an accurate estimate of the number of SMGs at z>4, thus to get a complet census of the star-formation at the most distant redshifts and add missing bits on the obscured universe at extreme redshifts to the Lilly-Madau Plot. I will discuss different approaches to find dusty starbursts at redshifts beyond z=4 and present our on-going Herschel and IRAM efforts on this research topic. Finally, I will discuss the prospects of ALMA studies on dusty starbursts in the very high-z universe.

The Cornell University Laboratory of Plasma Studies makes use of 1 trillion watt, 1 million ampere pulsed power generators for fundamental studies and applications of high energy density plasmas in several configurations. Some are as high density and temperature as $10^{22}/cm^3$ and 1.5 keV, respectively, with very short life, $<<$ 1 ns. Others last as long as a few hundred nanoseconds at somewhat lower density and temperature and take the form of plasma jets that can interact with other plasmas. These have been used for studies of the interaction of plasma jets with a cross wind in a configuration with dimensionless parameters that are of interest to the astrophysics community. The very short-lived, hot plasma is an extremely bright x-ray source that has been used for x-ray absorption spectroscopy in high energy density plasmas and could be used to determine the radiation transfer properties of materials that make up such astrophysical objects as supernova remnants.

I will review the recent work conducted in the last year regarding the detection and study of the distant high-redshift (z>6) galaxies. Of particular importance is the recent installation of the WFC3 camera onboard of Hubble which InfraRed imaging channel is delivering the deepest images ever obtained in the 1-1.6 micron window. The new HST images are allowing to identify a large number of high redshift galaxy candidates that can then be follow-up in spectroscopy with 8-10m telescopes. I will discuss whether these findings can account from the reionization of the Universe, and what are the current observational limitations that can be improved with current and future facilities.
Please see http://www.spacetelescope.org/news/heic1106/