Detection and characterisation of dark-matter halos by gravitational shear and flexion; constraints on the non-linear structure growth
M. Bartelmann (ITA Heidelberg)
Gravitational lensing is among the most powerful tools to study dark structures in the Universe and their growth over cosmological epochs. Over the last six years, the precise measurement of cosmic shear has advanced impressively quickly from a curiosity to one of the pillars supporting the cosmological standard model. The shear traces the gravitational tidal field, i.e. second derivatives of the gravitational potential. It has been argued in the recent past that important information is also contained in its third derivatives, which can conveniently be combined to form the two-component flexion. Despite its higher order, flexion has superior signal-to-noise properties compared to the shear. Its sensitivity to smaller scales in the matter distribution makes it a highly interesting and welcome tool to detect dark-matter halos and to study their internal composition, and thus to test generic
predictions of the CDM cosmogony which are still controversial. We have recently studied the shapelet technique for measuring flexion and demonstrated that proposed and existing implementations are partially flawed and can be substantially improved and accelerated. We here propose a programme to systematically calibrate shapelet measurements of the flexion and then to develop their application to substructure detection, halo filtering, and the study of nonlinear cosmic structure growth.
Dynamics of dense stellar systems around massive black holes
H. Baumgardt (AIFA Uni Bonn), P. Kroupa (AIFA Uni Bonn)
Supermassive black holes (SMBHs) are thought to exist in the centres of nearly all major galaxies and it is widely accepted that they are the power sources for the AGN activity. Despite significant observational and theoretical progress, the formation of SMBHs and the interplay with their host galaxies are still poorly understood. In the project outlined here, we suggest to do large-scale N-body simulations of the dynamics of galactic nuclei surrounding dormant SMBHs. All simulations will be carried out using our newly developed N-body code for galactic centre dynamics and the GRAPE6 computers of Bonn University, giving greatly improved accuracy and particle numbers far larger than what was possible hitherto. In our runs we will study the amount of mass segregation close to a SMBH and determine the initial stellar mass function in galactic nuclei. Of special interest will be the question whether mass segregation in stellar discs of young stars is established quickly enough to explain the presence of the S-stars close to SgrA∗ . We will also determine the tidal disruption rate of stars and the contribution which tidal disruptions and mergers give to the growth of central SMBHs. Finally, we will determine the amount of gravitational waves emitted during mergers of neutron stars or
stellar-mass black holes with SMBHs, since such events will be important sources for up-coming gravitational-wave instruments.
Black holes in low-mass bulges and bulge-less galaxies
R. Bender (USM Muenchen), R. Saglia (MPE Garching)
This is the continuation of a project started in May 2005 to detect super massive black holes (SMBH) and measure their masses at the centers of galaxies with pseudo-bulges, very lowmass bulges or bulge-less galaxies using the NIR spectrograph SINFONI at the ESO VLT with Adaptive Optics. Over the past decade we have learned that probably all ellipticals and bulges contain central SMBH. SMBH masses correlate well with the (luminosities, and therefore stellar) masses of the bulges harboring them, with about 0.15% of the bulge mass being found in the SMBH. In addition, there exists a very strong correlation of SMBH mass with the velocity dispersion of the bulge. With the present project we want to investigate whether these relations remain valid or how they change when galaxies with pseudo-bulges, very low-mass bulges or
bulge-less galaxies are considered. These object classes are of particular importance if we want to understand (a) how secular evolution and merging in
uence the growth of black holes, (b) whether bulge-less galaxies really do not harbor any black holes at all (or just lower mass black holes), and (c) whether seed black holes may exist. Many of the interesting low-mass bulges and bulge-less galaxies are dusty at their centers and could not be investigated with HST so far. SINFONI allows to focus on these crucial objects now, because it is working at near IR wavelengths and has high spatial and spectral resolving power. Our rst observations have demonstrated that the instrument delivers the required data quality and we report on our first SMBH measurement. Having achieved the pioneering goals of our first application, we seek now support to enter the production" phase of the project, where we will build and investigate a statistically signi cant sample of galaxies.
The connection between Quasars and Starbursts
F. Bertoldi (AIFA Uni Bonn) F. Walter (MPIA Heidelberg)
Understanding the relationship between star formation and AGN activity is one of the fundamental
topics of modern astrophysics, and one of the key aims of the DFG-Schwerpunkt
(SPP). Recent observations have suggested a coeval evolution of the central supermassive black
holes and the stellar bulges in QSO host galaxies, consistent with the strong correlation of
both components in local spheroids. (Sub)millimeter and radio observations provide powerful
means to investigate the star forming properties of galaxies at times when the stellar bulges
and supermassive black holes were formed. Submillimeter to radio observations of QSOs can
now even probe the properties of galaxies during the Epoch of Reionization (z>6).
We propose to continue our successful, collaborative SPP project (thus far four refereed
first-author publications by authors directly funded through the SPP). After our work on the
urgent issues proposed for the first funding period (constraining QSO SEDs of high-z QSOs,
detection of new molecular gas tracers at high z and constraining total molecular gas masses),
we now propose to move on to spatially resolved observations of the molecular gas and dust
emission in high-z (2<z < 6), and for comparison, local systems. Our program for the next 2
years aims at providing crucial insights on the relation between the central AGN/QSO activity
and star formation in the host galaxies. Our team has demonstrated expertise and leadership
in this field of research. In light of ALMA we aim to expand our very successful training of
young researchers in a field with great future opportunities, and therefore request funding for
one PhD student each at Bonn and Heidelberg, and for one experienced postdoc to lead the
technically challenging high-resolution interferometric observations.
The APEX Sunyaev-Zeldovich Galaxy Cluster Survey
F. Bertoldi (AIFA Uni Bonn), R. Kneissl (MPIfR Bonn), H. Boehringer (MPE Garching)
Galaxy clusters are ideal witnesses of the cosmic large-scale evolution, and good laboratories to trace the evolution of baryons. In the past, they were mostly studied in the optical, and more recently by X-ray observations. Today, the instrumentation to identify clusters as shadows in the cosmic microwave background (the so called Sunyaev-Zel'dovich [SZ] effect) has matured to offer a most powerful tool for comprehensive surveys for galaxy clusters. Since at z > 0.5 the detection efficiency of SZ shadows is nearly distance-independent, imaging the CMB in search for SZ shadows can be a superior approach to find the most distant galaxy clusters, thereby reaching an epoch where the formation of large scale structure commenced, and where our understanding of the evolution of galaxies and the intergalactic baryons is poor. From December 2006 on the new APEX Telescope will be equipped with a 320-element bolometer array to conduct a first large-area SZ cluster survey, expected to discover of order 1000 galaxy clusters within the following 2 years. We here request funding for two postdocs and two PhD students to work on the survey observations, the identification of galaxy clusters, the follow-up radio, optical, infrared and X-ray observations, and the development of novel methods to study the properties and evolution of galaxy clusters, their diffuse gas, and the embedded galaxy populations.
COSMOS: A Radio and (Sub)mm Study of Starbursts and AGN throughout Cosmic History
F. Bertoldi (AIFA Uni Bonn), E. Schinnerer (MPIA Heidelberg)
Studying the evolution of cosmic structure with distant X-ray selected clusters of galaxies
H. Boehringer (MPE Garching), A. Schwope (AIP Potsdam)
Galaxy clusters are ideal tracers of the cosmic large-scale structure
and its evolution, forming important laboratories to follow the
evolution of galaxies and the baryonic intergalactic medium as a function of environmental conditions. Therefore observations of the galaxy cluster population at various epochs allow us to test cosmological models.
They also give us the opportunity to study the galaxy and star formation history and their
effects on the intergalactic medium through heavy element pollution and entropy production.
Whereas a good understanding of the present day cluster population is emerging, our
knowledge of distant clusters and the cosmological implications of their properties
is still sparse. X-ray observations are currently the best means to find
massive distant galaxy clusters. The growing archive of X-ray observations
with XMM-Newton provides the best available resource to conduct a survey for
distant clusters, vastly superseding all similar efforts to date. To exploit this
unique chance we are conducting a comprehensive survey of the best archived XMM-Newton
data with sufficiently deep exposures. With a first pilot study have already discovered record-breaking
high-redshift clusters and have extended the horizon for X-ray
luminous galaxy clusters to redshifts of 1.45. We have also shown on
the basis of the larger photometric sample, that we well meet the
rough theoretical expectations to find enough distant cluster
candidates to secure about 1 z < 1 cluster per square degree of XMM
survey data. The photometric survey will soon cover more than 30
square degrees, while the corresponding spectroscopic survey is
expected to cover the time span addressed by this proposal.
The scientific goals of the project are to characterize the large-scale structure
evolution, to constrain cosmological model parameters, to obtain a statistical
description of the evolution of the internal and structural properties of clusters,
in particular information on the evolution of the observable-cluster mass relation,
and to provide the basis for the evolutionary characterization of the cluster
galaxy population and the intracluster plasma. With the first detections we have already
confirmed that a pronounced sequence of old red galaxies still exists at
redshifts around 1.4. With the scheduled and proposed X-ray observations
we will have first data points on the metallicity and scaling relations of
some clusters. With the completion of the survey in progress covering about
30 square degrees we will have a meaningful sample size
to get useful statistics on the scaling relations and on cosmological
model tests. This project will act as a very important pathfinder for the
upcoming large surveys of distant clusters using the Sunyaev-Zeldovich effect
and later with eROSITA.
Interactions between Active Galactic Nuclei and the intracluster medium
H. Boehringer (MPE Garching), M. Brueggen (IU Bremen), E. Churazov (MPA Garching)
Recent observations show a multitude of physical effects that occur when active galactic nuclei
(AGN) interact with the ambient intracluster medium (ICM). The interaction between AGN
and the ICM is essential for understanding feedback, which is believed to be the crucial ingredient
for the baryonic part of galaxy formation.
In the first stage of this project, we have made valuable contributions to the physics and
the phenomenology of the AGN-ICM interaction. We found new features in M87, pioneered
computer simulations of AGN in cluster with unprecedented realism, found that AGN can cause
the broad metal peaks and discovered correlations between cool cores and cluster properties.
Our results have raised new questions that have shaped this proposal. Many features that we
found in M87 are not understood and require a new level of modelling. Continuing our concerted
approach of observations and theory, we wish to address the following questions in this proposal:
What determines the variability of the AGN? How does feedback operate? How are the different
phases of the feedback duty cycle related to the observed cluster core X-ray morphologies? How
do observational features in several wavelength-regimes interrelate? How do similar physical
phenomena such as shocks and bubbles affect the ICM over a range of different energies and
mass deposition rates? How does the frequency of cooling cores evolve with redshift? What is
the effect of ICM motions on the thermal state of the gas and metal abundances?
The origin of galactic disks.
A. Burkert (USM Muenchen), T. Naab (USM Muenchen)
The subject of this proposal focuses on the so called cosmological angular momentum problem.
In numerical simulations of the formation of disk galaxies gas infalling into dark matter
halos loses its angular momentum which results in disks with scale-lengths that are too small
if compared to observations. We want to study if this problem arises from numerical problems
connected with smooth particle hydrodynamics (SPH). In previous studies it was pointed out
that in media with density contrasts the Kelvin Helmholtz instability (KHI) is completely suppressed
due to an incorrect smoothing procedure. The key goal of this project is therefore to
improve the SPH formalism in order to perform realistic cosmological simulations on the evolution
of galaxies. The influence of the KHI will be specified in more detail based on the example
of infalling cold gas clouds into large dark matter halos, that contain a hot gaseous corona.
By applying cosmological simulations the question will be investigated whether an artificial
suppression of the KHI causes the angular momentum problem and whether this problem can
be prevented using an improved SPH algorithm.
The structure and formation of elliptical galaxies
A. Burkert (USM Muenchen), T. Naab (USM Muenchen)
This project proposes a detailed investigation of the origin of elliptical galaxies and their internal
structure. The major merger hypothesis successfully explains many observational features
of early-type galaxies. However, it is now well established that dissipation must have been
important in the formation of fast rotating ellipticals, while slow rotating, very massive ellipticals
had more complex merging histories, including so called 'dry' merging. We are now
able to conduct more realistic galaxy merging experiments, including star formation, feedback
from supernovae and AGNs, which potentially have a dramatic impact on the structure of the
merger remnants. We will combine sophisticated gas physics with cosmologically motivated
merging geometries and a variety of merging histories, i.e. dry, wet and mixed merging and
fully self consistent cosmological simulations. With our expertise in analyzing complex particle
systems, we can compare both, the projected as well as the internal properties of our model
galaxies with observations from integral eld spectrogaphs like SAURON and Schwarzschild
models of galaxies from the Coma cluster, respectively. This should enable us to narrow down
on the dominant physical processes which shape the remnants during the merging and whether
observations are compatible with the hierarchical galaxy formation paradigm.
The physics of the intergalactic medium in relation to high redshift galaxies and quasars
B. Ciardi (MPA Garching)
The Intergalactic medium (IGM) is an extraordinary repository of information about cosmic
evolution and, more in particular, about the interplay between IGM and galaxies or quasars.
In fact, the IGM keeps the imprints of large scale structure evolution, reionization, thermal and
metallicity history as well as of all those feedback e ects that shape the formation and evolution
of structures. For this reason, the study of the properties of quasars' and galaxies' environment
can provide a wealth of information on e.g. their emitting spectra, intrinsic luminosities, lifetimes
and star formation activity.
Thus, the study of the IGM is fundamental for a better understanding of the galaxy/quasar
formation and evolution process as a whole.
The main aim of the project presented in this proposal is to improve our current knowledge
of the IGM physical state at di erent epochs, both during and after the reionization process.
Multi-wavelength studies of the luminous and dark mass profiles of galaxy-clusters in Wide-Field-Imaging surveys
T. Erben (AIFA Uni Bonn)
After the recent determination of the fundamental cosmological constants, a profound understanding of the dark and luminous matter distribution in the Universe is one of the key
problems in modern cosmology. Hereby, clusters of galaxies provide well-defined laboratory
environments to study the mass distribution and galaxy evolution over wide ranges of matter
and galaxy densities. Today’s wide-field imaging cameras offer a unique opportunity to obtain
large and statistically very well understood samples of clusters, with a selection based solely
on their mass properties, using their weak gravitational lensing imprint on the shape of faint
(background) galaxies. With the current proposal we ask for an extension of funding for a
project aiming at exploiting these unique future data sets. Galaxy clusters will be selected on
already available multi-colour data sets, a joint shear- and X-ray selection will be performed
on deep multi-colour images pointing towards long XMM exposures, and a comparison of the
efficiency of various cluster selection techniques will be performed. The galaxy population in
the differently selected clusters will be compared; in particular, we will investigate whether
shear-selected clusters have a particularly high mass-to-light ratio which would reveal a bias
in ‘classical’ cluster selection methods. In addition, we will work on several technical aspects
related to the data reduction and analysis of WFI data, in particular new methods for the
inhomogeneous illumination and PSF corrections; these technical issues are an essential step
for the full exploitation of future survey data, well beyond weak lensing applications.
Dark and luminous matter in the outer halos of elliptical galaxies
O. Gerhard (MPE Garching), R. Bender (USM Muenchen)
In the concordance cosmological model, substantial dark matter halos are predicted around
objects at all mass scales from galaxies to clusters. Yet there appear to exist some intermediate
luminosity elliptical galaxies with unexpectedly di use dark halos, possibly due to baryonic
processes in the formation of these systems. The goal of this project is to understand how
the dark matter content of elliptical galaxies depends on luminosity and environment, whether
indeed there exist ellipticals with di use DM halos as compared to theoretical predictions, and
what we can learn from the angular momentum content and orbital structure in the outer
halos of ellipticals about the formation mechanisms of these objects. To achieve these goals, we
propose to model a sample of both X-ray bright and X-ray faint ellipticals, acquiring long-slit
spectroscopic data and making use of velocities of planetary nebulae in the outer halos of these
galaxies measured with the Planetary Nebula Spectrograph.
An investigation of the structural properties of active and normal galaxies in the local Universe and at high redshifts
G. Kauffmann (MPA Garching)
Studies of the host galaxies of active galactic nuclei (AGN) can help us understand the conditions that are necessary to form and fuel black holes. In order to carry out detailed statistical analyses of host galaxy properties, one requires 1) a sample of galaxies with spectra of high
enough quality to identify AGN based on the characteristics of their emission lines, and 2) an
algorithm for carrying out quantitative analysis of the structural properties of the hosts. We
have made considerable progress in applying a galaxy image processing code – budda – to
subsets of galaxies and AGN in the local Universe. This analysis is leading to new insights into
how different galaxy components (disks, bulges and bars) relate to each other and the extent
to which the host galaxies of AGN differ from normal galaxies. We are requesting two years
of additional funding to extend the analysis to a sample of nearby normal and active galaxies
with multi-wavelength data from SDSS, GALEX and Spitzer to study the relation between the
internal structure of galaxies and star formation and AGN activity in more detail. We will also
extend the image processing work to high redshifts by analyzing HST images of AGN selected
from the ESO Distant Cluster Survey.
The formation and evolution of tidal dwarf galaxies
P. Kroupa (AIFA Uni Bonn)
Within the hierarchical structure formation scenario today’s galaxies emerge from the accumulation
of smaller, gas-rich objects, the cosmological “building blocks”. As a result of
angular momentum and energy conservation long, thin and gas-rich tidal arms are expelled
when two such building blocks merge. These tidal arms can fragment into a series of selfgravitating
dwarf galaxies under certain conditions. It is expected that the production of
tidal-dwarf galaxies (TDGs) would have been much more efficient in the early universe than
today, and so TDGs may form an important contribution to the faint-end of the galaxy
luminosity function. While their formation is an integral part of cosmological theory, the
existence of evolved TDGs has not yet been unambiguously proven. This proposal aims at
investigating the efficiency of the formation of TDGs in dependence of the gas fraction, the
interaction morphology and mass ratio of the interacting galaxies. We also aim to study the
chemical, hydro-dynamical and purely dynamical history of TDGs, in order to understand
their survival and to uncover observable features that would help distinguishing them from
the abundant cold-dark-matter sub-halos.
Constraining the dark matter halos of the Milky Way and Andromeda by micro-arcsecond VLBI astrometry
K. Menten (MPIfR Bonn)
Key and still largely missing parameters for measuring the dark matter content and distribution
of the Local Group are the proper motion vectors of its member galaxies. Currently,
measurements of extragalactic proper motions by optical telescopes are limited to the most
nearby companions of the Milky Way and have only provided marginal results, at best. On the
other hand, by VLBI observations of bright maser sources, we have recently been able to detect
extragalactic proper motions of two member galaxies of the Andromeda subgroup, M33 and
IC10. These measurements comprising the first part of the present proposal, together with further
research proposed here, will provide a decisive tool to distinguish between different models
of the evolution of the Local Group. The long term goal of the project is to construct a full
3-D kinematic model of the Local Group. Also a geometric distance to M33 will be measured,
ultimately to better than 5% accuracy by measuring the relative proper motions of three H2O
maser sources on opposite sides of M33 and comparing them with the inclination and rotation
speed of M33. This will allow also re-calibration of the extra-galactic distance scale based on
Cepheids. The structure, dynamics, and the dark matter content of the Milky Way are very uncertain.
The location and even the number of spiral arms is controversial, and values of the circular
rotation speed (Θ0) between 170 and 250 km /s are reported in the current literature. Most
conclusions about the Galactic structure are based only on measurements of positions and radial
velocities. Using VLBI, we can measure parallaxes accurate to 10 μas and proper motions to < 1 km /s out to distances of ≈ 10 kpc. As the second part of this proposal we plan to
conduct observations that will locate the spiral arms of the Milky Way and constrain models of
galactic rotation and the gravitational potential of the Milky Way. The observations will also
test predictions made by spiral density wave theory, which is important for the formation and
evolution of spiral galaxies in general.
The antennae galaxies - a key to galactic evolution
T. Naab (USM Muenchen), Ch. Theis (Uni Wien)
The Antennae system is a prototype for a galactic merger and interaction induced activity. Due to its
proximity very detailed observations ranging from radio, optical, up to X-ray are available providing
a multiwavelength access to its morphological and dynamical properties. However, the information
contained in the excellent observational data by far exceeds the capabilities of actual numerical models
to fully understand the relevant physics. We will use the Antennae galaxies to test and extend
current theories of stellar and gas dynamics, e.g. the physics of star formation and feedback, and
their implementation in numerical models. Three distinct, but strongly related tasks will be addressed.
First, the initial conditions (orbit, orientation, mass-ratio, dark matter distribution etc.) will
be constrained by applying and extending the package MINGA, a genetic algorithm based search
in parameter space. Second, the physics of star formation and feedback will be constrained using
high-resolution self-consistent simulations in direct and detailed comparison with observations. Third,
a chemo-dynamical model of the Antennae will be performed. Its deliverables are the distribution
of the multi-phase ISM and the chemical evolution. Mergers are the driver for galaxy evolution in
modern hierarchical theories. The results of this study can be generalized and will be applicable to simulations
of other interacting systems and galaxy-sized as well as large-scale cosmological simulations.
Studying the interrelation of the evolution of cool gas, supermassive black holes and galaxy masses in clusters of galaxies
T. Reiprich (AIFA Uni Bonn)
X-ray and radio, as well as optical/infrared observations of galaxy clusters are currently being
used extensively to gain deep insights into the evolution of galaxies, supermassive black holes,
and the cooling and heating processes in the intracluster gas. We propose to contribute to
this effort by analyzing in detail multi-wavelength observations of two statistical samples of
local and distant X-ray clusters. In this proposal, we demonstrate that the available radio and
X-ray observations appear quite promising for making significant progress in understanding the
interrelation of cool gas, supermassive black holes, and galaxy masses. Bonn is an ideal place
to carry out this study due to its growing X-ray cluster research group and being the primary
location for radio astronomy in Germany.
Probing galaxy formation at high redshift with damped Lyman alpha systems
P. Richter (AIFA, Uni Bonn/Uni Potsdam)
One of the few possibilities to study the formation and evolution of galaxies in the early
Universe directly is to investigate in detail the properties of damped Lyman α absorbers
(DLAs) at high reshift. DLAs produce very strong HI Lyman a absorption in the spectra of
quasars and are believed to represent protogalactic structures. However, the morphology
of DLA host systems at redshifts z>2 it is not well known, and the exact role of DLAs in the
hierarchical galaxy formation scenario yet needs to be explored. In this project we want to
study high-redshift DLAs using quasar absorption spectroscopy and integral field
spectroscopy. We want to analyze in detail the metal abundances in selected DLA
systems to search for characteristic abundance patterns and signatures of an enrichment
by the first generation of stars (Pop III) in the Universe. In addition, we want to study the
star-formation rate in merger-DLAs by measuring the intensity and distribution of Ly a and
H a emission in the DLA and sub-DLA host objects. The goal of this project is to better
understand the morphology and chemical evolution of DLA systems in the early Universe
and to characterize the role of DLAs as building blocks for present-day galaxies.
The evolution of the warm-hot intergalactic medium in a hierarchically evolving Universe
P. Richter (AIFA, Uni Bonn/Uni Potsdam)
Using quasar absorption-line spectroscopy and numerical simulations we want to study the
properties of the warm-hot intergalactic medium (WHIM) and its evolution from high to low
redshifts. Recent studies indicate that this high-temperature gas phase of the intergalactic
medium (IGM) contains about 30 percent of the total baryon budget in the local Universe and
further may represent a reservoir of the metals produced in galaxies at high redshift. With the
analysis of OVI absorption line systems and the so-called Broad Ly α Absorbers (BLAs) we
want to trace the distribution of baryons and metals in the WHIM at z=0-0.5 and z=2-3 and
study the relation between warm-hot intergalactic gas and galactic structures at different
epochs of the Universe. We will combine these observations with numerical simulations to
search for characteristic absorption patterns related to the various processes that contribute to
the occurrence of hot gas in the IGM, such as galactic winds and collapsing large-scale
filaments. Such measurements are important to tackle the problem of the “missing metals”
and “missing baryons” in the Universe. Our project thus will lead to a better understanding of
the evolution of the intergalactic medium in the context of a hierarchically evolving Universe.
Shaping our Galaxy now: The low-latitude stellar stream around the Milky Way
H.-W. Rix (MPIA Heidelberg)
Within the hierarchical framework for galaxy formation, tidal interactions, such as the accretion
of small satellites, continue to shape large galaxies to the present day. In our own Milky Way
(MW), the Sagittarius dwarf galaxy was found to undergo disruption by the MW's tides, and
the tidal debris has been found all the way around the MW. A few years ago, a second stellar
stream was found at low galactic latitudes, encircling the Milky Way (a.k.a. Monoceros, or Low
Latitude stream). The stellar overdensity detected towards the constellation of Canis Majoris
has been identi ed as a prime candidate for its progenitor.
Two years ago we proposed a research program to construct a comprehensive empirical
picture of the Low Latitude stellar stream around the MW and its possible progenitor, the
Canis Majoris stellar overdensity. The projects draws on SDSS/SEGUE data, other wide-
eld imaging data and spectroscopy data. In the initial funding period we have carried out
a large wide- eld color-magnitude-diagram survey towards Canis Majoris that has enabled us
to construct a rst large-scale picture of the structure. We have also developed and tested
tools based on the color magnitude diagram (CMD) tting package MATCH that will enable
a thorough analysis of this data set. Furthermore we have submitted a proposal to study the
kinematics of the system through spectroscopy of main sequence stars.
To complete the project we plan to apply our CMD tting tools to the full Canis Majoris
photometric survey and create a 3D model of the system, 6D including kinematic information.
We will also apply these same tools to SEGUE imaging data and search for more parts of the
low latitude stream all around the MW. With much of SEGUE spectroscopy complete at the
beginning of 2007, we will also be able to constrain the kinematics of the stream. The results
will be a crucial case study on how spiral galaxies evolve at the present epoch.
The progress in the rst two years has been rapid enough that we believe we can complete
the project in 1.5 (instead of 2) additional years. Feeding Black Holes: Gas Dynamics from the Outer Disk to the Very Nucleus in AGN Galaxies
E. Schinnerer (MPIA Heidelberg)
The 'M -σb' relation suggests a co-evolution of the central black hole and its host galaxy. Nearby AGN galaxies are ideal targets to test state-of-the-art dynamical models for the feeding - and
thus growth - of a galaxy's central region and black hole. The recently completed NUGA
IRAM 12CO survey of nearby AGN galaxies (D < 40Mpc) has been supplemented by us with
high quality VLA HI data. The NUGA sample spans the whole range of nuclear activity
from starburst to Seyfert activity. The nuclear gas kinematics traced by CO show a wealth
of dynamical modes such as lop-sided disks, two-armed spirals, or rings, whereas the HI data
provides crucial information on the dynamics of the outer gas disk and the environment. This
unique dataset is ideal to improve the understanding of disk kinematics on spatial scales ranging
over several orders of magnitude. For this project, it is anticipated to use the combined CO+HI
data to (a) establish a link between the nuclear and outer disk gas kinematics, (b) investigate
the dominance of dynamical modes over several orders of scale lengths, and (c) test this dataset
against detailed dynamical models of individual galaxies. Funding of one additional year
of the Ph.D. student S. Haan is requested to finish the most important goal of this project:
test gas dynamical models from the outer disk to the very nucleus against the data for ≈3
representative galaxies.
The great Laboratory M51: Probing the Physics of Star Formation
and Radio Emission on the 100pc-Scale
E. Schinnerer (MPIA Heidelberg), R. Beck (MPIfR Bonn)
The empirical radio-IR relation is widely used out to high-z to estimate star formation rates
(SFRs), despite the fact that its origin is poorly understood. Processes within giant molecular
clouds where stars form (at the 100 pc scale) must control it. The grand-design spiral M51 is
ideal for a detailed study of the underlying physics of the radio-SFR relation, due to the range of
physical conditions in the spiral disk, and the large body of high-resolution (1-2") data available
from the X-ray to the radio. Our imaging radio data from the VLA and Effelsberg observatories
at 20cm, 6cm and 4cm are ideally suited to study the nature of the radio emission (thermal/nonthermal
decomposition, turn-over frequency) and to test whether the radio emission is indeed
an unbiased tracer of star formation, over a wide range of physical environments. In addition,
we have high resolution mid-IR imaging spectroscopic data from the Spitzer telescope which
will be used for an in-depth study of a density wave in a spiral region. Both datasets combined
will provide new and critical insight into the star formation process in the disks of galaxies. In
short, funding for one PhD position is requested to (a) to study the radio-IR relation on GMC
scale, (b) to compare the applicability of star formation tracer from the UV to the radio, and
(c) to gain a physcial picture of a spiral density wave.
The key for probing galaxy evolution: relating luminous matter in
galaxies to their dark environments
P. Schneider (AIFA Uni Bonn), S. Seitz (USM Muenchen)
The dark matter governs the formation and evolution of galaxies, as well as their dynamical
properties at scales > 10 kpc. We propose to empirically study the relation between galaxies
and the dark matter distribution in the Universe. Weak gravitational lensing of distant faint
galaxies o ers a unique probe of the intervening mass distribution, which can then be correlated
with the distribution of foreground galaxies. There has been impressive progress recently in
the study of this galaxy-galaxy lensing (GGL) e ect, concerning (i) the study of the dark
matter pro le of galaxies well beyond the scale where dynamical tracers can be observed, as
well as the shape of dark matter halos, (ii) the statistical distribution of galaxies within their
cluster or group environment, and (iii) the measurement of the correlation between dark and
luminous matter on large scales, which is usually parameterized by the bias factor b. Surveys
with the upcoming wide- eld camera OmegaCAM and PanSTARRS in which our groups are
involved o er a unique opportunity to substantially improve earlier studies and to carry them to
higher redshifts (compared to the results from the SDSS). This will also allow us to separately
investigate the dark matter pro le and the bias properties of early- and late-type galaxies
separately, as well as their redshift dependence. Based on our expertise and available resources,
we plan to exploit the huge data sets from KIDS and PanSTARRS for a comprehensive GGL
study. In preparation for the new surveys, we will develop and apply methods and codes to
apply them to already existing data.
Co-evolution of galaxies and their dark matter environment:
constraining the standard structure formation paradigm through
simulation and analysis of galaxy-galaxy lensing
P. Schneider (AIFA, Uni Bonn), S. White (MPA Garching)
The formation and evolution of galaxies is driven primarily by the gravitational e ects of the
dark matter in which they are embedded. Lensing of distant galaxies by the mass associated
with nearer systems o ers a unique probe of the relation between galaxies and their dark matter
environment. There has been much recent progress in measuring this galaxy-galaxy lensing
(GGL), and even better measurements will soon be provided by a new generation of wide-
eld imaging cameras. Quantitative interpretation of such observations is impossible without
detailed numerical modeling. On small scales, GGL is sensitive to the mean mass pro le of
individual galaxies; on intermediate scales, it probes the galaxy content and internal structure of
group and cluster halos; on large scales, it constrains the statistical relation between galaxies and
dark matter. However, all these aspects of the dark matter distribution a ect the GGL signal
on all scales and are intimately related to evolutionary processes which determine the physical
properties of galaxies, hence the galaxy content of GGL surveys. We will employ the largest
ever N-body simulation of the evolution of the dark matter distribution (the Millennium Run
with ≈ 10^10; particles), together with galaxy formation modeling which can track the evolution
of all galaxies brighter than the SMC throughout this (500h^-1 Mpc)³ volume, to perform
detailed simulations of GGL within the current concordance cosmology. By tracing light rays
through this simulation we will mimic present and upcoming GGL surveys for a variety of
assumptions about galaxy formation and evolution. A study of second- and higher-order autoand
cross-correlation statistics and other structure measures on our simulated galaxy + shear-
eld sky maps will clarify their expected signal-to-noise, their relation to the three-dimensional
distribution of dark matter around galaxies, and their sensitivity to the evolutionary processes
shaping the observable properties of galaxies. Such a study is required if current and future
generations of GGL surveys are to test the standard paradigm, to constrain its parameters, or
to show how galaxy evolution depends on dark matter environment.
The assembly of high redshift galaxies probed by imaging spectroscopy
N. Schreiber (MPE Garching)
In recent years, it has become clear that models based on collisionless, cold dark matter that is only
substantially influenced by gravity can successfully explain the growth of fluctuations in the cosmic
microwave background to the large-scale structure seen in the distribution of present-day galaxies.
However, our understanding of how galaxies form and grow within this framework remains inadequate.
The origin of the massive spheroid and disk components of today’s galaxies, the connection
between bulge and disk formation, and the processes through which galaxies accrete their mass are
still unclear. The major limitation is our incomplete knowledge of the relevant underlying physics
that control the phase, angular momentum, cooling, and dynamics of baryons. In this context, we are
conducting an ambitious program of near-infrared imaging spectroscopy with SINFONI at the ESO
VLT (substantially build by MPE) and the IRAM Plateau de Bure mm interferometer for a substantial
sample of high redshift galaxies selected using a variety of methods. Our results from the past two
years reveal the dynamics and properties of several tens of distant galaxies in unprecendented detail,
including the exciting discovery of a massive turbulent protodisk at z = 2:4. In this proposal, we are
asking for an extension of the support for this program that provides new and unique insights into the
processes occurring as galaxies were assembled, as well as key constraints for theoretical models.
CO-evolution of supermassive black holes and galactic nuclei
R. Spurzem (ARI Heidelberg), D. Merrit (Rochester Intitute of
Technology), J. Fiestas (ARI Heidelberg)
The objectives of the work described in this proposal are to elucidate the interaction between
single and binary supermassive black holes and their nuclear environments, as a means of constraining
the dynamical histories of observed galaxies; the past and current rates of interactions
of supermassive black holes with stars; and the likely future evolution of supermassive black
hole nuclei. To achieve this, N-body and Fokker-Planck techniques will be used to evolve models
of nuclei containing one or more central massive black holes, in spherical, axisymmetric and
triaxial geometries. The in
uence of a mass spectrum, rotation, and stellar evolution will be
studied. Our simulations will provide realistic models of the formation and evolution of black
holes in the cores of galaxies and provide detailed kinematical and morphological data to t
with observations.
Unraveling the formation history of the Galaxy with RAVE
M. Steinmetz (AI Potsdam), A. Siebert (AI Potsdam)
RAVE (RAdial Velocity Experiment) is an ambitious program to conduct a 25000 square degree survey to measure radial velocities, metalicities and abundance ratios of up to 1 million stars. RAVE is using the 1.2-m UK Schmidt Telescope of the Anglo-Australian Observatory (AAO) and is scheduled to observe over the period 2004 - 2010. This survey represents a giant leap
forward in our understanding of our own Milky Way galaxy and its formation history, providing a vast stellar kinematic database about one order of magnitude larger than any other survey proposed for this coming decade. RAVE offers the first truly representative inventory of stellar radial velocities for all major components of the Galaxy. A first data release was published in February 2006 (DR1), a second data release is scheduled for early 2007. The completeness and homogeneity of RAVE makes it an invaluable stand-alone resource, but its full potential
is realized when the radial velocities and abundances are combined with proper motions and parallaxes from other sources. The data collected in the survey are confronted against the newest generation of high resolution gas dynamical simulations that focus on the formation of disk galaxies, allowing a detailed view on the mode of how the Galaxy has been assembled.
Hard X-ray census of nearby active galactic galaxies and implications for the cosmic history of black hole growth
R. Sunyaev (MPA Garching)
Recent observations demonstrate that the supermassive black holes (SMBHs) have dramatically
evolved over the Hubble time, in parallel with and crucially a ecting the formation and evolution
of their host galaxies. Despite the success of deep X-ray surveys in providing us rich information
about active galactic nuclei (AGN) at medium and high redshifts, the AGN census at low
redshifts (z < 0:1) remained scarce until recently. Therefore two years ago we proposed for
the DFG Priority Programme 1177 to ll this gap in the history of SMBH growth by means
of an all-sky hard X-ray survey with the INTEGRAL observatory, using the huge Russian
share of INTEGRAL data. We recently reported rst results from this survey, including the
hard X-ray luminosity function, cumulative emissivity and absorption distribution of local
AGN. In addition we used INTEGRAL to accurately measure the intensity of the cosmic Xray
background (CXB) near its peak at 20{40 keV. These results allowed to place interesting
constraints on the cosmic history of SMBH accretion as well as on the AGN uni cation theory.
We propose to continue this research. For an accurate census of the low-redshift SMBH
activity, we need to complete the catalog of AGN detected by INTEGRAL over the whole sky,
including the Galactic zone of avoidance. We also plan to sum up the hard X-ray spectra of
approximately 100 AGN measured with INTEGRAL to obtain a composite broad-band spectral
energy distribution of local AGN. In combination with data from deep X-ray surveys this will
allow us to test the synthesis models of the CXB more rigorously than ever before.
2
Star Formation Triggers Across the Hubble Sequence: Clues to Galaxy
Evolution
F. Walter (MPIA Heidelberg)
Studying the mechanisms that lead to star formation on galactic scales is of fundamental
importance in our attempts to understand the evolution of galaxies and is thus directly related
to the goals of the DFG-Schwerpunkt (SPP). In our ongoing SPP project we will continue to
study in detail the relationship between star formation regions in galaxies (as seen, e.g., by
GALEX and Spitzer) and the properties of the interstellar medium (distribution, kinematics).
For this study we are using high resolution radio observations from ‘The HI Nearby Galaxy
Survey’ (THINGS, based at MPIA; observations have been fully reduced in the last funding
period of the SPP), UV images obtained by GALEX, and infrared diagnostics from the ‘Spitzer
Infrared Nearby Galaxy Survey’ (SINGS) of a sample of 34 galaxies, spanning a wide range of
Hubble types, from low–mass dwarf galaxies to massive spirals. For the first time, we are able
to study what processes trigger star formation as a function of gas density, pressure, metallicity,
dust content and mass of the host galaxy. Our enormous database will enable us to study the
origin of the famous Schmidt Law and to investigate local thresholds for star formation as a
function of galaxy type and environment. This project is currently funded by the SPP through
one PhD position (SPP student Bigiel) and we here ask for funding for his final year and for
a new position after his PhD thesis is finished. This will allow us to continue our successful
SPP project on the structure and star formation processes in nearby galaxies. This study is
not only critical for a detailed understanding of star formation processes in the local universe,
but also at higher redshifts, and fits perfectly into the framework of the ongoing SPP.
Emission-line halos in quasars: The smoking gun of AGN feedback
L. Wisotzki (AI Potsdam)
Quasars are often surrounded by extended gaseous material, ionized by the nuclear UV continuum
and radiating in several distinct emission lines. This gaseous material may be related to
large-scale out
ows or 'feedback' from the active galactic nucleus into the host galaxy and its
environment. We propose a comprehensive observational study of such extended emission line
regions around quasars. In the first part of the proposal, we want to follow up on our recent
discovery (made in the context of another project) that Lyman α haloes appear to be common
around radio-quiet QSOs at redshifts z ≈ 3. We are guided by two key questions: (1) Is the
origin of Lyα haloes in radio-quiet quasars di erent than the out
ow-related emission known
for radio-loud quasars? (2) Can we distinguish between out
owing and infalling gas? In the
second part we want to investigate extended ionized gas in low redshift quasars. In particularly
we want to identify which types of QSOs preferentially show this phenomenon, and whether it
is universally related to outfows. This part of the project is supported by a substantial amount
of already available observational data.
Cosmic evolution of the black hole mass - bulge mass relation
L. Wisotzki (AI Potsdam)
The masses of supermassive black holes in nearby galaxies are well correlated with the masses
of their hosting bulges. It is of great interest to follow this correlation out to high redshifts, into
look-back times when galaxies were young. Such observations would fundamentally constrain
theories of galaxy formation.
We propose to conduct a study aiming at the determination of the black hole mass to bulge
mass ratio for many galaxies at many di erent redshifts. Outside the local universe, this can
only be done using host galaxies of quasars. We outline a method to obtain the stellar bulge
masses of quasar host galaxies by measuring an optical-UV colour in the deblended images. We
demonstrated in the past that quasar hosts have signi cantly blue colours, so the mass-to-light
ratios will in general be di erent from those of old ellipticals. We plan to submit a large VLT
programme, measuring luminosities and stellar masses for several z ≈ 2{4 quasar host galaxies.
We also propose a strategy to compare dynamical bulge masses with stellar masses for lowredshift
QSO host galaxies and suggest a survey for high-z QSOs with extended emission line
regions suitable for kinematic measurements.
The impact of environment on distant spiral galaxy evolution: velocity
elds and Tully-Fisher relation of intermediate-redshift cluster
galaxies; observations and numerical simulations
B. Ziegler (Uni Goettingen), S. Dreizler (Uni Goettingen),
S. Schindler (Uni Innsbruck)
Galaxy clusters play a fundamental role for the understanding of structure growth in the Universe.
Besides the expected assembly of galaxies via mergers in the CDM theory, other interaction
phenomena are important in the cluster environment (among galaxies but also hydrodynamic
processes between the Intracluster Medium and the galaxy gas, and the influence of a
cluster as a whole). To test the importance of these processes we study the stellar populations
(sizes, luminosities, morphologies) that heavily depend on the current star formation activity,
but also the total gravitational potential via their internal kinematics which are in
uenced
by both luminous and dark matter. We trace possible interaction mechanisms of galaxies in
clusters at z ≈ 0:5 by their signatures in structure (with our HST/ACS images) and in the
full 2-dimensional velocity field (with our VLT 3D-spectroscopy). To disentangle the various
interaction mechanisms and their importance for the evolution of the cluster population, we
compare our observations directly with N-body/hydrodynamic simulations we perform both
on galaxy scales and cluster scales. In the case of regular kinematics, the evolution of the
Tully-Fisher relation can be determined with high accuracy. We ask here for funding to nish
2 ongoing PhD thesis studies (1 observational, 1 numerical).
Dynamical evolution of compact groups of galaxies
Bodo Ziegler (Uni Goettingen), W. Kollatschny (Uni Goettingen)
In this work we will study the formation and dynamical evolution of
Hickson compact groups of galaxies. To this purpose we will perform for
the first time a joint analysis of the properties of three components of
those groups: the optical diffuse light component that permeates most of
those systems, the globular cluster systems of the member galaxies and
the properties of the galaxies themselves. We will use deep wide field
images obtained in different photometric bands. The diffuse intragroup
light component present in compact groups is emitted by stripped material
from the member galaxies which is dissolved in the groups' gravitational
potential. This low surface brightness structure will be analyzed with
unprecedented accuracy by a new technique, based on wavelet transforms,
and its properties correlated with the group ones. The globular cluster
systems associated to the group galaxies will be analyzed through their
spatial, color and metallicity distributions and luminosity functions. We
will also investigate the photometric properties of the galaxies and
optical signatures of interactions. From this study of the dynamical
evolution of compact groups we can establish constraints to models
of formation and evolution of the groups and the galaxies themselves,
to the Dark Matter haloes of those groups and provide possible initial
conditions to numerical simulations.