Astronomy and Cosmology
The USM-MPE extragalactic research group is a joint effort of
the University Observatory of Munich (USM) and the Max-Planck
Institute for Extraterrestical Physics. The group is located
both at the
(see `Extragalactic Astronomy') and at
MPE ). Senior group members are
Prof. R. Bender, Prof. J. Weller, Prof. O. Gerhard, Dr. U. Hopp, P.D. R.P. Saglia, Dr. S. Seitz.
The research of the group focusses on dark energy and dark matter in
the Universe, on local and distant galaxies, and planets. The
aims of our current science projects are:
We pursue these science questions with a combination of
optical and near-infrared observations, theory, numerical
modelling, and data interpretation. The group is one of the
principal partners in the
survey which images 3/4 of the sky with unprecedented depth.
It is also an important partner in several large international
collaborations (e.g., the
NUKER team, the PN.S project).
- to constrain the nature of dark matter, by
searching for MACHOS with pixellensing towards M31, and by
analysing cluster and galaxy dark matter halo profiles with
strong and weak lensing in combination with dynamical and
photometric information for nearby galaxies;
- to derive constraints on the nature of dark
energy, by measuring the power spectra of galaxies and
clusters of galaxies at various redshifts, the number
density of clusters as a function of mass and redshift, and
the redshift dependence of the gravitational lens effect;
- to understand the structure and dynamics of
local and distant galaxies, their stellar populations, their
formation and evolution;
- to build a model of the Milky Way which can
be used as a template for galaxy formation;
- to quantify the role of black holes and dark
matter in galaxies;
- to search for extrasolar planets using the
transit method in wide field surveys and understand their
properties (mass, density, atmosphere).
The observational data necessary for our
scientific programs come from running own telescope (Wendelstein),
partnership in the Hobby-Eberly-Telescope and
SDSS-III-BOSS and DES projects, from guaranteed time received
for providing instruments to ESO ( FORS , SPIFFI , OmegaCAM ,
KMOS), and from participation in public surveys (KIDS,
expected to start in 2011).
Furthermore we are members of the
524-orbit-HST-Multi-Cycle Treasury Program team and the
ESO VLT-large spectroscpy program on CLASH-clusters.
Last but not least,
we obtain time from applications to the ESO
telescopes and the german-spanish Calar-Alto Observatory. In
addition we use our Wendelstein observatory in the Alps for
pixellensing and other monitoring projects. We expect first
light for the new 2m telescope on the Wendelstein observatory
in 2011. The instrumentation for this telescopes is partly
finished (optical imaging camera, optical IFU spectrograph),
further instruments are built.
modelling uses state-of-the-art numerical methods run
on PC clusters. Some of these methods are developed or
implemented within our group for specific projects. Recent
examples are Schwarzschild's orbit superposition method used
for measuring black hole masses, and the NMAGIC adaptive
N-body code for modelling galaxy dynamics.
the USM-MPE extragalactic research group is designing
and building imaging and spectroscopy instruments for
1-10m class telescopes, together with national and
international partners. We built, e.g., the FORS instruments
for the VLT, and
(Low Resolution Spectrograph) for the 10m Hobby-Eberly-Telescope
in Texas (which we share with the Universities of Texas, Penn
State University, Standford and Göttingen). We currently wait
for our newly built 1-square degree imager
OmegaCam to start operations on the 2.6m VLT-survey
telescope (VST) in Chile. Right now we are in the final phase
of building the multi-IFU-infrared spectrograph (KMOS@VLT),
which is planned to become operational in 2011. In addition we
are partners of an international consortium building a giant
optical IFU spectrograph (VIRUS@HET).
Finally, we also develop data reduction and
analysis software. We are member of
ASTROWISE, a european
team (USM, Paris, Groeningen, Leiden and Naples) providing
data analysis software for the OmegaCAM and any wide field
data. This software is essential for all wide field imaging
surveys carried out within the ESO community in the future.
For the VIRUS project we are developing the pipeline for the
automatic reduction of the integral field spectra. We are also
members of the EUCLID-satellite team. Our focus here is the
design of the optics and combining EUCLID data with ground
We offer PhD projects within our group in any of the above
science areas and in instrumentation as well.
Some examples of
- Dynamical modelling of
galaxies, dark matter and black holes
- Imprints of Dark Energy in Galaxy Powerspectra
- Weak lensing and photometric cluster search
- Weak and strong lensing
by galaxies and clusters of galaxies using
HST, Panstarrs and DES data
- Photometric cluster
- Photomeric properties of
galaxies (galaxy evolution, based on
photometric redshift data)
- Stellar content and structure of the Milky Way
- New instruments.
- Distinguishing models of
cosmic acceleration with galaxy clusters with application to
realistic cluster data sets.
- Relastic modelling of
modified gravity theories of cosmic acceleration.
- The nonlinear power
spectrum in non-standard models of cosmic acceleration.
For more details see
Our homepages provide detailed information on currently
available PhD projects. See, e.g. the weblinks
Difference image movie of a 30 x 30 arcsec2
area in the bulge of M31 from our WECAPP pixellensing
project. Long period variables and other variable stars
show up as varying black and white spots. Towards the
end of the movie a microlens event is visible in the
center of the field.
Structure Formation and Cosmology
The research group on
Cosmology and Structure Formation is pursuing studies in
cosmology and the formation and evolution of large scale
structures in the universe. Our work is at the interface of
observation and theory, where we seek to bring together new
observational constraints with state of the art hydrodynamical
simulations of structure formation. We are pursuing
cosmological topics such as the nature of the cosmic
acceleration and the characteristics of the initial density
perturbations. Our ongoing structure formation studies focus
on the properties and evolution of the large scale structure,
including clusters of galaxies, the most massive collapsed
structures in the universe.
Senior group members are Prof. J. Mohr, Dr. G. Bazin.
Opportunities exist for those
who might be interested in the South Pole Telescope Sunyaev-Zel'dovich Effect survey for galaxy clusters. Here in
Munich we are centrally involved in the optical and X-ray
followup of these systems, which are very cleanly selected,
high mass systems extending to redshifts z>1. These are truly
unique and rare systems and are therefore well suited for
cosmology if we can successfully characterize their masses
using weak lensing, velocity dispersions and X-ray
observations. The SPT sample contains about 280 systems
presently and will end with approximately 500 massive clusters
with accurate individual cluster mass estimates, providing an
unparalleled sample for studies of cosmology, non-Gaussianity
and the evolution of large scale structure.
There are also opportunities to become involved in the
Dark Energy Survey,
which is a 5000 deg2, deep multiband optical survey of the
southern sky that will begin in Fall 2011. Our group is
focused on cluster science, large scale structure and weak
lensing studies. In addition, we are involved in the
development of the data management system for processing,
calibrating and archiving these data. This familiarity with
the data gives members of our group advantages in pursuing any
analyses that push the data to their limits.
We are working to develop the science case and novel analysis
techniques for the
all sky X-ray survey (PI Dr. Peter Predehl, MPE). This survey
will begin in 2013 and will deliver a sample of 105 galaxy
clusters and 106 AGN that, in combination with the
multi-wavelength optical surveys like the Dark Energy Survey
and Pan-STARRS1, should provide the ideal sample for
cosmological studies using galaxy clusters and for structure
formation and evolution studies using both clusters and AGN.
Finally, there are opportunities to get involved with
hydrodynamical simulations of large scale structure. Our group,
in collaboration with Dr. Klaus Dolag at USM, is also focused
on delivering a next generation hydrodynamical simulation that
will reach a volume of 1 cubic gigaparsec with sufficient
resolution to follow the formation and evolution of galaxies.
These simulations will be central to a wide range of forefront
studies, and we expect to pursue some of these studies in
combination with data from SPT, DES and eROSITA.
We offer PhD projects within our group in any of the above
Some examples of
- The evolution and nature
of density fluctuations out to redshifts
beyond z=1 using the SPT cluster sample.
- Clustering and evolution
of galaxies using large photometric
redshift samples from the DES and spectroscopic extensions
of these surveys that will deliver large samples of spec-z's.
- Evolution of the galaxy
population and the intracluster medium
within massive clusters from the time of the formation of
first such systems to the present.
- The underlying causes of
the cosmic acceleration using techniques
that include the evolution of galaxy cluster populations and
clustering of both galaxy clusters and galaxies.
- Development of novel
algorithms for the improved processing and
calibration of photometric and spectroscopic optical data.
contain dark matter and baryons in
the form of stars, galaxies and a diffuse high
temperature X-ray emitting plasma.
Galaxy clusters are the most massive
structures in the universe, and when they form all
material in their vicinity is dragged in.
The mix of baryonic and dark matter in
reflects the mix in the Universe as a whole,
allowing us to measure the dark matter density of
|The research of the computational astrophysics group at the USM is focussed on
dynamical processes in galaxies, related to galaxy formation and
evolution, the evolution of the interstellar medium and star and
planet formation. Senior group members are Prof. A. Burkert, Dr.
numerical methods and codes, coupled with special hardware
connected to local PC clusters for fast computations we explore
the complex non-linear evolution of gas in galaxies and its
condensation into dense molecular clouds and stars. We explore
the collapse of protostellar clumps and cores, the formation of
protostellar disks and their condensation into planets. On
larger scales we investigate galaxy-galaxy interactions
including dark matter, stars and gas and study the morphological
transitions of galaxies and the origin of their spheroidal
PhD Projects in this group
- Origin of very old, massive
- The cosmological angular
- The origin of turbulence in
the interstellar medium.
- Formation of clumpy,
turbulent molecular clouds.
- Formation of stellar
clusters and disruption of molecular clouds.
- Origin and evolution of
stellar disks around massive black holes
in the centers of galaxies.
- Evolution of protoplanetary
disks and their condensation into
brown dwarfs and massive planets.
for the Antennae Galaxies.
More infos are available
Atmospheres of Hot Stars, Gaseous Nebulae, and Planetary
cover sub-groups of objects in
different parts of the HR diagram and at different evolutionary
stages. The most important sub-groups are massive O/B Stars,
Central Stars of Planetary Nebulae, and Supernovae. All
these objects have in common that they are characterized by high
radiation energy densities and expanding atmospheres. Due to
these properties, the state of the outermost parts of these
objects is characterized by non-equilibrium thermodynamics and
USM Hot Star group
is experienced in the corresponding theory, especially of
radiative transfer (1d and 3d) and of stellar atmospheres, and
accordingly in model simulations and the computation of
realistic synthetic spectra for these astrophysically important
objects. Senior group members are Prof. A.W.A. Pauldrach, P.D.
J. Puls, P.D. K. Butler, Dr. A. Kutepov.
Specific topics address the
relevance of Hot Stars for current astronomical research:
- The present cosmological
question of the reionization of the universe requires
quantitative predictions about the influence of very massive,
extremely metal-poor Population III stars on their
galactic and intergalactic environment. The objective is to
deduce the ionization efficiency of a Top-heavy IMF via
realistic spectral energy distributions of these very
- Due to the impact of
massive stars on their environment the underlying physics for
the spectral appearance of
are rooted in the atmospheric expansion of massive O stars
which dominate the UV wavelength range in star-forming
galaxies. Therefore, the UV-spectral features of massive O stars
can be used as tracers of age and chemical composition of
starburst galaxies even at high redshift
- Distant SNe Ia appear
fainter than standard candles in an empty Friedmann model of
the universe. This surprising result requires investigating
the role of
Supernovae of Type Ia
as distance indicators with respect to diagnostic issues of
PhD Projects in this group
- Diagnostics of UV and
optical spectra of O type stars
- Synthetic spectra of the
x-ray range of O type stars
- Synthetic spectra for SN Ia
at late phases
- IR-spectroscopy of massive
- Clumping in hot star winds
- constraints from a multi-wavelength analysis
The main focus of the working
group thus is to develop diagnostic techniques in order to
extract the complete physical stellar information from the
spectra at all wavelength ranges.
Optical - UV - EUV - X-ray
Left: Eta Carinae.
Below: Calculated and observed UV spectrum for
zeta Puppis. The observed
spectrum shows the Copernicus and IUE high-resolution
observations, and the calculated spectrum represents a
More details about the
Star group and further
information on the projects can be found
The Plasma-Physic group at the
USM is involved in the research of the macroscopic dynamics of
Senior group member is Prof. H. Lesch.
99% of the visible Universe is
in the plasma state. Thus, the understanding of the dynamics
of cosmic multi-particle systems under the influence of
electromagnetic forces, is of outstanding importance.
Phenomena of special
interest to our group are:
- High-energy particle
acceleration processes in the context of (proto)-stellar
flares, pulsars, extragalactic jets and cosmic rays,
- Plasma heating in, e.g.,
(proto)stellar coronae, galactic high-velocity clouds and
the interstellar medium,
- The generation,
reconfiguration, filamentation and energy conversion of
magnetic fields in (proto)galaxies, accretion disks, active
Our analytical and numerical
investigations are carried out on the grounds of the (multi)fluid-
as well as the kinetic plasma theory.
- TeV Emission from Active
Centaurus A x-ray jet high-energy particles are continuously
accelerated on kpc length scales up to Lorentz factors of
Young Stars and Star Formation
The Young Stars & Star
Formation group at the USM is involved in the research of
individual young stars and whole star forming regions at
optical, infrared, X-ray, and sub-mm wavelengths.
Senior group member is Prof. Th. Preibisch.
Topics of special
interest to our group are:
- Infrared Interferometry.
- X-ray Studies of Young
- Stellar Populations and
Triggered Star Formation in OB Associations.
PhD projects can be
offered in the following fields:
Stellar Feedback and
Triggered Star Formation in OB Associations:
The interaction of the strong winds and the ionizing
radiation from massive stars can destroy surrounding clouds,
but, in the right circumstances, it can also trigger
secondary star formation by compressing the clouds and
driving them into collapse. The group is actively involved
in an international cooperation that performs a
comprehensive multi-wavelength study of the massive young
clusters in the Carina Nebula. Deep surveys in the X-ray,
near-infrared, and sub-mm bands are currently performed. One
possible PhD project would be to contribute to the analysis
and interpretation of these new data.
Infrared Interferometry of
Infrared Long-Baseline Interferometers such as the ESO Very
Large Telescope Interferometer can provide very high angular
resolution of down to the milli-arcsecond scale. This allows,
for the first time, to study the inner circumstellar regions
of young stellar objects with spatial resolution below 1 AU
and provides new and unique insight into the structure of
protoplanetary disks, accretion and outflow processes, and
on the multiplicity of the young stars.
summarizes results on the multiplicity of the Orion
Trapezium stars revealed by infrared interferometry.