Extragalactic Astronomy at the Munich University Observatory (USM) and the Optical & Interpretative Astronomy group (Opinas) at MPE




The MPE Optical and Interpretative Astronomy and USM Extragalactic Astronomy USM-MPE extragalactic research group is a joint effort of the University Observatory of Munich (USM) and the Max-Planck Institute for Extraterrestical Physics. Senior group members are Prof. Ralf Bender, Prof. O. Gerhard, Prof. J. Weller, Dr. U. Hopp, Dr. R.P. Saglia, Dr. S. Seitz, Dr. Ariel Sanchez and Dr. S. Phleps

The group is located both at the USM (see `Extragalactic Astronomy') and at MPE.

Our SCIENCE PROJECTS aim


TELESCOPES:
The observational data necessary for our scientific programs come from own telescope shares (LBT, HET, Wendelstein telescope), from guaranteed time observations which come in return for our instrument buildings (FORS, SPIFFI, OmegaCAM, KMOS), from participating in carrying out public surveys (KIDS) and from applications to the ESO telescopes and the german-spanish Calar-Alto Observatory. In addition we used our Wendestein observatory in the Alps for pixellensing and other monitoring projects. In spring 2008, the 0.8m telescope was de-commissioned and we have now replaced it by a 2m-telescope with adequadate imaging and spectroscopic instrumentation. Regular observations will start soon.

INSTRUMENTATION:
In addition, 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 instruments for the VLT, and the low resolution spectrograph LRS for the 10m Hobby-Eberly-Telescope HET 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 started to contribute to the multi-IFU-infrared spectrograph KMOS for the VLT and a giant optical IFU spectrograph ( VIRUS ). We further participate in the design study of the E-ELT instrument MICADO and the now accepted Cosmic Vision Survey Mission EUCLID , planned to be launched in 2019.

SOFTWARE:
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 (e.g. KIDS, see more, below) 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.

SURVEYS:
The USM-Opinas-group will carry out the Kilo Degree Imaging Survey (KIDS ) is a survey very similar to SDSS, but with an increased spatial resolution and more than two magnitudes deeper) together with the universities/astronomical institutes in Leiden, Groeningen, Paris, Napoli and Bonn using OmegaCAM and starting in 2011. The optical KIDS data will be complemented with NIR data in a collaboration with the UKIDSS and VISTA-teams.
The Opinas group at MPE is a member of the BOSS/SDSS3 consortium, which will obtain spectroscopic redshift for luminous red galaxies out to z=0.9. This will be used to analyse large scale clustering of galaxies as a function of redshift.
Moreover, the Opinas group at MPE is member of the PANSTARRS consortium consisting of the Institute for Astronomy (Hawaii), the Max-Planck Society, Havard University, John Hopkins University, Las Cumbres Observatory and a UK consortium (Durham, Edingburgh, Belfast). PANSTARRS is carrying out a multi wave band 3pi survey of the northern sky using a 7 square degree Giga-Pixel camera mounted on a 1.8 meter telescope on Haleakala (Hawaii).
PANSTARRS is also monitoring all of M31 in each visible night with its 7 square degree camera. The PAndromeda data will allow a search for variable stars and microlensing events (6 events have been already identified, Lee et al. 2011), as well as a detailed investigation of stellar populations in the coadded data set. Recently, we have also joined the dark energy survey DES.
Finally, we participate in HETDEX , the Hobby-Eberly Telescope Dark Energy Experiment, a project designed to understand the evolutionary history of dark energy.


We offer several PHD PROJECTS within our group that can be in any of the above science areas and instrumentation as well. We provide more details below. If you don't find your favorate PhD subject, you can still contact us.

Difference image movie of a 30x30 arcsec^2 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.





MASTER- AND PHD-THESIS PROJECTS :

Please use our webpages for further information about the research activities of the extragalactic research group at USM and the optical & interpretative astronomy group at MPE. We continously offer Master & PhD projects (please contact us also by email and ask for further projects). Below we have listed some research areas which are particulary suited for the start of a PhD thesis at around summer/fall 2012. Also, if you have a proposal for a PhD project matching our science interests, please don't hesitate to contact us.

PhD-THESIS PROJECTS SUPERVISOR/CONTACT
Project 1 (PhD project):
``Constraining cosmological models from large scale surveys''
Using numerical simulations and large cosmological surveys (PanSTARRS1, BOSS, etc.) to put constraints on the properties of dark matter and dark energy. Possible projects could be:

1. Investigating the impact of non-linear structure formation on cosmological constraints
2. Modelling Structure formation in theories of cosmic acceleration in the context of large scale surveys
3. Constraining the growth of structure from large scale velocity dispersions
4. Development and application of a generic framework for cosmological constraints from large scale structure surveys


Jochen Weller, Stefanie Phleps jochen.weller@usm.lmu.de
sphleps@mpe.mpg.de
Project 2 (PhD project):
``CLASH: Cluster Lensing and Supernova survey with Hubble (project already taken)"

CLASH is a 524 orbit, multi cycle HST treasury survey program (MCTP). It allows to map the dark matter distribution in massive clusters with weak and strong lensing to unprecedented accuracy, to identify z<2 supernovae, to study the internal structure and evolution of galaxies in and behind the clusters and to identfy gravitationally magnified high redshift (z>7) galaxies. Due to its coverage with 16 UV, optical and NIR filters the CLASH data set will be for many years the best data set ever available to analyze the strong lensing effect of galaxy clusters. The PhD project offered here is to analyze the dark matter distribution in the clusters with weak and/or strong lensing. The project will be done in an international collaboration and includes the world best experts in strong and weak lensing, in cluster properties, photometric redshift techniques, and high redshift galaxy identification.


Stella Seitz stella@usm.uni-muenchen.de ,
Ralf Bender
bender@mpe.mpg.de
Project 3 (PhD or Master Project in the Dynamics Group :
``Kinematics, dynamics and dark matter"

Research in the MPE Dynamics Group focusses on understanding the dynamical structure and evolution of galaxies including our own galaxy, the Milky Way. Using analytical and numerical models, we work on determining the dark matter mass distributions around galaxies, the orbits of stars in galaxies from kinematic measurements, and the dynamical constraints we can place on the origins and evolution of galaxies. PhD and master thesis projects are available within the following research projects:

* Structure and evolution of the Milky Way, in particular of its central bulge and bar;
* Dark matter haloes of elliptical and S0 galaxies;
* Angular momentum and kinematic signatures of accretion in massive elliptical galaxies;
* Developing made-to-measure particle models for galaxies containing rotating bars;
* Tidal stripping and evolution of galaxies in clusters and the formation of intracluster light.


Ortwin Gerhard gerhard@mpe.mpg.de
Project 4 (PhD project):
``New Instruments"
GOAL: Develop new optical and near infrared imagers and spectrographs for 2-10 meter telescopes
We encourage students with technical background (and astronomy interest) to also apply in instrumentation projects. The student will participate in the developement of design, the assembly and testing of new instruments and the writting and testing of the related control and data reduction software. Potential projects are a new `wide field imaging instrument' or a `3-band simultanous imager' or 'Wave-front sensor' at the new 2m Wendelstein telescope, a participation in the KMOS project (multiple NIR Integral Field Units), or in VIRUS (150 optical Integral Field Units and spectrographs). The science project of the thesis will be related to scientific questions that can be adressed with the instrumentation (co)developed by the student.


Ulrich Hopp
hopp@usm.uni-muenchen.de,
Ralf Bender
bender@mpe.mpg.de
Project 5 (PhD project):

Distinguishing models of cosmic acceleration with galaxy clusters with application to realistic cluster data sets
Clusters of galaxies and their spacial and redshift distribution are extremely sensitive probes of the growth of large scale structure and hence cosmological models. In particular modifications of gravity typically result in a change of this distribution and in turn can then distinguish these models from standard gravity. This PhD project will study the ability of surveys like PanStarrs, DES and Euclid to constrain these models under realistic survey assumptions. The findings will then be applied to data sets available to the group.


Jochen Weller jochen.weller@usm.uni-muenchen.de
Project 6 (PhD project):

Numerical simulations of modified gravity theories of cosmic acceleration
Modified gravity as a theory of cosmic acceleration is one of the possible alternatives to the standard dark energy scenario. In this project we will develop and/or exploit N-body simulations for these scenarios. This is important in order to understand the non-linear scales of structure formation, such as cluster of galaxies. This is then relevant to interpret data sets on these scales.


Jochen Weller jochen.weller@usm.uni-muenchen.de
Project 7 (PhD project):

The nonlinear power spectrum in non-standard models of cosmic acceleration
A notorious difficulty to exploit cosmological data sets, such as weak lensing and galaxy clustering, over a large range of scales, is that one has to understand the small scale, non-linear behaviour of the theories one wants to confront with the data. In recent years standard dark energy approaches have been pushed into this regime with the help of higher order perturbation theory calculations and numerical simulations. In this project we want to extend this approach to more exotic cosmic acceleration scenarios, such as modified gravity and coupled dark energy.


Jochen Weller jochen.weller@usm.uni-muenchen.de
Project 8 (PhD project):

Dynamical modeling of bulges and disks
Using the extensive set of stellar kinematics we have collected in the past for a large number of spiral galaxies, we aim at constraining the distribution functions of the disk and bulge components of these objects. What are the dynamical differences between classical and pseudo bulges? What is the relation between the radial and tangential velocity dispersions of stellar disks? What is the role of bars?


Roberto Saglia
Ralf Bender
saglia@mpe.mpg.de bender@mpe.mpg.de
Project 9 (PhD project):

Galaxy evolution with KMOS
At the beginning of 2012 KMOS will be commissioned at the VLT. This near-infrared multiobject spectrograph that we are building with our UK partners will allow us to study large samples of high redshift (z~2) galaxies, determine their dynamical masses and metallicities. Jump into the project from the very beginning and participate to the object selection, the data reduction and the astrophysical analysis!


Roberto Saglia
Ralf Bender
saglia@mpe.mpg.de bender@mpe.mpg.de
Project 10 (PhD project):

Improving large-scale structure observations by reconstruction techniques
The non-linear evolution of density fluctuations distorts the signal of the baryonic acoustic oscillations in the correlation function and the power spectrum. Although these distortions can be modelled accurately, they lead to a degradation of the cosmological constraints that can be achieved from these measurements. To deal with this problem, a correction can be applied to the observed galaxy positions which allows to partially reconstruct the linear density field. This procedure, dubbed reconstruction, reduces the impact of non-linearities, improving the obtained constraints. This technique is expected to play a mayor role in the analysis of future surveys. The aim of this Ph.D. thesis is to test if this technique can be successfully applied to real observational data. This will require a detailed study of the effect of reconstruction on the power spectrum and the correlation function. In particular, the Ph.D. student should test the ability of current models to describe the full shape of the correlation function recovered after the application of this technique. The student will also apply this technique to the available data sets from BOSS and HETDEX.


Ariel Sanchez
arielsan@mpe.mpg.de
Project 11 (PhD project):

Improving the modelling of redshift-space distortions
In spectroscopic surveys distances are inferred from the measured redshifts. These are affected by their peculiar velocities of the galaxies giving rise to a difference between their real and the apparent positions. This leads to a change in the shape and amplitude of the measured two-point statistics with respect to their real-space counterparts. However, as peculiar velocities are gravitationally induced by the inhomogeneities in the density field, the pattern of redshift-space distortions contains information on the underlying matter distribution which can be used to probe the rate at which cosmic structures grow. The aim of this Ph.D. thesis is to obtain a detailed model of the effect of redshift-space distortions in the shape of the correlation function. This model will allow us to test the accuracy with which growth rate measurements can be obtained from these observations and to asses if this test can be affected by uncertainties in galaxy bias. This model will be also applied to the available data from BOSS and HETDEX to obtain new measurements of the growth of fluctuations at different redshifts and constrain possible deviations from General Relativity.


Ariel Sanchez
arielsan@mpe.mpg.de
Project 12 (PhD project):

An inventory of the M31 variable star content
The goal of this project is to identify and analyze variable stars in M31 using the PANSTARRS PAndromeda data set and further data that will be acquired with the new 2m telescope on mount Wendelstein. The period luminosity relation of cepheids will be studied and compared with the relation in the LMC, M81 and other galaxies. The dependency of this relation on the position within M31 and the potential difference to other galaxies will allow to study systematic errors of the distance determinations with the PL relation. The derived M31 distance estimate will then be compared with the distance derived from M31 eclipsing binaries (identified in the PAndromeda data set) and other distance indicators. Other variables can be studied as well, partly in international collaboration with PANSTARRS members in Hawaii and Taiwan. Our variability study is a prototype study for projects that will be possible with the LSST for most of the nearby galaxies in the future.


Stella Seitz
stella@usm.uni-muenchen.de ,
Ralf Bender
bender@mpe.mpg.de
last update: October 2012