IMPRS projects at MPE/HEG

The High Energy Astrophysics group at MPE has its major scientific emphasis on the study of extreme processes mostly via X-ray observations, but also extends to other wavebands. Our main astrophysical themes are: 1.) Large scale structure, as probed hot gas in clusters and groups of galaxies, and the related cosmological implications; 2.) The cosmic history of black hole growth and its relationship to galaxy evolution; 3.)Investigating physical processes including strong gravity around black holes and other compact objects; 4) gamma-ray bursts. Research fields for which PhD projects are offered specifically for 2017 include:

Properties of galaxies in X-ray clusters

Large area surveys are a great information depository on properties of galaxies. We know that galaxy properties reflect their small and large scale environment. Galactic conformity, galaxy transformation, formation bias are subject headlines of studies that combine the knowledge of the environment with studies of galaxies. X-ray observations provide large samples of well-defined groups and clusters of galaxies, whose properties do not depend on galaxies properties. Deep surveys deliver the samples of high-z galaxy groups, wide survey allow us to study rare objects. Having well-defined link to the total mass releases clustering analysis to address other questions, such as galaxy conformity and formation bias and to gain an understanding on structure formation of the Universe.
Supervisors: A. Finoguenov, G. Erfanianfar, K. Nandra

Examples of Clusters in AEGIS field

The physics of the most luminous, distant AGN: accretion and feedback at the extremes

The highest luminosity quasars, at any cosmic epoch, are perhaps the most valuable jewels in the treasure chests of large astronomical surveys; such rare objects can uniquely shed light on the most extreme and violent process taking place in the nuclei of galaxies. These quasars represent short- lived phases during which the accretion process, probably operating at, or even above, the Eddington limit, deposits large amounts of energy into the surroundings. This process has been considered as a prime mover in models of galaxy formation, for its potential to strongly influence star-formation throughout the quasar’s host galaxy.
The goal of the project is to study the physical properties of the most luminous, distant QSOs, both by studying in great detail their X-ray spectral properties, revealing physical characteristics of the most rapidly accreting black holes, and the multi wavelength properties of their host galaxies, to reveal the “feedback” impact of the energy released by the QSOs at the height of their accretion history. In the first phase, data from past and currently operating X-ray telescopes (ROSAT, Swift, and, in particular XMM-Newton) will be used, together with optical/NIR photometric and spectroscopic data, most of which have been already secured. In the second phase, after mid-2017, eROSITA data will be available to expand the reach of the study to larger samples, enabling robust population studies of such objects.
Supervisors:A. Merloni, K. Nandra

Examples of SNR morphology (Curtesy: NASA CXC Photo album)
A multi-wavelength study of supernova remnants and neutron stars

The PhD project is in the field of exploring stellar endpoints, e.g. supernova remnants and neutron stars. The candidate shall make use of various data from current radio, optical and high energy observatories(e.g. XMM-Newton, Chandra and Fermi). The PhD candidate shall take active part in the preparation of observing proposals for the current optical, radio and high-energy observatories and shall be familiar with the common data analysis tools. Typically, a PhD research project develops by its own during the course of the PhD. However, a starting point could be the identification campaign of SNR candidates. Identified radio supernova remnants (SNRs) in the Galaxy comprise an incomplete sample of the SNR population due to various selection effects. ROSAT performed the first All-Sky Survey (RASS) with an imaging X-ray telescope and thus provided another window for finding SNRs and compact objects that may reside within them. eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the core instrument on the Russian Spektrum-Roentgen-Gamma (SRG) mission which is currently scheduled for launch in fall 2017. In the soft band (0.5-2 keV), it will be about 30 times more sensitive than ROSAT, while in the hard band (2-8 keV) it will provide the first ever true imaging survey of the sky. It supports to continue the previous SNR identification campaign and to search for new supernova remnants and neutron stars with a much higher sensitivity than was possible before. In the course of the PhD research the current identification campaign of SNR candidates and neutron stars shall be continued using existing multi-wavelength data from optical, radio and X-ray missions as well as from eROSITA once the mission is up. Along that research there will also be the possibility to look into the open questions on the internal structure of neutron stars, on the equation of state of super-nuclear matter, on the cooling of neutron stars as well as on their emission mechanisms for non-thermal radiation and on particle acceleration mechanisms in supernova remnants.
Supervisor: W. Becker

The transient X-ray sky of SRG/eROSITA - From prediction through observation to interpretation

The new generation of large survey facilities provides an unprecedented window into the transient and variable heavens across all wavelengths. At X-ray energies, the all-sky survey with the MPE-lead eROSITA instrument on-board the "Spectrum-Roentgen-Gamma" (SRG) satellite will provide the next leap in sensitivity. Reaching more than 30x deeper than its predecessor ROSAT and with in some areas of the sky up to hundreds of visits covering timescales from hours to years. eROSITA holds the promise to uncover countless new transient and variable objects. The challenge is to find the most interesting sources, such as stellar mass black holes, the orphan afterglows of Gamma-ray Bursts, or the tidal disruption signatures of stars by distant super-massive black holes, among the millions of Active Galactic Nuclei, clusters of galaxies, and X-ray emitting stars that will make up the large majority of the eROSITA detections. The PhD project starts with the preparation of detection and selection methods in the months before the launch of the satellite and culminates in the systematic mining of big data sets, the analysis of individual sources and source populations and their multi-wavelength characterization using the High-Energy Group GROND instrument at the La Silla 2.2m telescope. Supervisors: A. Rau, K. Nandra

Gamma-Ray Bursts and Neutrinos

Gamma-Ray Bursts (GRBs) are one of the leading contenders for explaining the high-eenrgy neutrinos detected with IceCube at the Southpole. We are looking for an engaged student to work on both, gamma-ray data from the GRB Monitor on the Fermi satellite, and neutrino data from IceCube. In particular, we want to set up analysis packages for rapid cross-correlation of data from both projects, and work on topological extensions of the IceCube alerts including event reconstruction. A substantial part of the thesis shall test new models against the observational constraints. The progress over the last years in our understanding of transient electromagnetic and neutrino sources has primarily been in excluding certain aspects of the standard model. Many of these observational constraints can be satisfied by specific modifications to the model. Yet, no attempt has been made to take a holistic view on the jet model(s), and try to integrate the various modifications into a common scenario - and this should be attempted in this thesis. Supervisor: J. Greiner

Jets are thought to accelerate particles, and emit photons and neutrinos. Each of these messengers has different propagation and interaction properties with us (Earth) and detectors. Credit:

Mara Salvato, Last update: 19/09/2016[Disclaimer]