Praktika für Studenten
Diese Praktika richten sich an Masterstudenten und umfassen grob 4 Wochen
Free-free continuum emission in a nearby starburst galaxy
Ansprechpartner: Kaustuv Basu, Frank Bertoldi
Ort des Praktikums: AIfA
The free-free emission from galaxies should carry one of the clearest signatures of their star forming activity, but it is notoriously difficult to detect this signal as compared to the much stronger radio (synchrotron) and thermal dust emissions. Our observation and analysis of the 3 millimeter continuum data (obtained from the Plateu de Bure Interferometer) for the nearby starburst galaxy IC 1623 have shown some interesting features. This cannot readily be explained from the known radio emission features in this merging galaxy. The goal of this project is to compare this data will all other publicly available radio and mm/sub-mm data for this galaxy to confirm whether this feature is really caused by the free-free emission, and whether it indicates the primary location of star formation in this merging system.
The entropy floor of galaxy clusters
Ansprechpartner: Kaustuv Basu, Frank Bertoldi
Ort des Praktikums: AIfA
Galaxy clusters contain most of their visible baryonic mass in the form of a diffuse plasma that fills up the space between the galaxies. Studying of this intra-cluster medium is an active field of cosmological research, as it helps us to estimate the mass of the cluster dark matter halos, and to use the clusters as cosmological tools. The entropy of the intra-cluster medium is an excellent tracer of all the heating and cooling processes that have taken place inside the cluster. Our work combining X-ray and millimeter data has opened a new model-independent way to estimate the entropy of this diffuse plasma, and to estimate the "height of the entropy floor", which is essentially a measure of the energy injected into the intra-cluster medium by non-gravitational processes. The goal of this project is to estimate the intra-cluster entropy for one or two clusters, and then compare these values with the predictions from some popular parametric models.
Wide-field imaging
Ansprechpartner: Thomas Erben, Peter Schneider
Ort des Praktikums: AIfA
Optical imaging surveys of the sky provide one of the major tools for studying the Milky Way and the distribution and properties of galaxies and clusters. Cosmological applications include weak gravitational lensing, which requires superb image quality and data in multiple wave-bands. To cover substantial solid angles, wide-field imaging cameras on large telescopes are used. During this internship, the student will become familiarized with the object contents of wide-field images; using available software, catalogs of objects (galaxies, stars) will be generated and their statistical properties (source counts, clustering properties) investigated. Alternatively, the student can learn how the reduction of these wide-field images proceeds -- how to proceed from noisy single exposures of a field, full of defects (cosmic rays, dead pixels, chip gaps, etc.) to a clean and well-calibrated coadded image.
Molecular gas in redshift galaxies
Ansprechpartner: Kirsten K. Knudsen, Frank Bertoldi
Ort des Praktikums: AIfA
Nearby massive galaxies have experienced some of the most intense episodes of star formation at high redshift. Using the Plateau de Bure Interferometer, we have observed high redshift quasars and starburst galaxies to study molecular line emission. This internship offers the opportunity to reduce millimeter interferometry data and study the interstellar medium of distant starbursts.
Stellar populations and dynamics
Ansprechpartner: Pavel Kroupa
Ort des Praktikums: AIfA
Internships can be offered for work on topics related to Stellar Populations, Stellar Dynamics, Star clusters, Dwarf Galaxies and Dark Matter. Please consult http://www.astro.uni-bonn.de/~pavel/resea.html for an overview of our research activities.
Study of molecular outflows from young stellar objects
Ansprechpartner: Silvia Leurini, Karl Menten
Ort des Praktikums: MPIfR
Young stellar objects are characterized by event of mass-loss which manifest as powerful "jet-like" molecular outflows. observable in the IR and at the millimeter wavelengths. They are a fundamental aspect of star formation, as they provide a record of the mass-loss history of the system. In this internship, the students will reduce, and analyze spectroscopic data taken with the APEX telescope in Chile using standard software for mm line data. This will allow them to determine the morphology of the emission, and study physical parameters associated to the outflows such as mass, moment, and energy. Comparison between systems of different masses will also be performed, to understand some of the problematics of the process of massive star formation.
Radio-emitting X-ray binaries
Ansprechpartner: Maria Massi
Ort des Praktikums: MPIfR
X-ray binary systems are formed by a normal star and a compact object (neutron star, or black hole). Some of these objects show well collimated radio jets and have been called micro-quasars. The structure of the jets is studied by high resolution interferometric observations. In this internship, the students will reduce with the Difmap software, an interactive program for synthesis imaging, radio interferometric data of a microquasar taken with the Multi-Element Radio Linked Interferometer Network (MERLIN). Aim is to determine if the radio structure is resolved at the given spatial resolution, how the morphology is changing in different epochs and finally how fast the jet is.
Cosmological N-body simulations (theoretical/numerical project)
Ansprechpartner: Cristiano Porciani
Ort des Praktikums: AIfA
The formation of the large-scale structure of the universe is usually studied by running high-resolution N-body simulations on supercomputers. During this internship the students will learn how cosmological simulation are performed, familiarize with their outcomes, and compute some statistical properties from a sample output.
The cosmic UV background (theoretical/numerical project)
Ansprechpartner: Cristiano Porciani
Ort des Praktikums: AIfA
The integrated emission from star-forming galaxies and quasars produces the cosmic ultraviolet background which keeps the intergalactic medium ionized at low redshift. The goal of this internship is to develop a computer code that computes the expected energy spectrum of the UV background.
The halo model of cosmic structure (phenomenological project)
Ansprechpartner: Cristiano Porciani
Ort des Praktikums: AIfA
Galaxy clustering can be efficiently described in terms of the halo model that links the galaxy distribution to that of the dark matter. During this internship the students will familiarize with the halo model and use it to derive the mass of the dark-matter halos hosting galaxies from the Sloan Digital Sky Survey.
X-ray Emission of Galaxy Clusters
Ansprechpartner: Thomas Reiprich
Ort des Praktikums: AIfA
X-rays are emitted from regions where the Universe is hot and wild. Galaxy clusters, the largest and most massive clearly defined structures we know, are strong X-ray emitters. Observations of these systems require space-based instruments. In this internship, the students will download, reduce, and analyze recent X-ray data of a galaxy cluster taken with a satellite observatory, using software existing in the research group. This will allow them to determine the intracluster gas mass and temperature, as well as the mass of the invisible and dominant component -- dark matter.
Cosmic shear analysis
Ansprechpartner: Peter Schneider
Ort des Praktikums: AIfA
Numerical simulations of the large-scale structure of the Universe provides the essential tool for predicting the density distribution of matter, given a specified cosmological model. By tracing light rays through the resulting matter distribution, the effects of weak gravitational lensing can be studied quantitatively from these simulations. Based on such ray-tracing, the student will analyze parts of the resulting gravitational shear fields, and study their dependence on the redshift of lensed sources. In addition, the student will get familiarized with the basic concepts of cosmic shear research.
Massive star formation magnetic field database
Ansprechpartner: Wouter Vlemmings
Ort des Praktikums: AIfA
The processes governing the formation of massive stars is still unknown, and magnetic fields potentially play a crucial role. However, observations of magnetic fields in these regions are few. In this project the student will reduce recent Effelsberg and Parkes telescope methanol maser observations to determine the role of the magnetic field in a large sample (~80) high mass star forming regions.
The shapes of stellar envelopes
Ansprechpartner: Wouter Vlemmings
Ort des Praktikums: AIfA
Planetary Nebulae (PNe) are the descendents of stars with a similar mass to our Sun. While the progenitor stars are spherically symmetric, a large fraction of PNe have asymmetric shapes (only 20% of the PNe are spherical). The origin of these spectacular shapes is still a matter of debate, and exactly when these asymmetries develop is a major piece of the puzzle. The student will reduce archive VLA data of OH masers around evolved stars using the new CASA data reduction package to extract information on the matter distribution in the envelopes of stars at the end of their evolution.
The birth sites of pulsars
Ansprechpartner: Wouter Vlemmings
Ort des Praktikums: AIfA
Using VLBI observations it has been possible to accurately determine distances and sky velocities of pulsar, which are essential ingredients for a good understanding of the birth properties of these compact objects. Born from Supernova explosions, pulsars have long been known to reach extremely high space and rotational velocities and recent astrometric observations strongly suggest that significant kick velocities are imparted upon the pulsar birth. This project will use the current astrometric data taken using the VLBA for a number of pulsars to computationally determine their likely orbits through the Galaxy and determine possible birth locations and birth properties crucial for constraining for example the physics of Supernova explosions.
Analysis of molecular line data from star forming regions
Ansprechpartner: Friedrich Wyrowski, Karl Menten
Ort des Praktikums: MPIfR
A main research topic of the millimeter & submillimeter astronomy group of the MPIfR are studies of the formation of stars using radio telescopes around the world. The students will participate in the initial data reduction, the analysis of the measured spectral lines and cubes and the modeling of the data.
Dust continuum studies of galactic star forming clumps
Ansprechpartner: Friedrich Wyrowski, Karl Menten
Ort des Praktikums: MPIfR
The millimeter & submillimeter astronomy group of the MPIfR is strongly involved in studies of the earliest phases of star formation using the powerful bolometer camera LABOCA at the APEX submillimeter telescope in Chile. A recent highlight is the unbiased cold dust continuum survey of our Milky Way (ATLASGAL). The students will be involved in the analysis and interpretation of the data to learn about Galactic structure, fragmentation in giant molecular clouds and the formation of massive stars in individual dense molecular cloud cores.
