Astrophysics I

Prof. Dr. W.-R. Hamann

Astrophysics II

Prof. Dr. P. Richter

Current observing campaigns at large teleskopes

Press Release NASA/Chandra 03.04.2013 NEU!

The cosmic recycling

Stars lose the largest part of their original matter. This material is provided for the formation of new generations of stars. Mass is lost from stars by stellar winds (continuously), eruptions and explosions (supernovae). Fascinating are the stellar winds from particularly hot stars; huge amounts of matter are continuously blown away with velocities of 10 Million kilometres per hour.

Spectral analysis and model atmospheres

Stellar spectra are observed with large telescopes (e.g. at the EuropaenSouthern Observatory, or with the Hubble Space Telescope). Their analyses are performed by comparing with elaborate model calculations. The results tell us about the violent physical processes that are at work.

The Fate of Stars

From the spectral analyses we can infer how stars evolve, and how they finally end their lifes (as white dwarfs, neutron stars of black holes). Hence we can understand better how the stars, being the driving engines of the cosmic circuit of matter, have contributed to the hitherto evolution of our universe.

The diffuse matter component of the Universe

A considerable fraction of the baryonic matter in the Universe exists in the form of diffuse gas. This gas resides in the space between the stars within galaxies (interstellar medium), as well as in the intergalactic space outside galaxies as part of the overall, filamentary network of large-scale structure in the Universe (intergalactic medium).

Quasar absorption-line spectroscopy

Interstellar and intergalactic gas clouds produces absorption signatures in the spectra of bright, extragalactic objects (e.g., quasars). Using high-resolution spectrographs one can identify and analyze interstellar/intergalactic absorption lines from a large number of different elements.

The distribution of gaseous matter in the Universe

From the analysis of interstellar and intergalactic absorption lines we can learn about the distribution and mass of the diffuse gas in the Universe. Moreover, the analysis of the abundance of heavy elements in the interstellar gas delivers important information on the chemical evolution of galaxies from the early Universe until today.