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Andreas Müller



Author and reader have a common interest just as artist and audience: interest in something beautiful. The beautiful thing that I present on my website is Nature - especially nature above us at the sky. It is not only an external, purely contemplative beauty that is characterized by nice coloring and shape but also some inner beauty that manifests in fascinating order and arrangement. Knowledge in inner beauty enhances external beauty and gives awe and humility of nature. So, we participate in sensing the beauty. We observe, model, understand and find ourselves in a sophisticated and complex world: our Universe.

We should not take for granted the way things are. I would like to give an insight in astronomy and astrophysics - the oldest discipline of natural sciences that awoke human's curiosity. Astronomy is one of the facets of modern science that proves the beauty of nature.


Why launching this website?

This website provides information about astrophysics. However there is more! It was anticipated in the prologue that there is something behind pure information, some kind of superstruction. Information building blocks are linked together to something global. Therefore, I decided to write down some of my interests - especially aspects from astrophysics. This knowledge implies aspects to arts.
But there is also another motivation: I wanted anybody to have an easy access to astrophysical knowledge. Hence, I developed a German dictionary for astrophysics. Now, it contains 550 entries with a compact explanation. Additionally, I present selected research topics, e.g. black holes. As intended the dictionary provides fast access to pure and compact information whereas the web essays link together these building blocks to something global: deep insights into nature.
Dear English-speaking people: I must apologize that these resources are only in German available. However, you may want to explore my popular and scientic talks that are partly in English.



1980 - 1993
Abitur certificate, grade: 1,6
1994 - 1995
community service
1995 - 2000
Master of Science (Dipl.-Phys.), grade: very good
Diploma thesis: Emission line profiles of accretion disks around rotating black holes at the State Observatory Heidelberg (Landessternwarte LSW)
supervisors: Prof. Dr. Max Camenzind (LSW), Prof. Dr. Jochen Wambach (TUD)
2001 - 2004
PhD in astronomy at the Ruperto-Carola University in Heidelberg, located at LSW
Doctor rerum naturalium in astronomy (PhD), magna cum laude
title of PhD thesis: Black Hole Astrophysics: Magnetohydrodynamics on the Kerr geometry
supervisors: Prof. Dr. Max Camenzind (LSW), Prof. Dr. John Kirk (Max-Planck-Institute for Nuclear Physics in Heidelberg)
2005 - 2007
Researcher (Postdoc) at the Max-Planck-Institute for Extraterrestrial Physics (MPE) in Garching in the X-ray group of Prof. Dr. Günther Hasinger
since 2007
Scientific Coordinator in the Cluster of Excellence "Origin and Structure of the Universe" at the Technical University of Munich located at the Campus Garching



I am particularly concerned with relativistic astrophysics, e.g.

My research interest is also directed to neighbouring branches such as cosmology, modern gravity theories, and astroparticle physics.

Diploma thesis

In my diploma thesis (2000), I treated the problem of light propagation in the vicinity of rotating black holes. Astronomers are interested in this aspect because of they found a number of candidates in the cosmos that fit nicely the features of black holes. These black hole candidates emit also radiation from their surroundings. This radiation carries information about the black hole and its neighbourhood - especially about the matter stream flowing into the hole, the so-called accretion flow. The flow may flatten and take the form of an accretion disk.
An interpretation of observational data requires theoretical understanding of the source. Mathematical and numerical techniques of theoretical physics provide a suitable approach to simulate on a computer what's happening. In my diploma thesis I applied a certain method called relativistic ray tracing. This technique allows to visualize images of accretion disks on a computer - relativistically correct! The black hole strongly distorts the usual images due to the fact that it acts like a gravitational lense. Light and any kind of radiation is bent by the curved space-time.
A special observational feature in X-ray astronomy is the relativistically broadened emission line - mainly emitted by ionized iron that constitutes the accretion disk. These relativistic iron K lines can also be simulated via ray tracing. Finally, observed and simulated lines can be compared. Then, astronomers get a physical understanding of the source and are able to derive parameters of black hole and accretion flow.
Typically, this model can be applied to AGN and X-ray binaries. A new aspect of my work in 2000 was the consideration of a more complex plasma kinematics beyond pure rotation. Hence, it became possible to investigate the influence of an overlayed radial plasma motion in computer simulations. Main result was that radial drift motion enhances gravitational redshift effects and lowers the line flux especially at the red wing. For details, please have a look into the following resources:

PhD thesis

I continued to wor on black holes in my PhD thesis. The challenge was to understand the kinematics of matter near the hole. Main question was: How does a magnetized fluid fall into a rotating black hole?
Therefore, I worked on magnetohydrodynamics (MHD) in curved spacetime (General Relativistic Magnetohydrodynamics, GRMHD). My dissertation presents black holes in Relativity and astrophysics, introduces into accretion physics and non-radiative GRMHD and reports on GRMHD codes. Concerning Kerr ray tracing, a new model is presented which includes also radial plasma motion towards the hole.
In particular, the PhD thesis ius dedicated to the formation of relativistic Jets by rotating black holes (see Frame-Dragging and Poynting fluxes in the German online dictionary). This theoretical research is connected to an understanding of the centres of galaxies and give insight in the centre of our own galaxy, the Milky Way, too.

  • DOWNLOAD my PhD thesis Black Hole Astrophysics: Magnetohydrodynamics on the Kerr geometry, pdf (9.9 MB) or zipped ps (14.4 MB)




Müller, A. & Camenzind, M.: Relativistic emission lines from accreting black holes - The effect of disk truncation on line profiles, Astronomy & Astrophysics 413, 861, 2004; pdf


Müller, A.: Wirbel der Raumzeit - Die Astrophysik rotierender Schwarzer Löcher, Sterne und Weltraum 10, 2004; pdf


Müller, A.: Black Hole Astrophysics: Magnetohydrodynamics on the Kerr geometry, PhD thesis, Ruperto-Carola University Heidelberg, 2004; pdf


Hasinger, G. & Müller, A.: Active Cores in Deep Fields, proceedings to the symposium of the International Astronomical Union No. 230: Populations of High Energy Sources in Galaxies, Aug 15-19 2005, Dublin, Eds: E.J.A. Meurs & G. Fabbiano; pdf, preprint pdf


Müller, A. & Wold, M.: On the Signatures of Gravitational Redshift: The Onset of Relativistic Emission Lines, Astronomy & Astrophysics 457, 485, 2006; pdf, preprint pdf


Müller, A. & Hasinger, G.: Iron K lines of AGN in the X-ray background, proceedings to Einstein's Legacy - International conference on relativistic astrophysics and cosmology, Nov 7-11 2005 in Munich, Eds: B. Aschenbach, V. Burwitz, G. Hasinger (MPE) & B. Leibundgut (ESO)


Müller, A.: The onset of General Relativity: Gravitationally redshifted emission lines, Astronomische Nachrichten 327, 1024-1027, 2006; proceedings to the ESAC/XMM-Newton Science Operations Centre Workshop: Variable and Broad Iron Lines around Black Holes, Jun 26-28 2006 in Madrid; preprint pdf


Müller, A.: Experimental Evidence of Black Holes, invited seminar talk at the School on Particle Physics, Gravity and Cosmology, Aug 21 - Sep 02 2006 in Dubrovnik, Proceedings of Science (P2GC) 017, 2007; Eds: L. Bonora, S. Fajfer, R. Iengo, D. Klabucar, S. Pallua, I. Picek; all conference proceedings, pdf, preprint pdf


Müller, A. & Aschenbach, B.: Non-monotonic orbital velocity profiles around rapidly rotating Kerr-(anti-)de Sitter black holes, Classical and Quantum Gravity 24, 2637-2644, 2007; preprint: arXiv:0704.3963 [gr-qc]



Exercises and substitute for Prof. Dr. Max Camenzind: Lectures on General Relativity, University of Heidelberg
Supervisor at the practical courses in astronomy and astrophysics with Prof. Dr. Max Camenzind, Landessternwarte Heidelberg


Public relations

I have fun and success in doing popular science:

Website for astronomy & astrophysics

Highlights: dictionary for astrophysics, articles, essays (all in German); since 2000

public talks

at observatories, planetaries, schools, universities, e.g. in Berlin, Munich, at the MPE Garching, Fulda, Heidelberg, Recklinghausen, Solingen, Stuttgart, Zweibrücken - List of all talks, selection of talks for DOWNLOAD

popular science articles

in German magazine for astronomy "Sterne und Weltraum" 10/2004: Wirbel der Raumzeit, DOWNLOAD pdf

on the website Einstein online: Luminous disks: How black holes light up their surroundings und Active black holes: Ultra-hot cosmic beacons; 2005 und 2006

in German popular science magazine Astronomie Heute in category "Readers ask - Experts answer" about black holes (April 2006)

scientific advice

at the German web project Sterngucker dealing with astronomical praxis and basic astronomy (Bayerischer Rundfunk 2006)

at popular science articles, e.g. in the German popular science magazines bild der wissenschaft (Februar 2007), GEOkompakt "Das Universum" (März 2006), Spektrum der Wissenschaft (Mai 2005)

at German popular science books, e.g. "RAAbits Physik" (for teachers, published 2007), and the German book "Tunnel durch Raum und Zeit" by Rüdiger Vaas (published 2005)

at developing German edutainment software Ruhemasse Null; 2004

at the Einstein exhibition at the Landesmuseum für Technik und Arbeit, Mannheim; 2004 und 2005

at German TV shows, e.g. Genial daneben (Sat.1)

interview at German radio station Radio Eins

about black holes, DOWNLOAD mp3 (3.6 MB); 2005

I am happy to have these possibilities and to give people insights into these fascinating science topics. No other discipline than astronomy is so much fundamental research, no other discipline than astronomy has so much impact on human culture - until today.


Looking inside

Astrophysics is really important to me but I also have some further interests such as interdisciplinarity, philosophy, languages, and rhetorics. Working in astronomy and particularly in cosmology stimulates questions where natural sciences and the arts overlap. Therefore, I have written some essays (only in German) which treat such topics.

I am interested in rhetorics, languages, speech, evolution of language, linguistics, semantics and etymology. The origin of expressions and idioms, their adequate use is exciting and challenging. On one hand, there is an psychological aspect: the spoken language unreveals many features of the speaker; on the other hand, the word is an image of human evolution, formed, merged and transformed in centuries.
History of language (with regard to dialects, language reforming, artificiel languages, even programming languages) shows always evolutionary steps of man.

Knowledge and information are very important for me. I love it to dive into an interesting context. Apart from the classical source for information, the book, the modern IT medium internet intervenes and has become an unexploitable source of knowledge that I don't want to miss neither professionally, nor in private life. I hope that my website contributes to that idea so that you can find some useful information.



My favorite relaxing hobbies are mountain biking, playing guitar, music and billard.


My biggest treasure is my family: my wife Anja and my sons Pascal und Dominic.


We return to aspects that were discussed in the prologue: Our interest in something beautiful gives us insights into the context of the whole thing. This knowledge brings us back to ourselves. We realize that we are human beings in the universe, something small in something large and something complex in something simple.

Don't take anything for granted! Observe, read, understand and be astonished about the miracles of the universe!

Yours Andreas Müller

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