NASA Insignia
Imagine the Universe!

Profile: Dr. Stefan Immler


Stefan was born in the 1,000 year old town of Nabburg in the Bavarian countryside of Germany. He developed an interest in astronomy when his parents bought him a small telescope, which he used to observe planets from his balcony. Then when he was 12, after watching Carl Sagan's "Cosmos" on TV, Stefan decided to become a professional astronomer.

His first science project in high school was to determine the mass of Jupiter by observing the orbits of its moons. He was able to do this at an observatory in Regensburg, Bavaria that dates back to the 17th century and was built shortly after Johannes Kepler developed his laws of planetary motion there. Ironically, this was the last time Stefan ever set foot inside an observatory.

Off to College

When he was 19, Stefan moved to Munich to pursue a career in astronomy and physics at the Ludwig Maximilians University, chosen because it has the highest concentration of astronomers in Europe and a wide range of astronomy classes. During his studies, Stefan spent one day a week and all semester holidays at the Max Planck Institute for Extraterrestrial Physics (MPE), building and testing detectors designed to study the composition of the solar wind, among other things, for space missions such as SOHO, Cluster, and FAST.

After his undergraduate studies, he spent one year at the Imperial College of Science, Technology, and Medicine in London studying astronomy and polishing his high-school English. For his M.Sc. and Ph.D. projects he returned to Munich and joined the MPE, which was then operating the X-ray observatory, ROSAT. He used data obtained from the Einstein and ROSAT missions to study X-ray emission from galaxies and supernovae.

A Career Takes Off

In 2000, just a few weeks before he finished his Ph.D. thesis, Stefan got a phone call from a professor at the University of Massachusetts. He was offered a job as a postdoctoral researcher to study X-ray emission from astronomical objects inside galaxies, such as black holes, binary systems, hot gas, and supernovae, using data from NASA's Chandra observatory. He packed right away and moved to the US, where he has been ever since.

Stefan's second postdoc position was at Penn State, where he worked on active galactic nuclei. Then in 2004 he came to NASA GSFC as a support and research scientist for the XMM-Newton observatory and Swift mission. He also began teaching cosmology to 3rd and 4th year non-science majors at the University of Maryland in College Park.


Chandra Composite

Composite Chandra X-ray (blue) and Palomar infrared (red and green) image of supernova remnant W49B. (Credit: NASA/CXC/SSC/J. Keohane et al.)

Stefan's research emphasis is on the X-ray and ultra-violet (UV) emission from supernovae. Supernovae occur when stars with masses more than 10 times that of our Sun run out of fuel to burn. At that point there is no longer enough energy being produced to counteract the gravity of the star, so it implodes. When the core reaches a critical density, much of that in-falling matter is violently bounced back out into space by powerful shockwaves, resulting in - you guessed it - a supernova.

Supernovae can outshine an entire galaxy and produce spectacular visual images. Even using a backyard telescope, they are often easy to spot in neighboring galaxies. In some cases the shock from the explosion will slam into the dense gas around the original star, which causes it to heat to millions of degrees and emit X-rays. By studying the X-rays from supernovae, we can study the origin, chemical composition, and density of the gas around the original stars. Stefan's goal is to study the environments of supernovae and their transition from young supernovae to old supernova remnants of the explosions.

Stefan's work was used in the development of these two posters:

Nearby Galaxies

Swift Observations of Galaxies

Swift observatory optical (left), ultraviolet (middle), and X-ray images (right) of nearby galaxies. The visible (V, B, and U filters) and ultraviolet (UVW1, UVM2 UVW2 filters) images were obtained with the UVOT instrument onboard Swift. The X-ray images (0.2-10 kV) were obtained simultaneously with the Swift XRT instrument. (Credit: NASA/Swift/S. Immler)
Click image for larger version. [PDF Version]

Supernova Host Galaxies

Swift Observations of Supernovae

Swift observatory optical (left), ultraviolet (middle), and X-ray images (right) of nearby supernova host galaxies. The visible (V, B, and U filters) and ultraviolet (UVW1, UVM2 UVW2 filters) images were obtained with the UVOT instrument onboard Swift. The X-ray images (0.2-10 keV) were obtained simultaneously with the Swift XRT instrument. (Credit: NASA/Swift/S. Immler)
Click image for larger version. [PDF Version]

Learn more about Stefan's recent work at:

Typical Day

Stefan starts his day by answering emails from colleagues around the world. He attends daily planning telecons for Swift, followed by other meetings and telecons about the status of Swift instruments. During the day, he usually spends some time with students, discussing their projects. Sometimes there are phone calls from journalists, which he happily answers. Most of the afternoon is devoted to analyzing data and writing publications. After going to the gym, having dinner, and watching a movie with his wife, he concentrates on analyzing data from some of his own favorite observations, and he prepares for the next day's meetings and telecons. Stefan is no couch potato!

The Best Part of Being a Scientist

For Stefan, it's the travel. He loves to attend meetings in different countries and learn about the culture and history of different people. Some of his favorite trips have taken him to China, Argentina, Spain, France, and Italy. As a scientist he also enjoys opportunities to gain a profound understanding of how the Universe ticks and how things work.

Other Interests

Stefan likes to have a balanced life in terms of creativity, fun, and professional work. He likes to play tenor saxophone, which keeps his creative juices flowing and lets him forget about work for a while.

Questions and Answers

If you weren't a scientist, what would you be?

Probably a poor musician - skills permitting. I have a recording studio and would love to pursue music more seriously, record and promote talented musicians, and record some of my own stuff. My favorite styles of music are electronic dance music, as well as old-fashioned jazz. My wife and I enjoy going out to jazz bars in the historic U Street district of Washington, DC, but we also go to bars and clubs to listen to more contemporary electronic dance music.

If you could invite people throughout history to your house for dinner, who would you invite?

I would like to sit down with Giordano Bruno, have a glass of wine on a warm Italian summer evening, and chat through the night. He is one of the most inspiring persons to me because he had the courage to stand up for his thoughts and didn't give in to authority. About 400 years ago, when galaxies were not even discovered yet, he had already speculated about numerous inhabitable worlds in the Universe, how vast the Universe is and that it should be filled with various form of life. Not even the Inquisition could stop his curious mind.

The other person I would like to visit with is Albert Schweitzer, who was a doctor, humanitarian, philosopher, and famous organ player, among many other interesting things. He was one of the last true universal geniuses. He gave up all his wealth, moved to Africa, built a hospital there and spent the rest of his life helping African kids and fighting diseases. What dedication and commitment!

And just for the fun, I would invite Ben Webster, my favorite saxophone player, into my house for a jazz jam session.

Who was your favorite teacher?

In high school I had a very gifted physics teacher, Mr. Lohmann. Most of my science teachers throughout my life were very 'old school', wearing three piece suites and ties, and they were very strict (I am sure that if they had been allowed, they would have carried a cane and hit the students). One of my math and physics teachers even told my parents that I didn't have the 'stuff' to go to University. Well, as you can imagine, this was not one my favorite teachers.

Mr. Lohmann was quite the opposite: he was a very relaxed, friendly and excellent science teacher who had my respect because he was very good at sparking the students' interest in science - a true gift. It was an epiphany for me to see that you can be a scientist and still be 'cool' (not to mention that he also operated a non-profit culture center and wine garden in his free time - where I spent a lot of time).

What do you think is the most important technological advance that has occurred in your lifetime?

Communication technologies. It's amazing how easily people can communicate these days and how small our planet has become. No person is isolated anymore, regardless of what remote part of the planet he or she lives in.

Do you have a family? A pet?

I am married to Silvina, who is a scientist and very talented physics teacher at Howard University in downtown DC. Since she is from Argentina and I am from Germany, we travel a lot to see our families. Even though they are from different continents, the two families have a lot in common (my German brother-in-law was born in Argentina, and my Argentinian brother-in-law went to a German school). This gives you a nice perspective on the diversity of people on this Earth, and also how much we all have in common in the end. No pets, just some tropical fish (they don't need to be walked and don't bark at night).

What is the one big dream you have, or the one thing you would like to accomplish during your lifetime?

I would like to still be alive when we establish contact with a different form of life in another part of our galaxy. I think it is not a question of "if" but "when" it will happen. My hope is that this might make people on Earth realize that we are all one species and that we should learn to get along.

Publication Date: August, 2006