Imagine the Universe!

Dr. Jim Lochner: Stories and Science

photo of Jim Lochner


Jim Lochner first got interested in astronomy when he came across "The Golden Book of Astronomy" in the 2nd grade. His father explained to him a picture illustrating Newton's Third Law and on subsequent nights he and his father went out with a 1.4 inch refractor telescope. Looking upon the rings of Saturn and the Orion Nebula convinced Jim he had found a career.

map of Antarctica
*What is this image?

*What is Jim's BIG question?

Jim received his undergraduate degree in astronomy at Villanova University. During the summers, he did research at Dartmouth College and at Villanova. He entered the physics department at the University of Maryland for graduate work. He did his thesis at NASA/Goddard under Dr. Jean Swank on the aperiodic X-ray variability from the black hole candidate Cygnus X-1.

* Tell me more about Jim's Ph.D. Research!

For his post-doctoral work, Jim escaped the big city and went to the Space Astronomy and Astrophysics Group at Los Alamos National Lab. There he studied long-term variability of X-ray sources using data from the Vela 5B All Sky Monitor. He also studied the timing properties of gamma-ray bursts using data from the gamma-ray burst detector on board the Pioneer Venus Orbiter spacecraft.


Jim joined the HEASARC ( in 1991 and became part of the Guest ObserverFacility ( for the Rossi X-ray TimingExplorer (RXTE) ( in 1992. Since then he has participated in many aspects of the development of the services astronomers use to carry out and analyze their RXTE observations. In particular, he oversees the distribution of calibration data and of data from RXTE's All Sky Monitor. He also assists astronomers in analyzing data from RXTE when they visit our Laboratory.

Research Interests

Jim's scientific interests revolve around questions of "how and why things change?" Jim is most interested in understanding the long-term variability and the timing properties of sources. "Long-term variability" generally refers to changes which occur over the course of weeks, months, or years and "timing properties" refers to whether the variability is regular and periodic, or random (or apparently so). Some questions he ponders include: What causes the long-term periods that we see in X-ray binaries? Is it a third body in the system? Does the accretion disk precess? Can we tell the difference?

On a Typical Day at Work

Jim writes for his job just about every day. He writes documentation and help files for software he has written, feasibility reports for submitted observing proposals, and responses to e-mailed questions about software and analysis techniques for the GOF. Jim answers a lot of email. And we do mean a LOT of email.

In addition to this more technical writing, Jim writes web pages for the Imagine the Universe! and the RXTE Learning Center ( web sites. These web sites are meant for the general public, from middle school aged kids to college undergraduates, to introduce them to astronomy and the phenomena studied at the Laboratory for High-Energy Astrophysics. It can be even more difficult to write for this kind of audience than to write for other scientists.

On a Typical Weekend Day...

During his free time, Jim enjoys woodworking (his favorite tool is his router - and Norm Abram is his hero !) and baseball. Jim is also a storyteller, particularly stories of the stars and of heroes. Jim is often "homesick" for the Southwest - he liked the small town life, the open spaces, and dark night skies while he was at Los Alamos. Jim still enjoys hikes in the woods on sunny days.

Questions and Answers

Q: You mention "summer research" at Dartmouth College and Villanova while you were an undergraduate. What kind of research WAS it? Had you already found high energy (X-rays) to be the scientific love of your life or were you using this time to explore different areas of astronomy?

A: It was primarily to explore different areas of astronomy. During the Dartmouth College summer, I did get to go out for a two week observing run at the McGraw-Hill Observatory on Kitt Peak. That was fun !

So I had not yet found X-rays during those summer stints. However, this does lead to a more interesting story. Back in my earth science class in ninth grade, we had to do a research project on some area covered during the course of the year. Since astronomy was covered, I of course did mine on a topic in astronomy. I chose the topics of black holes, likely because this was when there was just beginning to be some observational evidence for them. About a year before I had to do this project, there was an article in Scientific American about black holes in low mass X-ray binary systems, and the evolution of such systems. Cyg X-1 was mentioned in particular as the prime black hole candidate. So I based my project primarily on that article. We had to do an oral presentation of our topic to the class. Mine was scheduled for the Friday before Memorial Day weekend, as the last talk during our class period, which was at the end of the day. When I got done going through my explanation of X-ray binary evolution, the kids did something they hadn't done for any other talk - they applauded ! (Of course, they may have applauded because school was out for the long weekend !). But more importantly, my earth science teacher (for whom I had a lot of respect) said I'd done an excellent job and that "you should be a teacher - you have the knack for it." It was one of those moments in which you get validation for your abilities and aspirations.

Oh, such memories !!

Anyway, jump ahead 11 years or so (during which time I don't give X-ray binaries or Cyg X-1 any serious thought at all), and what do I find my thesis project to be on - Cyg X-1 !! When did I realize the connection ? Not until I finished - 15 years after my presentation in the ninth grade.

Q: What were the results of your post-doc research at Los Alamos (studying timing properties of gamma-ray bursts)? Did you solve any mysteries of gamma-ray bursts and what causes them to occur? Your thesis research seems to have been so successful! Is science always like that? You set out with a couple of hypotheses and after some number of years of hard work (blood, sweat, and tears...) you can conclude that one is ...

A: No, I solved no mysteries of gamma-ray bursts. I studied a phenomenology of bursts which seemed to consist of distinct multiple events. Since then, a few people have tried to follow through using the more complete and better data afforded by BATSE, but I'm not familiar with those results.

Hmm, how does one consider one's research a "success" ? I suppose you have to consider it a success in terms of coming to a conclusion about a hypothesis. Even if the conclusion is "That was wrong !" In my thesis, the chaos analysis was an interesting idea that was hampered by a methodology that at the time was not fully worked out (and has since been replaced by more robust methods) and by noisy data. The shot noise analysis was a necessary extension of ideas that had been discussed. I consider my analysis "successful" in that I was able to get definite answers, but somehow the idea embodied in the work just hasn't caught on.

Publication Date: October, 1996

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