6. Behind The Gamma-rays

As unbelievable as it may sometimes seem, gamma-ray astronomers are real people too! Below you will find brief introductions to 4 well-known gamma-ray astronomers, Drs. Thomas Cline, Neil Gehrels, Kevin Hurley, and Chryssa Kouveliotou. Their stories run the entire history of gamma-ray astronomy, and their work has helped us to understand the high-energy Universe a little bit better. But you have to be truly logical to discover some of their more personal preferences!

Dr. Cline was conceived in Manchuria on his mother's third trip around the world, but she traveled to Peking China to the only maternity hospital she trusted in the Orient to have him born. He graduated from Hiram College in Ohio with a major in mathematics, and from St. Lawrence University. in New York State for an extra year of physics. He obtained his PhD from MIT in Physics in Jan. 1961. Cline's PhD thesis became the first published experiment in gamma-ray astronomy, from a 1960 balloon-borne 1000-lb instrument to search for cosmic gamma-rays. This experiment established the first valid upper limit, but made no positive detection.

After graduation, Dr. Cline joined the cosmic ray group at NASA’s Goddard Space Flight Center. After 12 years of research on solar flares and interplanetary particles, the confirmation of the discovery of GRBs in 1973 brought him back to gamma-ray astronomy. His Helios-2 instrument, launched in January 1976 and put into an orbit 2 AU from the Sun, was the first experiment flown to study GRBs. By combining data from Helios-2 with Earth-orbiting satellite data, it was shown that GRBs could not have originated from known X-ray emitters or from any other previously identified sources. Dr. Cline also speculated that there was a different type of gamma-ray transient being detected, one uniquely separate from other GRBs. Thirteen years later, it finally became understood that these soft gamma repeaters (SGRs) were indeed a separate phenomenon, when the Japanese ASCA satellite was pointed at a supernova remnant and saw one occur.

When asked what he prefers to do in his time away from work, Dr. Cline included in his list "I like to read, watch classic movies, and play with my grandchildren."

Dr. Neil Gehrels is currently the Head of the Gamma-ray & Cosmic ray Astrophysics Branch at NASA’s Goddard Space Flight Center. He received bachelor’s degrees in Music and in Physics from the University of Arizona in 1976. He obtained his PhD in Physics from the California Institute of Technology in 1981. He has served as the Compton Gamma-ray Observatory (CGRO) Project Scientist since 1991 and the INTEGRAL Mission Scientist since 1995. CGRO is one of NASA's Great Observatories and is the first mission to comprehensively survey the gamma-ray sky. Dr. Gehrels is active in some NASA advisory committees and is the Secretary/Treasurer of the Division of Astrophysics of the American Physical Society. His wife, Ellen Williams, is a professor of physics in the surface physics group at the University of Maryland. The Gehrels have two children, Tommy and Emily, born in 1987 and 1990.

Dr. Gehrels is a research scientist in gamma-ray astronomy active in instrument development and data analysis. His interests include nuclear astrophysics, active galaxies, and black holes. He is also the Principal Investigator for a new NASA mission called Swift. Swift is a mission that will study GRBs.

Dr. Kevin C. Hurley received his BA in Physics from the University of California, Berkeley in 1966. Four years later, he received his PhD in Physics from the same institution. He has authored or co-authored over 450 articles in refereed journals, books, and conference proceedings. Currently, he holds the titles of Research Physicist and Space Sciences Laboratory Senior Space Fellow at UC Berkeley. He is the principle investigator for the solar and cosmic gamma-ray burst experiment aboard the Ulysses spacecraft.

About himself, Dr. Hurley says, "I run the Ulysses GRB experiment, which is in a heliocentric orbit. I also compare my data with the data from other spacecraft such as CGRO, KONUS-WIND, SAX, NEAR, etc. This keeps me on the road a lot, but when I'm home, I like to work on my house or my old cars." Dr. Hurley is just being modest about his accomplishments. He founded and still heads the Interplanetary Network (IPN), which uses spacecraft in both Earth-orbit and elsewhere in the solar system to establish the locations of GRBs. Before the detection of afterglows in other wavelengths, the triangulation method used by data from the IPN provided the most sensitive determination of locations of the events.

Dr. Kouveliotou received her Diploma in Physics from the University of Athens, Greece, in 1975. She later received her PhD in Astrophysics at the Max-Planck Institute of Extraterrestrial Physics and Technical University of Munich, Germany, in 1981.She has been working on gamma-ray bursts since the start of her Ph.D. work in 1978; current research projects include ground-based follow-up observations of GRBs, X-ray studies of X-ray binaries and soft gamma repeaters (SGRs), and variability studies of accreting black holes. In a recent paper she established the connection of SGRs with young neutron stars with superstrong magnetic fields (magnetars). She has co-authored over 250 papers in refereed journals and conference proceedings, and is co-editor of 2 books. Presently, she is a Senior scientist at the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-ray Observatory. In addition, she serves as the Director of the USRA Astronomy program in Huntsville and the Deputy Director of the Institute for Space Physics, Astrophysics and Education (ISPAE), a co-operative agreement between NASA’s Marshall Space Flight Center and the University of Alabama in Huntsville.

Dr. Kouveliotou is an avid cook. She finds it especially challenging to figure out how to incorporate her native Greek cooking into the fresh produce available in US supermarkets. Her husband, astrophysicist Jan van Paradijs, serves as the "taste tester" for her creations. She is also interested in the origins and evolutions of languages, and archeology. Currently, she is trying to learn how to garden in the Alabama climate.

Activity

When asked, Drs. Cline, Gehrels, Hurley, and Kouveliotou told us a little about what they consider their jobs to be, what their favorite kinds of food are, and what they enjoy doing in their time away from work. See if you can match each scientist to his or her preferences!

Here are your clues:

When asked, Drs. Cline, Gehrels, Hurley, and Kouveliotou told us a little about what they consider their jobs to be, what their favorite kinds of food are, and what they enjoy doing in their time away from work. See if you can match each scientist to his or her preferences!

Here are your clues:

• Dr. Kouveliotou likes Greek food, but in her spare time she prefers not to travel.

• Dr. Cline is an experimental physicist.

• The scientist who likes Italian food is neither an experimental physicist nor a hardware designer.

• The scientist who does not like Italian or Japanese food enjoys listening to classical music.

• Dr. Hurley is a data analyst/archivist.

• The hardware designer enjoys mountaineering, but not Greek food.

• The scientist who loves to eat fruits and veggies enjoys flying airplanes.

• Two of the scientists are data analysts/archivists.

You can use the chart below in solving this problem. Enter all the information obtained from the clues by using an "X" to indicate a definite "no" and a "•" to show a definite "yes" for the corresponding cell in the chart. Remember: Once you enter a definite yes ("•"), place a no ("X") in the remaining cells in each row and column that contain the "•".