Astrophysicists study what makes the universe tick: the fundamental physics of stars, galaxies, and all the other celestial stuff of the universe. Advancing our understanding depends strongly on ever-more-powerful space observatories.
Surely you've heard of a few, such as Hubble, Chandra, Spitzer, Compton, Fermi, and Swift? Or perhaps the James Webb Space Telescope (JWST), which is scheduled for launch in 2018. The massive spacecraft will unfurl 18 mirror segments like flower petals to form a 6.5-meter-wide (21.3 feet) array.
Space astronomy is an expensive and high-stakes game. The observatories that make it into space influence the work and careers of astrophysicists on Earth for years, so astronomers have to decide carefully, as a community, where to put their limited resources.
This week, Nicholas White, director of the Sciences and Exploration Directorate at Goddard Space Flight Center, assumes an additional position as the newly elected chair of the High Energy Astrophysics Division (HEAD) of the American Astronomical Society (AAS). White's election to the post was announced at the AAS meeting this week (Jan. 8-12) in Austin, Texas. He begins his 6-year term on January 13 as Vice Chair (for 2 years), and then Chair (2 years), and finally Former Chair.
Here at Goddard, White manages the work of scores of scientists who study Earth, the sun, the solar system, and the wider universe. As "head of the HEAD," White will help lead the larger high-energy astrophysics community of which NASA is only one part. The decisions that the HEAD will facilitate in coming years will have impacts on astrophysics well into the 2020s.
White is an X-ray astronomer, and his career has paralleled the development of space-based X-ray astronomy. "I started in X-ray astronomy when it was still a fairly young field," White says. "The first satellites were being launched."
He received a B.Sc. degree in Physics from the University of Leicester in 1970. That same year, NASA launched the first Earth-orbiting satellite dedicated entirely to celestial X-ray astronomy. It was called the Small Astronomical Satellite 1 (SAS-1), later renamed Uhuru. White did his graduate work at Mullard Space Science Laboratory at University College London, earning his Ph.D. in Space Science in 1977.
As X-ray astronomy and other aspects of astrophysics expanded, "the scientists wanted a forum where they could promote that science in the AAS," White says. That forum was the HEAD. The AAS has five such divisions, including the Division of Planetary Science, the Solar Physics Division, the Division of Dynamical Astronomy, and the Historical Astronomy Division.
Every 12-24 months, the HEAD sponsors a special division meeting. "For three or four days, we really focus on the science coming out of various missions," White says. "Having it in a more focused arena allows people to come together, collaborate, discuss results, and form new collaborations."
One of White's duties as Vice Chair will be to work with the six-member Executive Committee (also elected) and the other HEAD officers to set the agenda for the HEAD division meeting as well as the high-energy astrophysics portion of the general AAS meeting. White says one of his priorities will be to ensure that the conferences are "well structured, include all aspects of high energy astrophysics, pick speakers who engage the audience, and include a diverse range of speakers."
The division meetings also highlight the latest findings from science missions. The next meeting, in the spring of 2013, will come right after the planned March 14, 2012 launch of the Nuclear Spectroscopic Telescope Array (NuSTAR) mission. It will be the first Earth-orbiting observatory able to focus high-energy, or "hard," X-rays into an image.
Every year, the HEAD awards the Bruno Rossi Prize for "a significant contribution to High Energy Astrophysics, with particular emphasis on recent, original work." It also confers a Dissertation Prize to a young scientist and David Schramm award to exceptional science journalism about the field.
White says he would also like to work with the HEAD to find ways to acknowledge exceptional achievement beyond the scope of these few winner-take-all prizes. "I'm very keen to see if there are other ways to recognize people," he says. "These prizes are hard to come by, and there is a lot of other great stuff going on that needs to be recognized."
White will lead the HEAD at a crossroads for space-based astrophysics. Plans for large new international X-ray and gravity wave missions have been delayed or scaled down, partly due to the cost of keeping JWST on track for its 2018 launch. High-energy astrophysicists must reassess priorities and decide where their resources should go.
"There is a lot of concern in the community about the long-term prospects for X-ray astronomy, gamma ray astronomy, and gravitational wave astronomy," White says. "The HEAD is the forum where those issues can be discussed. At the next HEAD meeting that will be a very important discussion, as it was at the last HEAD meeting."
No big new missions can be considered until JWST is up and away. But in the meantime, high-energy astrophysicists can look forward to a few exciting new NASA missions to launch.
In addition to NuSTAR, there is the Gravity and Extreme Magnetism Small Explorer (GEMS). Launching no earlier than July 2014, GEMS will use X-ray optics to explore the magnetic fields around neutron stars and the distorted space around black holes.
Also on deck, with key NASA participation is the Japanese Astro-H mission. This satellite will do both imaging and spectroscopy using high-energy (hard) X-rays, and is slated for launch on February 15, 2014.
After these missions are underway, what is the future of space-based astrophysics? After JWST begins operating, the Wide-Field Infrared Survey Telescope (WFIRST) is likely to be the next big NASA astrophysics mission, White says. WFIRST will focus on exoplanet and dark energy research and other topics.
The HEAD, and its leadership, are influential. It's a big honor, but also a big responsibility. White takes it on in addition to managing the largest Earth and space science research organization in the world.
First of all, White says, "I wouldn't have taken it on if I didn't think I could make the time to do it." But more important, he thinks it's important for NASA scientists to be active in their communities, whether serving on committees here at Goddard Space Flight Center or participating in the professional societies like AAS.
"Doing something where you are giving back to the community you are part of is important," he says. "It's important for us to be active in the communities we are part of, not just focused on what we're doing here. People are very busy, but it's important to make the time."
What's next for space-based astrophysics after the launch of the James Webb Space Telescope? The American Astronomical Society's High Energy Astrophysics Division (HEAD) will help to figure it out, chaired by Goddard's Nicholas White.
Nicholas E. White, Director of the Sciences and Exploration Directorate, Goddard Space Flight Center.