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The astronomy community lost a good friend when Tom Metcalf was killed in a skiing accident on Saturday, 7 July 2007, in the mountains near Boulder, Colorado. Tom was widely known for prolific work on solar magnetic fields, hard-X-ray imaging of solar flares, and spectral line diagnostics. He was often characterized as "one of the nicest guys in science."
Born October 5, 1961 in Cheverly, Maryland, to Fred and Marilyn, Thomas R. Metcalf joined his sister, Karen, two years his elder, in a close family that loved sailing, inquisitiveness, and the natural world. Sibling rivalry (usually a Tonka truck intruding on Barbie's sub-table "castle") melted when Tom and Karen collaborated on elaborately engineered room-sized blanket-forts. Tom confidently signed up at age of three to crew for his family's sailboat; when the family moved to California in 1966, as Tom's father took a Professor of Mathematics position at the University of California Riverside, Tom's love for sailing was well-established. Week-long cruises or short trips in the harbor were all fun; when school friends came aboard, it was even better--if "only slightly too crowded" from the adults' points of view.
Tom's introduction to astronomy began one cold, very clear, December night in the early 1970s, on a family camping trip to Death Valley. The "Sidewalk Astronomers of San Francisco" had lined the sidewalk near the visitors' center with all sorts of telescopes for public viewing. Soon after, Tom and his boyhood friend Jim O'Linger were building their own scopes, attending "Amateur Telescope Makers" conferences, and Tom was setting up his scope on a sidewalk for public viewing. In 1986, Tom set up his telescope on the bluffs above Dana Point Harbor, and gave numerous strangers a stunning view of Halley's Comet.
His interest in physics and mathematics became evident during Tom's last years in high school (Poly High in Riverside), and as a senior he qualified to take freshman Physics at the University of California-Riverside (UCR). Computers entered Tom's life then as well: In a 1970s example of technological generation-gapping, he learned to program his father's new desktop computer. Soon, he was exploiting UCR's time-shared machines for that honorable endeavor, writing computer games. Those "great games that Metcalf wrote" brought Tom's father quite a reputation amongst the undergraduates.
Tom earned his B.A. in Physics from the University of California-San Diego (UCSD) in 1983. He continued at his alma mater for graduate school in 1984, and joined the "solar group" there headed by Dr. Richard C. Canfield. After earning an M.S. in Physics in 1985, Tom moved to the Institute for Astronomy (IfA) of the University of Hawai`I, with Dr. Canfield's group, in 1986. Tom completed his Ph.D. through UCSD in 1990, "Flare Heating and Ionization of the Low Solar Chromosphere", then stayed at the IfA as first a Post-Doctoral Fellow and then Associate Astronomer. While at the IfA, his participation in Mees Solar Observatory operations and Yohkoh mission support developed along two themes: the observation, analysis, and interpretation of solar magnetic fields, and hard X-ray imaging of solar flares. Tom was a key member of the group that demonstrated the hemispheric "handedness" trend in the twist of solar active region magnetic fields. He applied his considerable mathematical expertise to the application of a "pixon" algorithm for hard X-ray image reconstruction. To this day, this approach remains the algorithm of choice for the Reuven Ramaty High Energy Solar Spectroscopic Imager [RHESSI) mission, on which he was a Co-Investigator.
Tom moved to the Lockheed-Martin Solar and Astrophysics Laboratory (LMSAL) of Palo Alto, California, in 1996, once again sharing an office with Dr. Jean-Pierre Wülser, his old office-mate from the IfA. During his tenure at LMSAL, Tom became a Co-Investigator on several space experiments: the X-Ray Telescope (XRT) on the Japanese Hinode mission, and the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) on the Solar Dynamics Observatory (SDO). During this time Tom continued work on interpreting solar magnetic fields, specifically the pioneering use of the Na-D2 spectral line to map the solar chromospheric magnetic field.
In 2005, Tom joined the growing solar group at NorthWest Research Associates' (NWRA) division in Boulder, Colorado. Tom was an integral part of efforts comparing algorithms for magnetic field data analysis and coronal diagnostics afforded by the spectacular new data from Hinode. Of note were his work on 180∘ disambiguation algorithms for vector magnetic-field data and non-linear force-free extrapolation methods for modeling the coronal magnetic field.
Tom's professional interests were so wide and varied that colleagues who survive him are continually uncovering projects to try to bring to closure. Every meeting brings new heartfelt condolences and shy inquiries, "...if you don't mind, Tom had some data for me . . . could you . . . ???" He developed a navigation package using Hewlett-Packard calculators, still used by many sailors. Tom's IfA-vintage hurricane-tracking website still sees visitation spikes when major storms threaten. At the time of his death, Tom had 77 publications with easily over one hundred colleagues, including his father. Tom represented NWRA/Colorado Research Associates at the recently formed "Boulder Solar Alliance"; through it, a new National Science Foundation Research Experience for Undergraduates program was funded, and many Boulder-area research groups, including NWRA, hosted students in its 2007 inaugural summer.
Tom was routinely teased as a "closet granola-head" by friends and family; as he moved inland his interests switched to mountain bike riding, rock climbing, and year-round skiing. Tom would eagerly join in any new adventure that sounded interesting. He was an avid bike commuter who relished the challenge of learning to ride in snow and ice. He recycled everything.
Tom is survived by his daughters Shanon Brower, Alyssa Metcalf, and Keri Metcalf to whom he was a devoted father, their mother Janet Biggs, his parents Fred and Marilyn Metcalf, and his sister Karen (Metcalf) Swartz. A vast array of friends, colleagues, and extended family will also sorely miss him.
To honor Tom's long-standing support for young researchers in solar physics, Tom's family and the Solar Physics Division of the AAS have established a travel fund for young scientists, to which contributions are most welcome:
The Thomas Metcalf SPD Travel Fund American Astronomical Society 2000 Florida Ave., NW Suite 400 Washington, DC 20009-1231, USA https://members.aas.org/contributions/ Thomas_Metcalf_SPD_Travel_Fund.cfm
Obituary written by: K. D. Leka (NorthWest Research Associates)
BAAS Citation: BAAS, 2007, 39, 1074
SAO/NASA ADS Bibcode: 2007BAAS...39.1074L