Free Astronomy Magazine January-February 2015

SPACE CHRONICLES A n international team of re- searchers analyzing decades of observations from many facilities — including the W. M. Keck Observatory on Mauna Kea, the Pan- STARRS1 telescope on Haleakala and NASA's Swift satellite — has discover- ed what appears to be a black hole booted from its host galaxy. The team was led by Michael Koss, who was a postdoctoral fellow at the Institute for Astronomy (IfA) at the University of Hawaii at Manoa during most of the time the study was on- going. The study will be published in the Nov. 21 edition of Monthly No- tices of the Royal Astronomical So- ciety . The mystery object is part of the dwarf galaxy Markarian 177, lo- cated in the bowl of the Big Dipper, a well-known star pattern within the constellation Ursa Major. Although supermassive black holes usually oc- cupy galactic centers, SDSS1133 is lo- cated at least 2,600 light-years from its host galaxy's core. The team was able to detect it in astronomical surveys dating back more than 60 years. In June 2013, the researchers obtained high-resolution near- infrared images of the object using the 10-meter Keck II telescope at Keck Observatory. “When we analyzed the Keck data, we found the emitting region of SDSS1133 is less than 40 light-years across, and that the center of Markarian 177 shows evidence of intense star formation and other features indicating a recent disturbance that matched what we expect- ed for a recoiling black hole,” said Chao-Ling Hung, a UH Manoa graduate student per- forming the analysis of the Keck Observatory imaging in the study. "We suspect we're seeing the aftermath of a merger of two small galaxies and their central black holes," said co-author Laura Blecha, an Einstein Fel- low in the University of Mary- land's Department of Astrono- my and a leading theorist in Evicted? Possible black hole found 2,600 light years from home U sing the Keck II telescope in Hawaii, researchers obtained high-resolution images of Markarian 177 and SDSS1133 using a near-infrared filter. Twin bright spots in the gal- axy's central region are consistent with recent star formation, a disturbance that hints this galaxy may have merged with another. [W. M. Keck Observatory/M. Koss (Eth Zurich) et al.] by Keck Observatory