%0 Generic %1 witzel2014detection %A Witzel, Gunther %A Ghez, Andrea %A Morris, Mark %A Sitarski, Breann %A Boehle, Anna %A Naoz, Smadar. %A Campbell, Randall %A Becklin, Eric %A Canalizo, Gabriela %A Chappell, Samantha %A Do, Tuan %A Lu, Jessica %A Matthews, Keith %A Meyer, Leo %A Stockton, Alan %A Wizinowich, Peter %A Yelda, Sylvana %D 2014 %K center g2 galactic star %T Detection of Galactic Center source G2 at 3.8 $\mu$m during periapse passage %U http://arxiv.org/abs/1410.1884 %X We report new observations of Galactic Center source G2 from the W. M. Keck Observatory. G2 is a dusty red object associated with gas that shows tidal interactions as it nears closest approach (periapse) with the Galaxy's central black hole. Our observations, conducted as G2 passed through periapse, were designed to test the proposal that G2 is a 3 earth mass gas cloud. Such a cloud should be tidally disrupted during periapse passage. The data were obtained using the Keck II laser guide star adaptive optics system (LGSAO) and the facility near-infrared camera (NIRC2) through the K' 2.1 $\mu$m and L' 3.8 $\mu$m broadband filters. Several key results emerge from these observations: 1) G2 has survived its closest approach to the central black hole as a compact, unresolved source at L'; 2) G2's L' brightness measurements are consistent with those over the last decade; 3) G2's motion continues to be consistent with a Keplerian model. These results rule out G2 as a pure gas cloud and imply that G2 has a central star. This star has a luminosity of 30 $L_ødot $ and is surrounded by a large (2 AU) optically thick dust shell. We suggest that G2 is a binary star merger product and will ultimately appear similar to the B-stars that are tightly clustered around the black hole (the so-called S-star cluster). In memoriam of Gerry Neugebauer (1932-2014).

@misc{witzel2014detection, abstract = {We report new observations of Galactic Center source G2 from the W. M. Keck Observatory. G2 is a dusty red object associated with gas that shows tidal interactions as it nears closest approach (periapse) with the Galaxy's central black hole. Our observations, conducted as G2 passed through periapse, were designed to test the proposal that G2 is a 3 earth mass gas cloud. Such a cloud should be tidally disrupted during periapse passage. The data were obtained using the Keck II laser guide star adaptive optics system (LGSAO) and the facility near-infrared camera (NIRC2) through the K' [2.1 $\mu$m] and L' [3.8 $\mu$m] broadband filters. Several key results emerge from these observations: 1) G2 has survived its closest approach to the central black hole as a compact, unresolved source at L'; 2) G2's L' brightness measurements are consistent with those over the last decade; 3) G2's motion continues to be consistent with a Keplerian model. These results rule out G2 as a pure gas cloud and imply that G2 has a central star. This star has a luminosity of 30 $L_{\odot} $ and is surrounded by a large (2 AU) optically thick dust shell. We suggest that G2 is a binary star merger product and will ultimately appear similar to the B-stars that are tightly clustered around the black hole (the so-called S-star cluster). In memoriam of Gerry Neugebauer (1932-2014).}, added-at = {2014-10-09T09:46:47.000+0200}, author = {Witzel, Gunther and Ghez, Andrea and Morris, Mark and Sitarski, Breann and Boehle, Anna and Naoz, Smadar. and Campbell, Randall and Becklin, Eric and Canalizo, Gabriela and Chappell, Samantha and Do, Tuan and Lu, Jessica and Matthews, Keith and Meyer, Leo and Stockton, Alan and Wizinowich, Peter and Yelda, Sylvana}, biburl = {https://www.bibsonomy.org/bibtex/2dcbeaa5e95a07801a83fea1f71832810/miki}, description = {[1410.1884] Detection of Galactic Center source G2 at 3.8 $\mu$m during periapse passage}, interhash = {85321b36ba0109e2a7c22e0155c8f2b7}, intrahash = {dcbeaa5e95a07801a83fea1f71832810}, keywords = {center g2 galactic star}, note = {cite arxiv:1410.1884Comment: Submitted to ApJ letters. This paper is provided by the Galactic Center team at UCLA, led by Andrea Ghez. For questions please contact ghez@astro.ucla.edu}, timestamp = {2014-10-09T09:46:47.000+0200}, title = {Detection of Galactic Center source G2 at 3.8 $\mu$m during periapse passage}, url = {http://arxiv.org/abs/1410.1884}, year = 2014 }