Detection of Galactic Center Source G2 at 3.8 μm during Periapse Passage
Creators
-
1.
University of California, Los Angeles
-
2.
W.M. Keck Observatory
-
3.
University of California, Riverside
-
4.
University of Toronto
-
5.
University of Hawaii at Manoa
-
6.
California Institute of Technology
Abstract
We report new observations of the 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 its closest approach 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 μm] and L' [3.8 μm] broadband filters. Several results emerge from these observations: (1) G2 has survived its closest approach to the 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_☉ and is surrounded by a large (~2.6 AU) optically thick dust shell. The differences between the L' and Br-γ observations can be understood with a model in which L' and Br-γ emission arises primarily from internal and external heating, respectively. 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).
Additional Information
© 2014 American Astronomical Society. Received 2014 October 7; accepted 2014 October 14; published 2014 November 3. We wish to dedicate this paper to Gerry Neugebauer (1932–2014). We thank the anonymous referee and the generous financial support from the NSF (AST-0909218 and AST-1412615), the Galactic Center Board of Advisors, the Lauren Leichtman & Arthur Levine Chair in Astrophysics, the Preston Family Graduate Student Fellowship, and the Janet Marott Student Travel Awards. The W. M. Keck Observatory is operated as a scientific partnership among Caltech, the University of California, and NASA. The Observatory was made possible by through a gift from the W. M. Keck Foundation.Attached Files
Published - 2041-8205_796_1_L8.pdf
Submitted - 1410.1884v2.pdf
Files
1410.1884v2.pdf
Additional details
Identifiers
- Eprint ID
- 52800
- Resolver ID
- CaltechAUTHORS:20141215-090620639
Related works
- Describes
- http://arxiv.org/abs/1410.1884 (URL)
Funding
- NSF
- AST-0909218
- NSF
- AST-1412615
- Galactic Center Board of Advisors
- Lauren Leichtman and Arthur Levine Chair in Astrophysics
- Preston Family Graduate Student Fellowship
- Janet Marott Student Travel Awards
- W. M. Keck Foundation
Dates
- Created
-
2014-12-15Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field