An Extended Star Formation History for the Galactic Center from Hubble Space Telescope/NICMOS Observations

Donald F. Figer (2,3), R. Michael Rich (4), Sungsoo S. Kim (5), Mark Morris (4), Eugene Serabyn (6)


(2) Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218; figer@stsci.edu
(3) Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218
(4) Department of Physics and Astronomy, University of California, Los Angeles, Division of Astronomy, Los Angeles, CA, 90095-1562
(5) Dept. of Astronomy & Space Science, Kyung Hee University, Yongin-shi 449-701, Korea
(6) Caltech, 320-47, Pasadena, CA 91125; eserabyn@huey.jpl.nasa.gov

Paper: ApJ, accepted

Weblink: http://www.stsci.edu/~figer/papers/gcsfrate/ms.ps

EPrint Server: astro-ph/0309757


Abstract:

We present Hubble Space Telescope (HST) Near-Infrared Camera and Multiobject Spectrometer (NICMOS) observations as evidence that continuous star formation has created much of the central stellar cusp of the Galaxy. The data are the deepest ever obtained for a Galactic Center (GC) population, being >50% complete for \mnk<19.3, or initial stellar masses > 2 \Msun. We use Geneva and Padova stellar evolution models to produce synthetic luminosity functions for burst and continuous star formation scenarios, finding that the observations are fit best by continuous star formation at a rate that is consistent with the recent star formation activity that produced the three massive young clusters in the central 50 \pc. Further, it is not possible to fit the observations with ancient burst models, such as would be appropriate for an old population like that in Baade's Window or NGC6528.


Preprints available from the authors at figer@stsci.edu , or the raw TeX (no figures) if you click here.

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