JHKL Photometry and the K-band Luminosity Function at the Galactic Center

R. D. Blum(1,2,3), K. Sellgren(1,4), and D. L. DePoy(1)

(1) Department of Astronomy, The Ohio State University, 174 W. 18th Ave., Columbus, Oh, 43210, Visiting Astronomer, Cerro Tololo Inter--American Observatory, National Optical Astronomy Observatories, which are operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation. (2) Hubble Fellow (3) Current address: University of Colorado, JILA, Campus Box 440, Boulder CO, 80309 (4) Alfred P. Sloan Research Fellow

Paper: accepted by ApJ

Weblink: ftp://degobah.colorado.edu/pub/rblum/RCS1/

EPrint-Server: astro-ph/9512093
Abstract:

J, H, K, and L photometry for the stars in the central ~ 2' (~ 5 pc) of the Galaxy are presented. Using the observed J-H, H-K, and K-L colors and assumed intrinsic colors, we determine the interstellar extinction at 2.2 \mic (A_K) for approximately 1100 individual stars. The mean A_K (= 3.3 mag) is similar to previous results, but we find that the reddening is highly variable and some stars are likely to be seen through A_K > 6 mag. The de--reddened K-band luminosity function points to a significantly brighter component to the stellar population (> 1.5 mag at K) than found in the stellar population in Baade's window, confirming previous work done at lower spatial resolution. The observed flux of all Galactic center stars with estimated K_\circ (de--reddened magnitude) \lelt;=q 7.0 mag is ~ 25 % of the total in the 2' * 2' field. Our observations confirm the recent finding that several bright M stars in the Galactic center are variable. Our photometry also establishes the near--infrared variability of the M1--2 supergiant, IRS 7.


Preprints available from the authors at rblum@casa.Colorado.EDU , or the raw TeX (no figures) if you click here.

Back to the gcnews home-page.