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

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 μm (AK) for approximately 1100 individual stars. The mean AK (= 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 AK > 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◦ (de–reddened magnitude) ≤ 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. Subject headings: dust, extinction — Galaxy: center, stellar content — infrared: stars — stars: luminosity function, mass function accepted for publication in the ApJ 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. Hubble Fellow Current address: University of Colorado, JILA, Campus Box 440, Boulder CO, 80309 Alfred P. Sloan Research Fellow