======================================================================== G C N E W S * Newsflash * - The Newsletter for Galactic Center Research - gcnews@aoc.nrao.edu http://www.aoc.nrao.edu/~gcnews ======================================================================== Vol. 24, No. 10 Jul 20, 2006 Recently submitted papers: -------------------------- 1) The Distance to the Galactic Center Derived From Infrared Photometry of Bulge Red Clump Stars (Nishiyama et al., ApJ) ------------------------------------------------------------------------ Email : shogo@optik.mtk.nao.ac.jp Title : The Distance to the Galactic Center Derived From Infrared Photometry of Bulge Red Clump Stars Author(s): Shogo Nishiyama^1, Tetsuya Nagata^2, Shuji Sato^1, Daisuke Kato^1, Takahiro Nagayama^2, Nobuhiko Kusakabe^3, Noriyuki Matsunaga^4, Takahiro Naoi^5, Koji Sugitani^6, and Motohide Tamura^7 Institute: (1) Department of Astrophysics, Nagoya University, Nagoya 464-8602, Japan (2) Department of Astronomy, Kyoto University, Kyoto 606-8502, Japan (3) Department of Astronomical Sciences, Graduate University for Advanced Studies (Sokendai), Mitaka, Tokyo 181-8588, Japan (4) Institute of Astronomy, School of Science, University of Tokyo, Mitaka, Tokyo, 181-0015, Japan (5) Department of Infrared Astrophysics, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510, Japan (6) Graduate School of Natural Sciences, Nagoya City University, Nagoya, 467-8501, Japan (7) National Astronomical Observatory of Japan, Mitaka, Tokyo, 181-8588, Japan Paper : ApJ, Aug 2006, in press EPrint : astro-ph/0607408 Abstract: On the basis of the near infrared observations of bulge red clump stars near the Galactic center, we have determined the galactocentric distance to be R_0 = 7.52 +- 0.10 (stat) +- 0.35 (sys) kpc. We observed the red clump stars at |l| < 1.0 deg and 0.7 deg < |b| < 1.0 deg with the IRSF 1.4 m telescope and the SIRIUS camera in the H and Ks bands. After extinction and population corrections, we obtained (m - M)_0 = 14.38 +- 0.03 (stat) +- 0.10 (sys). The statistical error is dominated by the uncertainty of the intrinsic local red clump stars' luminosity. The systematic error is estimated to be +- 0.10 including uncertainties in extinction and population correction, zero-point of photometry, and the fitting of the luminosity function of the red clump stars. Our result, R_0 = 7.52 kpc, is in excellent agreement with the distance determined geometrically with the star orbiting the massive black hole in the Galactic center. The recent result based on the spatial distribution of globular clusters is also consistent with our result. In addition, our study exhibits that the distance determination to the Galactic center with the red clump stars, even if the error of the population correction is taken into account, can achieve an uncertainty of about 5 percent, which is almost the same level as that in recent geometrical determinations. ------------------------------------------------------------------------ (Older versions of the Newsflash can be found at the gcnews web-page) ======================================================================== Edited by Sera Markoff, Loránt Sjouwerman, Joseph Lazio, Cornelia Lang, Rainer Schödel, Robin Herrnstein - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - For Abstract submission please follow the instructions which are at http://www.aoc.nrao.edu/~gcnews/home/submission.shtml ========================================================================