Spitzer Survey of the Large Magellanic Cloud, Surveying the Agents of a Galaxy's Evolution (SAGE) I: Overview and Initial Results
Creators: name: Meixner, Margaret
name: Gordon, Karl D.
name: Indebetouw, Remy
name: Hora, Joseph L.
name: Whitney, Barbara
name: Blum, Robert
name: Reach, William
name: Bernard, Jean-Philippe
name: Meade, Marilyn
name: Babler, Brian
name: Engelbracht, Charles W.
name: For, Bi-Qing
name: Misselt, Karl
name: Vijh, Uma
name: Leitherer, Claus
name: Cohen, Martin
name: Churchwell, Ed B.
name: Boulanger, Francois
name: Frogel, Jay A.
name: Fukui, Yasuo
name: Gallagher, Jay
name: Gorjian, Varoujan
name: Harris, Jason
name: Kelly, Douglas
name: Kawamura, Akiko
name: Kim, SoYoung
name: Latter, William B.
name: Madden, Suzanne
name: Markwick-Kemper, Ciska
name: Mizuno, Akira
name: Mizuno, Norikazu
name: Mould, Jeremy
name: Nota, Antonella
name: Oey, M. S.
name: Olsen, Knut
name: Onishi, Toshikazu
name: Paladini, Roberta
name: Panagia, Nino
name: Perez-Gonzalez, Pablo
name: Shibai, Hiroshi
name: Shuji, Sato
name: Smith, Linda
name: Staveley-Smith, Lister
name: Tielens, A. G. G. M.
name: Ueta, Toshiya
name: Van Dyk, Schuyler
name: Volk, Kevin
name: Werner, Michael
name: Zaritsky, Dennis
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We are performing a uniform and unbiased, ~7x7 degrees imaging survey of the Large Magellanic Cloud (LMC), using the IRAC and MIPS instruments on board the Spitzer Space Telescope in order to survey the agents of a galaxy's evolution (SAGE), the interstellar medium (ISM) and stars in the LMC. The detection of diffuse ISM with column densities &gt;1.2x10^21 H cm^-2 permits detailed studies of dust processes in the ISM. SAGE's point source sensitivity enables a complete census of newly formed stars with masses &gt;3 solar masses that will determine the current star formation rate in the LMC. SAGE's detection of evolved stars with mass loss rates &gt;1x10^-8 solar masses per year will quantify the rate at which evolved stars inject mass into the ISM of the LMC. The observing strategy includes two epochs in 2005, separated by three months, that both mitigate instrumental artifacts and constrain source variability. The SAGE data are non-proprietary. The data processing includes IRAC and MIPS pipelines and a database for mining the point source catalogs, which will be released to the community in support of Spitzer proposal cycles 4 and 5. We present initial results on the epoch 1 data with a special focus on the N79 and N83 region. The SAGE epoch 1 point source catalog has ~4 million sources. The point source counts are highest for the IRAC 3.6 microns band and decrease dramatically towards longer wavelengths consistent with the fact that stars dominate the point source catalogs and that the dusty objects, e.g. young stellar objects and dusty evolved stars that detected at the longer wavelengths, are rare in comparison. We outline a strategy for identifying foreground MW stars, that may comprise as much as 18% of the source list, and background galaxies, that may comprise ~12% of the source list.
description: Accepted by the Astronomical Journal