B. A. Whitney et al. 2008 The Astronomical Journal 136 18 doi:10.1088/0004-6256/136/1/18
B. A. Whitney1, M. Sewilo2, R. Indebetouw3, T. P. Robitaille4, M. Meixner2, K. Gordon5, M. R. Meade6, B. L. Babler6, J. Harris5, J. L. Hora7, S. Bracker6, M. S. Povich6, E. B. Churchwell6, C. W. Engelbracht5, B-Q For5,8, M. Block5, K. Misselt5, U. Vijh2, C. Leitherer2, A. Kawamura9, R. D. Blum10, M. Cohen11, Y. Fukui9, A. Mizuno9, N. Mizuno9, S. Srinivasan12, A. G. G. M. Tielens13, K. Volk14, J-P. Bernard15, F. Boulanger16, J. A. Frogel17, J. Gallagher6, V. Gorjian18, D. Kelly5, W. B. Latter19, S. Madden20, F. Kemper21, J. R. Mould10, A. Nota2, M. S. Oey22, K. A. Olsen23, T. Onishi9, R. Paladini24, N. Panagia2, P. Perez-Gonzalez5, W. Reach24, H. Shibai9, S. Sato9, L. J. Smith2,25, L. Staveley-Smith26, T. Ueta27, S. Van Dyk24, M. Werner18, M. Wolff1 and D. Zaritsky5
Show affiliationsWe present ~1000 new candidate Young Stellar Objects (YSOs) in the Large Magellanic Cloud selected from Spitzer Space Telescope data, as part of the Surveying the Agents of a Galaxy's Evolution (SAGE) Legacy program. The YSOs, detected by their excess infrared (IR) emission, represent early stages of evolution, still surrounded by disks and/or infalling envelopes. Previously, fewer than 20 such YSOs were known. The candidate YSOs were selected from the SAGE Point Source Catalog from regions of color-magnitude space least confused with other IR-bright populations. The YSOs are biased toward intermediate- to high-mass and young evolutionary stages, because these overlap less with galaxies and evolved stars in color-magnitude space. The YSOs are highly correlated spatially with atomic and molecular gas, and are preferentially located in the shells and bubbles created by massive stars inside. They are more clustered than generic point sources, as expected if star formation occurs in filamentary clouds or shells. We applied a more stringent color-magnitude selection to produce a subset of "high-probability" YSO candidates. We fitted the spectral-energy distributions (SEDs) of this subset and derived physical properties for those that were well fitted. The total mass of these well-fitted YSOs is ~2900 M
and the total luminosity is ~2.1 × 106 L
. By extrapolating the mass function with a standard initial mass function and integrating, we calculate a current star-formation rate of ~0.06 M
yr–1, which is at the low end of estimates based on total ultraviolet and IR flux from the galaxy (~0.05 – 0.25 M
yr–1), consistent with the expectation that our current YSO list is incomplete. Follow-up spectroscopy and further data mining will better separate the different IR-bright populations and likely increase the estimated number of YSOs. The full YSO list is available as electronic tables, and the SEDs are available as an electronic figure for further use by the scientific community.
circumstellar matter; galaxies: dwarf; infrared: stars; Magellanic Clouds; stars: formation; stars: pre-main sequence
Issue 1 (2008 July)
Received 2007 June 20, accepted for publication 2008 April 1
Published 2008 May 27
B. A. Whitney et al. 2008 The Astronomical Journal 136 18
G Massiera et al 2003 J. Phys.: Condens. Matter 15 S225
Murat Durandurdu 2009 J. Phys.: Condens. Matter 21 452204
V V Brazhkin et al 2005 J. Phys.: Condens. Matter 17 1869
Juan P Neirotti and Nestor Caticha 2006 J. Phys. A: Math. Gen. 39 10355
K Jänkälä et al 2007 J. Phys. B: At. Mol. Opt. Phys. 40 3435
J. Schulz et al 2008 EPL 83 53001
A G Kochur et al 2008 J. Phys. B: At. Mol. Opt. Phys. 41 215002
Ph Wernet et al 2002 J. Phys. B: At. Mol. Opt. Phys. 35 3887
G Öhrwall et al 2003 J. Phys. B: At. Mol. Opt. Phys. 36 3937