Over 1000 Newly Discovered Young Stellar Objects in the Large Magellanic Cloud fromtheSpitzer SAGE Survey

Abstract

We have identified over 1000 candidate Young StellarObjects (YSOs) in the Large Magellanic Cloud as part of the Spitzer Space Telescope Surveying the Agents of a Galaxy's Evolution (SAGE) Legacy program. The YSOs, detected by their excess infrared emission above a stellar photosphere, representearly stages of evolution, still surrounded by disks and/or infalling envelopes.The candidate YSOs were selected from regions of color-magnitude space least confused with other IR-bright populations.Our YSO list is therefore biased towards intermediate- to high-mass and young evolutionarystages, because these overlap less with galaxies and evolved starsin color-magnitude space.We derived masses of the YSOs from SED-fitting, and extrapolated the mass function usinga standard IMF to compute a current star formation rate of ~0.06 M_๏/yr, which is at the low-end ofestimates based on total ultraviolet and infrared flux from the galaxy (~0.05-0.25 M_๏/yr); and consistent with the expectation that our current YSO list is incomplete.High spatial resolution K_dark- and L-band observations at Dome C could distinguish the lower-mass YSOs from galaxies, based on their morphologies(diffuse vs. point sources).This will add thousands more YSOs to our census and improve our estimates of star formationrate, molecular cloud lifetimes, and hierarchical star formation.In addition, the high spatial resolution Dome C observations can detect multiplicity in the SAGE-identified YSOs which can be incorporated into our YSO SED models.