Star Formation in the Central 400 pc of the Milky Way: Evidence for a Population of Massive YSOs

Understand

The central kpc of the Milky Way might be expected to differ significantly from the rest of the Galaxy with regard to gas dynamics and the formation of YSOs.

• We probe this possibility with mid-infrared observations obtained with IRAC and MIPS on Spitzer and with MSX.
• We use color-color diagrams and SED fits to explore the nature of YSO candidates (including objects with 4.5 micron excesses possibly due to molecular emission).
• There is an asymmetry in the distribution of the candidate YSOs, which tend to be found at negative Galactic longitudes; this behavior contrasts with that of the molecular gas, approximately 2/3 of which is at positive longitudes.