Planck-dust-allsky

Solange Ramirez (IPAC) : Spectroscopic Identification of Massive Young Stellar Objects in the Galactic Center

February
23
S M T W T F S

MR 102 (Morrisroe Large Conference Room) (Pizza @ $2/slice, $0.75 / soda can) We present results from our spectroscopic study, using the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope, designed to identify massive young stellar objects (YSOs) in the Galactic Center (GC). Our sample of 107 YSO candidates was selected based on IRAC colors from the high spatial resolution, high sensitivity Spitzer/IRAC images in the Central Molecular Zone (CMZ), which spans the central ~300 pc region of the Milky Way Galaxy. We obtained IRS spectra over 5 um to 35 um using both high- and low-resolution IRS modules. We spectroscopically identify massive YSOs by the presence of a 15.4 um shoulder on the absorption profile of 15um CO2 ice, suggestive of CO2 ice mixed with CH3OH ice on grains. This 15.4 um shoulder is clearly observed in 16 sources and possibly observed in an additional 19 sources. We show that 9 massive YSOs also reveal molecular gas-phase absorption from CO2, C2H2, and/or HCN, which traces warm and dense gas in YSOs. Our results provide the first spectroscopic census of the massive YSO population in the GC.

Date: February 23rd, 2011
Location: MR LCR