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M. F. Campbell (Colby C), M. Kassis, J. D. Adams (BU), J. L. Hora (CfA), L. K. Deutsch (BU/CfA)
We used MIRSI on the IRTF to make 10 and 20 \micron images of four candidate high-mass protosetllar objects (HMPOs) from the sample of Sridharan et al. (2002). These candidate HMPOs were selected from the IRAS database using FIR color criteria derived for UCHIIs. The HMPOs had been detected in CS, but not in 5 GHz radio continuum single dish surveys above 25 mJy. Most were detected in the MSX mid-IR survey. Beuther et al. (2002) presented maps of 1.2 mm dust emission of the sample of HMPOs. Our selection criteria were that the sources appear compact in MSX bands C (12.1 \micron) and E (21.3 \micron), and in the 1.2 mm maps. Three sources were detected by MIRSI at the IRTF at both 10 \micron (47% width 10.6 \micron, N band or a 10% width 11.6 \micron filter) and 20 \micron (42% width 20.9 \micron filter): IRAS 22134+5834, 23033+5951, and 23151+5912. Their sizes are marginally larger than the diffraction limited beams of about one arcsec. The MIRSI flux densities are significant fractions of those observed in larger beams on IRAS and MSX. The MIRSI high resolution flux densities for these sources at 10 \micron are between about 4 and 20 Jy, 1/3 to 1/2 the IRAS 12 \micron PSC flux densities. The MIRSI 20 \micron flux densities are between 20 and 120 Jy, 1/3 to 2/3 of those in the IRAS PSC, and between 1/2 and 9/10 of the MSX band E flux densities. The source IRAS 22570+5912 was detected at only 1 Jy at 10 \micron, and was not detected at 20 \micron; its MSX flux densities were 11 and 75 Jy in bands C and E. Each of the sources detected at both mid-IR bands has the appearance of an obscured cluster in the 2MASS survey. References: Sridharan, T. K. et al. 2002 ApJ, 566, 931. Beuther, H. et al. 2002 ApJ, 566, 945. This material is based upon work supported by NASA under Cooperative Agreement NCC 5-538 issued through the OSS Planetary Astronomy Program.
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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.