The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) 2005: A 4 sq. deg Galactic Plane Survey in Vulpecula (l=59)

TL;DR

This paper reports on a submillimeter survey of the Galactic Plane using BLAST, identifying and characterizing high-mass proto-stellar objects and compact sources, with detailed analysis of their properties and potential as early star formation sites.

Contribution

First large-area submillimeter survey with BLAST focusing on high-mass proto-stellar objects in the Galactic Plane, providing new data on their properties and distribution.

Findings

Detected 60 compact sources in all three bands.

Identified candidate high-mass proto-stellar objects with no internal radiation.

Mass spectrum consistent with other high-mass star forming regions.

Abstract

We present the first results from a new 250, 350, and 500 micron Galactic Plane survey taken with the Balloon-borne Large-Aperture Submillimeter Telescope (BLAST) in 2005. This survey's primary goal is to identify and characterize high-mass proto-stellar objects (HMPOs). The region studied here covers 4 sq. deg near the open cluster NGC 6823 in the constellation Vulpecula (l=59). We find 60 compact sources (<60'' diameter) detected simultaneously in all three bands. Their spectral energy distributions (SEDs) are constrained through BLAST, IRAS, Spitzer MIPS, and MSX photometry, with inferred dust temperatures spanning ~12-40K assuming a dust emissivity index beta=1.5. The luminosity-to-mass ratio, a distance-independent quantity, spans ~0.2-130 L_\odot M_\odot^{-1}. Distances are estimated from coincident 13CO (1->0) velocities combined with a variety of other velocity and morphological data in the literature. In total, 49 sources are associated with a molecular cloud complex encompassing NGC 6823 (distance ~2.3kpc), 10 objects with the Perseus Arm (~8.5kpc) and one object is probably in the outer Galaxy (~14kpc). Near NGC 6823, the inferred luminosities and masses of BLAST sources span ~40-10^4 L_\odot, and ~15-700 M_\odot, respectively. The mass spectrum is compatible with molecular gas masses in other high-mass star forming regions. Several luminous sources appear to be Ultra Compact HII regions powered by early B stars. However, many of the objects are cool, massive gravitationally-bound clumps with no obvious internal radiation from a protostar, and hence excellent HMPO candidates.