A GALACTIC MOLECULAR CLOUD CLUMP CATALOG FROM HI-GAL DATA: METHOD AND INITIAL RESULTS COMPARISON WITH BGPS

Journal Article · Wed Feb 01 04:00:00 EST 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/835/2/203· OSTI ID:22869456

Zetterlund, Erika; Glenn, Jason ^[1]; Rosolowsky, Erik ^[2]

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1. CASA, Department of Astrophysical and Planetary Sciences, University of Colorado 389-UCB, Boulder, CO 80309 (United States)
2. Department of Physics, University of Alberta, Edmonton, Alberta, AB T6G 2E1 (Canada)

As the precursors to stellar clusters, it is imperative that we understand the distribution and physical properties of dense molecular gas clouds and clumps. Such a study has been done with the ground-based Bolocam Galactic Plane Survey (BGPS). Now the Herschel infrared GALactic plane survey (Hi-GAL) allows us to do the same with higher-quality data and complete coverage of the Galactic plane. We have made a pilot study comparing dense molecular gas clumps identified in Hi-GAL and BGPS, using six 2° × 2° regions centered at Galactic longitudes of ℓ=11{sup ∘}, 30°, 41°, 50°, 202°, and 217°. We adopted the BGPS methodology for identifying clumps and estimating distances, leading to 6198 clumps being identified in our substudy, with 995 of those having well-constrained distances. These objects were evenly distributed with Galactic longitude, a consequence of Hi-GAL being source confusion limited. These clumps range in mass from 10{sup −2} to 10{sup 5} M{sub ⊙} and have heliocentric distances of up to 16 kpc. When clumps found in both surveys are compared, we see that distances agree within 1 kpc and ratios of masses are of the order of unity. This serves as an external validation for BGPS and instills confidence as we move forward to cataloging the clumps from the entirety of Hi-GAL. In addition to the sources that were in common with BGPS, Hi-GAL found many additional sources, primarily due to the lack of atmospheric noise. We expect Hi-GAL to yield 2 × 10{sup 5} clumps, with 20% having well-constrained distances, an order of magnitude above what was found in BGPS.

• OSTI ID: 22869456
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 835; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CATALOGS
COMPARATIVE EVALUATIONS
COSMIC GASES
DISTANCE
DISTRIBUTION
GALAXIES
MASS
MOLECULES
PHYSICAL PROPERTIES