THE LIFE AND DEATH OF DENSE MOLECULAR CLUMPS IN THE LARGE MAGELLANIC CLOUD

Journal Article · Sun May 20 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/751/1/42· OSTI ID:22037254

Seale, Jonathan P; Looney, Leslie W; Wong, Tony ^[1]; Ott, Juergen ^[2]; Klein, Uli ^[3]; Pineda, Jorge L ^[4]

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1. Department of Astronomy, University of Illinois, MC-221, 1002 W. Green Street, Urbana, IL 61801 (United States)
2. National Radio Astronomy Observatory, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801 (United States)
3. Argelander-Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany)
4. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA (United States)

We report the results of a high spatial (parsec) resolution HCO{sup +} (J = 1 {yields} 0) and HCN (J = 1 {yields} 0) emission survey toward the giant molecular clouds of the star formation regions N 105, N 113, N 159, and N 44 in the Large Magellanic Cloud (LMC). The HCO{sup +} and HCN observations at 89.2 and 88.6 GHz, respectively, were conducted in the compact configuration of the Australia Telescope Compact Array. The emission is imaged into individual clumps with masses between 10{sup 2} and 10{sup 4} M{sub Sun} and radii of <1 pc to {approx}2 pc. Many of the clumps are coincident with indicators of current massive star formation, indicating that many of the clumps are associated with deeply embedded forming stars and star clusters. We find that massive young stellar object (YSO) bearing clumps tend to be larger ({approx}>1 pc), more massive (M {approx}> 10{sup 3} M{sub Sun }), and have higher surface densities ({approx}1 g cm{sup -2}), while clumps without signs of star formation are smaller ({approx}<1 pc), less massive (M {approx}< 10{sup 3} M{sub Sun }), and have lower surface densities ({approx}0.1 g cm{sup -2}). The dearth of massive (M > 10{sup 3} M{sub Sun }) clumps not bearing massive YSOs suggests that the onset of star formation occurs rapidly once the clump has attained physical properties favorable to massive star formation. Using a large sample of LMC massive YSO mid-IR spectra, we estimate that {approx}2/3 of the massive YSOs for which there are Spitzer mid-IR spectra are no longer located in molecular clumps; we estimate that these young stars/clusters have destroyed their natal clumps on a timescale of at least {approx}3 Multiplication-Sign 10{sup 5} yr.

• OSTI ID: 22037254
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 751; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
DENSITY
GHZ RANGE
HYDROCYANIC ACID
INFRARED SPECTRA
MAGELLANIC CLOUDS
PHOTON EMISSION
RESOLUTION
STAR CLUSTERS
STAR EVOLUTION
STARS
SURFACES
TELESCOPES