Star formation scales and efficiency in Galactic spiral arms

Abstract

We positionally match a sample of infrared-selected young stellar objects (YSOs), identified by combining the Spitzer GLIMPSE, WISE and Herschel Space Observatory Hi-GAL surveys, to the dense clumps identified in the millimetre continuum by the Bolocam Galactic Plane Survey in two Galactic lines of sight centred towards l = 30deg and l = 40deg. We calculate the ratio of infrared luminosity, L_IR, to the mass of the clump, M_clump, in a variety of Galactic environments and find it to be somewhat enhanced in spiral arms compared to the interarm regions when averaged over kiloparsec scales. We find no compelling evidence that these changes are due to the mechanical influence of the spiral arm on the star-formation efficiency rather than, e.g., different gradients in the star-formation rate due to patchy or intermittent star formation, or local variations that are not averaged out due to small source samples. The largest variation in L_IR/M_clump is found in individual clump values, which follow a log-normal distribution and have a range of over three orders of magnitude. This spread is intrinsic as no dependence of L_IR/M_clump with M_clump was found. No difference was found in the luminosity distribution of sources in the arm and interarm samples and a strong linear correlation was found between L_IR and M_clump.

13 pages, 12 figures, accepted for publication in MNRAS

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• The Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
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Cited by in corpus (16)

• ATLASGAL --- properties of a complete sample of Galactic clumps
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• The EDGE-CALIFA survey: The role of spiral arms and bars in driving central molecular gas concentrations
• The prevalence of star formation as a function of Galactocentric radius
• SCOPE: SCUBA-2 Continuum Observations of Pre-protostellar Evolution - Survey Description and Compact Source Catalogue
• Spiral Structure Boosts Star Formation in Disk Galaxies
• SEDIGISM-ATLASGAL: Dense Gas Fraction and Star Formation Efficiency Across the Galactic Disk
• Young stars as tracers of a barred-spiral Milky Way
• Star cluster formation and feedback in different environments of a Milky Way-like galaxy
• Beyond the Solar Circle $-$ Trends in Massive Star Formation Between the Inner and Outer Galaxy
• Identification of molecular clouds in emission maps: a comparison between methods in the \ce{^{13}CO}/\ce{C^{18}O} ($J=3-2$) Heterodyne Inner Milky Way Plane Survey
• Solenoidal turbulent modes and star formation efficiency in Galactic-plane molecular clouds
• Source clustering in the Hi-GAL survey determined using a minimum spanning tree method
• Bar-spiral interaction produces radial migration and star formation bursts
• Autonomous Gaussian decomposition of the Galactic Ring Survey. II. The Galactic distribution of 13CO
• A 260 pc resolution ALMA map of HCN(1-0) in the galaxy NGC 4321