The prevalence of star formation as a function of Galactocentric radius

Abstract

We present large-scale trends in the distribution of star-forming objects revealed by the Hi-GAL survey. As a simple metric probing the prevalence of star formation in Hi-GAL sources, we define the fraction of the total number of Hi-GAL sources with a 70-micron counterpart as the "star-forming fraction" or SFF. The mean SFF in the inner galactic disc (3.1 kpc < R_GC < 8.6 kpc) is 25%. Despite an apparent pile-up of source numbers at radii associated with spiral arms, the SFF shows no significant deviations at these radii, indicating that the arms do not affect the star-forming productivity of dense clumps either via physical triggering processes or through the statistical effects of larger source samples associated with the arms. Within this range of Galactocentric radii, we find that the SFF declines with R_GC at a rate of -0.026 +/- 0.002 per kiloparsec, despite the dense gas mass fraction having been observed to be constant in the inner Galaxy. This suggests that the SFF may be weakly dependent on one or more large-scale physical properties of the Galaxy, such as metallicity, radiation field, pressure or shear, such that the dense sub-structures of molecular clouds acquire some internal properties inherited from their environment.

accepted for publication in MNRAS, 8 pages, 6 figures

References in corpus (7)

• The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
• The observed spiral structure of the Milky Way
• ATLASGAL --- towards a complete sample of massive star forming clumps
• Smoothed Particle Hydrodynamics simulations of expanding HII regions. I. Numerical methods and tests
• A self-consistent model of Galactic stellar and dust infrared emission and the abundance of polycyclic aromatic hydrocarbons
• Catalog of observed tangents to the spiral arms in the Milky Way galaxy
• Star formation scales and efficiency in Galactic spiral arms

Cited by in corpus (24)

• ATLASGAL --- properties of a complete sample of Galactic clumps
• Properties of Hi-GAL clumps in the inner Galaxy]{The Hi-GAL compact source catalogue. I. The physical properties of the clumps in the inner Galaxy ($-71.0^{\circ }<\ell <67.0^{\circ }$)
• Multi-temperature mapping of dust structures throughout the Galactic Plane using the PPMAP tool with Herschel Hi-GAL data
• The Hi-GAL compact source catalogue -- II. The 360° catalogue of clump physical properties
• The Star Formation Rate of the Milky Way as seen by Herschel
• A guided map to the Spiral arms in the galactic disk of the Milky Way
• The EDGE-CALIFA survey: The role of spiral arms and bars in driving central molecular gas concentrations
• Distance biases in the estimation of the physical properties of Hi-GAL compact sources-I. Clump properties and the identification of high-mass star forming candidates
• Spiral Structure Boosts Star Formation in Disk Galaxies
• SEDIGISM-ATLASGAL: Dense Gas Fraction and Star Formation Efficiency Across the Galactic Disk
• Constraining the pitch angle of the Galactic spiral arms in the Milky Way
• Young stars as tracers of a barred-spiral Milky Way
• Streaming Motions and Kinematic Distances to Molecular Clouds
• The Norma spiral arm: large-scale pitch angle
• Beyond the Solar Circle $-$ Trends in Massive Star Formation Between the Inner and Outer Galaxy
• OGHReS: Star formation in the Outer Galaxy ($\ell =250^{\circ }$-$280^{\circ }$)
• On the star-forming ability of Molecular Clouds
• Solenoidal turbulent modes and star formation efficiency in Galactic-plane molecular clouds
• A Herschel study of G214.5-1.8: a young, cold and quiescent giant molecular filament on the shell of a HI superbubble
• Molecular clouds in M51 from high-resolution extinction mapping
• A 260 pc resolution ALMA map of HCN(1-0) in the galaxy NGC 4321
• Autonomous Gaussian decomposition of the Galactic Ring Survey. II. The Galactic distribution of 13CO
• OGHReS: Star formation in the Outer Galaxy II ($\ell =180^{\circ }$-$280^{\circ }$)
• Molecular cloud matching in CO and dust in M33 II. Physical properties of giant molecular clouds