Beyond the Solar Circle $-$ Trends in Massive Star Formation Between the Inner and Outer Galaxy

Abstract

We have compiled the most complete compact and ultracompact HII region catalogue to date via multi-wavelength inspection of survey data. We utilise data from the recently available SASSy 850$\mu$m survey to identify massive star forming clumps in the outer Galaxy ($R_{\mathrm{GC}}>8.5$ kpc) and cross-match with infrared and radio data of known UC HII regions from the RMS database. For the inner Galaxy sample ($R_{\mathrm{GC}}<8.5$ kpc), we adopt the compact HII regions from previous works that used similar methods to cross match ATLASGAL with either CORNISH or RMS, depending on the location within the Galactic plane. We present a new UC HII region catalogue that more than doubles the original sample size of previous work, totaling 536 embedded HII regions and 445 host clumps. We examine the distance independent values of N${}_{\mathrm{Ly}}/$M and L${}_{\mathrm{bol}}/$M as proxies for massive star formation efficiency and overall star formation efficiency, respectively. We find a significant trend showing that L${}_{\mathrm{bol}}/$M decreases with increasing $R_{\mathrm{GC}}$, suggesting that the overall star formation per unit mass is less in the outer Galaxy.

arXiv commentupdated to correct typos. 15 pages

References in corpus (50)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy
• A new calibration of stellar parameters of Galactic O stars
• Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample
• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• On the Star Formation Rates in Molecular Clouds
• The Evolution of the Elemental Abundances in the Gas and Dust Phases of the Galaxy
• The CO-to-H2 Conversion Factor and Dust-to-Gas Ratio on Kiloparsec Scales in Nearby Galaxies
• A Molecular Star Formation Law in the Atomic Gas Dominated Regime in Nearby Galaxies
• The Resolved Properties of Extragalactic Giant Molecular Clouds
• ATLASGAL --- properties of a complete sample of Galactic clumps
• The Australia Telescope 20 GHz Survey: The Source Catalogue
• Parallaxes and proper motions of interstellar masers toward the Cygnus X star-forming complex. I. Membership of the Cygnus X region
• SCUBA-2: on-sky calibration using submillimetre standard sources
• Three-Dimensional Distribution of the ISM in the Milky Way Galaxy: II. The Molecular Gas Disk
• ATLASGAL --- towards a complete sample of massive star forming clumps
• The ATLASGAL survey: a catalog of dust condensations in the Galactic plane
• 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 ($-71.0^{\circ }<\ell <67.0^{\circ }$)
• The Co-ordinated Radio and Infrared Survey for High-Mass Star Formation - II. Source Catalogue
• The RMS Survey: 6 cm continuum VLA observations towards candidate massive YSOs in the northern hemisphere
• ATLASGAL --- Environments of 6.7\,GHz methanol masers
• The Population of the Galactic Plane as Seen by MSX
• The RMS Survey: Critical Tests of Accretion Models for the Formation of Massive Stars
• ATLASGAL --- properties of compact HII regions and their natal clumps
• An all-sky Support Vector Machine selection of WISE YSO Candidates
• Comparing molecular gas across cosmic time-scales: the Milky Way as both a typical spiral galaxy and a high-redshift galaxy analogue
• The distribution of the ISM in the Milky Way A three-dimensional large-scale model
• Overlapping abundance gradients and azimuthal gradients related to the spiral structure of the Galaxy
• The first Hi-GAL observations of the outer Galaxy: a look to star formation in the third Galactic quadrant in the longitude range 216.5 < l < 225.5
• The RMS Survey: The Bolometric Fluxes and Luminosity Distributions of Young Massive Stars
• ATLASGAL-selected massive clumps in the inner Galaxy III. Dust Continuum Characterization of an Evolutionary Sample
• A SCUBA imaging survey of ultracompact HII regions: The environments of massive star formation
• Star Formation Relations in the Milky Way
• Star formation in Galactic spiral arms and the inter-arm regions
• The RMS Survey: Mid-Infrared Observations of Candidate Massive YSOs in the Southern Hemisphere
• Distribution and mass of diffuse and dense CO gas in the Milky Way
• The Dense Gas Mass Fraction of Molecular Clouds in the Milky Way
• On the dust abundance gradients in late-type galaxies: II. Analytical models as evidence for massive interstellar dust growth in SINGS galaxies
• A New Catalog of Radio Compact HII Regions in the Milky Way
• The JCMT Plane Survey: First complete data release - emission maps and compact source catalogue
• The almost ubiquitous association of 6.7 GHz methanol masers with dust
• The Coordinated Radio and Infrared Survey for High-Mass Star Formation III. A catalogue of northern ultra-compact H II regions
• Star formation scales and efficiency in Galactic spiral arms
• The prevalence of star formation as a function of Galactocentric radius
• Extended emission associated with young HII regions
• Infrared Dark Cloud Cores in the SCUBA Legacy Catalogue
• Infrared dark clouds on the far side of the Galaxy
• Effects of dust evolution on the abundances of CO and H${}_2$
• The SCUBA-2 Ambitious Sky Survey: a catalogue of beam-sized sources in the Galactic longitude range 120 to 140

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• The Hi-GAL compact source catalogue -- II. The 360° catalogue of clump physical properties
• Asymmetrical tidal tails of open star clusters: stars crossing their cluster's prah challenge Newtonian gravitation
• Bursting Bubbles: Feedback from Clustered SNe and the Trade-off Between Turbulence and Outflows
• SEDIGISM-ATLASGAL: Dense Gas Fraction and Star Formation Efficiency Across the Galactic Disk
• Exploring the s-process history in the Galactic disk: Cerium abundances and gradients in Open Clusters from the OCCAM/APOGEE sample
• The Co-Ordinated Radio and Infrared Survey for High-Mass Star Formation. V. The CORNISH-South Survey and Catalogue
• OGHReS: Star formation in the Outer Galaxy ($\ell =250^{\circ }$-$280^{\circ }$)
• A Catalog of Molecular Clumps and Cores with Infall Signatures
• A Possible Chemical Clock in High-mass Star-forming Regions: N(HC3N)/N(N2H+)?
• Investigating the Impact of Metallicity on Star Formation in the Outer Galaxy. I. VLT/KMOS Survey of Young Stellar Objects in Canis Major
• OGHReS: Star formation in the Outer Galaxy II ($\ell =180^{\circ }$-$280^{\circ }$)