ATLASGAL -- Star forming efficiencies and the Galactic star formation rate

Abstract

The ATLASGAL survey has characterised the properties of approximately 1000 embedded HII regions and found an empirical relationship between the clump mass and bolometric luminosity that covers 3-4 orders of magnitude. Comparing this relation with simulated clusters drawn from an initial mass function and using different star formation efficiencies we find that a single value is unable to fit the observed luminosity to mass ($L/M$) relation. We have used a Monte Carlo simulation to generate 200,000 clusters using the $L/M$-ratio as a constraint to investigate how the star formation efficiency changes as a function of clump mass. This has revealed that the star formation efficiency decreases with increasing clump mass with a value of 0.2 for clumps with masses of a few hundred solar masses and dropping to 0.08 for clumps with masses of a few thousand solar masses. We find good agreement between our results and star formation efficiencies determined from counts of embedded objects in nearby molecular clouds. Using the star formation efficiency relationship and the infrared excess time for embedded star formation of $2\pm 1$, Myr we estimate the Galactic star formation rate to be approximately $0.9\pm 0.45$ Msun yr${}^{-1}$, which is in good agreement with previously reported values. This model has the advantage of providing a direct means of determining the star formation rate and avoids the difficulties encountered in converting infrared luminosities to stellar mass that affect previous galactic and extragalactic studies.

arXiv comment13 pages, 10 figures, accepted for publication in MNRAS

References in corpus (68)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• Galactic Stellar and Substellar Initial Mass Function
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• On the variation of the Initial Mass Function
• The Global Schmidt Law in Star Forming Galaxies
• Embedded Clusters in Molecular Clouds
• Star Formation in the Milky Way and Nearby Galaxies
• The Star Formation Law in Nearby Galaxies on Sub-Kpc Scales
• The Spitzer c2d Legacy Results: Star Formation Rates and Efficiencies; Evolution and Lifetimes
• GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy
• Toward Understanding Massive Star Formation
• The Star Formation Rate and Dense Molecular Gas in Galaxies
• On the Star Formation Rates in Molecular Clouds
• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• ATLASGAL - The APEX Telescope Large Area Survey of the Galaxy at 870 microns
• Hi-GAL: the Herschel infrared Galactic Plane Survey
• From Molecular Cores to Planet-forming Disks: A SIRTF Legacy Program
• High-Mass Star and Massive Cluster Formation in the Milky Way
• Improved Estimates of the Milky Way's Stellar Mass and Star Formation Rate from Hierarchical Bayesian Meta-Analysis
• HCN Survey of Normal Spiral, IR-luminous and Ultraluminous Galaxies
• High-Mass Proto-Stellar Candidates - I : The Sample and Initial Results
• The Star Formation Rate and Gas Surface Density Relation in the Milky Way: Implications for Extragalactic Studies
• Evolution of Massive Protostars with High Accretion Rates
• Physical properties of molecular clouds for the entire Milky Way disk
• ATLASGAL --- properties of a complete sample of Galactic clumps
• Connecting Dense Gas Tracers of Star Formation in our Galaxy to High-z Star Formation
• Toward a Unification of Star Formation Rate Determinations in the Milky Way and Other Galaxies
• 2MASS Observations of the Perseus, Orion A, Orion B, and Monoceros R2 Molecular Clouds
• The Physical Conditions for Massive Star Formation: Dust Continuum Maps and Modeling
• The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
• The present-day star formation rate of the Milky-Way determined from Spitzer detected young stellar objects
• The Red MSX Source Survey: the Massive Young Stellar Population of our Galaxy
• ATLASGAL - Compact source catalogue: 330 < l < 21 degrees
• Star Formation Relations in Nearby Molecular Clouds
• ATLASGAL --- towards a complete sample of massive star forming clumps
• The Properties of Massive, Dense, Clumps: Mapping Surveys of HCN and CS
• The ATLASGAL survey: a catalog of dust condensations in the Galactic plane
• A Correlation Between Surface Densities of Young Stellar Objects and Gas in Eight Nearby Molecular Clouds
• The Co-ordinated Radio and Infrared Survey for High Mass Star Formation (The CORNISH Survey) - I. Survey Design
• The Co-ordinated Radio and Infrared Survey for High-Mass Star Formation - II. Source Catalogue
• The RMS Survey: Critical Tests of Accretion Models for the Formation of Massive Stars
• ATLASGAL --- properties of compact HII regions and their natal clumps
• How Protostellar Outflows Help Massive Stars Form
• The Luminosity Functions and Timescales of MYSOs and Compact HII regions
• The Luminosities of Protostars in the Spitzer c2d and Gould Belt Legacy Clouds
• Infall through the evolution of high-mass star-forming clumps
• ATLASGAL --- Complete compact source catalogue: 280\degr\ $<\ell <$ 60\degr
• ATLASGAL-selected massive clumps in the inner Galaxy III. Dust Continuum Characterization of an Evolutionary Sample
• The Three-mm Ultimate Mopra Milky Way Survey. I. Survey Overview, Initial Data Releases, and First Results
• The Mass-Size Relation from Clouds to Cores. I. A new Probe of Structure in Molecular Clouds
• The Age, Stellar Content and Star Formation Timescale of the B59 Dense Core
• SiO outflows in high-mass star forming regions: A potential chemical clock?
• Impact of Protostellar Outflow on Star Formation: Effects of Initial Cloud Mass
• Galactic structure based on the ATLASGAL 870mum survey
• A multi-wavelength view of the Galactic center dust ridge reveals little star formation
• Massive outflows associated with ATLASGAL clumps
• Massive stars reveal variations of the stellar initial mass function in the Milky Way stellar clusters
• Star-Gas Surface Density Correlations in Twelve Nearby Molecular Clouds I: Data Collection and Star-Sampled Analysis
• The Single-Cloud Star Formation Relation
• The nature of the dense core population in the pipe nebula: core and cloud kinematics from C18O observations
• Initial phases of massive star formation in high infrared extinction clouds. II. Infall and onset of star formation
• H2, CO, and Dust Absorption through Cold Molecular Clouds
• The G305 star-forming complex: Embedded Massive Star Formation Discovered by Herschel Hi-GAL
• The SEDIGISM survey: a search for molecular outflows
• Feedback in W49A diagnosed with radio recombination lines and models
• 6.7GHz Methanol Maser Associated Outflows: An evolutionary sequence
• Testing 24 micron and Infrared Luminosity as Star Formation Tracers for Galactic Star Forming Regions

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