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Table · dataset · 2014

Massive field OB stars in the SMC

Listed in IVOA Registry (Virtual Observatory)

Some theories of star formation suggest massive stars may only form in clustered environments, which would create a deficit of massive stars in low-density environments.

Description

Observationally, Massey (2002, Cat. II/236) finds such a deficit in samples of the field population in the Small and Large Magellanic Clouds, with an initial mass function (IMF) slope of {Gamma}_IMF_~4.

These IMF measurements represent some of the largest known deviations from the standard Salpeter IMF slope of {Gamma}_IMF_=1.35. Here, we carry out a comprehensive investigation of the mass function above 20M_{sun}_ for the entire field population of the Small Magellanic Cloud (SMC), based on data from the Runaways and Isolated O Type Star Spectroscopic Survey of the SMC (RIOTS4). This is a spatially complete census of the entire field OB star population of the SMC obtained with the IMACS multi-object spectrograph and MIKE echelle spectrograph on the Magellan telescopes.

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Based on Monte Carlo simulations of the evolved present-day mass function, we find the slope of the field IMF above 20M_{sun}_ is {Gamma}_IMF_=2.3+/-0.4. We extend our IMF measurement to lower masses using BV photometry from the OGLE II survey. We use a statistical approach to generate a probability distribution for the mass of each star from the OGLE photometry, and we again find {Gamma}_IMF_=2.3+/-0.6 for stellar masses from 7M_{sun}_ to 20M_{sun}_.

The discovery and removal of ten runaways in our RIOTS4 sample steepens the field IMF slope to {Gamma}_IMF_=2.8+/-0.5. We discuss the possible effects of binarity and star formation history on our results, and conclude that the steep field massive star IMF is most likely a real effect.

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Catalogue records · 2

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Provenance · 1 source records, 8 field assertions
SourceKeyLast seenRaw
IVOA Registry (Virtual Observatory)ivo://cds.vizier/j/apj/763/10115 d agoJSON v1
FieldAssertionExtractorEvidence
access_levelsource · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[field].local:field:astronomymapping · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[modality].ivoa_waveband:opticalsource · IVOA Registryconnector:ivoa_registry@1.0.0
descriptionsource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_description
license_textsource · IVOA Registryconnector:ivoa_registry@1.0.0
publication_datesource · IVOA Registryconnector:ivoa_registry@1.0.0
titlesource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_title
updated_datesource · IVOA Registryconnector:ivoa_registry@1.0.0