VLA 33GHz obs. of star-forming regions Virtual Observatory Resource

Authors
  1. Murphy E.J.
  2. Dong D.
  3. Momjian E.
  4. Linden S.
  5. Kennicutt R.C.
  6. Meier D.S.,Schinnerer E.
  7. Turner J.L.
  8. Published by
    CDS
Abstract

We present 33GHz imaging for 112 pointings toward galaxy nuclei and extranuclear star-forming regions at ~2" resolution using the Karl G. Jansky Very Large Array (VLA) as part of the Star Formation in Radio Survey. A comparison with 33GHz Robert C. Byrd Green Bank Telescope single-dish observations indicates that the interferometric VLA observations recover 78%+/-4% of the total flux density over 25" regions (~kpc scales) among all fields. On these scales, the emission being resolved out is most likely diffuse non-thermal synchrotron emission. Consequently, on the ~30-300pc scales sampled by our VLA observations, the bulk of the 33GHz emission is recovered and primarily powered by free-free emission from discrete HII regions, making it an excellent tracer of massive star formation. Of the 225 discrete regions used for aperture photometry, 162 are extranuclear (i.e., having galactocentric radii rG>=250pc) and detected at >3{sigma} significance at 33GHz and in H{alpha}. Assuming a typical 33GHz thermal fraction of 90%, the ratio of optically-thin 33GHz to uncorrected H{alpha} star formation rates indicates a median extinction value on ~30-300pc scales of A_H{alpha}_~1.26+/-0.09mag, with an associated median absolute deviation of 0.87mag. We find that 10% of these sources are "highly embedded" (i.e., A_H{alpha}_>~3.3mag), suggesting that on average, HII regions remain embedded for <~1Myr. Finally, we find the median 33GHz continuum-to-H{alpha} line flux ratio to be statistically larger within rG<250pc relative to the outer disk regions by a factor of 1.82+/-0.39, while the ratio of 33GHz to 24{mu}m flux densities is lower by a factor of 0.45+/-0.08, which may suggest increased extinction in the central regions.

Keywords
  1. galaxies
  2. infrared-sources
  3. radio-continuum-emission
  4. interferometry
  5. visible-astronomy
  6. h-alpha-photometry
  7. active-galactic-nuclei
  8. star-forming-regions
Bibliographic source Bibcode
2018ApJS..234...24M
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/234/24
IVOA Identifier IVOID
ivo://CDS.VizieR/J/ApJS/234/24
Document Object Identifer DOI
doi:10.26093/cds/vizier.22340024

Access

Web browser access HTML
http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/234/24
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/234/24
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/234/24
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http://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/234/24/table6?
https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/234/24/table6?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/234/24/table6?
IVOA Cone Search SCS
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http://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/234/24/table1?
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http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/234/24/table1?
IVOA Cone Search SCS
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http://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/234/24/table2?
https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/234/24/table2?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/234/24/table2?
IVOA Cone Search SCS
For use with a cone search client (e.g., TOPCAT).
http://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/234/24/table5?
https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/234/24/table5?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/234/24/table5?

History

2018-08-29T15:05:14Z
Resource record created
2018-08-29T15:05:14Z
Created
2019-11-11T22:00:00Z
Updated

Contact

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CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr