VLA 33GHz obs. of star-forming regions

DOI

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.

Cone search capability for table J/ApJS/234/24/table6 (*Source photometry at 7" resolution)

Cone search capability for table J/ApJS/234/24/table1 (Galaxy properties and nuclear source positions)

Cone search capability for table J/ApJS/234/24/table2 (Extranuclear source positions)

Cone search capability for table J/ApJS/234/24/table5 (Source photometry (full resolution))

Identifier
DOI http://doi.org/10.26093/cds/vizier.22340024
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJS/234/24
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/234/24
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/234/24
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJS/234/24
Provenance
Creator Murphy E.J.; Dong D.; Momjian E.; Linden S.; Kennicutt R.C.; Meier D.S.,Schinnerer E.; Turner J.L.
Publisher CDS
Publication Year 2018
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Cosmology; Galactic and extragalactic Astronomy; High Energy Astrophysics; Interstellar medium; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy