The Young and the Dustless: Interpreting Radio Observations of UltraViolet Luminous Galaxies - AstrophysicsReportar como inadecuado

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Abstract: Ultraviolet Luminous Galaxies UVLGs have been identified as intenselystar-forming, nearby galaxies. A subset of these, the supercompact UVLGs, arebelieved to be local analogs of high redshift Lyman Break Galaxies. Here weinvestigate the radio continuum properties of this important population for thefirst time. We have observed 42 supercompact UVLGs with the VLA, all of whichhave extensive coverage in the UV-optical by GALEX and SDSS. Our analysisincludes comparison samples of multiwavelength data from the Spitzer First LookSurvey and from the SDSS-Galex matched catalogs. In addition we have SpitzerMIPS data for 24 of our galaxies and find that they fall on the radio-FIRcorrelation of normal star-forming galaxies. We find that our galaxies havelower radio-to-UV ratios and lower Balmer decrements than other local galaxieswith similar high star formation rates. Optical spectra show they have lowerDn4000 and HdeltaA indices, higher Hbeta emission-line equivalents widths,and higher OIII5007-Hbeta emission-line ratios than normal star forminggalaxies. Comparing these results to galaxy spectral evolution models weconclude that supercompact UVLGs are distinguished from normal star forminggalaxies firstly by their high specific star formation rates. Moreover,compared to other types of galaxies with similar star formation rates, theyhave significantly less dust attenuation. In both regards they are similar toLyman Break Galaxies. This suggests that the process that causes star formationin the supercompact UVLGs differs from other local star forming galaxies, butmay be similar to Lyman Break Galaxies.

Autor: Antara R. Basu-Zych, David Schiminovich, Benjamin D. Johnson, Charles Hoopes, Roderik Overzier, Marie A. Treyer, Timothy M. Heckm


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