The VLA Frontier Field Survey: A Comparison of the Radio and UV/Optical Size of 0.3 ≲ z ≲ 3 Star-forming Galaxies

April 2021 • 2021ApJ...910..106J

Authors • Jiménez-Andrade, E. F. • Murphy, E. J. • Heywood, I. • Smail, I. • Penner, K. • Momjian, E. • Dickinson, M. • Armus, L. • Lazio, T. J. W.

Abstract • To investigate the growth history of galaxies, we measure the rest-frame radio, ultraviolet (UV), and optical sizes of 98 radio-selected, star-forming galaxies (SFGs) distributed over 0.3 ≲ z ≲ 3 with a median stellar mass of $\mathrm{log}({M}_{\star }/{M}_{\odot })\approx 10.4$ . We compare the size of galaxy stellar disks, traced by rest-frame optical emission, relative to the overall extent of star formation activity that is traced by radio continuum emission. Galaxies in our sample are identified in three Hubble Frontier Fields: MACS J0416.1-2403, MACS J0717.5+3745, and MACS J1149.5+2223. Radio continuum sizes are derived from 3 and 6 GHz radio images (≲0"6 resolution, ≈0.9 μJy beam^-1 noise level) from the Karl G. Jansky Very Large Array. Rest-frame UV and optical sizes are derived using observations from the Hubble Space Telescope and the Advanced Camera for Surveys and Wide Field Camera 3 instruments. We find no clear dependence between the 3 GHz radio size and stellar mass of SFGs, which contrasts with the positive correlation between the UV/optical size and stellar mass of galaxies. Focusing on SFGs with $\mathrm{log}({M}_{\star }/{M}_{\odot })\gt 10$ , we find that the radio/UV/optical emission tends to be more compact in galaxies with high star formation rates (≳100 M_⊙ yr^-1), suggesting that a central, compact starburst (and/or an active galactic nucleus) resides in the most luminous galaxies of our sample. We also find that the physical radio/UV/optical size of radio-selected SFGs with log(M_⋆/M_⊙) > 10 increases by a factor of 1.5-2 from z ≈ 3 to z ≈ 0.3, yet the radio emission remains two to three times more compact than that from the UV/optical. These findings indicate that these massive, radio-selected SFGs at 0.3 ≲ z ≲ 3 tend to harbor centrally enhanced star formation activity relative to their outer disks.

Links

• PREPRINT http://arxiv.org/abs/2103.07807
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2021ApJ...910..106J
• ELECTR https://doi.org/10.3847%2F1538-4357%2Fabe876
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2021ApJ...910..106J
• PDF https://iopscience.iop.org/article/10.3847/1538-4357/abe876/pdf
• PDF https://stacks.iop.org/0004-637X/910/106/pdf
• DATA http://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/910/106
• DATA https://archive.stsci.edu/mastbibref.php?bibcode=2021ApJ...910..106J
• DATA https://hst.esac.esa.int/ehst/#/pages/search;bibcode=2021ApJ...910..106J