2022ApJ...940...52S -
Astrophys. J., 940, 52 (2022/November-3)
Characterizing Compact 15-33 GHz Radio Continuum Sources in Local U/LIRGs.
SONG Y., LINDEN S.T., EVANS A.S., BARCOS-MUNOZ L., MURPHY E.J., MOMJIAN E., DIAZ-SANTOS T., LARSON K.L., PRIVON G.C., HUANG X., ARMUS L., MAZZARELLA J.M., U V., INAMI H., CHARMANDARIS V., RICCI C., EMIG K.L., McKINNEY J., YOON I., KUNNERIATH D., LAI T.S.-Y., RODAS-QUITO E.E., SARAVIA A., GAO T., MEYNARDIE W. and SANDERS D.B.
Abstract (from CDS):
We present the analysis of ∼100 pc scale compact radio continuum sources detected in 63 local (ultra)luminous infrared galaxies (U/LIRGs; LIR ≥ 1011L⊙), using FWHM ≲ 0.″1-0.″2 resolution 15 and 33 GHz observations with the Karl G. Jansky Very Large Array. We identify a total of 133 compact radio sources with effective radii of 8-170 pc, which are classified into four main categories-“AGN” (active galactic nuclei), “AGN/SBnuc” (AGN-starburst composite nucleus), “SBnuc” (starburst nucleus), and “SF” (star-forming clumps)-based on ancillary data sets and the literature. We find that “AGN” and “AGN/SBnuc” more frequently occur in late-stage mergers and have up to 3 dex higher 33 GHz luminosities and surface densities compared with “SBnuc” and “SF,” which may be attributed to extreme nuclear starburst and/or AGN activity in the former. Star formation rates (SFRs) and surface densities (ΣSFR) are measured for “SF” and “SBnuc” using both the total 33 GHz continuum emission (SFR ∼ 0.14-13 M⊙ yr–1, ΣSFR ∼ 13-1600 M⊙ yr–1 kpc–2) and the thermal free-free emission from H II regions (median SFRth ∼ 0.4 M⊙ yr–1, ${{\rm{\Sigma }}}_{{\mathrm{SFR}}_{\mathrm{th}}}\sim 44\,{M}_{\odot }$ yr–1 kpc–2). These values are 1-2 dex higher than those measured for similar-sized clumps in nearby normal (non-U/LIRGs). The latter also have a much flatter median 15-33 GHz spectral index (∼-0.08) compared with “SBnuc” and “SF” (∼-0.46), which may reflect higher nonthermal contribution from supernovae and/or interstellar medium densities in local U/LIRGs that directly result from and/or lead to their extreme star-forming activities on 100 pc scales.
Abstract Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Luminous infrared galaxies - Radio continuum emission - Galaxy nuclei - Very Large Array - Star forming regions
Status at CDS
:
Examining the need for a new acronym. // Large table(s) will be appraised for possible ingestion in VizieR.
Simbad objects:
84
Full paper
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