Dwarf Galaxies with Radio-excess Active Galactic Nuclei in the Very Large Array Sky Survey Journal Article uri icon

Overview

abstract

  • Abstract; We present a systematic search for radio active galactic nuclei (AGNs) in dwarf galaxies using recent observations taken by the Very Large Array Sky Survey (VLASS). To select these objects, we first establish a criterion to identify radio-excess AGNs using the infrared-radio correlation parameter, q, that describes the tight relation between radio and IR emission in star-forming galaxies. We find a 2σ threshold of q < 1.94 to select radio-excess AGNs, which is derived from a sample of ∼7000 galaxies across the full mass range in the NASA-Sloan Atlas that have radio and IR detections from VLASS and the Wide-Field Infrared Survey Explorer, respectively. We create catalogs of radio-excess AGNs and star-forming galaxies and make these available to the community. Applying our criterion to dwarf galaxies with stellar masses M; ≲ 3 × 109; M; and redshifts z ≤ 0.15, and carefully removing interlopers, we find 10 radio-excess AGNs with radio-optical positional offsets between ∼0″ and 2.′3 (0–2.7 kpc). Based on statistical arguments and emission line diagnostics, we expect the majority of these radio-excess AGNs to be associated with the dwarf host galaxies rather than background AGNs. Five of the objects have evidence for hosting AGNs at other wavelengths, and five objects are identified as AGNs in dwarf galaxies for the first time. We also identify eight variable radio sources in dwarf galaxies by comparing the VLASS epoch 1 and epoch 2 observations to Faint Images of the Radio Sky at Twenty-centimeters detections presented in A. E. Reines et al. (2020).

publication date

  • January 1, 2025

has restriction

  • gold

Date in CU Experts

  • January 13, 2025 12:56 PM

Full Author List

  • Eberhard J-M; Reines AE; Gim HB; Darling J; Greene JE

author count

  • 5

Other Profiles

International Standard Serial Number (ISSN)

  • 0004-637X

Electronic International Standard Serial Number (EISSN)

  • 1538-4357

Additional Document Info

start page

  • 158

end page

  • 158

volume

  • 978

issue

  • 2