A Statistical Study of a Large Sample of Changing-look Active Galactic Nuclei with Multi-frequency Radio Sky Surveys
Journal article, 2023

Optically “changing-look” active galactic nuclei (AGNs) are a class of objects that exhibit appearance or disappearance of broad lines. Recent studies have shown that these “changing-look” activities very likely result from the accretion activities of the central supermassive black holes. Large variation of the accretion rate might cause jet ejection and fading events, thus lead to a certain variability of observational radio properties. From the published literature, 74 “changing-look” AGNs and 90 “changing-look” AGNs candidates identified in optical observations were collected. Based on this largest, complex, and incomplete sample to date, the radio properties of “changing-look” AGNs were investigated. The radio counterparts of 51 “changing-look” AGNs (including 21 candidates) were discovered from the all-sky surveys conducted by the Australian Square Kilometre Array Pathfinder (ASKAP) and Very Large Array (VLA) covering the frequency range of 0.9–3 GHz. This corresponds to a detection rate of about 41 percent, which is similar to general AGNs. The radio spectral indices between 0.9 and 1.4 GHz and between 1.4 and 3 GHz were calculated, which suggest that these “changing-look” AGNs tend to have flatter radio spectra than normal AGNs. This statistical result indicates that “changing-look” AGNs might host some young, compact, and faint radio jets.

Statistics—radio continuum

Active—galaxies

Galaxies

Seyfert—galaxies

Jets—galaxies

Author

Wu Ye

Yunnan University

Jun Yang

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Sun Xiao-hui

Yunnan University

Chinese Astronomy and Astrophysics

0275-1062 (ISSN)

Vol. 47 2 285-308

Subject Categories

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Climate Research

DOI

10.1016/j.chinastron.2023.06.007

More information

Latest update

9/14/2023