COSMOS2020: Ubiquitous AGN Activity of Massive Quiescent Galaxies at 0 < z < 5 Revealed by X-Ray and Radio Stacking
Abstract
We characterize the average X-ray and radio properties of quiescent galaxies (QGs) with $\mathrm{log}({M}_{\star }/{M}_{\odot })\gt 10$ at 0 < z < 5. QGs are photometrically selected from the latest COSMOS2020 catalog. We conduct the stacking analysis of X-ray images of the Chandra COSMOS Legacy Survey for individually undetected QGs. Thanks to the large sample and deep images, the stacked X-ray signal is significantly detected up to z ~ 5. The average X-ray luminosity cannot be explained by the X-ray luminosity of X-ray binaries, suggesting that the low-luminosity active galactic nuclei (AGNs) ubiquitously exist in QGs. Moreover, the X-ray AGN luminosity of QGs at z > 1.5 is higher than that of star-forming galaxies (SFGs), derived in the same manner as QGs. The stacking analysis of the VLA-COSMOS images is conducted for the identical sample, and the radio signal for QGs is also detected up to z ~ 5. We find that the radio AGN luminosity of QGs at z > 1.5 is also higher than SFGs, which is in good agreement with the X-ray analysis. The enhanced AGN activity in QGs suggested by the individual analysis in the X-ray and radio wavelength supports its important role for quenching at high redshift. Their enhanced AGN activity is less obvious at z < 1.5, which can be interpreted as an increasing role of others at lower redshifts, such as environmental quenching.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2022
- DOI:
- 10.3847/1538-4357/ac5aaf
- arXiv:
- arXiv:2203.04322
- Bibcode:
- 2022ApJ...929...53I
- Keywords:
-
- Galaxy evolution;
- Galaxy formation;
- Elliptical galaxies;
- Active galactic nuclei;
- Galaxy quenching;
- 594;
- 595;
- 456;
- 16;
- 2040;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 24 pages, 20 figures, 2 tables, Accepted for publication in ApJ