We characterize the average X-ray and radio properties of quiescent galaxies (QGs) with log(M⋆/M⊙)>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.
Ito K., Tanaka M., Miyaji T., Ilbert O., Kauffmann O.B., Koekemoer A.M., et al. (2022). COSMOS2020: Ubiquitous AGN Activity of Massive Quiescent Galaxies at 0 < z < 5 Revealed by X-Ray and Radio Stacking. THE ASTROPHYSICAL JOURNAL, 929(1), 1-19 [10.3847/1538-4357/ac5aaf].
COSMOS2020: Ubiquitous AGN Activity of Massive Quiescent Galaxies at 0 < z < 5 Revealed by X-Ray and Radio Stacking
Marchesi S.Writing – Review & Editing
;
2022
Abstract
We characterize the average X-ray and radio properties of quiescent galaxies (QGs) with log(M⋆/M⊙)>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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
