TY - JOUR
T1 - Morphological asymmetries of quasar host galaxies with Subaru Hyper Suprime-Cam
AU - Tang, Shenli
AU - Silverman, John D.
AU - Yesuf, Hassen M.
AU - Ding, Xuheng
AU - Li, Junyao
AU - Bottrell, Connor
AU - Goulding, Andy
AU - Omori, Kiyoaki Christopher
AU - Toba, Yoshiki
AU - Kawaguchi, Toshihiro
N1 - Publisher Copyright:
© 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.
PY - 2023/6/1
Y1 - 2023/6/1
N2 - How does the host galaxy morphology influence a central quasar or vice versa? We address this question by measuring the asymmetries of 2424 SDSS quasar hosts at 0.2 < z < 0.8 using broad-band (grizy) images from the Hyper Suprime-Cam Subaru Strategic Program. Control galaxies (without quasars) are selected by matching the redshifts and stellar masses of the quasar hosts. A two-step pipeline is run to decompose the PSF and Sérsic components and then measure asymmetry indices (ACAS, Aouter, and Ashape) of each quasar host and control galaxy. We find a mild correlation between host asymmetry and AGN bolometric luminosity (Lbol) for the full sample (spearman correlation of 0.37) while a stronger trend is evident at the highest luminosities (Lbol > 45). This then manifests itself into quasar hosts being more asymmetric, on average, when they harbour a more massive and highly accreting black hole. The merger fraction also positively correlates with Lbol and reaches up to 35 per cent for the most luminous. Compared to control galaxies, quasar hosts are marginally more asymmetric (excess of 0.017 in median at 9.4σ level) and the merger fractions are similar ($sim 16.5~ rm per cent$). We quantify the dependence of asymmetry on optical band that demonstrates that mergers are more likely to be identified with the bluer bands and the correlation between Lbol and asymmetry is also stronger in such bands. We stress that the band dependence, indicative of a changing stellar population, is an important factor in considering the influence of mergers on AGN activity.
AB - How does the host galaxy morphology influence a central quasar or vice versa? We address this question by measuring the asymmetries of 2424 SDSS quasar hosts at 0.2 < z < 0.8 using broad-band (grizy) images from the Hyper Suprime-Cam Subaru Strategic Program. Control galaxies (without quasars) are selected by matching the redshifts and stellar masses of the quasar hosts. A two-step pipeline is run to decompose the PSF and Sérsic components and then measure asymmetry indices (ACAS, Aouter, and Ashape) of each quasar host and control galaxy. We find a mild correlation between host asymmetry and AGN bolometric luminosity (Lbol) for the full sample (spearman correlation of 0.37) while a stronger trend is evident at the highest luminosities (Lbol > 45). This then manifests itself into quasar hosts being more asymmetric, on average, when they harbour a more massive and highly accreting black hole. The merger fraction also positively correlates with Lbol and reaches up to 35 per cent for the most luminous. Compared to control galaxies, quasar hosts are marginally more asymmetric (excess of 0.017 in median at 9.4σ level) and the merger fractions are similar ($sim 16.5~ rm per cent$). We quantify the dependence of asymmetry on optical band that demonstrates that mergers are more likely to be identified with the bluer bands and the correlation between Lbol and asymmetry is also stronger in such bands. We stress that the band dependence, indicative of a changing stellar population, is an important factor in considering the influence of mergers on AGN activity.
KW - galaxies: active
KW - galaxies: evolution
KW - galaxies: interactions
KW - methods: observational
KW - methods: statistical
KW - quasars: supermassive black holes
UR - http://www.scopus.com/inward/record.url?scp=85153521222&partnerID=8YFLogxK
U2 - 10.1093/mnras/stad877
DO - 10.1093/mnras/stad877
M3 - Article
AN - SCOPUS:85153521222
SN - 0035-8711
VL - 521
SP - 5272
EP - 5297
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -