TY - JOUR
T1 - Evident black hole-bulge coevolution in the distant universe
AU - Yang, G.
AU - Brandt, W. N.
AU - Alexander, D. M.
AU - Chen, C. T.J.
AU - Ni, Q.
AU - Vito, F.
AU - Zhu, F. F.
N1 - Publisher Copyright:
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
PY - 2019/2/28
Y1 - 2019/2/28
N2 - Observations in the local universe show a tight correlation between the masses of supermassive black holes (SMBHs; MBH) and host-galaxy bulges (Mbulge), suggesting a strong connection between SMBH and bulge growth.However, direct evidence for such a connection in the distant universe remains elusive. We have studied sample-averaged SMBH accretion rate (BHAR) for bulge-dominated galaxies at z = 0.5–3. While previous observations found BHAR is strongly related to host-galaxy stellar mass (M*) for the overall galaxy population, our analyses show that, for the bulge-dominated population, BHAR is mainly related to SFR rather than M*. This BHAR–SFR relation is highly significant, e.g. 9.0σ (Pearson statistic) at z = 0.5–1.5. Such a BHAR–SFR connection does not exist among our comparison sample of galaxies that are not bulge dominated, for which M* appears to be the main determinant of SMBH accretion. This difference between the bulge-dominated and comparison samples indicates that SMBHs only coevolve with bulges rather than the entire galaxies, explaining the tightness of the local MBH−Mbulge correlation. Our best-fitting BHAR–SFR relation for the bulge-dominated sample is log BHAR = log SFR − (2.48 ± 0.05) (solar units). The best-fitting BHAR/SFR ratio (10−2.48) for bulge-dominated galaxies is similar to the observed MBH/Mbulge values in the local universe. Our results reveal that SMBH and bulge growth are in lockstep, and thus non-causal scenarios of merger averaging are unlikely the origin of the MBH−Mbulge correlation. This lockstep growth also predicts that the MBH−Mbulge relation should not have strong redshift dependence.
AB - Observations in the local universe show a tight correlation between the masses of supermassive black holes (SMBHs; MBH) and host-galaxy bulges (Mbulge), suggesting a strong connection between SMBH and bulge growth.However, direct evidence for such a connection in the distant universe remains elusive. We have studied sample-averaged SMBH accretion rate (BHAR) for bulge-dominated galaxies at z = 0.5–3. While previous observations found BHAR is strongly related to host-galaxy stellar mass (M*) for the overall galaxy population, our analyses show that, for the bulge-dominated population, BHAR is mainly related to SFR rather than M*. This BHAR–SFR relation is highly significant, e.g. 9.0σ (Pearson statistic) at z = 0.5–1.5. Such a BHAR–SFR connection does not exist among our comparison sample of galaxies that are not bulge dominated, for which M* appears to be the main determinant of SMBH accretion. This difference between the bulge-dominated and comparison samples indicates that SMBHs only coevolve with bulges rather than the entire galaxies, explaining the tightness of the local MBH−Mbulge correlation. Our best-fitting BHAR–SFR relation for the bulge-dominated sample is log BHAR = log SFR − (2.48 ± 0.05) (solar units). The best-fitting BHAR/SFR ratio (10−2.48) for bulge-dominated galaxies is similar to the observed MBH/Mbulge values in the local universe. Our results reveal that SMBH and bulge growth are in lockstep, and thus non-causal scenarios of merger averaging are unlikely the origin of the MBH−Mbulge correlation. This lockstep growth also predicts that the MBH−Mbulge relation should not have strong redshift dependence.
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U2 - 10.1093/mnras/stz611
DO - 10.1093/mnras/stz611
M3 - Article
AN - SCOPUS:85067174431
SN - 0035-8711
VL - 485
SP - 3721
EP - 3737
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -