Oral Presentation

Correlation test between Eddington ratio and gas fraction of AGN host galaxies

Author(s): Yui Yamashita (The University of Tokyo) Kotaro Kohno (The University of Tokyo) Fumi Egusa (The University of Tokyo) Bunyo Hatsukade (The University of Tokyo)

Presenter: Yui Yamashita (The University of Tokyo)

Eddington ratio (λ_Edd) is a key parameter to describe the black hole growth and AGN activity. However, the connection between λ_Edd and host galaxy evolution was not studied well. We present the results of our correlation test between λ_Edd of the local AGN and the gas fraction (f_gas = M_gas / M_star) of their host galaxies. Our samples were originally selected from the Swift/BAT AGN Spectroscopic Survey catalog (Koss et al. 2017), which is one of the most complete local AGN catalogs so far. We derived the gas mass of our samples from their galaxy-scale CO measurements. Our recent CO survey with ALMA and Nobeyama 45m telescope expands the number of the samples. We finally performed the Kendall-tau correlation test using 33 sources and found that there was no correlation between λ_Edd and f_gas in our samples (correlation coefficient = -0.06). This result contradicts the previous study using the local quasar samples, they reported the weak positive correlation (correlation coefficient = 0.49) between λ_Edd and f_gas (Izumi 2018b). That discrepancy can be attributed to the difference in the molecular gas distribution between luminous quasars and less luminous AGN hosts.