Informazioni sull’evento


Astrophysics Talk

Probing supermassive black hole growth and its dependence on stellar mass and star-formation rate in low-redshift galaxies

Olena Torbaniuk (DIFA - Alma Mater Studiorum Univ. di Bologna)

Tuesday 27/02/2024 @ 14:00, Sala Antonio Sollima (IV piano Battiferro)

The growth of galaxies (via stellar formation processes) and of the supermassive black hole (SMBH) at their centers (via mass-accretion potentially triggering an Active Galactic Nucleus or AGN) appear to proceed coherently over cosmic times. Such AGN/host galaxy connection has been suggested by a number of studies based on empirical correlations between BH mass and integrated galaxy properties (e.g. stellar velocity dispersion, bulge mass, total stellar mass), as well as on the global cosmological evolution of star-formation rates and AGN accretion rates which appear to follow similar patterns with cosmic time (i.e. redshift). So far most studies have explored intermediate/high redshift ranges, mainly due to the lack of large, homogeneous X-ray surveys at low redshift. In our work we present the study of the AGN activity as a function of stellar mass and star-formation rate in the local Universe (z < 0.33). We build an extensive sample combining spectroscopic measurements of star-formation rate and stellar mass from Sloan Digital Sky Survey, with specific Black Hole accretion rate (?sBHAR) derived from the Chandra Source Catalog (CSC 2.0) and the XMM-Newton Serendipitous Source Catalog (3XMM-DR8). We find that the sBHAR probability distribution for both star-forming and quiescent galaxies has a power-law shape peaking at log ?sBHAR ~ ?3.5 and declining toward lower sBHAR in all stellar mass ranges. This finding confirms the decrease of AGN activity in the local Universe compared to higher redshifts. We observe a significant correlation between log ?sBHAR and log SFR in almost all stellar mass ranges, but the relation is shallower compared to higher redshifts, indicating a reduced availability of accreting material in the local Universe.