AMUSE-Virgo: on the survival of super-massive black holes in faint spheroids
Elena Gallo (UCSB) , T. Treu, J.-H. Woo, J. Jacob, P. Marshall, R. Antonucci (UCSB)
I will present the first Chandra results from the AGN Multiwavelength Survey of Early-type galaxies in the Virgo cluster (AMUSE-Virgo). This large program targets 100 early-type Virgo galaxies with Chandra ACIS-S and Spitzer MIPS, with the aim to provide an unbiased census of super-massive black hole (SMBH) activity in the local universe. The sample covers over 4 orders of magnitude in black hole mass as estimated from the mass-velocity dispersion relation, large enough that it can be divided in SMBH mass bins to test whether the nuclear activity duty cycle is mass dependent. I will report on the Chandra observations of the first 16 targets, combined with results from archival data of other, more massive, 16 targets. Hard X-ray emission from a position coincident with the galaxy nucleus is detected in 50 per cent of the galaxies, and ascribed to low-level accretion-powered activity from a SMBH. Two of the detected nuclei are hosted in galaxies with absolute B magnitudes fainter than -18, indicating that SMBHs are still being harbored in such faint, low-mass objects.