Day 853

Friday.

1503.05558
The inner mass distribution of the gravitational lens SDP.81 from ALMA observations
Wong, Suyu, Matsushita

The central image of a SL BG source places constraints on the FG lens galaxy's inner mass profile slept, core radius and mass of its nuclear SMBH.  Using high-res long-baseline ALMA observations and archival HST imaging, model the gravitational lens H-ATLAS J090311.6+003906 (also known as SDP.81) and search for the demagnified central image.  There is central continuum emission from the lens galaxy's AGN but no evidence of the central lensed image in any molecular line.  Use the CO J=5-4 map to determine the flux limit of the central image excluding the AGN continuum.  Predict the flux density of the central image and use the limits from the ALMA data to constrain the inner mass distribution of the lens.  For the core radius of 0.15" measured from HST photometry of the lens galaxy assuming that the central flux is completely attributed to the AGN, find that the BH mass of log (M_BH/M_sun)>0.84 is preferred.  Deeper observations with a detection of the central image will significantly improve the constraints of the inner mass distribution of the lens galaxy.