Constraints on the mass accretion rate onto the supermassive black hole of cygnus : A using the Submillimeter Array
Document Type
Article
Publication Date
4-1-2021
Abstract
We present the first detailed polarimetric studies of Cygnus A at 230 GHz with the Submillimeter Array (SMA) to constrain the mass accretion rate onto its supermassive black hole. We detected the polarized emission associated with the core at a fractional polarization of 0.73 +/- 0.15%. This low fractional polarization suggests that the polarized emission is highly depolarized. One of the possible explanations is due to a significant variance in the Faraday rotation measure within the synthesized beam. By assuming the Faraday depolarization caused by inhomogeneous column density of the magnetized plasma associated with the surrounding radiatively-inefficient accretion flow within the SMA beam, we derived the constraint on the mass accretion rate to be larger than 0.15 M-circle dot yr(-1) at the Bondi radius. The derived constraint indicates that an adiabatic inflow-outflow solution or an advection-dominated accretion flow should be preferable as the accretion flow model in order to explain the jet power of Cygnus A.
Keywords
Submillimeter Array (SMA), Supermassive black hole
Funders
Smithsonian Institution,Academia Sinica - Taiwan,Ministry of Science and Technology, Taiwan[MOST 105-2119-M-001-042],Ministry of Science and Technology, Taiwan[MOST 106-2119-M-001-013]
Publication Title
Astrophysical Journal
Volume
911
Issue
1
Publisher
IOP Publishing Ltd
Publisher Location
TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND