VLBA23A-234

Evidence for a new disk maser in the LINER galaxy IC485.

Abstract

Water megamasers allow us to investigate accretion disks and jets/outflows in AGN. In particular, disk masers permit to map molecular material around the supermassive black holes, and estimate BH masses and distances to the host galaxies. While the number of disk masers studied into details has recently grown, it is still relatively low despite their acclaimed relevance.
Our recent study led with the VLBA on the megamaser galaxy IC485 (D=122 Mpc), strongly suggests that the bulk of the maser emission is associated with an edge-on accretion disk, thus adding a particularly important case. In order to confirm our findings, however, the simultaneous detection of the three maser components, in particular, of the weak blue-shifted one is mandatory.
In this proposal, we request sensitive HSA observations to: i) detect the three main maser features associated with the putative disk; ii) detect, for the first time the blue-shifted component at VLBI scales; iii) derive the distribution of the maser emission and set the basis for a monitoring campaign of the feature to derive possible velocity drift of the systemic lines; iv) create, for the first time, a reliable model of an accretion disk in a LINER at the remarkable distance of IC485.

Investigators

Name	Institution
Willem Baan	Netherlands Institute for Radio Astronomy
Dominic Pesce	Virginia, University of; Smithsonian Astrophysical Observatory
Francesca Panessa	Istituto Nazionale di Astrofisica
Jim Braatz	National Radio Astronomy Observatory
Paola Castangia	Istituto Nazionale di Astrofisica
Gabriele Surcis	Istituto Nazionale di Astrofisica
Andrea Tarchi	Istituto Nazionale di Astrofisica
Elisabetta Ladu *	Istituto Nazionale di Astrofisica; Cagliari, Università degli Studi di
GBT Operator	Green Bank Observatory

* indicates the PI