Mapping the Dynamics of Cold Gas around Sgr A* through 21 cm Absorption

Abstract

The presence of a circumnuclear stellar disk around Sgr A* and megamaser systems near other black holes indicates that dense neutral disks can be found in galactic nuclei. We show that depending on their inclination angle, optical depth, and spin temperature, these disks could be observed spectroscopically through 21 cm absorption. Related spectroscopic observations of Sgr A* can determine its HI disk parameters and the possible presence of gaps in the disk. Clumps of dense gas similar to the G2 could could also be detected in 21 cm absorption against Sgr A* radio emission.

5 figures, Accepted to ApJL

References in corpus (5)

• Imaging an Event Horizon: Mitigation of Scattering Toward Sagittarius A*
• The Intrinsic Two-Dimensional Size of Sagittarius A*
• Radio light curves during the passage of cloud G2 near Sgr A*
• The structure of the accretion disk in NGC 4258 derived from observations of its water vapor masers
• 21cm Absorption by Compact Hydrogen Disks Around Black Holes in Radio-Loud Nuclei of Galaxies