Constraints on jet-driven disk accretion in Sagittarius A

• Published in: arXiv.org
• Main Authors: Jolley, Erin J D, Kuncic, Zdenka
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 28.11.2007
• Subjects: Accretion disks; Activation; Cold gas; Inclination angle; Inflow; Luminosity; Outflow; Physics - Astrophysics of Galaxies; Physics - Cosmology and Nongalactic Astrophysics; Physics - Earth and Planetary Astrophysics; Physics - High Energy Astrophysical Phenomena; Physics - Instrumentation and Methods for Astrophysics; Physics - Solar and Stellar Astrophysics; Relativism; Relativistic effects
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0711.4626

We revisit theoretical and observational constraints on geometrically-thin disk accretion in Sagittarius A* (Sgr A*). We show that the combined effects of mass outflows and electron energization in the hot part of the accretion flow can deflate the inflowing gas from a geometrically-thick structure. This allows the gas to cool and even thermalize on an inflow timescale. As a result, a compact, relatively cool disk may form at small radii. We show that magnetic coupling between the relativistic disk and a steady-state jet results in a disk that is less luminous than a standard relativistic disk accreting at the same rate. This relaxes the observational constraints on thin-disk accretion in Sgr A* (and by implication, other Low-Luminosity Active Galactic Nulcei, LLAGN). We find typical cold gas accretion rates of a few * 10^{-9} solar masses / yr. We also find that the predicted modified disk emission is compatible with existing near-infrared (NIR) observations of Sgr A* in its quiescent state provided that the disk inclination angle is > 87 degrees and that the jet extracts more than 75% of the accretion power.