Close stars and an inactive accretion disk in Sgr A*: Eclipses and flares

Abstract

A cold neutral and extremely dim accretion disk may be present as a remnant of a past vigorous activity around the black hole in our Galactic Center (GC). Here we discuss ways to detect such a disk through its interaction with numerous stars present in the central ~0.1 parsec of the Galaxy. The first major effect expected is X-ray and near infrared (NIR) flares arising when stars pass through the disk. The second is eclipses of the stars by the disk. We point out conditions under which the properties of the expected X-ray flares are similar to those recently discovered by Chandra. Since orbits of bright stars are now being precisely measured, the combination of the expected flares and eclipses offers an invaluable tool for constraining the disk density, size, plane and even direction of rotation. The winds of the O-type stars are optically thick to free-free absorption in radio frequencies. If present near Sgr A* core, such powerful stellar winds can modulate and even occult the radio source.

arXiv commenttypo in eq. 3 corrected

References in corpus (12)

• Advection-Dominated Accretion: A Self-Similar Solution
• Closest Star Seen Orbiting the Supermassive Black Hole at the Centre of the Milky Way
• The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy's Central Black Hole: A Paradox of Youth
• Rapid X-ray flaring from the direction of the supermassive black hole at the Galactic Centre
• The Supermassive Black Hole at the Galactic Center
• The Spectral Energy Distributions of Low-Luminosity Active Galactic Nuclei
• The Proper Motion of SgrA*: I. First VLBA Results
• Possible Evidence for Truncated Thin Disks in the Low-Luminosity Active Galactic Nuclei M81 and NGC 4579
• A New X-Ray Flare from the Galactic Nucleus Detected with the XMM-Newton Photon Imaging Cameras
• Radio Variability of Sagittarius A* - A 106 Day Cycle
• Limits on the Short Term Variability of Sagittarius A* in the Near-Infrared
• Adaptive Optics Near-Infrared Spectroscopy of the Sgr A* Cluster

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