Estimating the Parameters of Sgr A*'s Accretion Flow Via Millimeter VLBI

Abstract

Recent millimeter-VLBI observations of Sagittarius A* (Sgr A*) have, for the first time, directly probed distances comparable to the horizon scale of a black hole. This provides unprecedented access to the environment immediately around the horizon of an accreting black hole. We leverage both existing spectral and polarization measurements and our present understanding of accretion theory to produce a suite of generic radiatively inefficient accretion flow (RIAF) models of Sgr A*, which we then fit to these recent millimeter-VLBI observations. We find that if the accretion flow onto Sgr A* is well described by a RIAF model, the orientation and magnitude of the black hole's spin is constrained to a two-dimensional surface in the spin, inclination, position angle parameter space. For each of these we find the likeliest values and their 1-sigma & 2-sigma errors to be a=0(+0.4+0.7), inclination=50(+10+30)(-10-10) degrees, and position angle=-20(+31+107)(-16-29) degrees, when the resulting probability distribution is marginalized over the others. The most probable combination is a=0(+0.2+0.4), inclination=90(-40-50) degrees and position angle=-14(+7+11)(-7-11) degrees, though the uncertainties on these are very strongly correlated, and high probability configurations exist for a variety of inclination angles above 30 degrees and spins below 0.99. Nevertheless, this demonstrates the ability millimeter-VLBI observations, even with only a few stations, to significantly constrain the properties of Sgr A*.

10 pages, 7 figures, accepted by ApJ

References in corpus (15)

• Monitoring stellar orbits around the Massive Black Hole in the Galactic Center
• Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits
• Some Aspects of Measurement Error in Linear Regression of Astronomical Data
• Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
• An Unambiguous Detection of Faraday Rotation in Sagittarius A*
• Methods for detecting flaring structures in Sagittarius A* with high frequency VLBI
• How to hide large scale outflows: size constraints on the jets of Sgr A*
• The Rotation Measure and 3.5mm Polarization of Sgr A*
• Black Hole Shadow Image and Visibility Analysis of Sagittarius A*
• The Submillimeter Polarization of Sgr A*
• A Catalog of Diffuse X-ray-Emitting Features within 20 pc of Sgr A*: Twenty Pulsar Wind Nebulae?
• On the orientation of the Sagittarius A* system
• General Relativistic Flux Modulations from Disk Instabilities in Sagittarius A*
• Using Millimeter VLBI to Constrain RIAF Models of Sagittarius A*
• Properties of the Radio-Emitting Gas Around SgrA*

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