Astronomy and Astrophysics – Astronomy
Scientific paper
May 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...426..577m&link_type=abstract
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 426, no. 2, p. 577-585
Astronomy and Astrophysics
Astronomy
130
Astronomical Models, Black Holes (Astronomy), Sagittarius Constellation, Space Plasmas, Stellar Mass Accretion, Angular Momentum, Bremsstrahlung, Cyclotron Radiation, Infrared Radiation, Stellar Luminosity, Synchrotron Radiation, Temperature Distribution
Scientific paper
Sgr A(*) is a unique, compact radio source at the Galactic center whose characteristics suggest that it may be a massive (i.e., approximately 106 solar mass) black hole accreting from an ambient wind in that region. Earlier (simplified) calculations suggested that its 108 - 1020 Hz spectrum could be derived from bremsstrahlung and magnetic bremsstrahlung emission from plasma descending toward the event horizon at a rate of roughly 1022 g/s. Here, we introduce several significant improvements to the model, including (1) an exact treatment of the cyclotron/synchrotron emissivity that is valid for all temperatures, (2) the actual determination of the temperature distribution in the inflow, and (3) the effect on the spectrum should the accreting plasma have a residual angular momentum, possibly forming a disk at small radii. We find that the most likely value of the mass in this improved model is approximately equals 2 +/- 1 x 106 solar mass, close to the range inferred earlier, but about a factor of 2 greater than the previous 'best-fit' number. The main reason for this difference is that the more realistic (new) formulation of the magnetic bremsstrahlung emissivity has fluctuations with frequency that decrease the overall line-of-sight intensity, thereby pointing to a slightly larger mass in order to account for the observed spectrum. We also find that a slight excess of angular momentum in the accreting gas may be necessary in order to account for the IR luminosity from this source. Such an excess is consistent with the results of ongoing three-dimensional simulations that will be reported elsewhere.
No associations
LandOfFree
An accreting black hole model for Sagittarius A(*). 2: A detailed study does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with An accreting black hole model for Sagittarius A(*). 2: A detailed study, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An accreting black hole model for Sagittarius A(*). 2: A detailed study will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-884989