Astronomy and Astrophysics – Astronomy
Scientific paper
Mar 1998
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998apj...495..774w&link_type=abstract
Astrophysical Journal v.495, p.774
Astronomy and Astrophysics
Astronomy
20
Accretion, Accretion Disks, Galaxy: Center, Ism: Kinematics And Dynamics, Masers, Turbulence
Scientific paper
The spectrum of maser radiation from a thin Keplerian disk viewed edge-on is computed when idealized turbulent velocities are present in the disk. Representative turbulent velocity fields ("realizations") are created by statistical sampling from Kolmogorov-like distributions (suggested by simulations) for the turbulence and combined with the Keplerian velocities of rotation. Parameters are chosen for the numerical computations to facilitate a detailed comparison to refined observational data available for the bulk of the maser emission that occurs near the systemic velocity in the subparsec disk of water masers around a presumed massive black hole at the nucleus of the galaxy NGC 4258. Spectra are obtained that are similar in appearance to the irregular spectra that are observed. Microstructure with Doppler breadths comparable to the expected thermal velocities occur in both the observed and computed spectra, even though the turbulent velocities in the computations are much greater than the thermal velocities. The observed deviations in the maser emission from the Keplerian relationship between Doppler velocity and location indicate that the turbulence is somewhat supersonic. It may still be sub-Alfvenic. A relationship between the radial extent of the masing gas and the magnitude of the turbulent velocities is provided by the range of Doppler velocities at which maser emission is observed. The computed spectra are consistent with (but do not require) the presence of a strong continuum source that is being amplified by the masing disk and that is associated with the presumed black hole at the nucleus of the galaxy.
Wallin Bradley Karl
Watson William D.
Wyld H. W.
No associations
LandOfFree
Spectra of Maser Radiation from a Turbulent, Circumnuclear Accretion Disk 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 Spectra of Maser Radiation from a Turbulent, Circumnuclear Accretion Disk, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spectra of Maser Radiation from a Turbulent, Circumnuclear Accretion Disk will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1656770