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Title: VLBA studies of the accretion region in NGC 1275
Authors: Walker, R.C.
Kellermann, K.I.
Dhawan, V.
Romney, J.D.
Anantharamaiah, K.R.
Vermeulen, R.C.
Alef, W.
Issue Date: Jan-2001
Publisher: Astronomical Society of the Pacific
Citation: IAU Symposium, 2001, Vol.205, p48
Abstract: The results of VLBA studies of material associated with the accretion disk in NGC1275 will be reported. These studies are made possible by the presence of a two-sided structure in the radio continuum on parsec scales. The emission from one side --- the northern feature --- passes through the presumed accretion disk on its way to the Earth, while the emission from the southern feature does not. Multifrequency continuum observations made in 1995 (Walker et al 2000, Ap. J. 530, 233) show strong free-free absorption of the northern feature only, with a radial gradient, providing constraints on the amount and the distribution of ionized gas in in the accretion region. New observations were made in 2000 to look for changes in the absorption. The 1995 results, along with reliminary results from the 2000 observations, will be presented. Also results from a 1998 attempt to detect a stimulated recombination line at 23 GHz from the absorbing material will be presented. No such line was detected, which, in combination with the free-free results, constrains the physical conditions in the absorbing region.
Description: Restricted Access. Galaxies and their Constituents at the Highest Angular Resolutions, Proceedings of IAU Symposium #205, held 15-18 August 2000 at Manchester, United Kingdom. Ed. R. T. Schilizzi, 2001.
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Copyright: 2001 Astronomical Society of the Pacific
Appears in Collections:Research Papers (A&A)

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