منابع مشابه
Accelerations of Water Masers in NGC 4258
The water masers in NGC4258 delineate the structure and dynamics of a sub-parsec-diameter accretion disk around a supermassive black hole. VLBA observations provide precise information about the positions in the plane of the sky and the three-dimensional velocity vectors for the maser emission, but the positions along the line of sight must be inferred from models. Previous measurements placed ...
متن کامل0 Accelerations of Water Masers in NGC 4258
The water masers in NGC4258 delineate the structure and dynamics of a sub-parsec-diameter accretion disk around a supermassive black hole. VLBA observations provide precise information about the positions in the plane of the sky and the three-dimensional velocity vectors for the maser emission, but the positions along the line of sight must be inferred from models. Previous measurements placed ...
متن کاملWater Masers in NGC 4258: Saturation and GR
NGC 4258 is well known for its 22 GHz water maser features that appear to reside in a thin Keplerian disk orbiting at R0 = 0.13 pc. The influence of gravitational redshift on the level of saturation and the line shape and strength of water maser emission is studied. It is found, for a Schwarzschild metric, that a time-dependent and asymmetric absorption dip occurs in the systemic emission for a...
متن کاملThe structure of the accretion disk in NGC 4258 derived from observations of its water vapor masers
A wealth of new information about the structure of the maser disk in NGC 4258 has been obtained from a series of 18 VLBA observations spanning three years, as well as from 32 additional epochs of spectral monitoring data from 1994 to the present, acquired with the VLA, Effelsberg, and GBT. The warp of the disk has been defined precisely. The thickness of the maser disk has been measured to be 1...
متن کاملDiscovery of Water Vapor Megamaser Emission from Mrk 1419 (ngc 2960): an Analogue of Ngc 4258?
Water vapor emission at 22GHz is reported from the nucleus of the LINER galaxy Mrk 1419 (NGC 2960). Single-dish spectra of the maser source show properties that are similar to those seen in NGC4258, namely (1) a cluster of systemic (V∼Vsys) H2O features, (2) two additional H2O clusters, one redand one blue-shifted with respect to Vsys, (3) a likely acceleration of the systemic features (dV /dt ...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2000
ISSN: 0004-637X,1538-4357
DOI: 10.1086/308829