Open AccessHigh‐resolution observations of 6.7‐GHz methanol masers with the Long Baseline Array
Author(s) -
Dodson R.,
Ojha R.,
Ellingsen S. P.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07844.x
Subject(s) - maser , physics , astrophysics , very long baseline array , perpendicular , line of sight , astronomy , high resolution , planar , line (geometry) , methanol , remote sensing , geometry , active galactic nucleus , mathematics , galaxy , geology , chemistry , computer graphics (images) , organic chemistry , computer science
We have used the Australian Long Baseline Array (LBA) to produce milliarcsecond images of five sites of methanol (CH 3 OH) maser emission at 6.7 GHz. These are all sites that have linear morphologies at arcsecond resolutions, which have been hypothesized to be due to the masers forming in edge‐on circumstellar discs. We find that a simple disc model cannot explain the observations. We discuss various alternatives, and suggest a new model that explains how linear velocity gradients can be produced in methanol masers that arise in planar shocks propagating nearly perpendicular to the line of sight.