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Very High Resolution Observations of the Luminous Water Masers in NGC 4258

Published online by Cambridge University Press:  03 August 2017

M. J. Claussen
Affiliation:
FCRAO, Univ. of Massachusetts, Amherst, MA USA
M. J. Reid
Affiliation:
CfA, Harvard Univ., Cambridge, MA USA
M. H. Schneps
Affiliation:
CfA, Harvard Univ., Cambridge, MA USA
K.-Y. Lo
Affiliation:
Univ. Illinois, Urbana, IL USA
J. M. Moran
Affiliation:
CfA, Harvard Univ., Cambridge, MA USA
R. Gusten
Affiliation:
MPI, Bonn, FRG

Abstract

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We summarize the results and interpretation of a four station transcontinental VLBI experiment of the luminous water masers in the nearby galaxy NGC 4258. At a distance of 5 Mpc, the longest baseline of the experiment provides spatial resolution of less than 1016 cm. The strongest maser emission was detected on all baselines, and was found to consist of at least two features separated by about 0.1 mas (1016 cm). Weaker features are possibly spread over a region up to 1 mas in size. These results provide evidence that supports the scenario described by Claussen and Lo (1986) which suggests that the very luminous water masers reside in molecular gas that immediately surrounds the central, active nucleus.

Type
Galactic
Copyright
Copyright © Reidel 1988 

References

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