A search for OH 6 GHz maser emission towards supernova remnants

10Citations
Citations of this article
9Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

OH masers at 1720 MHz have proven to be excellent indicators of interactions between supernova remnants and molecular clouds. OH-excitation calculations suggest that the 6049-MHz OH-maser line is excited for higher column densities than for the 1720-MHz line. Previous observations and modelling of 1612-, 1665- and 1667-MHz OH absorption and 1720-MHz OH masers indicated that the column densities in some supernova remnants, ∼1017 cm-2, may be high enough for 6049-MHz OH masers to exist. It is therefore a potentially valuable indicator of remnant-cloud interaction. We present excitation calculations predicting the formation of 6049-MHz OH masers and results of a survey, using the Parkes Methanol Multibeam receiver for 6049-, 6035- and 6030-MHz OH masers toward 35 supernova remnants, a star-forming region and four fields in the Large and Small Magellanic Clouds. Two new sites of 6035- and 6030-MHz OH-maser emission associated with star-forming regions have been discovered, but no 6049-MHz masers were detected to a brightness temperature limit of ∼0.3-0.6 K, even though modelling of the OH excitation suggests that maser emission should have been detected. Our upper limits indicate the OH column density for a typical remnant ≲1016.4 cm-2, which conflicts with observed and modelled column densities. One possible explanation is that 6049-MHz OH masers may be more sensitive to velocity coherence than 1720-MHz OH masers under some conditions. © 2008 RAS.

Cite

CITATION STYLE

APA

McDonnell, K. E., Wardle, M., & Vaughan, A. E. (2008). A search for OH 6 GHz maser emission towards supernova remnants. Monthly Notices of the Royal Astronomical Society, 390(1), 49–58. https://doi.org/10.1111/j.1365-2966.2008.13728.x

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free