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dc.contributor.authorBoboltz, David Allen Jr.en
dc.contributor.authorSimonetti, John H.en
dc.contributor.authorDennison, Brian K.en
dc.contributor.authorDiamond, Philip J.en
dc.contributor.authorUphoff, J. A.en
dc.date.accessioned2014-03-10T13:18:52Zen
dc.date.available2014-03-10T13:18:52Zen
dc.date.issued1998-12en
dc.identifier.citationD. A. Boboltz et al. 1998 ApJ 509 256 doi:10.1086/306482en
dc.identifier.issn0004-637Xen
dc.identifier.urihttp://hdl.handle.net/10919/25855en
dc.description.abstractWe monitored the 22 GHz H2O maser emission toward W49N from December 1989 through May 1990. During this period we observed an outburst in a component at -66.25 km s(-1). The flux density of the flaring component increased by a factor of greater than or similar to 10 to a maximum of 4020 Jy over a period of 24 days and decreased over the following 34 days to 1400 Jy on the last day of monitoring. During the flux increase the line narrowed from about 1.1 to 0.8 k s(-1); it subsequently rebroadened to 1.0 km s(-1) Most interestingly, during the flaring behavior the line center shifted by approximately 0.5 km s(-1) over the 58 day period. To explain the flare, particularly its shifting line center, we present a model of two interacting maser clouds. In the model, saturated maser radiation produced in a background cloud is amplified by an unsaturated, masing foreground cloud. Motion of the foreground cloud across the line of sight produces a flaring line, accompanied by line narrowing. We demonstrate that the observed flare in W49N may be explained by such a model where a rotating foreground cloud passes in front of a non-rotating background cloud. The differential amplification of the background cloud's radiation produces the observed increase in flux density, line narrowing, and systematic shift in center velocity.en
dc.description.sponsorshipNSF 93-19670en
dc.language.isoen_USen
dc.publisherIOP PUBLISHING LTDen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectism : individual (w49)en
dc.subjectism : moleculesen
dc.subjectmasersen
dc.subjectradio lines : ismen
dc.subjectstar-forming regionsen
dc.subjecth2o masersen
dc.subjectcepheus-aen
dc.titleA Water Maser Flare in W49N: Amplification by a Rotating Foreground Clouden
dc.typeArticle - Refereeden
dc.contributor.departmentInstitute for Particle, Nuclear and Astronomical Sciences (IPNAS)en
dc.contributor.departmentPhysicsen
dc.identifier.urlhttp://iopscience.iop.org/0004-637X/509/1/256en
dc.date.accessed2014-02-28en
dc.title.serialAstrophysical Journalen
dc.identifier.doihttps://doi.org/10.1086/306482en


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