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Related papers: Discovery of New Interacting Supernova Remnants in…

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Radio surveys of supernova remnants (SNRs) in the Galaxy have uncovered 19 SNRs accompanied by OH maser emission at 1720 MHz. This unusual class of maser sources is suggested to be produced behind a shock front from the expansion of a…

Astrophysics · Physics 2009-11-07 F. Yusef-Zadeh , M. Wardle , J. Rho , M. Sakano

A survey of the inner 8$^\circ \times 1^\circ$ of the Galactic plane toward the Galactic center has been carried out at the 1720 MHz transition of OH molecule using the VLA in its D configuration with a resolution of…

Astrophysics · Physics 2009-05-20 F. Yusef-Zadeh , W. M. Goss , D. A. Roberts , B. Robinson , D. A. Frail

We present the results of GBT observations of all four ground-state hydroxyl (OH) transitions toward 15 supernova remnants (SNRs) which show OH(1720 MHz) maser emission. This species of maser is well established as an excellent tracer of an…

Astrophysics · Physics 2009-11-13 J. W. Hewitt , F. Yusef-Zadeh , M. Wardle

A new class of OH (1720 MHz) masers unaccompanied by main-line transitions have recently been discovered (Frail, Goss and Slysh 1994). These masers lie at the interface between supernova remnants (SNRs) interacting with molecular clouds. We…

Astrophysics · Physics 2007-05-23 F. Yusef-Zadeh , D. A. Roberts , G. Bower , M. Wardle

We present molecular-line observations at millimetre, centimetre and infrared wavelengths of the region containing OH(1720 MHz) masers in the supernova remnant (SNR) G349.7+0.2, using the Australia Telescope (AT) Mopra antenna, the…

Astrophysics · Physics 2011-04-20 J. S. Lazendic , M. Wardle , J. B. Whiteoak , M. G. Burton , A. J. Green

OH(1720 MHz) masers unaccompanied by 1665/7 MHz line masers have recently been proposed as indicators of the interaction of supernova remnants (SNRs) and molecular clouds. We present a model for the masing region in which water produced in…

Astrophysics · Physics 2007-05-23 Mark Wardle , Farhad Yusef-Zadeh , T. R. Geballe

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…

Astrophysics · Physics 2008-10-28 Korinne E. McDonnell , Mark Wardle , Alan E. Vaughan

We present Very Large Array (VLA) radio interferometry observations of the 1720 MHz OH masers in the Galactic Center (GC). Most 1720 MHz OH masers arise in regions where the supernova remnant Sgr A East is interacting with the interstellar…

Astrophysics · Physics 2009-11-13 L. O. Sjouwerman , Y. M. Pihlstrom

We present the first variability study of the 1720 MHz OH masers located in the Galactic Center. Most of these masers are associated with the interaction between the supernova remnant SgrAEast and the interstellar medium, but a few masers…

Astrophysics of Galaxies · Physics 2015-05-28 Y. M. Pihlström , L. O. Sjouwerman , R. A. Mesler

OH(1720 MHz) masers are created by the interaction of supernova remnants with molecular clouds. These masers are pumped by collisions in warm, shocked molecular gas with OH column densities in the range 10^{16}--10^{17} cm^{-2}. Excitation…

Astrophysics of Galaxies · Physics 2015-06-04 Mark Wardle , Korinne McDonnell

Sgr B2 is a well-known star forming molecular cloud complex in the Galactic center region showing evidence of high energy activity as traced by the K$\alpha$ neutral FeI line at 6.4 keV, as well as GeV and TeV $\gamma$-ray emission. Here we…

High Energy Astrophysical Phenomena · Physics 2016-03-23 F. Yusef-Zadeh , W. Cotton , M. Wardle , H. Intema

OH masers at 1720 MHz have proven to be excellent indicators of interactions between supernova remnants and molecular clouds. Recent calculations suggest that the 6049 MHz OH maser line is excited for higher column densities than for the…

Astrophysics · Physics 2009-11-13 Korinne E. McDonnell , Alan E. Vaughan , Mark Wardle

Supernova remnants expanding into adjacent molecular clouds are believed to be sites of cosmic ray acceleration and sources of energetic gamma-rays. Under certain environmental conditions, such interactions also give rise to unusual OH…

Astrophysics · Physics 2009-11-06 Z. Arzoumanian , F. Yusef-Zadeh , T. J. W. Lazio

We present the results of VLA observations in the ground-state hydroxyl (OH) transition at 1720 MHz toward 20 supernova remnants (SNRs). We detect compact emission from four objects. For three of these objects (G32.8-0.1, G337.8-0.1, and…

Astrophysics · Physics 2009-10-30 Barron Koralesky , D. A. Frail , W. M. Goss , M. J. Claussen , A. J. Green

OH (1720 MHz) masers serve as indicators of SNR - molecular cloud interaction sites. These masers are collisionally excited in warm (50-100K) shocked gas with densities of order 1e5 cm^-3 when the OH column density is in the range 1e16-1e17…

Astrophysics · Physics 2009-11-13 Mark Wardle

We have used the Karl G. Jansky Very Large Array (VLA) to search for 36 GHz and 44 GHz methanol (CH3OH) lines in a sample of 21 Galactic supernova remnants (SNRs). Mainly the regions of the SNRs with 1720 MHz OH masers were observed.…

Astrophysics of Galaxies · Physics 2015-06-18 Y. M. Pihlström , L. O. Sjouwerman , D. A. Frail , M. J. Claussen , R. A. Mesler , B. C. McEwen

We report new CO observations and a detailed molecular-line study of the mixed morphology (MM) supernova remnant (SNR) G359.1-0.5, which contains six OH (1720 MHz) masers along the radio shell, indicative of shock-cloud interaction.…

Astrophysics of Galaxies · Physics 2020-02-26 L. K. Eppens , E. M. Reynoso , J. Lazendic-Galloway , J. A. Combi , J. F. Albacete Colombo , -

Compact OH(1720 MHz) masers have proven to be excellent signposts for the interaction of supernova remnants with adjacent molecular clouds. Less appreciated has been the weak, extended OH(1720 MHz) emission which accompanies strong compact…

Astrophysics · Physics 2009-11-13 J. W. Hewitt , F. Yusef-Zadeh , M. Wardle , D. A. Roberts

About 30 Galactic supernova remnants (SNRs) are thought to be physically associated with molecular clouds (MCs). These systems are prime \g-ray source candidates as the accelerated particles from shock fronts collide with the surrounding…

Astrophysics of Galaxies · Physics 2019-08-14 D. Fernandez , M. Dalton , P. Eger , H. Laffon , J. Mehault , S. Ohm , I. Oya , M. Renaud

We present observations of molecular gas made with the 15-m James Clark Maxwell Telescope toward the sites of OH(1720 MHz) masers in three supernova remnants: W28, W44 and 3C391. Maps made in the 12CO J=3-2 line reveal that the OH masers…

Astrophysics · Physics 2009-10-30 Dale A. Frail , George F. Mitchell
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