1999/07/27 by F. Yusef-Zadeh, F. Yusef‐Zadeh, W. M. Goss +4 · 68 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Galactic Center #Galactic plane #Galaxy #Line (geometry) #Maser #Nebula #Physics #Stars #Supernova #Supernova remnant #astro-ph
paper · pdf · doi:10.1086/308087
published in The Astrophysical Journal 527(1), 172-179 (IOP Publishing) · 22 pages, 5 figures, one table, Astrophysical Journal (in press)
arxiv created 1999/07/27 · openalex publication_date 1999/12/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A survey of the inner 8° × 1° of the Galactic plane toward the Galactic center has been carried out at the 1720 MHz transition of the OH molecule using the VLA in its D configuration with a resolution of ≈70'' × 45''. The detection of compact 1720 MHz OH masers associated with three supernova remnants G357.7+0.3, G1.13-0.1 (Sgr D), and G1.4-0.1 as well as new extended maser line emission from G357.7+0.3 and G357.7-0.1 (the Tornado Nebula) were then followed up by A-array observations with spectral and spatial resolutions of 0.3 km s -1 and ≈3'' × 2'', respectively. The 1720 MHz OH maser line emission is considered to be a powerful shock diagnostic and is collisionally pumped by H 2 molecules at the site where C-type supernova shocks drive into adjacent molecular clouds. The new observations show clear evidence of extended features coincident with compact and bright masers, the best example of which is a coherent feature over a scale of about 20 pc surrounding the shell of the SNR G357.7+0.3. We argue that this remarkable feature is an OH maser and is physically associated with the remnant. This implies that the ambient molecular cloud is uniform in its density and temperature with a restricted range of pumping conditions and survives the passage of a large-scale shock front.