2004/12/02 by S. Goedhart, V. Minier, M. J. Gaylard +1 · 49 citations
Physics and Astronomy · #Active galactic nucleus #Angular resolution (graph drawing) #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Binary number #Flare #Galaxy #Gamma-ray bursts and supernovae #Maser #Physics #Solar flare #Stellar, planetary, and galactic studies #Very Long Baseline Array #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2004.08519.x
published in Monthly Notices of the Royal Astronomical Society 356(3), 839-848 (Oxford University Press) · 11 pages, accepted for publication in MNRAS
arxiv created 2004/12/02 · openalex publication_date 2005/01/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The class II methanol maser source G9.62+0.20E undergoes periodic flares at both 6.7 and 12.2 GHz. The flare starting in 2001 October was observed at seven epochs over three months using the Very Long Baseline Array (VLBA) at 12.2 GHz. High angular resolution images (beam size ∼1.7 × 0.6 mas) were obtained, enabling us to observe changes in 16 individual maser components. It was found that while existing maser spots increased in flux density, no new spots developed and no changes in morphology were observed. This rules out any mechanism which disturbs the masing region itself, implying that the flares are caused by a change in either the seed or pump photon levels. A time delay of one to two weeks was observed between groups of maser features. These delays can be explained by light travel time between maser groups. The regularity of the flares can possibly be explained by a binary system.