SWAG Water Masers in the Galactic Center

Abstract

The Galactic Center contains large amounts of molecular and ionized gas as well as a plethora of energetic objects. Water masers are an extinction-insensitive probe for star formation and thus ideal for studies of star formation stages in this highly obscured region. With the Australia Telescope Compact Array, we observed 22 GHz water masers in the entire Central Molecular Zone with sub-parsec resolution as part of the large SWAG survey: ``Survey of Water and Ammonia in the Galactic Center''. We detect of order 600 22 GHz masers with isotropic luminosities down to ~10^-7 Lo. Masers with luminosities of >~10^-6 Lo are likely associated with young stellar objects. They appear to be close to molecular gas streamers and may be due to star formation events that are triggered at pericenter passages near Sgr A*. Weaker masers are more widely distributed and frequently show double line features, a tell-tale sign for an origin in evolved star envelopes.

arXiv comment4 pages, 2 figues, conference proceedings for IAU Symposium 336: "Astrophysical Masers: Unlocking the Mysteries of the Universe"

References in corpus (7)

• A 100-parsec elliptical and twisted ring of cold and dense molecular clouds revealed by Herschel around the Galactic Center
• The dynamical evolution of molecular clouds near the Galactic Centre - I. Orbital structure and evolutionary timeline
• Star Formation in the Central 400 pc of the Milky Way: Evidence for a Population of Massive YSOs
• Candidate super star cluster progenitor gas clouds possibly triggered by close passage to Sgr A*
• The Survey of Water and Ammonia in the Galactic Center (SWAG): Molecular Cloud Evolution in the Central Molecular Zone
• Seeding the Galactic Centre gas stream: gravitational instabilities set the initial conditions for the formation of protocluster clouds
• Nuclear Spirals in the inner Milky Way