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An astrophysical MASER (Microwave Amplification by Stimulated Emission of Radiation) is a source of stimulated spectral line emission. Maser emission is observed from the circumstellar envelopes of evolved stars, molecular clouds/star-forming regions, active galactic nuclei, supernova remnants, comets, and the Saturnian moons. It arises from molecules such as water (H2O), hydroxyl radicals (OH), methanol (CH3OH), formaldehyde (CH2O), silicon monoxide (SiO), ammonia (NH3), silicon sulphide (SiS), hydrogen cyanide (HCN), and from atomic hydrogen recombination lines. Masers are compact, of high brightness temperature, and often display narrow spectral line widths, polarized emission and variability. Free electron-cyclotron astrophysical masers additionally exist.
In this paper, we present a database of class I methanol masers. The compiled information from the available literature provides an open and fast access to the data on class I methanol maser emission, including search, analysis and visualization of t
(Abridged) Astronomical masers have been effective tools to study magnetic fields for many years. In particular, methanol can be used to probe different parts of protostars such as accretion discs and outflows, since it produces one of the strongest
We present a new database of circumstellar OH masers at 1612, 1665, and 1667 MHz in the Milky Way galaxy. The database (version 2.4) contains 13655 observations and 2341 different stars detected in at least one transition. Detections at 1612,MHz are
We report the discovery of water maser emission at frequencies above 1 THz. Using the GREAT instrument on SOFIA, we have detected emission in the 1.296411 THz 8(27)-7(34) transition of water toward three oxygen-rich evolved stars: W Hya, U Her, and V
The Australia Telescope Compact Array has been used to search for 22-GHz water masers towards the 119 6.7-GHz methanol masers detected in the Methanol Multi-Beam survey between Galactic longitudes 6 and 20 degrees; we find water masers associated wit