Related papers: The Physics of Water Masers observable with ALMA a…

We study in details a pumping mechanism for the lambda=1.35 cm maser transition 6_16 -> 5_23 in ortho-water based on the difference between gas and dust temperatures. The upper maser level is populated radiatively through 4_14 -> 5_05 and…

Here we aim to characterise submillimetre water masers at 437, 439, 471, and 474 GHz towards a sample of evolved stars. We used the Atacama Pathfinder Experiment (APEX) to observe submillimetre water transitions and the CO (4-3) line…

The deuterium fractionation of water can serve as a tracer for the chemical and physical evolution of water during star formation and can constrain the origin of water in Solar System bodies. We determine the HDO/H$_2$O ratio in the inner…

The ATCA has been used to measure positions with arcsecond accuracy for 379 masers at the 22-GHz transition of water. The principal observation targets were 202 OH masers of the variety associated with star formation regions (SFR)s in the…

Context. Water vapor emission at 22 GHz from masers associated with star-forming regions is highly variable. Aims. We present a database of up to 20 years of monitoring of a sample of 43 masers within star-forming regions. The sample covers…

Water masers are common in star-forming regions (SFRs), with the 22.235 GHz transition widely detected in both high- and low-mass protostars. In contrast, (sub)millimeter water maser transitions remain poorly studied, especially in low-mass…

We present our past and current long-term monitoring program of water masers in the circumstellar envelopes of evolved stars, augmented by occasional interferometric observations. Using as example the Mira-variable U Her, we identify three…

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…

Water and the hydroxyl radical are major constituents of the envelope of O-rich late-type stars. Transitions involving energy levels that are highly excited have been observed in both H$_2$O and OH. These and more recently discovered…

Following up on our discovery of terahertz water masers, reported in 2017, we report two further detections of water maser emission at frequencies above 1 THz. Using the GREAT instrument on SOFIA, we have detected emission in the 1.296411…

Cool, evolved stars undergo copious mass loss but the details of how the matter is returned to the ISM are still under debate. We investigated the structure and evolution of the wind at 5 to 50 stellar radii from Asymptotic Giant Branch and…

We report ALMA high-resolution observations of water emission lines $p-{\rm{H_2O}} (2_{02}-1_{11}$), $o-{\rm{H_2O}} (3_{21}-3_{12})$, $p-{\rm{H_2O}} (4_{22}-4_{13})$, in the strongly lensed galaxy HATLASJ113526.2-01460 at redshift z $\sim$…

Cool, evolved stars have copious, enriched winds. The structure of these winds and the way they are accelerated is not well known. We need to improve our understanding by studying the dynamics from the pulsating stellar surface to about 10…

We report VLBI monitoring observations of the 22 GHz water (H$_{2}$O) masers around the Mira variable BX Cam, which were carried out as a part of the EAVN Synthesis of Stellar Maser Animations (ESTEMA) project. Data of 37 epochs in total…

The changes in the spectral line profile of the 22GHz H2O maser are calculated as a function of emerging maser flux. We address not only the narrowing and re-broadening of the maser lines, but also the deviations of Gaussian symmetry as a…

The Red MSX Source (RMS) survey has identified a sample of ~1200 massive young stellar objects (MYSOs), compact and ultra compact HII regions from a sample of ~2000 MSX and 2MASS colour selected sources. We have used the 100 m Green Bank…

We have conducted multi-epoch EVN observations of the 22.2 GHz water masers towards four high-mass star forming regions (Sh 2-255 IR, IRAS 23139+5939, WB89-234, and OMC2). The (three) observing epochs span a time range of 6 months. In each…

Context: Maser emission from the H2O molecule probes the warm, inner circumstellar envelopes of oxygen-rich red giant and supergiant stars. Multi-maser transition studies can be used to put constraints on the density and temperature of the…

We have conducted a sensitive water maser search with the ATCA towards 267 1.2-mm dust clumps presented in the literature. We combine our new observations with previous water maser observations to extend our sample to 294 1.2-mm dust…

Within low-mass star formation, water vapor plays a key role in the chemistry and energy balance of the circumstellar material. The Herschel Space Observatory will open up the possibility to observe water lines originating from a wide range…