Related papers: Excited-state OH Masers and Supernova Remnants

We present an interferometric survey of the 44 GHz class I methanol maser transition toward a sample of 69 sources consisting of High Mass Protostellar Object candidates and Ultracompact (UC) H II regions. We found a 38% detection rate (16…

Deep optical CCD images of the supernova remnant G 15.1-1.6 were obtained and filamentary and diffuse emission has been discovered. The images, taken in the emission lines of Halpha+[N II], [S II] and [O III], reveal filamentary and diffuse…

We have conducted OH 18 cm survey toward 141 molecular clouds in various environments, including 33 optical dark clouds, 98 Planck Galactic cold clumps (PGCCs) and 10 Spitzer dark clouds with the Arecibo telescope. The deviations from local…

We used the Very Long Baseline Array (VLBA) and the European VLBI Network (EVN) to perform phase-referenced VLBI observations of the three most powerful maser transitions associated with the high-mass star-forming region G28.87+0.07: the…

We present a survey of 56 massive star-forming regions in the 44 GHz methanol maser transition made with the Karl G. Jansky Very Large Array (VLA); 24 of the 56 fields showed maser emission. The data allow us to demonstrate associations, at…

Supernova remnant (SNR) Kes 69 is morphologically characterized by brightened radio, infrared, and X-ray emission on the southeastern rim, with the 1720 MHz OH masers detected in the northeastern and southeastern regions at various local…

OH megamasers (OHMs) emit primarily in the main lines at 1667 and 1665 MHz, and differ from their Galactic counterparts due to their immense luminosities, large linewidths and 1667/1665 MHz flux ratios, which are always greater than one. We…

OH megamasers (OHMs) are extragalactic masers found primarily in gas-rich galaxy major mergers. To date, only $\sim$120 OHMs have been cataloged since their discovery in 1982, and efforts to identify distinct characteristics of OHM host…

Several new main line OH masers have been detected in the nearby starburst galaxy M82. Eight masers have been detected to 5 sigma, six of which are new detections. Observations covering both the 1665 and 1667 MHz lines with both the Very…

In the early days of methanol maser discoveries the 9(2)-10(1) A+ transition at 23.1 GHz was found to exhibit maser characteristics in the northern star-forming region W3(OH), and probable maser emission in two other sources. Attention…

Bright OH megamaser galaxies, radiating 1667/1665 MHz lines, could be detected at redshifts from z from 1 to 3 in moderate integration times with existing radio telescopes. The superluminous FIR galaxies that host the megamasers are…

We report the detection of the satellite 18 cm OH lines at 1612 and 1720 MHz in the z=0.2467 molecular absorption system toward the radio source PKS 1413+135. The two OH lines are conjugate; the 1612 MHz line is seen in absorption while the…

Methanol masers are often detected in regions of intense star formation. Several studies in the last decade indicate that they may even be the earliest signpost of a high-mass star-forming region. Their powerful emission make them very good…

We report a multi-epoch, simultaneous 22 GHz H2O and 44 GHz class I CH3OH maser line survey towards 180 intermediate-mass young stellar objects, including 14 Class 0, 19 Class I objects, and 147 Herbig Ae/Be stars. We detected H2O and CH3OH…

Recent studies of methanol and ground-state OH masers at very high spectral resolution have shed new light on small-scale maser processes. The nearby source W3(OH), which contains numerous bright masers in several different transitions,…

The 1612 MHz hydroxyl maser in circumstellar envelopes has long been thought to be pumped by 34.6um photons. Only recently, the Infrared Space Observatory has made possible spectroscopic observations which enable the direct confirmation of…

We present phase-referenced VLBI results on the radio continuum and the OH 18 cm megamaser emission from the Ultra-Luminous Infrared Galaxy, IRAS 17208--0014. The observations were carried out at 1599 MHz using the Very Long Baseline Array,…

The present paper focuses on the high-mass star-forming region G23.01-0.41. Methods: Using the VLBA and the EVN arrays, we conducted phase-referenced observations of the three most powerful maser species in G23.01-0.41: H2O at 22.2 GHz (4…

We report on one of the highest sensitivity surveys for molecular lines in the frequency range 6.0 to 7.4 GHz conducted to date. The observations were done with the 305m Arecibo Telescope toward a sample of twelve intermediate/high-mass…

We have carried out a multi-epoch simultaneous survey of 22 GHz H$_2$O and 44 GHz Class I CH$_3$OH masers toward 103 ultracompact HII regions (UCHIIs) between 2010 and 2017. We detected H$_2$O and CH$_3$OH maser emission in 74 (72%) and 55…