相关论文: VLA observations of 6-cm excited OH

Recent observational and theoretical advances have called into question traditional OH maser pumping models in evolved (OH/IR) stars. The detection of excited-state OH lines would provide additional constraints to discriminate amongst these…

We report VLBA observations of maser emission from the rotationally excited doublet Pi 1/2, J=1/2 state of OH at 4765 MHz. We made phase-referenced observations of W3(OH) at both 4765 MHz and 1720 MHz and found emission in three fields…

Using the Very Large Array (VLA), we observed all three of the 6-cm lines of the doublet Pi 1/2, J=1/2 state of OH with sub-arcsecond resolution (about 0.4 arcsec) in W49A. While the spatial distribution and the range in velocities of the…

We report on a second epoch of VLBA observations of the 1665 and 1667 MHz OH masers in the massive star-forming region W75 N. We find evidence to confirm the existence of very strong (~40 mG) magnetic fields near source VLA 2. The masers…

We have used the Australia Telescope Compact Array (ATCA) to make a sensitive (5-$\sigma$ $\simeq$ 100 mJy) search for maser emission from the 4765-MHz $^2\Pi_{1/2}$ F=1$\to$0 transition of OH. Fifty five star formation regions were…

We present results of a high resolution survey of OH masers in Galactic Star Forming Regions in order to study the maser emission and establish a list of suitable candidates for higher resolution instruments follow up. We used the Very Long…

We have used the Australia Telescope Compact Array (ATCA) to make a sensitive search for maser emission from the 4765-MHz transition of OH towards a sample of 55 star formation regions. Maser emission with peak flux densities in excess of…

We present VLA observations in the hydroxyl line OH(1720 MHz) towards the supernova remnant W28. These high resolution images show a more extensive distribution of 1720 MHz emission than had previously been suspected from earlier…

We report on the multi-epoch observations of H2O maser emission in star forming region OH 43.8-0.1 carried out with VLBI Exploration of Radio Astrometry (VERA). The large-scale maser distributions obtained by single-beam VLBI mapping reveal…

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 new Jansky Very Large Array (VLA) images of the central region of the W49A star-forming region at 3.6~cm and at 7~mm at resolutions of 0\farcs15 (1650 au) and 0\farcs04 (440 au), respectively. The 3.6~cm data reveal new…

We analyze radio continuum and line observations from the archives of the Very Large Array, as well as X-ray observations from the \emph{Chandra} archive of the region of massive star formation W75N. Five radio continuum sources are…

W75N(B) is a massive star-forming region that contains three radio continuum sources (VLA 1, VLA 2, and VLA 3), which are thought to be three massive young stellar objects at three different evolutionary stages. VLA 1 is the most evolved…

We present VLBA observations of 1667 MHz OH maser emission from the massive star formation region G5.89-0.39. The observations were phase referenced allowing the absolute positions of the masers to be obtained. The 1667 MHz masers have…

We have undertaken a comprehensive search for 5-cm excited OH maser emission from evolved stars representative of various stages of late stellar evolution. Observed sources were selected from known 18-cm OH sources. This survey was…

Several radio sources have been detected in the HMSFR W75N(B), among them the massive YSOs VLA1 and VLA2 are of great interest. These are thought to be in different evolutionary stages. In particular, VLA1 is at the early stage of the…

The star-forming region W75N hosts bright OH masers that are observed to be variable. We present observations taken in 2008 of the ground-state OH maser transitions with the Very Long Baseline Array (VLBA) and the Multi-Element Radio-Linked…

Using the VLA, a series of high velocity resolution observations have been made of the M82 starburst at 1.6 GHz. These observations follow up on previous studies of the main line OH maser emission in the central kiloparsec of this starburst…

The source G25.65+1.05 (RAFGL7009S, IRAS 18316-0602) is the least studied of the three regions of massive star formation known to show exceptionally powerful H$_2$O maser bursts. We report spectral line observations of the H$_2$O maser at…

We present multi-epoch Very Long Baseline Array (VLBA) H$_2$O maser observations toward the massive young stellar objects (YSOs) VLA 2 and VLA 3 in the star-forming region AFGL 2591. Through these observations, we have extended the study of…