Related papers: A search for the 55 MHz OH line
Sub-Doppler, saturation dip, spectra of lines in the $v_1 + v_3$, $v_1 + 2v_4$ and $v_3 + 2v_4$ bands of $^{14}$NH$_3$ have been measured by frequency comb-referenced diode laser absorption spectroscopy. The observed spectral line widths…
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…
Centimeter-wave transitions are important counterparts to the rotational mm-wave transitions usually observed to study gas in star-forming regions. However, given their relative weakness, these transitions have historically been neglected.…
A new methanol maser line 6(-1)-5(0)E at 133 GHz was detected with the 12-m Kitt Peak radio telescope using remote observation mode from Moscow. Moderately strong, narrow maser lines were found in DR21(OH), DR21-W, OMC-2, M8E, NGC2264,…
We estimate limits on non-universal coupling of hypothetical hidden fields to standard matter by evaluating the fractional changes in the electron-to-proton mass ratio, mu = m_e/m_p, based on observations of ClassI methanol 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…
VLA observations of OH absorption towards the elliptical galaxy NGC 1052 are presented. Both OH lines, at 1665 and 1667 MHz, were detected in absorption towards the center of NGC 1052. The hyperfine ratio of the two OH lines…
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 the first space-VLBI observations of the OH34.26+0.15 maser in two main line OH transitions at 1665 and 1667 MHz. The observations involved the space radiotelescope on board the Japanese satellite HALCA and an array of ground…
Gas in the million degree range occurs in a variety of astronomical environments, and it may be the main component of the elusive missing baryons at low redshift. The NVII ion is found in this material and it has a hyperfine spin-flip…
High-resolution infrared spectroscopy in the 2.3-4.6 micron region is reported for the peculiar A supergiant, single-lined spectroscopic binary HR 4049. Lines from the CO fundamental and first overtone, OH fundamental, and several H2O…
A new class of OH (1720 MHz) masers unaccompanied by main-line transitions have recently been discovered (Frail, Goss and Slysh 1994). These masers lie at the interface between supernova remnants (SNRs) interacting with molecular clouds. We…
Spectral line surveys are useful since they allow identification of new molecules and new lines in uniformly calibrated data sets. Nonetheless, large portions of the sub-millimetre spectral regime remain unexplored due to severe absorptions…
We investigate the constraints that OH microwave transitions in megamasers and molecular absorbers at cosmological distances may place on the evolution of the fine structure constant alpha=e^2/(hbar c). The centimeter OH transitions are a…
Massive star-forming regions exhibit a rich chemistry with complex gas distributions, especially on small scales. While surveys have yielded constraints on typical gas conditions, they often have coarse spatial resolution and limited…
We performed a search for the HeH+ J=1-0 line (\nu_{rest} = 2010.183873 GHz) and simultaneously for the CH ^2\Pi_{3/2}(F_2)J=3/2 - ^2\Pi_{1/2}(F_2)J=1/2 lines (\nu_{rest}\approx 2006.8 and 2010.8 GHz) toward one of the highest-redshift…
The polarized emission of astrophysical masers, especially OH and methanol lines, is an effective tool to study the magnetic field in high-mass star-forming regions. The magnetic field strength measurement via the Zeeman effect of OH maser…
Precise molecular transition frequencies are of great interest in the test of fundamental physics and also in various applications. Two well isolated ro-vibrational transitions of $^{12}$C$^{16}$O at 1.57 $\mu$m, R(9) and R(10) in the…
We present constraints on the molecular outflows in a sample of five Hyper-Luminous Infrared Galaxies using Herschel observations of the OH doublet at 119 {\mu}m. We have detected the OH doublet in three cases: one purely in emission and…
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…