Survey of OH Masers at 1665 and 1667 MHz. I. Galactic Longitudes 326° to 40°

Phase-Referenced VLBA Observations of OH Masers at 4765 MHz

We report VLBA observations of maser emission from the rotationally excited Π1/2, 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 within a ∼2000 AU diameter region and verified that in two of the three fields, 4765 MHz and 1720 MHz emission arise from the same position to within ∼4 mas (∼8 AU). We ...

Robert Hooke's Micrographia of 1665 and 1667.

High - resolution Observations of OH ( 1720 MHz ) Masers Toward the Galactic Center

High-resolution VLA observations of 1720 MHz OH maser emission from Sgr A East and the circumnuclear disk with spatial and spectral resolutions of ≈ 2. ′′ 5 × 1. ′′ 3 and 0.27 kms −1 are reported. This follow-up observational study focuses on the recent discovery of a number of such OH maser features and their intense circularly polarized maser lines detected toward these Galactic center source...

The Effect of 53 μm IR Radiation on 18 cm OH Megamaser Emission

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 find that these maser properties result from strong 53 μm radiative pumping combined with line overlap effects caused by turbulent linewidths ∼ 20 km s; pum...

OH (1720 MHz) MASERS AND MIXED-MORPHOLOGY SUPERNOVA REMNANTS

Radio surveys of supernova remnants (SNRs) in the Galaxy have uncovered 19 SNRs accompanied by OH maser emission at 1720 MHz. This unusual class of maser sources is suggested to be produced behind a shock front from the expansion of a supernova remnant running into a molecular cloud. An important ingredient of this model is that X-ray emission from the remnant enhances the production of OH mole...