The Discovery of Time Variability in OH Megamasers
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چکیده
منابع مشابه
The Discovery of Time Variability in Oh Megamasers
We report the discovery of variability in the OH megamaser in IRAS 21272+2514 at z = 0.15. This is the first OH megamaser (OHM) observed to vary in time. The variation is broadband, spanning 0.5–1.5 MHz or 100–300 km s in the rest frame, and strong, showing rms modulations of 10%–15% while the largest change in flux density between extremal epochs is 34%. Timescales sampled range from 39 to 821...
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We detected significant Zeeman splitting in the 1667MHz OH megamaser emission from four ultraluminous galaxies. These detections, in addition to being the first extragalactic detection of the Zeeman effect in an emission line, suggest that OH megamasers are excellent extragalactic magnetometers.
متن کاملExtragalactic Zeeman Detections in Oh Megamasers
We have measured the Zeeman splitting of OH megamaser emission at 1667 MHz from five (ultra)luminous infrared galaxies ([U]LIRGs) using the 305 m Arecibo telescope and the 100 m Green Bank Telescope. Five of eight targeted galaxies show significant Zeeman-splitting detections, with 14 individual masing components detected and line-of-sight magnetic field strengths ranging from ≃ 0.5 − 18 mG. Th...
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HCN and CO line diagnostics provide new insight into the OH megamaser (OHM) phenomenon, suggesting a dense gas trigger for OHMs. We identify three physical properties that differentiate OHM hosts from other starburst galaxies: (1) OHMs have the highest mean molecular gas densities among starburst galaxies; nearly all OHM hosts have n̄(H2) = 103–104 cm−3 (OH line-emitting clouds likely have n(H2)...
متن کاملOH megamasers , starburst and AGN activity in Markarian 231
We present MERLIN observations of OH maser and radio continuum emission within a few hundred pc of the core of the Ultra Luminous IR Galaxy Markarian 231. This is the only known OH megamaser galaxy classed as a Seyfert 1. Maser emission is identified with the 1665and 1667-MHz transitions over a velocity extent of 720 km s. Both lines show a similar position-velocity structure including a gradie...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2002
ISSN: 0004-637X,1538-4357
DOI: 10.1086/340773