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相关论文: Testing OH Megamaser Identification Methods in HI …

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We used Arecibo Observatory and the Green Bank Telescope to observe OH in twelve early-type galaxies with known reservoirs of dense gas. We present three new detections of OH in absorption in the 1667 MHz line. One objective of our survey…

星系天体物理 · 物理学 2015-06-23 James McBride , Katherine Alatalo , Kristina Nyland

The discovery of a previously unknown 21cm HI line source identified as an ultra-compact high velocity cloud in the ALFALFA survey is reported. The HI detection is barely resolved by the Arecibo 305m telescope ~4' beam and has a narrow HI…

We conducted radio observations searching for OH 18-cm maser emission from a sample of 169 unclassified MIPSGAL compact Galactic bubbles. These sources are thought to be the circumstellar envelopes of different kinds of evolved stars. Our…

太阳与恒星天体物理 · 物理学 2015-10-02 A. Ingallinera , C. Trigilio , P. Leto , G. Umana , C. Buemi , L. Cerrigone , C. Agliozzo

We have used the NRAO Very Long Baseline Array (VLBA) to image OH(1720 MHz) masers in the supernova remnants W28 and W44 at a resolution of 40 mas. We also used MERLIN to observe the same OH(1720 MHz) masers in W44 at a resolution of 290 x…

天体物理学 · 物理学 2009-10-31 M. J. Claussen , W. M. Goss , D. A. Frail , K. Desai

We have used the Australia Telescope Compact Array (ATCA) to search for 6.7-GHz methanol maser emission towards 87 galaxies. We chose the target sources using several criteria, including far-IR luminosities and the presence of known OH…

天体物理学 · 物理学 2020-11-25 C. J. Phillips , R. P. Norris , S. P. Ellingsen , D. P. Rayner

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…

天体物理学 · 物理学 2009-11-07 Jeremy Darling

I report detections of four new HI 21-cm absorbers associated with sources at intermediate redshifts, 0.7 < z < 1.0. The sources are part of a sample of 11 radio-loud galaxies, all at 0.7 < z < 1.0, that were searched for associated HI…

星系天体物理 · 物理学 2018-11-28 J. N. H. S. Aditya

We study the radio variability of galaxies with and without sources of hydroxyl (OH) megamaser radiation based on the continuum radio measurements conducted in 2019-2022 with the radio telescope RATAN-600 at frequencies of 2.3, 4.7, 8.2,…

We present the results of HI and OH absorption measurements towards a sample of radio sources using the Arecibo 305-m telescope and the GMRT. In total, 27 radio sources were searched for associated 21-cm HI absorption. One totally new HI…

天体物理学 · 物理学 2009-11-11 Neeraj Gupta , C. J. Salter , D. J. Saikia , T. Ghosh , S. Jeyakumar

In preparation for the full Arecibo Legacy Fast ALFA extragalactic HI survey, precursor observations were carried out in Aug--Sep 2004 with the 7-beam Arecibo L-band feed array (ALFA) receiver system and the WAPP spectral processors. While…

Aims: A pilot project has been carried out to measure circumstellar CO emission from three OH/IR stars close to the Galactic centre. The intention was to find out whether it would be possible to conduct a large-scale survey for mass-loss…

星系天体物理 · 物理学 2009-11-13 A. Winnberg , S. Deguchi , M. J. Reid , J. Nakashima , H. Olofsson , H. J. Habing

The Arecibo Legacy Fast ALFA (ALFALFA) survey is designed to explore the z=0 HI mass function (HIMF) over a cosmologically significant volume. ALFALFA will improve on previous determinations of the HIMF by its combination of depth, wide…

天体物理学 · 物理学 2008-02-13 Martha P. Haynes

Very luminous extragalactic water masers, the megamasers, are associated with active galactic nuclei (AGN) in galaxies characterized by accretion disks, radio jets, and nuclear outflows. Weaker masers, the kilomasers, seem to be mostly…

宇宙学与河外天体物理 · 物理学 2015-05-19 A. Tarchi , P. Castangia , C. Henkel , G. Surcis , K. M. Menten

Studying stars that are located off the Galactic plane is important for understanding the formation history of the Milky Way. We searched for SiO masers toward off-plane O-rich asymptotic giant branch (AGB) stars from the catalog presented…

星系天体物理 · 物理学 2023-10-23 Wenjin Yang , Yuanwei Wu , Yan Gong , Nicolas Mauron , Bo Zhang , Karl M. Menten , Xiaofeng Mai , Dejian Liu , Juan Li , Jingjing Li

Thermally broadened Ly alpha absorbers (BLAs) offer an alternative method to highly-ionized metal lines for tracing the WHIM. We compile a catalog of reliable BLA candidates along seven AGN sight lines from a larger set of Lya absorbers…

宇宙学与河外天体物理 · 物理学 2014-11-20 Charles W. Danforth , John T. Stocke , J. Michael Shull

The {\bf H}$_2${\bf O} Southern Galactic {\bf P}lane {\bf S}urvey (HOPS) has observed 100 square degrees of the Galactic plane, using the Mopra radio telescope to search for emission from multiple spectral lines in the 12\,mm band…

天体物理仪器与方法 · 物理学 2015-06-03 Andrew J. Walsh , Cormac Purcell , Steven Longmore , Christopher H. Jordan , Vicki Lowe

We describe a deep, systematic imaging study of satellites in the outer halo of the Milky Way. Our sample consists of 58 stellar overdensities --- i.e., substructures classified as either globular clusters, classical dwarf galaxies, or…

We present a sample of 115 very low optical surface brightness, highly extended, HI-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently…

OH masers at 1720 MHz have proven to be excellent indicators of interactions between supernova remnants and molecular clouds. Recent calculations suggest that the 6049 MHz OH maser line is excited for higher column densities than for the…

天体物理学 · 物理学 2009-11-13 Korinne E. McDonnell , Alan E. Vaughan , Mark Wardle

We present OH maser observations at 1612, 1665, 1667, and 1720 MHz for 86 post-asymptotic giant branch (post-AGB) stars selected from a survey of 1612 MHz maser sources in the Galactic Plane. The observations were taken with the Parkes…

天体物理学 · 物理学 2009-11-10 R. M. Deacon , J. M. Chapman , A. J. Green