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相关论文: A Neutral Hydrogen Self-Absorption Cloud in the SG…

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Using the Westerbork Synthesis Radio Telescope, we have detected HI 21 cm-line absorption in the Warm Neutral Medium of the Galaxy toward the extragalactic source 3C147. This absorption, at an LSR velocity of -29+/-4 km/s with a full width…

天体物理学 · 物理学 2009-11-07 K. S. Dwarakanath , C. L. Carilli , W. M. Goss

We present a study of the cold atomic hydrogen (HI) content of molecular clouds simulated within the SILCC-Zoom project. We produce synthetic observations of HI at 21 cm including HI self-absorption (HISA) and observational effects. We find…

星系天体物理 · 物理学 2022-03-14 D. Seifried , H. Beuther , S. Walch , J. Syed , J. D. Soler , P. Girichidis , R. Wünsch

The Galactic Arecibo L-band Feed Array HI (GALFA-HI) survey is mapping the entire Arecibo sky at 21-cm, over a velocity range of -700 to +700 km/s (LSR), at a velocity resolution of 0.18 km/s and a spatial resolution of 3.5 arcmin. The…

We report the direct detection of cold HI gas in a cloud ejected from the Small Magellanic Cloud (SMC) towards the Magellanic Stream. The cloud is part of a fragmented shell of HI gas on the outskirts of the SMC. This is the second direct…

星系天体物理 · 物理学 2020-06-17 J. Dempsey , N. M. McClure-Griffiths , K. Jameson , F. Buckland-Willis

We present a statistical method for measuring the average HI spin temperature in distant galaxies using the expected detection yields from future wide-field 21cm absorption surveys. As a demonstrative case study we consider a simulated…

星系天体物理 · 物理学 2016-08-17 J. R. Allison , M. A. Zwaan , S. W. Duchesne , S. J. Curran

New 21 cm HI observations have revealed a giant HI cloud in the Galactic plane that has unusual properties. It is quite well defined, about 150 pc in diameter at a distance of 5 kpc, and contains as much as 100,000 Solar Masses of atomic…

天体物理学 · 物理学 2009-11-06 Anthony H. Minter , Felix J. Lockman , Glen I. Langston , Jennifer A. Lockman

We have created synthetic neutral hydrogen (HI) Galactic Plane Survey data cubes covering 90 degrees < l < 180 degrees, using a model spiral galaxy from SPH simulations and the radiative transfer code TORUS. The density, temperature and…

星系天体物理 · 物理学 2011-03-18 Kevin A. Douglas , David M. Acreman , Clare L. Dobbs , Christopher M. Brunt

We have observed a 3 degree x 3 degree area centered on the M81/M82 group of galaxies using the Robert C. Byrd Green Bank Telescope (GBT) in a search for analogs to the High Velocity Clouds (HVCs) of neutral hydrogen found around our…

We report a deep Giant Metrewave Radio Telescope (GMRT) search for Galactic H{\sc i} 21cm absorption towards the quasar B0438$-$436, yielding the detection of wide, weak H{\sc i} 21cm absorption, with a velocity-integrated H{\sc i} 21cm…

The discovery of an HI cloud with peculiar properties at equatorial coordinates (J2000) ra=07h49m, dec=04d30m is presented. The HI object was detected at 21cm using the 300-m NAIC Arecibo telescope. Subsequent follow-up high-resolution…

天体物理学 · 物理学 2009-11-13 L. Dedes , C. Dedes , P. W. M Kalberla

We present the results of a blind search for intervening HI 21 cm absorption toward 260 radio sources in the redshift range 0<z<2.74 with the Green Bank Telescope. The survey has the sensitivity to detect sub-damped Lyman-alpha (DLA)…

星系天体物理 · 物理学 2020-08-25 Kathryn Grasha , Jeremy Darling , Adam K. Leroy , Alberto D. Bolatto

We present results from MUSE observations of a 21-cm HI absorption system detected with the Australian Square Kilometre Array Pathfinder radio telescope at redshift $z = 0.4503$ towards the $z = 1.71$ quasar PKS 1610-771. We identify four…

The Southern Galactic Plane Survey (SGPS) is a project to image the HI line emission and 1.4 GHz continuum in the fourth quadrant of the Milky Way at high resolution using the Australia Telescope Compact Array (ATCA) and the Parkes Radio…

We have carried out deep, high velocity resolution, interferometric Galactic HI 21 cm absorption spectroscopy towards 32 compact extra-galactic radio sources with the Giant Metrewave Radio Telescope (GMRT) and the Westerbork Synthesis Radio…

星系天体物理 · 物理学 2014-07-30 Nirupam Roy , Nissim Kanekar , Robert Braun , Jayaram N. Chengalur

We present the first direct detection of cold atomic gas in the Magellanic Stream, through 21 cm line absorption toward a background radio source, J0119 - 6809, using the Australia Telescope Compact Array. Two absorption components were…

星系天体物理 · 物理学 2011-02-11 D. Matthews , L. Staveley-Smith , P. Dyson , E. Muller

We have observed 12CO J = 2-1 and J = 1-0, and 13CO J = 1-0 emission in two regions of HI Self-Absorption (HISA) in Perseus: a small, isolated HISA feature called the globule and a more extended HISA cloud called the complex. Using both…

天体物理学 · 物理学 2009-11-13 P. D. Klaassen , R. Plume , S. J. Gibson , A. R. Taylor , C. M. Brunt

The H2O Southern Galactic Plane Survey (HOPS) has mapped a 100 degree strip of the Galactic plane (-70deg > l > 30deg, |b| < 0.5deg) using the 22-m Mopra antenna at 12-mm wavelengths. Observations were conducted in on-the-fly mode using the…

We have detected HI 21cm line absorption by the Warm Neutral Medium (WNM) using the Westerbork Synthesis Radio Telescope. The absorption was detected toward Cygnus A at LSR velocities of -40 and -70 km s^{-1}. These two velocity ranges were…

天体物理学 · 物理学 2009-10-30 C. L. Carilli , K. S. Dwarakanath , W. M. Goss

In this study, we analyze molecular gas formation in neutral atomic hydrogen (HI) clouds using the latest CO data obtained from the four-beam receiver system on a 45-m telescope (FOREST) unbiased Galactic plane imaging survey with the…

We report Arecibo 21 cm absorption-emission observations to characterise the physical properties of neutral hydrogen (HI) in the proximity of five giant molecular clouds (GMCs): Taurus, California, Rosette, Mon OB1, and NGC 2264. Strong HI…