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Related papers: HI Absorption in GPS/CSS Sources

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We have observed the Galactic Center (GC) region at 0.154 and 0.255 GHz with the GMRT. A total of 62 compact likely extragalactic sources are detected. Their scattering sizes go down linearly with increasing angular distance from the GC up…

Astrophysics of Galaxies · Physics 2015-06-16 Subhashis Roy

We present a complete catalog of H I emission and absorption spectrum pairs, toward H II regions, detectable within the boundaries of the Southern Galactic Plane Survey (SGPS I), a total of 252 regions. The catalog is presented in…

Astrophysics of Galaxies · Physics 2015-06-18 C Brown , J. M. Dickey , J. R. Dawson , N. M. McClure-Griffiths

We present spectroscopic observations of a sample of faint Gigahertz Peaked Spectrum (GPS) radio sources drawn from the Westerbork Northern Sky Survey (WENSS). Redshifts have been determined for 19 (40%) of the objects. The optical spectra…

Compact Steep Spectrum (CSS) radio sources are active galactic nuclei that have radio jets propagating only on galactic scales, defined as having projected linear sizes (LS) of up to $20\,$kpc. CSS sources are generally hosted by massive…

Astrophysics of Galaxies · Physics 2023-05-10 Yjan A. Gordon , Christopher P. O'Dea , Stefi A. Baum , Keith Bechtol , Chetna Duggal , Peter S. Ferguson

We present searches for molecular gas (CO, OH, CS, and Ammonia) in six GHz Peaked Spectrum (GPS) radio sources. We do not detect gas in any source and place upper limits on the mass of molecular gas which are generally in the range 1E9 to a…

Astrophysics · Physics 2009-11-10 C. P. O'Dea , J. Gallimore , C. Stanghellini , S. A. Baum , J. M. Jackson

We present the results from our survey of HI 21-cm absorption, using GMRT, VLA and WSRT, in a sample of 55 z<0.4 galaxies towards radio sources with impact parameters (b) in the range ~0-35 kpc. In our primary sample (defined for…

Astrophysics of Galaxies · Physics 2016-12-14 R. Dutta , R. Srianand , N. Gupta , E. Momjian , P. Noterdaeme , P. Petitjean , H. Rahmani

Cold, neutral interstellar gas, the reservoir for star formation, is traced through the absorption of the 21-centimetre continuum radiation by neutral hydrogen (HI). Although detected in one hundred cases in the host galaxies of distant…

Astrophysics of Galaxies · Physics 2024-01-03 S J Curran

Using a sample of 38 radio-loud galaxy mergers at z<=0.2, we confirm the high detection rate (~84%) of HI 21-cm absorption in mergers, which is significantly higher (~4 times) than in non-mergers. The distributions of the HI column density…

Astrophysics of Galaxies · Physics 2019-08-14 Rajeshwari Dutta , Raghunathan Srianand , Neeraj Gupta

We have selected a sample of 80 candidates for obscured radio-loud active galactic nuclei and presented their basic optical/near-infrared (NIR) properties in Paper 1. In this paper, we present both high-resolution radio continuum images for…

Astrophysics of Galaxies · Physics 2016-03-16 Ting Yan , John T. Stocke , Jeremy Darling , Emmanuel Momjian , Soniya Sharma , Nissim Kanekar

H{\sc i} absorption studies of active galaxies enable us to probe their circumnuclear regions and the general interstellar medium, and study the supply of gas which may trigger the nuclear activity. In this paper, we investigate the…

Astrophysics of Galaxies · Physics 2016-12-12 Yogesh Chandola , D. J. Saikia

We present an X-ray absorption line spectroscopic study of the large-scale hot interstellar medium (HISM) in the Galaxy. We detect Ne IX K$_\alpha$ absorption lines in the {\sl Chandra} grating spectra of seven Galactic low-mass X-ray…

Astrophysics · Physics 2009-11-10 Yangsen Yao , Q. Daniel Wang

Using archival data from the HI Parkes All Sky Survey (HIPASS) we have searched for 21 cm line absorption in 204 nearby radio and star-forming galaxies with continuum flux densities greater than $S_{1.4} \approx 250$ mJy within the redshift…

Astrophysics of Galaxies · Physics 2015-06-18 J. R. Allison , E. M. Sadler , A. M. Meekin

We report the GMRT detection of HI 21cm absorption from the $z \sim 3.39$ damped Lyman-$\alpha$ absorber (DLA) towards PKS 0201+113, the highest redshift at which 21cm absorption has been detected in a DLA. The absorption is spread over…

Astrophysics · Physics 2008-11-26 N. Kanekar , J. N. Chengalur , W. M. Lane

During the past decade or so, measurements of Galactic HI absorption using VLBI against extra-galactic sources, as well as multi-epoch observatios in pulsar directions, have detected small-scale transverse variations corresponding to tens…

Astrophysics · Physics 2008-11-26 Avinash A. Deshpande

We present new high-precision measurements of the opacity of the intergalactic and circumgalactic medium (IGM, CGM) at <z>=2.4. Using Voigt profile fits to the full Lyman alpha and Lyman beta forests in 15 high-resolution high-S/N spectra…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Gwen C. Rudie , Charles C. Steidel , Alice E. Shapley , Max Pettini

The Westerbork Northern Sky Survey (WENSS) has been used to select a sample of Gigahertz Peaked Spectrum (GPS) radio sources at flux densities one to two orders of magnitude lower than bright GPS sources investigated in earlier studies.…

We derive the distribution of neutral and ionized gas in high redshift clouds which are optically thick to hydrogen ionizing radiation, using published data on Lyman-limit and Damped Lyman-alpha absorption systems in the redshift range 1.75…

Astrophysics · Physics 2009-10-31 Edvige Corbelli , Edwin E. Salpeter , Rino Bandiera

We present the Green Bank Telescope absorption survey of cold atomic hydrogen ($\lesssim 300$K) in the inner halo of low-redshift galaxies. The survey aims to characterize the cold gas distribution and to address where condensation - the…

Astrophysics of Galaxies · Physics 2016-10-05 Sanchayeeta Borthakur

We present a 21cm line HI self-absorption (HISA) survey of cold atomic gas within Galactic longitudes 75 to 146 degrees and latitudes -3 to +5 degrees. We identify HISA as spatially and spectrally confined dark HI features and extract it…

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