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Related papers: Associated HI in Absorbers at High Redshift

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We present an overview of the occurrence and properties of atomic gas associated with compact radio sources at redshifts up to z=0.85. Searches for HI 21cm absorption were made with the Westerbork Synthesis Radio Telescope at UHF-high…

We present an analysis of the HI absorption in a sample of 101 flux-selected radio AGN (S_1.4 GHz > 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). HI absorption is detected in 32 galaxies, showing a broad variety of…

Astrophysics of Galaxies · Physics 2015-06-23 K. Gereb , F. M. Maccagni , R. Morganti , T. A. Oosterloo

HI absorption studies yield information on both AGN feeding and feedback processes. This AGN activity interacts with the neutral gas in compact radio sources, which are believed to represent the young or recently re-triggered AGN…

Astrophysics of Galaxies · Physics 2017-02-01 M. Glowacki , J. R. Allison , E. M. Sadler , V. A. Moss , S. J. Curran , A. Musaeva , C. Deng , R. Parry , M. C. Sligo

We present a search for associated HI 21 cm absorption in a sample of 29 radio-loud active galactic nuclei (AGNs) at $0.7 < z < 1$, carried out with the upgraded Giant Metrewave Radio Telescope. We detect HI 21 cm absorption against none of…

Astrophysics of Galaxies · Physics 2022-03-30 Suma Murthy , Raffaella Morganti , Nissim Kanekar , Tom Oosterloo

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…

Astrophysics of Galaxies · Physics 2018-11-28 J. N. H. S. Aditya

We report the discovery of three HI absorbers toward low-power radio active galactic nuclei (AGNs) in a pilot HI absorption survey with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Compared to past studies, FAST…

Astrophysics of Galaxies · Physics 2023-08-04 Qingzheng Yu , Taotao Fang , Junfeng Wang , Jianfeng Wu

We present MeerKAT observations searching for HI absorption in a sample of 17 powerful ($L_{\rm 1.4GHz}> 10^{27}$ W Hz$^{-1}$) radio sources at intermediate redshifts ($0.25<z<0.7$). The sample is well characterised at radio and optical…

Astrophysics of Galaxies · Physics 2026-02-11 Raffaella Morganti , Tom Oosterloo , Clive Tadhunter , Suma Murthy

We conducted a HI 21cm absorption study of a sample of 147 nearby (z < 0.1) low-power radio sources with $10\,\mathrm{mJy} < S_{1.4\,\mathrm{GHz}} < 30\,\mathrm{mJy}$ and $\log(P_{1.4\,\mathrm{GHz}}/\mathrm{W\,Hz^{-1}}) = 20.5-23.7$, using…

Astrophysics of Galaxies · Physics 2026-03-06 Yang Su , Qingzheng Yu , Taotao Fang , Junfeng Wang , Jianfeng Wu , Bo Zhang

From a survey for redshifted HI 21-cm and OH 18-cm absorption in the hosts of a sample of radio galaxies and quasars, we detect HI in three of the ten and OH in none of the fourteen sources for which useful data were obtained. As expected…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 S. J. Curran , M. T. Whiting , M. T. Murphy , J. K. Webb , C. Bignell , A. G. Polatidis , T. Wiklind , P. Francis , G. Langston

We present an HI 21cm absorption study of a sample of 26 radio-loud active galactic nuclei (AGN) at $0.25 < z < 0.4$ carried out with the Karl G. Jansky Very Large Array. Our aim was to study the rate of incidence of HI in various classes…

Astrophysics of Galaxies · Physics 2021-10-20 Suma Murthy , Raffaella Morganti , Tom Oosterloo , Filippo M. Maccagni

We present an extragalactic HI 21-cm absorption lines catalog from a blind search at z $\leqslant$ 0.35, using drift-scan data collected in 1325.6 hours by the ongoing Commensal Radio Astronomy FasT Survey (CRAFTS) and FAST All Sky HI…

We report the GMRT detection of associated HI 21 cm-line absorption in the z=1.1946 red quasar 3C 190. Most of the absorption is blue-shifted with respect to the systemic redshift. The absorption, at $\sim$ 647.7 MHz, is broad and complex,…

Astrophysics · Physics 2009-11-23 C. H. Ishwara-Chandra , K. S. Dwarakanath , K. R. Anantharamaiah

We have searched for HI 21cm absorption toward the two brightest radio AGN at high redshift, J0924--2201 at $z = 5.20$, and J0913+5919 at $z=5.11$, using the Giant Meter Wave Radio Telescope (GMRT). These data set a 3$\sigma$ upper limit to…

Astrophysics · Physics 2008-11-26 C. L. Carilli , Ran Wang , M. van Hoven , K. Dwarakanath , J. Chengalur , S. Wyithe

We detect the 21 cm line of neutral hydrogen in absorption at a redshift of 0.673 towards the 1 Jy radio source 1504+377. The 1504+377 radio source is located toward the center of what appears to be an inclined disk galaxy at z = 0.674. The…

Astrophysics · Physics 2009-10-28 C. L. Carilli , Karl M. Menten , Mark J. Reid , M. P. Rupen

We present the results of a large search for intrinsic HI 21 cm and OH 18 cm absorption in 145 compact radio sources in the redshift range 0.02< z <3.8 with the Green Bank Telescope. We re-detect HI 21 cm absorption toward six known…

Astrophysics of Galaxies · Physics 2019-11-27 Kathryn Grasha , Jeremy Darling , Alberto Bolatto , Adam K. Leroy , John T. Stocke

The presence, distribution and kinematics of atomic neutral hydrogen in the central regions of galaxies can be traced by the HI 21~cm line observed in absorption. Depending only on the strength of the radio continuum, the associated…

Astrophysics of Galaxies · Physics 2024-12-11 Raffaella Morganti

We report a new, rare detection of HI 21-cm absorption associated with a quasar (only six known at $1<z<2$) here towards J2339-5523 at $z_{em}$ = 1.3531, discovered through the MeerKAT Absorption Line Survey (MALS). The absorption profile…

At present neutral atomic hydrogen (HI) gas in galaxies at redshifts above $z \sim 0.3$ (the extent of 21-cm emission surveys in individual galaxies) and below $z \sim 1.7$ (where the Lyman-$\alpha$ line is not observable with ground-based…

We report the first detections of associated H{\sc i} 21\,cm absorption in Gigahertz-peaked-spectrum (GPS) sources at high redshifts, $z > 1$, using the Giant Metrewave Radio Telescope (GMRT). Our GMRT search for associated H{\sc i} 21\,cm…

Astrophysics of Galaxies · Physics 2017-10-25 J. N. H. S. Aditya , Nissim Kanekar

We present the results of HI absorption measurements towards a sample of nearby Compact Steep-Spectrum (CSS) and Giga-Hertz Peaked Spectrum (GPS) radio sources, the CORALZ sample, using the Giant Metrewave Radio Telescope (GMRT). We…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Yogesh Chandola , S. K. Sirothia , D. J. Saikia
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