English
Related papers

Related papers: HI Absorption in High-Frequency Peaker Galaxies

200 papers

We report on WSRT observations of HI and OH absorption at z=0.885 towards the radio lens PKS 1830-21, mm wave transitions of several molecular species have already been observed at this redshift. At mm wavelengths the source structure is…

Astrophysics · Physics 2011-05-23 Jayaram N. Chengalur , A. G. de Bruyn , D. Narasimha

We carried out deep mapping observations of the atomic hydrogen (HI) 21 cm line emission in a field centered on the famous galaxy group Stephan's Quintet (SQ), using the Five-hundred-meter Aperture Spherical Telescope (FAST) equipped with…

Using the Parkes radio telescope, we study the 21cm neutral hydrogen (HI) properties of a sample of galaxies with redshifts z<0.13 extracted from the optical 2dF Galaxy Redshift Survey (2dFGRS). Galaxies at 0.04<z<0.13 are studied using new…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-24 Jacinta Delhaize , Martin Meyer , Lister Staveley-Smith , Brian Boyle

We present morphological and statistical results of a study of neutral hydrogen (HI) in a complete sample of nearby, non-cluster radio galaxies. We detect large-scale HI emission in the early-type host galaxies of 25% of our sample sources.…

Astrophysics · Physics 2008-11-26 B. H. C. Emonts , R. Morganti , T. A. Oosterloo

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 present results of a study of neutral hydrogen (HI) in a complete sample of nearby non-cluster radio galaxies. We find that radio galaxies with large amounts of extended HI (M_HI >= 10^9 M_solar) all have a compact radio source. The host…

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

In this study we present 18 to 24 GHz and high angular resolution radio wavelength Australia Telescope Compact Array follow up observations towards a sample of 39 HC HII region candidates. These objects, taken from a sample hosting 6.7 GHz…

Astrophysics of Galaxies · Physics 2024-08-15 A. L. Patel , J. S. Urquhart , A. Y. Yang , T. Moore , M. A. Thompson , K. M. Menten , T. Csengeri

In this paper we further explore the implications that this has for the currently popular consensus that it is the orientation of the circumnuclear obscuring torus which determines whether absorption is present along our sight-line. The…

Cosmology and Nongalactic Astrophysics · Physics 2010-03-04 S. J. Curran , M. T. Whiting

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 Giant Metrewave Radio Telescope and Very Large Array observations of HI 21-cm absorption in ten z<=0.2 galaxy mergers that host strong radio sources. Seven of these mergers show strong absorption [with N(HI) ~10^{21-22} cm^{-2},…

Astrophysics of Galaxies · Physics 2018-08-01 Rajeshwari Dutta , Raghunathan Srianand , Neeraj Gupta

While massive quiescent galaxies are known to be poor in atomic hydrogen (HI), their true HI content remains poorly constrained due to the limited sensitivity and morphological biases of existing surveys. We present deep HI observations…

Astrophysics of Galaxies · Physics 2025-10-20 Xiao Li , Cheng Li , Cheng Cheng , Houjun Mo , Jing Wang , Amélie Saintonge

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 present the results of Giant Metrewave Radio Telescope (GMRT) observations to detect H{\sc i} in absorption towards the cores of a sample of radio galaxies. From observations of a sample of 16 sources, we detect H{\sc i} in absorption…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Yogesh Chandola , Neeraj Gupta , D. J. Saikia

Recent VLBI observations have identified several compact radio sources which have symmetric structures on parsec scales, and exhibit HI absorption which appears to be associated with the active nucleus. These sources are uniquely well…

Astrophysics · Physics 2009-10-31 A. B. Peck , G. B. Taylor

We report the detection of a deep broad HI 21 cm absorption system at z = 0.78 toward the radio source [HB89] 2351+456 (4C+45.51) at z = 1.992. The HI absorption was identified in a blind spectral line survey conducted at the Green Bank…

HII regions made of gas ionized by radiations from young massive stars, are widely distributed in the Milky Way. They are tracers for star formation, and their distributions are correlated with the Galactic spiral structure. Radio…

Astrophysics of Galaxies · Physics 2021-11-03 Chuan-Peng Zhang , Jin-Long Xu , Guang-Xing Li , Li-Gang Hou , Nai-Ping Yu , Peng Jiang

Observations of neutral hydrogen can provide a wealth of information about the kinematics of galaxies. To learn more about the large scale structures and accretion processes, the extended environment of galaxies have to be observed.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Attila Popping , Robert Braun

A systematic search for HI 21-cm absorption in Quasar-Galaxy Pairs (QGPs) provides a powerful means to map the distribution of cold gas around high-redshift star-forming galaxies. Fiber spectroscopy of high-redshift quasars enables the…

Astrophysics of Galaxies · Physics 2026-01-06 Labanya Kumar Guha , Raghunathan Srianand , Rajeshwari Dutta

Using long-slit optical spectra obtained with the 2-m telescope at IUCAA Girawali Observatory, we show that the radio source J094221.98+062335.2 (z=0.123) is associated with a galaxy pair undergoing a major merger. Its companion is a normal…

Astrophysics of Galaxies · Physics 2015-08-06 R. Srianand , N. Gupta , E. Momjian , M. Vivek