Observations of H I absorbing gas in compact radio sources at cosmological redshifts

  title={Observations of H I absorbing gas in compact radio sources at cosmological redshifts},
  author={Ren{\'e} C. Vermeulen and Y. M. Pihlstroem and Wolfgang Tschager and Willem Hendrik de Vries and J. Conway and Peter Barthel and S. A. Baum and Robert Joseph Braun and Malcolm N. Bremer and George K. Miley and Christopher P. O’Dea and Huub J. A. Roettgering and Richard T. Schilizzi and I. A. G. Snellen and Gregory B. Taylor},
  journal={Astronomy and Astrophysics},
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 H i 21cm absorption were made with the Westerbork Synthesis Radio Telescope at UHF-high frequencies (725-1200 MHz). Detections were obtained for 19 of the 57 sources with usable spectra (33%). We have found a large range in line depths, from � = 0.16 to � � 0.001. There is a substantial variety of line profiles, including Gaussians of less than… 

Figures and Tables from this paper

Tracing the neutral gas environments of young radio AGN with ASKAP
At present neutral atomic hydrogen (H I) gas in galaxies at redshifts above z ∼ 0.3 (the extent of 21 cm emission surveys in individual galaxies) and below z ∼ 1.7 (where the Lyman-α line is not
Probing the gas content of radio galaxies through H I absorption stacking
Using the Westerbork Synthesis Radio Telescope, we carried out shallow H i absorption observations of a flux-selected (S1.4 GHz > 50 mJy) sample of 93 radio active galactic nuclei (AGN), which have
H i absorption towards nearby compact radio sources
We present the results of H i absorption measurements towards a sample of nearby compact steep-spectrum (CSS) and gigahertz-peaked spectrum (GPS) radio sources, the Compact Radio sources at Low
A survey for H i in the distant Universe: the detection of associated 21-cm absorption at z = 1.28
We have undertaken a survey for H I 21-cm absorption within the host galaxies of z ∼ 1.2−1.5 radio sources, in the search of the cool neutral gas currently ‘missing’ at z 1. This deficit is believed
Ionization of the atomic gas in redshifted radio sources
We report the results of a survey for H I 21-cm absorption at z ≲ 0.4 in a new sample of radio sources with the Giant Metrewave Radio Telescope. Of the 11 sources for which there are good data, we
Small-scale Properties of Atomic Gas in Extended Disks of Galaxies
We present high-resolution HI 21 cm observations with the Karl G. Jansky Very Large Array (VLA) for three HI rich galaxies in absorption against radio quasars. Our sample contains six sightlines with
Atomic and Molecular Absorption in Redshifted Radio Sources
We report on a survey for associated HI 21-cm and OH 18-cm absorption with the Giant Metrewave Radio Telescope at redshifts z = 0.2-0.4. Although the low redshift selection ensures that our targets
H i absorption in high-frequency peaker galaxies
Abstract: WSRT observations have been used to investigate the presence of neutral hydrogen in extremely young radio galaxies. These objects were selected from a sample of High-Frequency Peakers
The mid-infrared properties and gas content of active galaxies over large lookback times
Upon an expansion of all of the searches for redshifted HI 21-cm absorption (0.0021 < z 5.19), we update recent results regarding the detection of 21-cm in the non-local Universe. Specifically, we
A survey for redshifted molecular and atomic absorption lines – II. Associated H i, OH and millimetre lines in the z≳ 3 Parkes quarter-Jansky flat-spectrum sample
We present the results of a z ≥ 2.9 survey for Hi 21-cm and molecular absorption in the hosts of radio quasars using the Giant Metrewave Radio Telescope and the Tidbinbilla 70-m telescope. Although


Associated Hi in Absorbers at High Redshift
WSRT observations have provided a first inventory of the incidence of H i 21 cm line absorption associated with AGN at redshifts up to z=1.0. There is a large range in line depths, from τ = 0.44 to τ
H i Absorption in the Steep-Spectrum Superluminal Quasar 3C 216.
It is argued that the most plausible site for the H i absorption is in the jet-cloud interaction observed in this source, and it is more likely to be located in the central kiloparsec.
Associated HI in Absorbers at High Redshift
WSRT observations have provided a first inventory of the incidence of HI 21 cm line absorption associated with AGN at redshifts up to z=1.0. There is a large range in line depths, from tau=0.44 to
H i absorption in radio galaxies: effect of orientation or interstellar medium?
A search for H i absorption has been made in 23 radio galaxies selected from a complete sample. The observations were made with the Australia Telescope Compact Array (ATCA), with the Very Large Array
Evidence for a Circumnuclear Disk in 1946+708
A number of extragalactic radio sources that exhibit symmetric jets on parsec scales have now been found to have neutral hydrogen absorption at or near the systemic velocities of their host galaxies.
The presence and distribution of HI absorbing gas in sub-galactic sized radio sources
We consider the incidence of Hi absorption in intrinsically small sub-galactic sized extragalactic sources selected from sources classified as Gigahertz Peaked Spectrum (GPS) and Compact Steep
The Shroud Around the Twin Radio Jets in NGC 1052
We discuss multiple Very Long Baseline Interferometry (VLBI) continuum and spectral line imaging observations and Westerbork Synthesis Radio Telescope spectroscopy of the compact variable nuclear
Quasars, their host galaxies and their central black holes
We present the final results from our deep Hubble Space Telescope (HST) imaging study of the host galaxies of radio-quiet quasars (RQQs), radio-loud quasars (RLQs) and radio galaxies (RGs). We
A Search for ``Dwarf'' Seyfert Nuclei. V. Demographics of Nuclear Activity in Nearby Galaxies
We use the sample of emission-line nuclei derived from a recently completed optical spectroscopic survey of nearby galaxies to quantify the incidence of local (z ≈ 0) nuclear activity. Particular
An Unusual Radio Galaxy in Abell 428: A Large, Powerful FR I Source in a Disk-dominated Host
We report the discovery of a powerful (~1024 h−275 WHz−1 at 20 cm) FR I radio source in a highly flattened disk-dominated galaxy. Half the radio flux from this source is concentrated within the host