SIMBAD references

2003A&A...404..861V - Astronomy and Astrophysics, volume 404, 861-870 (2003/6-4)

Observations of HI absorbing gas in compact radio sources at cosmological redshifts.

VERMEULEN R.C., PIHLSTROEM Y.M., TSCHAGER W., DE VRIES W.H., CONWAY J.E., BARTHEL P.D., BAUM S.A., BRAUN R., BREMER M.N., MILEY G.K., O'DEA C.P., ROETTGERING H.J.A., SCHILIZZI R.T., SNELLEN I.A.G. and TAYLOR G.B.

Abstract (from CDS):

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 frequencies (725-1200MHz). Detections were obtained for 19 of the 57 sources with usable spectra (33%). We have found a large range in line depths, from τ=0.16 to τ≤0.001. There is a substantial variety of line profiles, including Gaussians of less than 10km/s, to more typically 150km/s, as well as irregular and multi-peaked absorption profiles, sometimes spanning several hundred km/s. Assuming uniform coverage of the entire radio source, we obtain column depths of atomic gas between 1x1019 and 3.3x1021(Tsp/100K)(1/f)cm–2. There is evidence for significant gas motions, but in contrast to earlier results at low redshift, there are many sources in which the HI velocity is substantially negative (up to v=-1420km/s) with respect to the optical redshift, suggesting that in these sources the atomic gas, rather than falling into the centre, may be be flowing out, interacting with the jets, or rotating around the nucleus.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: evolution - galaxies: ISM - radio lines: galaxies

Simbad objects: 63

goto Full paper

goto View the reference in ADS

To bookmark this query, right click on this link: simbad:2003A&A...404..861V and select 'bookmark this link' or equivalent in the popup menu


2019.10.20-12:11:00

© Université de Strasbourg/CNRS

    • Contact