SIMBAD references

2003A&A...404..871P - Astronomy and Astrophysics, volume 404, 871-881 (2003/6-4)

The presence and distribution of H I absorbing gas in sub-galactic sized radio sources.

PIHLSTROEM Y.M., CONWAY J.E. and VERMEULEN R.C.

Abstract (from CDS):

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 Spectrum (CSS) sources. We find that the smaller sources (<0.5kpc) have larger Hi column densities than the larger sources (>0.5kpc). Both a spherical and an axi-symmetric gas distribution, with a radial power law density profile, can be used to explain this anti-correlation between projected linear size and Hi column density. Since most detections occur in objects classified as galaxies, we argue that if the unified schemes apply to GPS/CSSs a disk distribution for the Hi is more likely. The most favoured explanation for the compact sizes of the GPS/CSSs is that they are young sources evolving in a power law density medium. For the GPSs with measured expansion velocities, our derived densities are within an order of magnitude of those estimated from ram-pressure confinement of the lobes assuming equipartition. Our results therefore support the youth model.

Abstract Copyright:

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

CDS comments: Table 1 : OM 214 = OHIO M 214.

Simbad objects: 49

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2019.09.18-01:56:08

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