Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-04-16
Astron.Astrophys. 404 (2003) 871-882
Astronomy and Astrophysics
Astrophysics
12 pages, 8 figures, accepted for publication in A&A
Scientific paper
10.1051/0004-6361:20030469
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 (<0.5 kpc) have larger HI column densities than the larger sources (>0.5 kpc). 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.
Conway John E.
Pihlstroem Ylva M.
Vermeulen Rene C.
No associations
LandOfFree
The Presence and Distribution of HI Absorbing Gas in Sub-galactic Sized Radio Sources does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Presence and Distribution of HI Absorbing Gas in Sub-galactic Sized Radio Sources, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Presence and Distribution of HI Absorbing Gas in Sub-galactic Sized Radio Sources will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-608148