A Sensitive Search for High-Velocity Galactic HI

Astronomy and Astrophysics – Astronomy

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Scientific paper

We have conducted a sensitive 21--cm search for Galactic Hi high--velocity (|VLSR|\: > \: 100 ;km;s(-1) ) clouds in the directions of quasars which have appeared on planning lists for the Quasar Absorption Line Key Project of the Hubble Space Telescope. Our aim was to understand the distribution and properties of the high--velocity galactic clouds that will be seen in UV absorption lines against the quasars. We have found that 37% of the sky is covered by high--velocity clouds, excluding the Galactic warp, to a 5\:sigma completeness limit of 7 times 10(17) \:cm(-2) . This is a significant increase over the 18% found by previous surveys. The majority of this new high--velocity emission can be associated with previously known HVC complexes. From this, we conclude that the HVC complexes are surrounded by extensive low column density, neutral envelopes. This result may have important implications for the hypothesis that the narrow metal line systems seen in the spectra of quasars arise in the intervening gaseous halos of galaxies. If there is a population of HVCs not associated with the complexes, they must have a column density less than 7 times 10(17) \:cm(-2) , cover a small fraction of the sky, or they must be ionized.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

A Sensitive Search for High-Velocity Galactic HI 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 A Sensitive Search for High-Velocity Galactic HI, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Sensitive Search for High-Velocity Galactic HI will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1318688

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.