First Detection of NaI D lines in High-Redshift Damped Lyman-alpha Systems

Details First Detection of NaI D lines in High-Redshift Damped Lyman-alpha Systems First Detection of NaI D lines in High-Redshift Damped Lyman-alpha Systems

2006-03-12

arxiv.org/abs/astro-ph/0603290v1

Astrophys.J. 643 (2006) 667-674

Astronomy and Astrophysics

Astrophysics

22 pages, 6 Postscript figures, 3 tables, ApJ in press (Vol.643, 2 June 2006)

Scientific paper

10.1086/502960

A Near-infrared (1.18-1.35 micron) high-resolution spectrum of the gravitationally-lensed QSO APM 08279+5255 was obtained with the IRCS mounted on the Subaru Telescope using the AO system. We detected strong NaI D 5891,5897 doublet absorption in high-redshift DLAs at z=1.062 and 1.181, confirming the presence of NaI, which was first reported for the rest-frame UV NaI 3303.3,3303.9 doublet by Petitjean et al. This is the first detection of NaI D absorption in a high-redshift (z>1) DLA. In addition, we detected a new NaI component in the z=1.062 DLA and four new components in the z=1.181 DLA. Using an empirical relationship between NaI and HI column density, we found that all "components" have large HI column density, so that each component is classified as DLA absorption. We also detected strong NaI D absorption associated with a MgII system at z=1.173. Because no other metal absorption lines were detected in this system at the velocity of the NaI absorption in previously reported optical spectra (observed 3.6 years ago), we interpret this NaI absorption cloud probably appeared in the line of sight toward the QSO after the optical observation. This newly found cloud is likely to be a DLA based upon its large estimated HI column density. We found that the N(NaI)/N(CaII) ratios in these DLAs are systematically smaller than those observed in the Galaxy; they are more consistent with the ratios seen in the Large Magellanic Cloud. This is consistent with dust depletion generally being smaller in lower metallicity environments. However, all five clouds of the z=1.181 system have a high N(NaI)/N(CaII) ratio, which is characteristic of cold dense gas. We tentatively suggest that the host galaxy of this system may be the most significant contributor to the gravitational-lens toward APM 08279+5255.

Affiliated with

Also associated with

No associations

Rating

First Detection of NaI D lines in High-Redshift Damped Lyman-alpha Systems 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 First Detection of NaI D lines in High-Redshift Damped Lyman-alpha Systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and First Detection of NaI D lines in High-Redshift Damped Lyman-alpha Systems will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-339984