High resolution observations of the QSO BR 1202-0725: deuterium and ionic abundances at redshifts above z=4.
We present results from 12km/s resolution echelle spectroscopy of the bright z=4.694 QSO BR 1202-0725. A preliminary analysis shows that high metallicity narrow line absorption clouds are present up to the redshift of the quasar. A damped Lyα system with an H I column density of 3.1x10^20^cm^-2^ at z=4.383 has an [O/H] ratio that is about 0.01 solar, while another absorption system with an H I column density of 5.0x10^16^cm^-2^ at z=4.672, may have an O/H ratio that is twice solar. An upper limit, or the possible detection of deuterium in this absorption cloud gives a D/H ratio of about 1.5x10^-4^. Because this cloud is metal rich at least some of the cloud gas has been processed after the beginning of the Universe.
Astronomy and Astrophysics
- Pub Date:
- December 1996
- QUASARS: ABSORPTION LINES;
- QUASARS: INDIVIDUAL: BR 1202-0725;
- COSMOLOGY: OBSERVATIONS;
- 23 pages, including 5 Postscript figures, in gzip-ed uuencoded postscript format. Accepted for publication in A&