D/H in a new Lyman limit quasar absorption system at z=3.256 towards PKS1937-1009
Abstract
We have identified a new Lyman limit absorption system towards PKS1937-1009, with log N(HI)=18.25 +/- 0.02 at z=3.256. It is suitable for measuring D/H, and we find a 68.3% confidence range for D/H of 1.6+0.25-0.30 × 10-5, and a 95.4% range of 1.6+0.5-0.4 × 10-5. The metallicity of the cloud where D/H was measured is low, [Si/H] = -2.0 +/- 0.5. At these metallicities we expect that D/H will be close to the primordial value. Our D/H disagrees at a level of 99.4% with the predicted D/H using the baryon density calculated from the cosmic background radiation measured by WMAP, 2.60+0.19-0.17 × 10-5. Our result also exacerbates the scatter in D/H values around the mean primordial D/H.
Turn this paper into a full lesson
ArcXiv compiles a staged curriculum from this paper: 8-12 lessons across beginner → advanced, synthesised section guides, visuals, flashcards, a quiz, exercises, and on-demand deep dives per section. Grounded in the abstract, never invented.