2001/09/17 by Romeel Davé, Davé, Romeel, S. R. Heap +10
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0109242
4 pages, to appear in the Proceedings of the Meeting on Gaseous Matter in Galactic and Intergalactic Space, XVIIth IAP Colloquium, Paris, June 2001
openalex publication_date 2001/09/17 · arxiv created 2001/11/05 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present a preliminary study of the metallicity of low-redshift Lyman alpha absorbers from the HST/STIS spectrum of 3C273. Using a pixel-based shift-and-coadd technique, we compare observations to carefully-constructed mock quasar spectra from a cosmological hydrodynamic simulation. We place an upper limit of [C/H]90% confidence using two Ly-alpha absorbers with NHI>1014 cm-2, from the fact that we see little absorption near the expected CIV positions, whereas the artificial spectra predict significant absorption. We assume a Haardt & Madau (quasar-based) ionizing background spectrum, but a softer spectrum results in a stronger constraint on the metallicity. With only two absorbers and various modeling uncertainties, it is too early to make a definitive determination of the diffuse IGM metallicity, but upcoming observations should improve constraints.