2008/03/31 by Xinyu Dai, C. S. Kochanek, Christopher S. Kochanek · 2 citations
Chemistry · Physics and Astronomy · #Absorption (acoustics) #Analytical Chemistry (journal) #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Chemistry #Dispersion (optics) #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Materials science #Optics #Physics #ROSAT #astro-ph
paper · pdf · doi:10.1088/0004-637x/692/1/677
published as Astrophys.J.692:677-683,2009 · 20 pages, 6 figures, Accepted by ApJ
openalex publication_date 2009/02/10 · arxiv created 2009/02/19 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We analyzed Chandra observations of three gravitational lenses, SBS 0909+523, FBQS 0951+2635, and B 1152+199, to measure the differential X-ray absorption and the dust-to-gas ratio of the lens galaxies. We successfully detected the differential X-ray absorption in SBS 0909+523 and B 1152+199, and failed to detect it in FBQS 0951+2635 due to the dramatic drop in its flux from the ROSAT epoch. These measurements significantly increase the sample of dust-to-gas ratio measurements in cosmologically distant, normal galaxies. Using the larger sample, we obtain an average dust-to-gas ratio of E ( B − V )/ N H = (1.5 ± 0.5) × 10 −22 mag cm 2 atoms −1 with an estimated intrinsic dispersion in the ratio of ≃40%. This average dust-to-gas ratio is consistent with our previous measurement and the average Galactic value of 1.7 × 10 −22 mag cm 2 atoms −1 , and the estimated intrinsic dispersion is also consistent with the 30% observed in the Galaxy. A larger sample size is still needed to improve the measurements and to begin studying the evolution in the ratio with cosmic time. We also detected X-ray microlensing in SBS 0909+523 and significant X-ray variability in FBQS 0951+2635.