2003/04/02 by David G. Barnes, P. E. J. Nulsen, Paul E. J. Nulsen · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.2003.06676.x
published as Mon.Not.Roy.Astron.Soc. 343 (2003) 315 · 17 pages, 5 figures, MNRAS accepted 2 April 2003
arxiv created 2003/04/02 · openalex publication_date 2003/07/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Radio maps at 21 cm of foreground neutral hydrogen over three cooling flow clusters of galaxies show that the foreground gas is uniform on scales from ∼1–10 arcmin. Five sigma limits on fluctuations in the foreground column density for Abell 3581, Sersic 159–03 and Abell 2597 are 6.2 × 1019, 7.8 × 1019 and 4.3 × 1019 cm−2, or 14, 43 and 17 per cent of the mean foreground column density in the region of the system, respectively. Fluctuations in the column density of neutral gas in the Galaxy are unlikely to account for any excesses of photoelectric absorption in these or other cooling flow clusters. Fluctuations in the foreground neutral gas on arcmin scales are also unlikely to be the cause of excess extreme ultraviolet and soft X-ray emission from clusters.