2008/01/10 by J. N. Reeves, James Reeves, Chris Done +6 · 182 citations
Physics and Astronomy · #Absorption (acoustics) #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Intergalactic medium #Intergalactic travel #Optics #Physics #Pulsars and Gravitational Waves Research #Redshift #Shell (structure) #Signature (topology) #astro-ph
paper · pdf · doi:10.1111/j.1745-3933.2008.00443.x
published in Monthly Notices of the Royal Astronomical Society Letters 385(1), L108-L112 (Oxford University Press) · accepted for publication in MNRAS LETTERS. 5 pages, 4 figures
arxiv created 2008/01/10 · openalex publication_date 2008/02/07 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present a comparison between the 2001 XMM–Newton and 2005 Suzaku observations of the quasar, PG 1211+143, at z = 0.0809. Variability is observed in the 7 keV iron K-shell absorption line (at 7.6 keV in the quasar frame), which is significantly weaker in 2005 than during the 2001 XMM–Newton observation. From a recombination time-scale of <4 yr, this implies an absorber density n > 4 × 103 cm−3, while the absorber column is 5 × 1022 < NH < 1 × 1024 cm−2. Thus, the size scale of the absorber is too compact (pc scale) and the surface brightness of the dense gas too high (by 9–10 orders of magnitude) to arise from local hot gas, such as the local bubble, group or warm/hot intergalactic medium (WHIM), as suggested by McKernan, Yaqoob & Reynolds. Instead, the iron K-shell absorption must be associated with an active galactic nucleus (AGN) outflow with mildly relativistic velocities. Finally, we show that the association of the absorption in PG 1211+143 with local hot gas is simply a coincidence, and the comparison between the recession and iron K absorber outflow velocities in other AGN does not reveal a one-to-one kinematic correlation.