2002/07/15 by Stefanie Komossa, S. Komossa, G. Hasinger +3
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0207321
8 pages, to appear in the proc. of the workshop "XEUS - studying the evolution of the universe", G. Hasinger et al. (eds), MPE Report, in press. Related papers on the high-z BAL quasar APM 08279+5255 (and MPG press release), and on ionized absorbers are available at http://www.xray.mpe.mpg.de/~skomossa/
arxiv created 2002/07/15 · openalex publication_date 2002/07/15 · openalex created_date 2022/09/01 · openalex updated_date 2026/07/28
(Abridged) Cold and warm absorbers have beeen detected in all types of active\ngalaxies (AGN) from low to high redshift. This gas, located in the black hole\nregion of AGN, is thought to play an important role in AGN unification\nscenarios, in explaining the X-ray background, in black hole growth and AGN\nevolution.\n We provide a review of the observations of dusty and dust-free warm and cold\nabsorbers at low and high redshift, including most recent results and exciting\nquestions still open. Emphasis is on the science issues that we will be able to\naddress with XEUS for the first time, particularly at high redshift, including:\n(i) determination of metal abundances of X-ray (cold) absorbers by detection of\nmetal absorption edges, (ii) analysis of the composition of dust mixed with\ncold and ionized gas (K-edges of metals in cold dust and cold gas will be\nresolvable from each other for the first time), (iii) measurement of the\nvelocity field of the gas, (iv) utilization of these results to investigate the\nevolution of gas and dust in AGN from high to low redshift: the evolution of\nabundances, dust content, ionization state, amount and velocity of gas, and its\nrole in feeding the black hole.\n We emphasize the importance of iron absorption measurements with XEUS at high\nredshift for two key issues of cosmology: the early star formation history of\nthe universe, and the measurement of cosmological parameters. As an example, we\ndiscuss recent XMM-Newton observations of the high-redshift BAL quasar APM\n08279+5255.\n