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| Format: | Artículo científico |
| Language: | en |
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Universidad Nacional Autónoma de México
2008
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| Online Access: | https://www.redalyc.org/articulo.oa?id=57103243 |
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Table of Contents:
- Chandra Letgs spectroscopy of ionized absorbers: The quasar MR 2251-178 Stefanie Komossa J. M. Ramírez Vadim Burwitz Smita Mathur Física, Astronomía y Matemáticas rays: galaxies Quasars: absorption lines We analyze the Chandra Low Energy Transmission Grating Spectrometer (LETGS) observation of the quasar MR 2251-178. The warm absorber of MR 2251-178 is well described by a hydrogen column density of ≈ 2x 1021 cm ֿ², an ionization parameter log(ξ) ≈ 0.6, and a global best-fit outflow velocity of ≈-1100 kms ֿ¹. We find in the spectrum evidence of narrow absorption lines. The Kα and Kβ transitions of C VI and N VI ions display an outflow with (at least three) components traveling at ≈-600, -2000 and -3000kms ֿ¹. We measure a (0.1-2) keV flux of 2.58 +0.03 |-0.04 x10 ֿ11 erg s cm ֿ² s ֿ¹, and a (2-10) keV flux of 1.64 +0.05 | -0.05 x10 ֿ11 erg s cm ֿ² s ֿ¹. This flux implies that the nuclear source of MR 2251-178 is in a relatively low state. We did not find evidence for an extra cold material in the line of sight, that would be associated to the giant [O III] emission region surrounding the nucleus of MR 2251-178. If present, we can set an upper limitof ≈1.2 x10 20cm ֿ². The X-ray spectrum does not appear to show evidence for dusty material, though an upper limit in the neutral carbon and oxygen column densities can only be set to NC I ≈ 2 x10 19 cm ֿ² and NO I≈9 x10 19 cm ֿ², respectively. 2008 artículo científico 0185-1101 https://www.redalyc.org/articulo.oa?id=57103243 en http://www.redalyc.org/revista.oa?id=571 Revista Mexicana de Astronomía y Astrofísica application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Astronomía y Astrofísica (México) Vol.32