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XMM-Newton observations of the red type 1.8 Quasar 2M 1049+5837:Reflection from cold and warm (ionized) matter

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journal contribution
posted on 2016-02-08, 12:03 authored by Kenneth Alwyne Pounds, B. J. Wilkes, G. D. Schmidt
Chandra observations of the type 1.8, low-redshift (z = 0.115), red (J − KS ~ 2) quasar 2MASSJ 104943+583750 (2M1049+5837) indicated an unusually hard X-ray spectrum (HR ~ 0.6), suggesting obscuration of NH ~ 4 × 10[Superscript: 22] cm[Superscript: −2] and a flat Γ ~ 0.4 power-law slope. A higher signal-to-noise ratio XMM-Newton observation reported here reveals a more complex spectrum, being extremely hard above ~2 keV, Γ ~ − 0.6, with a well-defined soft excess similar to the bright, nearby Seyfert 2 galaxy Mrk 3. Such extremely hard quasar spectra cannot be a dominant contributor to the cosmic X-ray background (CXRB; Γ ~ 1.4). Modeling of 2M1049+5837 shows the observed 2-10 keV spectrum to be the sum of a strongly absorbed "normal" Γ ~ 1.8 underlying quasar X-ray continuum, and a cold reflection component (R ~ 2). The strong attenuation of the intrinsic X-ray continuum by a sub-Compton-thick line-of-sight column, NH ~ 3.4 × 10[Superscript: 23] cm[Superscript: −2], reveals a soft X-ray emission component whose spectrum indicates reprocessing/emission from, possibly extended, photoionized gas. The luminosity of the soft X-ray component is similar to Seyfert 2 galaxies, an order of magnitude less than comparable type 1 AGNs, suggesting partial obscuration of core-bright emission. The optical emission is complex, with distinct red and blue scattered light components believed to originate in two extended regions visible in HST imaging data. The unusual combination of properties: optical and X-ray obscuration of the nuclear emission, partially obscured broad but unobscured narrow emission lines, and partially obscured soft X-ray excess, implies an intermediate viewing angle, over or through the edge of an obscuring disk + wind or torus. 2M1049+5837 again demonstrates both the ambiguity of low signal-to-noise X-ray spectra/hardness ratios and the potential of 2MASS-selected red sources for exploring the complex obscuration and geometry of the nuclear regions in AGNs.



The Astrophysical Journal, 2008, 680, 110

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


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