Browsing by Author "Holczer, T."

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    Multiwavelength campaign on Mrk 509 III. The 600 ks RGS spectrum: unravelling the inner region of an AGN
    Detmers, R. G.; Kaastra, J. S.; Steenbrugge, K. C.; Ebrero, J.; Kriss, G. A.; Arav, Nahum; Behar, E.; Costantini, E.; Branduardi-Raymont, G.; Mehdipour, M.; Bianchi, S.; Cappi, M.; Petrucci, P. O.; Ponti, G.; Pinto, C.; Ratti, E. M.; Holczer, T. (EDP Sciences, 2011-10)
    We present the results of our 600 ks RGS observation as part of the multiwavelength campaign on Mrk 509. The very high quality of the spectrum allows us to investigate the ionized outflow with an unprecedented accuracy due to the long exposure and the use of the RGS multipointing mode. We detect multiple absorption lines from the interstellar medium and from the ionized absorber in Mrk 509. A number of emission components are also detected, including broad emission lines consistent with an origin in the broad line region, the narrow O VII forbidden emission line and also (narrow) radiative recombination continua. The ionized absorber consists of two velocity components (upsilon = -13 +/- 11 km s(-1) and upsilon = -319 +/- 14 km s(-1)), which both are consistent with earlier results, including UV data. There is another tentative component outflowing at high velocity, -770 +/- 109 km s(-1), which is only seen in a few highly ionized absorption lines. The outflow shows discrete ionization components, spanning four orders of magnitude in ionization parameter. Due to the excellent statistics of our spectrum, we demonstrate for the first time that the outflow in Mrk 509 in the important range of log. between 1-3 cannot be described by a smooth, continuous absorption measure distribution, but instead shows two strong, discrete peaks. At the highest and lowest ionization parameters we cannot differentiate smooth and discrete components.
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    Multiwavelength campaign on Mrk 509 VII. Relative abundances of the warm absorber
    Steenbrugge, K. C.; Kaastra, J. S.; Detmers, R. G.; Ebrero, J.; Ponti, G.; Costantini, E.; Kriss, G. A.; Mehdipour, M.; Pinto, C.; Branduardi-Raymont, G.; Behar, E.; Arav, Nahum; Cappi, M.; Bianchi, S.; Petrucci, P. O.; Ratti, E. M.; Holczer, T. (EDP Sciences, 2011-10)
    Context. The study of abundances in the nucleus of active galaxies allows us to investigate the evolution of the abundance by comparing local and higher redshift galaxies. However, the methods used so far have substantial drawbacks or rather large uncertainties. Some of the measurements are at odds with the initial mass function derived from the older stellar population of local elliptical galaxies. Aims. We determine accurate and reliable abundances of C, N, Ne, and Fe relative to O from the narrow absorption lines observed in the X-ray spectra of Mrk 509. Methods. We use the stacked 600 ks XMM-Newton RGS and 180 ks Chandra LETGS spectra. Thanks to simultaneous observations with INTEGRAL and the optical monitor on-board XMM-Newton for the RGS observations and HST-COS and Swift for the LETGS observations, we have an individual spectral energy distribution for each dataset. Owing to the excellent quality of the RGS spectrum, the ionisation structure of the absorbing gas is well constrained, allowing for a reliable abundance determination using ions over the whole observed range of ionisation parameters. Results. We find that the relative abundances are consistent with the proto-solar abundance ratios: C/O = 1.19  ±  0.08, N/O = 0.98  ±  0.08, Ne/O = 1.11  ±  0.10, Mg/O = 0.68  ±  0.16, Si/O = 1.3  ±  0.6, Ca/O = 0.89  ±  0.25, and Fe/O = 0.85  ±  0.06, with the exception of S, which is slightly under-abundant, S/O = 0.57  ±  0.14. Our results, and their implications, are discussed and compared to the results obtained using other techniques to derive abundances in galaxies.
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    X-ray absorption analysis of MCG-6-30-15: Discerning three kinematic systems
    Holczer, T.; Behar, E.; Arav, Nahum (IOP Publishing Ltd., 2010-01)
    By analyzing the X-ray spectrum of MCG -6-30-15 obtained with the High Energy Transmission Grating (HETGS) spectrometer on board the Chandra observatory, we identify three kinematically distinct absorption systems; two outflow components intrinsic to MCG -6-30-15, and one local at z = 0. The slow outflow at -100 +/- 50 km s(-1) has a large range of ionization manifested by absorption from 24 different charge states of Fe, which enables a detailed reconstruction of the absorption measure distribution (AMD). This AMD spans 5 orders of magnitude in ionization parameter: -1.5 < log xi < 3.5 (erg s(-1) cm), with a total column density of N(H) = (5.3 +/- 0.7) x 10(21) cm(-2). The fast outflow at -1900 +/- 150 km s(-1) has a well-defined ionization parameter with log xi = 3.82 +/- 0.03 (erg s(-1) cm) and column density N(H) = 8.1 +/- 0.7 x 10(22) cm(-2). Assuming this component is a thin, uniform, spherical shell, it can be estimated to lie within 11 light days of the active galactic nucleus center. The third component, most clearly detected in the lower oxygen charge states O(+1)-O(+6), has been confused in the past with the fast outflow, but is identified here with local gas (z = 0) and a total column density N(H) of a few 10(20) cm(-2). Finally, we exploit the excellent spectral resolution of the HETGS and use the present spectrum to determine the rest-frame wavelengths of oxygen inner-shell lines that were previously uncertain.