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Browsing by Author "Borguet, B."

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    Multiwavelength campaign on Mrk 509 VI. HST/COS observations of the far-ultraviolet spectrum
    Kriss, G. A.; Arav, Nahum; Kaastra, J. S.; Ebrero, J.; Pinto, C.; Borguet, B.; Edmonds, Douglas; Costantini, E.; Steenbrugge, K. C.; Detmers, R. G.; Behar, E.; Bianchi, S.; Blustin, A. J.; Branduardi-Raymont, G.; Cappi, M.; Mehdipour, M.; Petrucci, P. O.; Ponti, G. (EDP Sciences, 2011-10)
    We present medium-resolution (lambda/Delta lambda similar to 20 000) ultraviolet spectra covering the 1155-1760 angstrom spectral range of the Seyfert 1 galaxy Mrk 509 obtained using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST). Our observations were obtained simultaneously with a Low Energy Transmission Grating Spectrometer observation using the Chandra X-ray Observatory, and they are part of a multiwavelength campaign in September through December 2009 which also included observations with XMM-Newton, Swift, and INTEGRAL. Our spectra are the highest signal-to-noise observations to date of the intrinsic absorption components seen in numerous prior ultraviolet observations. To take advantage of the high S/N, we describe special calibrations for wavelength, flat-field and line-spread function corrections that we applied to the COS data. We detect additional complexity in the absorption troughs compared to prior observations made with the Space Telescope Imaging Spectrograph (STIS) on HST. We attribute the UV absorption to a variety of sources in Mrk 509, including an outflow from the active nucleus, the interstellar medium and halo of the host galaxy, and possible infalling clouds or stripped gaseous material from a merger that are illuminated by the ionizing radiation of the active nucleus. Variability between the STIS and COS observation of the most blue-shifted component (#1) allows us to set an upper limit on its distance of <250 pc. Similarly, variability of component 6 between FUSE observations limits its distance to <1.5 kpc. The absorption lines in all components only partially cover the emission from the active nucleus with covering fractions that are lower than those seen in the prior STIS observations and are comparable to those seen in spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE). Given the larger apertures of COS and FUSE compared to STIS, we favor scattered light from an extended region near the active nucleus as the explanation for the partial covering. As observed in prior X-ray and UV spectra, the UV absorption has velocities comparable to the X-ray absorption, but the bulk of the ultraviolet absorption is in a lower ionization state with lower total column density than the gas responsible for the X-ray absorption. We conclude that the outflow from the active nucleus is a multiphase wind.
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    Simultaneous XMM-Newton and HST-COS observation of 1H0419-577 The absorbing and emitting ionized gas
    Di Gesu, L.; Arav, Nahum; Borguet, B.; Detmers, R. G.; Ebrero, J.; Edmonds, Douglas; Kaastra, J. S.; Piconcelli, E.; Verbunt, F.; Constantini, E. (EDP Sciences, 2013-08)
    In this paper we analyze the X-ray, UV, and optical data of the Seyfert 1.5 galaxy 1H0419-577 with the aim of detecting and studying an ionized-gas outflow. The source was observed simultaneously in the X-rays with XMM-Newton and in the UV with HST-COS. Optical data were also acquired with the XMM-Newton Optical Monitor. We detected a thin, lowly ionized warm absorber (log xi approximate to 0.03, log N-H approximate to 19.9 cm(-2)) in the X-ray spectrum, which is consistent to be produced by the same outflow already detected in the UV. Provided the gas density estimated in the UV, the outflow is consistent to be located in the host galaxy at similar to kpc scale. Narrow emission lines were detected in the X-rays, in the UV and also in the optical spectrum. A single photoionized-gas model cannot account for all the narrow lines emission, indicating that the narrow line region is probably a stratified environment, differing in density and ionization. X-ray lines are unambiguously produced in a more highly ionized gas phase than the one emitting the UV lines. The analysis also suggests that the X-ray emitter may just be a deeper portion of the same gas layer producing the UV lines. Optical lines are probably produced in another disconnected gas system. The different ionization condition and the similar to pc scale location, suggested by the line width for the narrow lines emitters, are evidences against a connection between the warm absorber and the narrow line region in this source.