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Browsing by Author "Blustin, A. J."

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    Multiwavelength campaign on Mrk 509 I. Variability and spectral energy distribution
    Kaastra, J. S.; Petrucci, P. O.; Cappi, M.; Arav, Nahum; Behar, E.; Bianchi, S.; Bloom, J.; Blustin, A. J.; Branduardi-Raymont, G.; Costantini, E.; Dadina, M.; Detmers, R. G.; Ebrero, J.; Jonker, P. G.; Klein, C.; Kriss, G. A.; Lubinski, P.; Malzac, J.; Mehdipour, M.; Paltani, S.; Pinto, C.; Ponti, G.; Ratti, E. M.; Smith, R. A. N.; Steenbrugge, K. C.; de Vries, C. P. (EDP Sciences, 2011-10)
    Context. Active galactic nuclei (AGN) show a wealth of interesting physical processes, some of which are poorly understood. In a broader context, they play an important role in processes that are far beyond their immediate surroundings, owing to the high emitted power. Aims. We want to address a number of open questions, including the location and physics of the outflow from AGN, the nature of the continuum emission, the geometry and physical state of the X-ray broad emission line region, the Fe-K line complex, the metal abundances of the nucleus, and finally the interstellar medium of our own Galaxy as seen through the signatures it imprints on the X-ray and UV spectra of AGN. Methods. We study one of the best targets for these aims, the Seyfert 1 galaxy Mrk 509 with a multiwavelength campaign using five satellites (XMM-Newton, INTEGRAL, Chandra, HST, and Swift) and two ground-based facilities (WHT and PAIRITEL). Our observations cover more than five decades in frequency, from 2 μm to 200 keV. The combination of high-resolution spectroscopy and time variability allows us to disentangle and study the different components. Our campaign covers 100 days from September to December 2009, and is centred on a simultaneous set of deep XMM-Newton and INTEGRAL observations with regular time intervals, spanning seven weeks. Results. We obtain a continuous light curve in the X-ray and UV band, showing a strong, up to 60% flux increase in the soft X-ray band during the three weeks in the middle of our deepest monitoring campaign, and which is correlated with an enhancement of the UV flux. This allows us to study the time evolution of the continuum and the outflow. By stacking the observations, we have also obtained one of the best X-ray and UV spectra of a Seyfert galaxy ever obtained. In this paper we also study the effects of the spectral energy distribution (SED) that we obtained on the photo-ionisation equilibrium. Thanks to our broad-band coverage, uncertainties on the SED do not strongly affect the determination of this equilibrium. Conclusions. Here we present our very successful campaign and in a series of subsequent papers we will elaborate on different aspects of our study.
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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.