Browsing FAS Scholarly Articles by Keyword "Galaxies: Seyfert"

Now showing items 1-20 of 21

    • ASCA observations of two steep soft X-ray quasars 

      Fiore, F.; Matt, G.; Cappi, M.; Elvis, Martin S.; Leighly, K. M.; Nicastro, F.; Piro, L.; Siemiginowska, Aneta L.; Wilkes, Belinda Jane (Oxford University Press (OUP), 1998)
      Steep soft X-ray (0.1-2 keV) quasars share several unusual properties: narrow Balmer lines, strong FeII emission, large and fast X-ray variability, rather steep 2-10 keV spectrum. These intriguing objects have been suggested ...

    • The BeppoSAX View of the X‐Ray Active Nucleus of NGC 4258 

      Fiore, F.; Pellegrini, S.; Matt, G.; Antonelli, L. A.; Comastri, A.; della Ceca, R.; Giallongo, E.; Mathur, S.; Molendi, S.; Siemiginowska, Aneta L.; Trinchieri, G.; Wilkes, Belinda Jane (IOP Publishing, 2001)
      BeppoSAX observed the Seyfert 1.9 galaxy NGC 4258 in 1998 December, when its 2-10 keV luminosity was about 1041 ergs s-1. Large amplitude (100%) variability is observed in the 3-10 keV band on timescales of a few tens of ...

    • The Cambridge-Cambridge ROSAT Serendipity Survey -- IV. The X-ray properties 

      Ciliegi, P.; Elvis, Martin S.; Wilkes, Belinda Jane; Boyle, B. J.; McMahon, R. G. (Oxford University Press (OUP), 1997)
      We present a detailed X-ray spectral analysis in the 0.1–2.4 keV ROSAT band of a complete sample of X-ray-selected AGN using the 80 AGNs in the Cambridge-Cambridge ROSAT Serendipity Survey (68 QSOs and 12 narrow-emission-line ...

    • The Cambridge–Cambridge ROSAT Serendipity Survey – II. Classification of X-ray-luminous Galaxies 

      Boyle, B.J.; McMahon, R.G.; Wilkes, Belinda Jane; Elvis, Martin S. (Royal Astronomical Society, 1995)
      We present the results of an intermediate-resolution (1.5\AA) spectroscopic study of 17 X-ray luminous narrow emission-line galaxies previously identified in the Cambridge-Cambridge {\it ROSAT} Serendipity Survey and the ...

    • The Complex X‐Ray Absorbers of NGC 3516 Observed by BEPPOSAX 

      Costantini, E.; Nicastro, F.; Fruscione, Antonella; Mathur, S.; Comastri, A.; Elvis, Martin S.; Fiore, F.; Salvini, C.; Stirpe, G. M.; Vignali, C.; Wilkes, Belinda Jane; O’Brien, P. T.; Goad, M. R. (IOP Publishing, 2000)
      In this paper we present the analysis of two broadband (0.1-150 keV) BeppoSAX observations of the Seyfert 1 galaxy NGC 3516. The two observations were taken 4 months apart, on 1996 November 8 and 1997 March 12. We report ...

    • An Empirical Ultraviolet Template for Iron Emission in Quasars as Derived from I Zwicky 1 

      Vestergaard, M.; Wilkes, Belinda Jane (IOP Publishing, 2001)
      We present an empirical template spectrum suitable for fitting and subtracting/studying the Fe II and Fe III emission lines in the rest frame ultraviolet spectra of quasars and active galactic nuclei, the first empirical ...

    • Mid-Infrared-Selected Quasars. I. Virial Black Hole Mass and Eddington Ratios 

      Dai, Y. Sophia; Elvis, Martin S.; Bergeron, Jacqueline; Fazio, Giovanni Gene; Huang, Jia-Sheng; Wilkes, Belinda Jane; Willmer, Christopher N. A.; Omont, Alain; Papovich, Casey (IOP Publishing, 2014)
      We provide a catalog of 391 mid-infrared-selected (MIR; 24 μm) broad-emission-line (BEL; type 1) quasars in the 22 deg2 SWIRE Lockman Hole field. This quasar sample is selected in the MIR from Spitzer MIPS with S 24 > 400 ...

    • Monitoring of the optical and 2.5 – 11.7 µm spectrum and mid-IR imaging of the Seyfert 1 galaxy Mrk 279 with ISO 

      Santos-Lleó, M.; Clavel, J.; Schulz, B.; Altieri, B.; Barr, P.; Alloin, D.; Berlind, Perry; Bertram, R.; Crenshaw, D. M.; Edelson, R. A.; Giveon, U.; Horne, K.; Huchra, J. P.; Kaspi, S.; Kriss, G. A.; Krolik, J. H.; Malkan, M. A.; Malkov, Yu. F.; Netzer, H.; O, P. T.; Peterson, B. M.; Pogge, R. W.; Pronik, V. I.; Qian, B.-C.; Reichert, G. A.; Rodríguez-Pascual, P. M.; Sergeev, S. G.; Tao, J.; Tokarz, S.; Wagner, R. M.; Wamsteker, W.; Wilkes, Belinda Jane (EDP Sciences, 2001)
      Mid-infrared images of the Seyfert 1 galaxy Mrk 279 obtained with the ISO satellite are presented together with the results of a one-year monitoring campaign of the 2.5-11.7 micron spectrum. Contemporaneous optical photometric ...

    • Multiple Velocity Components in the C iv Absorption Line of NGC 5548 

      Mathur, Smita; Elvis, Martin S.; Wilkes, Belinda Jane (IOP Publishing, 1999)
      We have observed the much-studied Seyfert 1 galaxy NGC 5548 with the Goddard High-Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST). Our 14 ks observation covers the C IV emission line at a resolution of ...

    • Multiwavelength Observations of Short-Timescale Variability in NGC 4151. I. Ultraviolet Observations 

      Crenshaw, D. M.; Rodriguez-Pascual, P. M.; Penton, S. V.; Edelson, R. A.; Alloin, D.; Ayres, T. R.; Clavel, J.; Horne, K.; Johnson, W. N.; Kaspi, S.; Korista, K. T.; Kriss, G. A.; Krolik, J. H.; Malkan, M. A.; Maoz, D.; Netzer, H.; O, P. T.; Peterson, B. M.; Reichert, G. A.; Shull, J. M.; Ulrich, M.-H.; Wamsteker, W.; Warwick, R. S.; Yaqoob, T.; Balonek, T. J.; Barr, P.; Bromage, G. E.; Carini, M.; Carone, T. E.; Cheng, F.-Z.; Chuvaev, K. K.; Dietrich, M.; Doroshenko, V. T.; Dultzin-Hacyan, D.; Filippenko, A. V.; Gaskell, C. M.; Glass, I. S.; Goad, M. R.; Hutchings, J.; Kazanas, D.; Kollatschny, W.; Koratkar, A. P.; Laor, A.; Leighly, K.; Lyutyi, V. M.; MacAlpine, G. M.; Malkov, Yu. F.; Martin, P. G.; McCollum, B.; Merkulova, N. I.; Metik, L.; Metlov, V. G.; Miller, H. R.; Morris, S. L.; Oknyanskij, V. L.; Penfold, J.; Perez, E.; Perola, G. C.; Pike, G.; Pogge, R. W.; Pronik, I.; Pronik, V. I.; Ptak, R. L.; Recondo-Gonzalez, M. C.; Rodriguez-Espinoza, J. M.; Rokaki, E. L.; Roland, J.; Sadun, A. C.; Salamanca, I.; Santos-Lleo, M.; Sergeev, S. G.; Smith, S. M.; Snijders, M. A. J.; Sparke, L. S.; Stirpe, G. M.; Stoner, R. E.; Sun, W.-H.; van Groningen, E.; Wagner, R. M.; Wagner, S.; Wanders, I.; Welsh, W. F.; Weymann, R. J.; Wilkes, Belinda Jane; Zheng, W. (IOP Publishing, 1996)
      We present the results of an intensive ultraviolet monitoring campaign on the Seyfert I galaxy NGC 4151, as part of an effort to study its short-timescale variability over a broad range in wavelength. The nucleus of NGC ...

    • Multiwavelength Observations of Short-Timescale Variability in NGC 4151. IV. Analysis of Multiwavelength Continuum Variability 

      Edelson, R. A.; Alexander, T.; Crenshaw, D. M.; Kaspi, S.; Malkan, M. A.; Peterson, B. M.; Warwick, R. S.; Clavel, J.; Filippenko, A. V.; Horne, K.; Korista, K. T.; Kriss, G. A.; Krolik, J. H.; Maoz, D.; Nandra, K.; O, P. T.; Penton, S. V.; Yaqoob, T.; Albrecht, P.; Alloin, D.; Ayres, T. R.; Balonek, T. J.; Barr, P.; Barth, A. J.; Bertram, R.; Bromage, G. E.; Carini, M.; Carone, T. E.; Cheng, F.-Z.; Chuvaev, K. K.; Dietrich, M.; Dultzin-Hacyan, D.; Gaskell, C. M.; Glass, I. S.; Goad, M. R.; Hemar, S.; Ho, L. C.; Huchra, J; Hutchings, J.; Johnson, W. N.; Kazanas, D.; Kollatschny, W.; Koratkar, A. P.; Kovo, O.; Laor, A.; MacAlpine, G. M.; Magdziarz, P.; Martin, P. G.; Matheson, T.; McCollum, B.; Miller, H. R.; Morris, S. L.; Oknyanskij, V. L.; Penfold, J.; Perez, E.; Perola, G. C.; Pike, G.; Pogge, R. W.; Ptak, R. L.; Qian, B.-C.; Recondo-Gonzalez, M. C.; Reichert, G. A.; Rodriguez-Espinoza, J. M.; Rodriguez-Pascual, P. M.; Rokaki, E. L.; Roland, J.; Sadun, A. C.; Salamanca, I.; Santos-Lleo, M.; Shields, J. C.; Shull, J. M.; Smith, D. A.; Smith, S. M.; Snijders, M. A. J.; Stirpe, G. M.; Stoner, R. E.; Sun, W.-H.; Ulrich, M.-H.; van Groningen, E.; Wagner, R. M.; Wagner, S.; Wanders, I.; Welsh, W. F.; Weymann, R. J.; Wilkes, Belinda Jane; Wu, H.; Wurster, J.; Xue, S.-J.; Zdziarski, A. A.; Zheng, W.; Zou, Z.-L. (IOP Publishing, 1996)
      This paper combines data from the three preceding papers in order to analyze the multi-wave-band variability and spectral energy distribution of the Seyfert I galaxy NGC 4151 during the 1993 December monitoring campaign. ...

    • Optical Continuum and Emission‐Line Variability of the Seyfert 1 Galaxy Markarian 509 

      Carone, T. E.; Peterson, B. M.; Bechtold, J.; Bertram, R.; Bischoff, K.; Dietrich, M.; Filppenko, A. V.; Ho, L. C.; Huchra, J; Kollatchny, W.; Korista, K. T.; Matheson, T.; Pogge, R. W.; Shields, J. C.; Smith, P. S.; Wagner, R. M.; Wilkes, Belinda Jane (IOP Publishing, 1996)
      We report on the results of a 5 year coordinated program of spectroscopic monitoring of the luminous Seyfert 1 galaxy Markarian 509. The Hβ and He II λ4686 emission lines are found to respond to continuum variations with ...

    • Steps toward Determination of the Size and Structure of the Broad‐Line Region in Active Galactic Nuclei. IX. Ultraviolet Observations of Fairall 9 

      Rodriguez‐Pascual, P. M.; Alloin, D.; Clavel, J.; Crenshaw, D. M.; Horne, K.; Kriss, G. A.; Krolik, J. H.; Malkan, M. A.; Netzer, H.; O, P. T.; Peterson, B. M.; Reichert, G. A.; Wamsteker, W.; Alexander, T.; Barr, P.; Blandford, R. D.; Bregman, J. N.; Carone, T. E.; Clements, S.; Courvoisier, T.‐J.; De Robertis, M. M.; Dietrich, M.; Dottori, H.; Edelson, R. A.; Filippenko, A. V.; Gaskell, C. M.; Huchra, J. P.; Hutchings, J. B.; Kollatschny, W.; Koratkar, A. P.; Korista, K. T.; Laor, A.; MacAlpine, G. M.; Martin, P. G.; Maoz, D.; McCollum, B.; Morris, S. L.; Perola, G. C.; Pogge, R. W.; Ptak, R. L.; Recondo‐Gonzalez, M. C.; Rodriguez‐Espinoza, J. M.; Rokaki, E. L.; Santos‐Lleo, M.; Sekiguchi, K.; Shull, J. M.; Snijders, M. A. J.; Sparke, L. S.; Stirpe, G. M.; Stoner, R. E.; Sun, W.‐H.; Wagner, S. J.; Wanders, I.; Wilkes, Belinda Jane; Winge, C.; Zheng, W. (IOP Publishing, 1997)
      An 8 month monitoring campaign on the Seyfert 1 galaxy Fairall 9 has been conducted with the International Ultraviolet Explorer in an attempt to obtain reliable estimates of continuum-continuum and continuum-emission-line ...

    • Steps toward Determination of the Size and Structure of the Broad‐Line Region in Active Galactic Nuclei. XV. Long‐Term Optical Monitoring of NGC 5548 

      Peterson, B. M.; Barth, A. J.; Berlind, P.; Bertram, R.; Bischoff, K.; Bochkarev, N. G.; Burenkov, A. N.; Cheng, F.‐Z.; Dietrich, M.; Filippenko, A. V.; Giannuzzo, E.; Ho, L. C.; Huchra, J; Hunley, J.; Kaspi, S.; Kollatschny, W.; Leonard, D. C.; Malkov, Yu. F.; Matheson, T.; Mignoli, M.; Nelson, B.; Papaderos, P.; Peters, J.; Pogge, R. W.; Pronik, V. I.; Sergeev, S. G.; Sergeeva, E. A.; Shapovalova, A. I.; Stirpe, G. M.; Tokarz, S.; Wagner, R. M.; Wanders, I.; Wei, J.‐Y.; Wilkes, Belinda Jane; Wu, H.; Xue, S.‐J.; Zou, Z.‐L. (IOP Publishing, 1999)
      We present the results of 3 yr of ground-based observations of the Seyfert 1 galaxy NGC 5548, which, combined with previously reported data, yield optical continuum and broad-line Hβ light curves for a total of 8 yr. The ...

    • Steps toward Determination of the Size and Structure of the Broad‐Line Region in Active Galactic Nuclei. XVI. A 13 Year Study of Spectral Variability in NGC 5548 

      Peterson, B. M.; Berlind, Perry; Bertram, R.; Bischoff, K.; Bochkarev, N. G.; Borisov, N.; Burenkov, A. N.; Calkins, Michael Lee; Carrasco, L.; Chavushyan, V. H.; Chornock, R; Dietrich, M.; Doroshenko, V. T.; Ezhkova, O. V.; Filippenko, A. V.; Gilbert, A. M.; Huchra, J. P.; Kollatschny, W.; Leonard, D. C.; Li, W.; Lyuty, V. M.; Malkov, Yu. F.; Matheson, T.; Merkulova, N. I.; Mikhailov, V. P.; Modjaz, M.; Onken, C. A.; Pogge, R. W.; Pronik, V. I.; Qian, B.; Romano, P.; Sergeev, S. G.; Sergeeva, E. A.; Shapovalova, A. I.; Spiridonova, O. I.; Tao, J.; Tokarz, S.; Valdes, J. R.; Vlasiuk, V. V.; Wagner, R. M.; Wilkes, Belinda Jane (IOP Publishing, 2002)
      We present the final installment of an intensive 13 year study of variations of the optical continuum and broad Hβ emission line in the Seyfert 1 galaxy NGC 5548. The database consists of 1530 optical continuum measurements ...

    • Suzaku Monitoring of the Iron K Emission Line in the Type 1 Active Galactic Nucleus Ngc 5548 

      Liu, Yuan; Elvis, Martin S.; McHardy, Ian M.; Grupe, Dirk; Wilkes, Belinda Jane; Reeves, James; Brickhouse, Nancy S; Krongold, Yair; Mathur, Smita; Minezaki, Takeo; Nicastro, Fabrizio; Yoshii, Yuzuru; Zhang, Shuang Nan (IOP Publishing, 2010)
      We present seven sequential weekly observations of NGC 5548 conducted in 2007 with the Suzaku X-ray Imaging Spectrometer (XIS) in the 0.2–12 keV band and Hard X-ray Detector (HXD) in the 10–600 keV band. The iron Kα line ...

    • Suzaku Monitoring of the Seyfert 1 Galaxy Ngc 5548: Warm Absorber Location and Its Implication for Cosmic Feedback 

      Krongold, Y.; Elvis, Martin S.; Andrade-Velazquez, M.; Nicastro, F.; Mathur, S.; Reeves, J. N.; Brickhouse, Nancy S; Binette, L.; Jimenez-Bailon, E.; Grupe, D.; Liu, Y.; McHardy, I. M.; Minezaki, T.; Yoshii, Y.; Wilkes, Belinda Jane (IOP Publishing, 2010)
      We present seven sequential weekly observations of NGC 5548 conducted in 2007 with the Suzaku X-ray Imaging Spectrometer (XIS) in the 0.2–12 keV band and Hard X-ray Detector (HXD) in the 10–600 keV band. The iron Kα line ...

    • Testing Unified X-Ray/Ultraviolet Absorber Models with NGC 5548 

      Mathur, Smita; Elvis, Martin S.; Wilkes, Belinda Jane (IOP Publishing, 1995)
      The bright Seyfert galaxy NGC 5548 shows absorption features in its X-ray and UV spectra. The large amount of optical/UV and X-ray monitoring data available for this object makes it an ideal candidate to test our model of ...

    • What Do the Ultraviolet Spectra of Narrow‐Line Seyfert 1 Galaxies Tell Us about Their Broad‐Line Regions? 

      Kuraszkiewicz, Joanna; Wilkes, Belinda Jane; Czerny, Bo?ena; Mathur, Smita (IOP Publishing, 2000)
      We study the UV spectra of narrow-line Seyfert 1 (NLSy1) galaxies and compare them with "normal" active galactic nuclei. Similar to their optical lines, the NLSy1s show narrower UV lines. They are also characterized by ...

    • X‐Ray and Optical Variability in NGC 4051 and the Nature of Narrow‐Line Seyfert 1 Galaxies 

      Peterson, B. M.; McHardy, I. M.; Wilkes, Belinda Jane; Berlind, Perry; Bertram, R.; Calkins, Michael Lee; Collier, S. J.; Huchra, J. P.; Mathur, S.; Papadakis, I.; Peters, J.; Pogge, R. W.; Romano, P.; Tokarz, S.; Uttley, P.; Vestergaard, M.; Wagner, R. M. (IOP Publishing, 2000)
      We report on the results of a three-year program of coordinated X-ray and optical monitoring of the narrow-line Seyfert 1 galaxy NGC 4051. The rapid continuum variations observed in the X-ray spectra are not detected in ...