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University of Nebraska - Lincoln

C. Martin Gaskell Publications

1998

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. Xiii. Ultraviolet Observations Of The Broad-Line Radio Galaxy 3c 390.3, Paul T. O'Brien, M. Dietrich, K. Leighly, D. Alloin, J. Clavel, D. Michael Crenshaw, K. Horne, G. A. Criss, Julian Henry Krolik, Matthew A. Malkan, Hagai Netzer, Bradley M. Peterson, G. A. Reichert, P. M. Rodriguez-Pascual, W. Wamsteker, K. S.J. Anderson, N. G. Bochkarev, F.-Z. Cheng, A. V. Filippenko, C. Martin Gaskell, I. M. George, M. R. Goad, L. C. Ho, Shai Kaspi, W. Kollatschny, Kirk T. Korista, G. Macalpine, D. Marlow, P. G. Martin, S. L. Morris, Richard William Pogge, B. C. Qian, M. C. Recondo-Gonzalez, J. M. Rodriguez Espinosa, M. Santos-Lleo, A. I. Shapovalova, J. M. Shull, G. M. Stirpe, W.-H. Sun, T. J. Turner, R. Vio, S. Wagner, I. Wanders, K. A. Wills, H. Wu, S. J. Xue, Z.-L. Zou Dec 1998

Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. Xiii. Ultraviolet Observations Of The Broad-Line Radio Galaxy 3c 390.3, Paul T. O'Brien, M. Dietrich, K. Leighly, D. Alloin, J. Clavel, D. Michael Crenshaw, K. Horne, G. A. Criss, Julian Henry Krolik, Matthew A. Malkan, Hagai Netzer, Bradley M. Peterson, G. A. Reichert, P. M. Rodriguez-Pascual, W. Wamsteker, K. S.J. Anderson, N. G. Bochkarev, F.-Z. Cheng, A. V. Filippenko, C. Martin Gaskell, I. M. George, M. R. Goad, L. C. Ho, Shai Kaspi, W. Kollatschny, Kirk T. Korista, G. Macalpine, D. Marlow, P. G. Martin, S. L. Morris, Richard William Pogge, B. C. Qian, M. C. Recondo-Gonzalez, J. M. Rodriguez Espinosa, M. Santos-Lleo, A. I. Shapovalova, J. M. Shull, G. M. Stirpe, W.-H. Sun, T. J. Turner, R. Vio, S. Wagner, I. Wanders, K. A. Wills, H. Wu, S. J. Xue, Z.-L. Zou

C. Martin Gaskell Publications

As part of an extensive multi-wavelength monitoring campaign, the International Ultraviolet Explorer satellite was used to observe the broad-line radio galaxy 3C 390.3 during the period 1994 December 31-1996 March 5. Spectra were obtained every 6È10 days. The UV continuum varied by a factor of 7 through the campaign, while the broad emission lines varied by factors of 2È5. Unlike previously monitored Seyfert 1 galaxies, in which the X-ray continuum generally varies with a larger amplitude than the UV, in 3C 390.3 the UV continuum light curve is similar in both amplitude and shape to the X-ray light curve observed …


Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. Xiv. Intensive Optical Spectrophotometric Observations Of Ngc 7469, S.J. Collier, Keith Horne, Shai Kaspi, Hagai Netzer, Bradley M. Peterson, I. Wanders, T. Alexander, R. Bertram, A. Comastri, C. Martin Gaskell, Yu. F. Malkov, D. Maoz, M. Mignoli, Richard William Pogge, V.I. Pronik, S.G. Sergeev, Stephanie A. Snedden, G.M. Stirpe, N.G. Bochkarev, A.N. Burenkov, A.I. Shapovalova, R.M. Wagner Jun 1998

Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. Xiv. Intensive Optical Spectrophotometric Observations Of Ngc 7469, S.J. Collier, Keith Horne, Shai Kaspi, Hagai Netzer, Bradley M. Peterson, I. Wanders, T. Alexander, R. Bertram, A. Comastri, C. Martin Gaskell, Yu. F. Malkov, D. Maoz, M. Mignoli, Richard William Pogge, V.I. Pronik, S.G. Sergeev, Stephanie A. Snedden, G.M. Stirpe, N.G. Bochkarev, A.N. Burenkov, A.I. Shapovalova, R.M. Wagner

C. Martin Gaskell Publications

We present results of an intensive 2 month campaign of ground-based spectrophotometric monitoring of the Seyfert 1 galaxy NGC 7469, with a temporal resolution [approximately less than]1 day. The broad Hα and Hβ emission lines respond to ~35% ultraviolet continuum variations with an amplitude of ~10% and time delays of 5.6±1.3 days and 5.4±0.8 days, respectively. We interpret this as evidence of variable Balmer line gas ~5-6 light days from the central source in this object, widely believed to be a supermassive black hole. The virial mass of the central source implied by line widths and time delays is ~10 …


Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei, Xii: Ground-Based Monitoring Of 3c 390.3, M. Dietrich, Bradley M. Peterson, P. Albrecht, M. Altmann, A. J. Barth, P. J. Bennie, R. Bertram, N. G. Bochkarev, H. Bock, J. M. Braun, A. Burenkov, S. Collier, L.-Z. Fang, O. P. Francis, A. V. Filippenko, C. B. Foltz, W. Gassler, C. Martin Gaskell, M. Geffert, K. K. Ghosh, R. W. Hilditch, R.K. Honeycutt, K. Horne, J. P. Huchra, Shai Kaspi, M. Kummel, K. M. Leighly, D. C, Leonard, Yu. F. Malkov, V. Mikhailov, H. Richard Miller, A. C. Morrill, J. Noble, Paul T. O'Brien, T. D. Oswalt, S. P. Pebley, M. Pfeiffer, V. I. Pronik, B.-C. Qian, J. W. Robertson, A. Robinson, Kenneth S. Rumstay, J. Schmoll, S. G. Sergeev, E. A. Sergeeva, A. I. Shapovalova, D. R. Skillman, Stephanie A. Snedden, S. Soundararajaperumal, G. M. Stirpe, J. Tao, G. W. Turner, R. M. Wagner, S. J. Wagner, J. Y. Wei, H. Wu, W. Zheng, Z. L. Zhou Apr 1998

Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei, Xii: Ground-Based Monitoring Of 3c 390.3, M. Dietrich, Bradley M. Peterson, P. Albrecht, M. Altmann, A. J. Barth, P. J. Bennie, R. Bertram, N. G. Bochkarev, H. Bock, J. M. Braun, A. Burenkov, S. Collier, L.-Z. Fang, O. P. Francis, A. V. Filippenko, C. B. Foltz, W. Gassler, C. Martin Gaskell, M. Geffert, K. K. Ghosh, R. W. Hilditch, R.K. Honeycutt, K. Horne, J. P. Huchra, Shai Kaspi, M. Kummel, K. M. Leighly, D. C, Leonard, Yu. F. Malkov, V. Mikhailov, H. Richard Miller, A. C. Morrill, J. Noble, Paul T. O'Brien, T. D. Oswalt, S. P. Pebley, M. Pfeiffer, V. I. Pronik, B.-C. Qian, J. W. Robertson, A. Robinson, Kenneth S. Rumstay, J. Schmoll, S. G. Sergeev, E. A. Sergeeva, A. I. Shapovalova, D. R. Skillman, Stephanie A. Snedden, S. Soundararajaperumal, G. M. Stirpe, J. Tao, G. W. Turner, R. M. Wagner, S. J. Wagner, J. Y. Wei, H. Wu, W. Zheng, Z. L. Zhou

C. Martin Gaskell Publications

Results of a ground-based optical monitoring campaign on 3C 390.3 in 1994-1995 are presented. The broadband fluxes (B, V , R, and I), the spectrophotometric optical continuum flux Fλ(5177 Å), integrated emission-line fluxes of Hα, Hβ, Hγ, He I λ5876, and He II λ4686 all show a nearly monotonic increase with episodes of milder short-term variations superposed. The amplitude of the continuum variations increases with decreasing wavelength (4400-9000 Å). The optical continuum variations follow the variations in the ultraviolet and X-ray with time delays, measured from the centroids of the crosscorrelation functions, typically around …