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Browsing by Author "Soundararajaperumal, S"

Browsing by Author "Soundararajaperumal, S"

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  • First X-ray spectrum of the most luminous quasar PKS 2126 - 158 
    Ghosh, K. K; Soundararajaperumal, S (EDP Sciences, 1992-11)
    For the first time the detailed results of the spectral analysis of the X-ray (0.1 - 10 keV) spectrum of the luminous radio-loud quasar PKS 2126 - 158 are presented. Power law and fixed absorption model fits well with the ...
  • Multifrequency Spectra of EXOSAT Blazars. 
    Ghosh, K. K; Soundararajaperumal, S (University of Chicago Press, 1995-09)
    Blazars have been divided into two groups: radio-selected blazars (RBLs) and X-ray-selected blazars (XBLs). Results of the X-ray spectral analysis of 28 such blazars which were observed with EXOSAT are presented in this ...
  • Optical Microvariability of Blazars 
    Ghosh, K. K; Kim, C; Ramsey, B. D; Soundararajaperumal, S (Korean Astronomical Society, 2001-04)
    We present the results of optical differential photometry of five blazars [PKS 0219+428(3C66A), PKS 0235+164(AO 0235+16), H0414+019, PKS 0851+202(OJ 287), and QSO 1807+698(3C371)] that were observed on 7 nights between ...
  • Optical to Far-IR Observations of 3C 446 
    Leech, K. J; Saxton, R; Barr, P; Santos-Lleo, M; Jiminez-Bailon; Soundararajaperumal, S (Astronomical Society of Australia, 2002)
    The OVV blazar 3C 446 was monitored over seven months in 1997 with ground based telescopes and instruments on ESA's Infrared Space Observatory (ISO). The aim was to try to detect variations in the IR and see if these were ...
  • Optical Variability of BL Lacertae during the Major Outburst of 1997 
    Ghosh, K. K; Ramsey, B. D; Sadun, A. C; Soundararajaperumal, S; Wang, J (The American Astronomical Society, 2000-07)
    We have undertaken an investigation of recent flux variability in BL Lac. We present optical observations taken over 22 nights documenting major as well as minor outbursts. This has been combined, for purposes of multifrequency ...
  • Optical Variability of Blazars 
    Ghosh, K. K; Ramsey, B. D; Sadun, A. C; Soundararajaperumal, S (The American Astronomical Society, 2000-03)
    In this paper we show the results of our monitoring the flux variability of 15 blazars, within the redshift range of 0.07-2.06, all with a visual magnitude range between 14 and 20 mag. Because blazars have displayed ...
  • Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. X. Variability of Fairall 9 from Optical Data 
    Santos-Lleo, M; Chatzichristou, E; de Oliveira, C. M; Winge, C; Alloin, D; Peterson, B. M; Rodriguez-Pascual, P. M; Stirpe, G. M; Beers, T; Bragaglia, A; Claeskens, J. F; Federspiel, M; Giannuzzo, E; Gregorio-Hetem, J; Mathys, G; Salamanca, I; Stein, P; Stenholm, B; Wilhelm, R; Zanin, C; Albrecht, P; Calderon, J; Caretta, C. A; Carranza, G; da Costa, R. D. D; Diaz, R; Dietrich, M; Dottori, H; Elizalde, F; Goldes, G; Ghosh, K. K; Maia, M. A. G; Paolantonio, S; de Oliveira Filho, R. I; Rodriguez-Ardila, A; Schmitt, H. R; Soundararajaperumal, S; de Souza, R. E; Willmer, C. N. A; Zheng, W (American Astronomical Society, 1997-10)
    The results of an optical monitoring campaign on the active nucleus in the luminous Seyfert 1 galaxy Fairall 9 are presented. This campaign was undertaken in parallel with ultraviolet spectroscopic monitoring with the IUE ...
  • 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 
    Dietrich, M; Peterson, B. M; Albrecht, P; Altmann, M; Barth, A. J; Bennie, P. J; Bertram, R.; Bochkarev, N. G; Bock, H; Braun, J. M; Burenkov, A; Collier, S; Fang, L. Z; Francis, O. P; Filippenko, A. V; Foltz, C. B; Gaessler, W; Gaskell, C. M; Geffert, M; Ghosh, K. K; Hilditch, R. W; Honeycutt, R. K; Horne, K; Huchra, J. P; Kaspi, S; Kuemmel, M; Leighly, K. M; Leonard, D. C; Malkov, Yu. F; Mikhailov, V; Miller, H. R; Morrill, A. C; Noble, J; O'Brien, P. T; Oswalt, T. D; Pebley, S. P; Pfeiffer, M; Pronik, V. I; Qian, B. C; Robertson, J. W; Robinson, A.; Rumstay, K. S; Schmoll, J; Sergeev, S. G; Sergeeva, E. A; Shapovalova, A. I; Skillman, D. R; Snedden, S. A; Soundararajaperumal, S; Stirpe, G. M; Tao, J; Turner, G. W; Wagner, R. M; Wagner, S. J; Wei, J. Y; Wu, H.; Zheng, W; Zou, Z. L (The American Astronomical Society, 1998-04)
    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 F lambda (5177 A), and the integrated ...
  • X Ray Studies of Active Galactic Nuclei 
    Soundararajaperumal, S (Indian Institute of Astrophysics, Bangalore, 1999-01)
  • X Ray Studies of Active Galactic Nuclei 
    Soundararajaperumal, S (Indian Institute of Astrophysics, Bangalore, 1999)
  • X-ray continuum with an iron emission line from the radio-quiet quasar PHL 909 
    Ghosh, K. K; Soundararajaperumal, S (University of Chicago Press, 1992-04)
    Results of the spectral analysis of the X-ray (0.1-10 keV) spectrum of the radio-quiet quasar, PHL 909, are presented. A spectrum of this quasar, which was observed on 1984/349, was obtained from the Exosat archives. ...
  • X-ray observations of the Seyfert 1 galaxy MCG 2-58-22 
    Ghosh, K. K; Soundararajaperumal, S (University of Chicago Press, 1992-10)
    Results of the detailed X-ray (0.1-10 keV) spectral analysis of the Seyfert 1 galaxy, MGC 2-58-22, are presented based on the Exosat observations on 1984 November 16-26. X-ray spectra of this source were obtained from the ...
  • X-ray spectra of Seyfert galaxies 
    Ghosh, K. K; Soundararajaperumal, S (Blackwell Publishing, 1992-11)
    A spectra analysis of eight Seyfert galaxies shows that while seven have soft excesses in their spectra, with no low-energy absorption, ESO 140-G43 exhibits low energy absorption, and may have weak soft excess that is ...
  • X-Ray Spectral Variability of the Seyfert Galaxy NGC4593 
    Ghosh, K. K; Soundararajaperumal, S (European Southern Observatory, 1993-06)
    X-ray (0.1-10 keV) spectra of NGC 4593 were obtained with EXOSAT on seven epochs between 1984 and 1986 using the low and medium energy detectors. Detailed results of the spectral analysis of the seven spectra (obtained ...
  • X-ray spectrum of NGC 3783 - Detection of soft excess and an emission line 
    Ghosh, K. K; Soundararajaperumal, S; Kalai Selvi, M; Sivarani, T (EDP Sciences, 1992-02)
    Results of the X-ray (0.1-10 keV) spectral analysis of the Seyfert I galaxy, NGC 3783, which was observed with EXOSAT on three epochs between 1983 and 1985, are presented here. No low energy absorption, intrinsic to the ...
  • X-ray spectrum of the radio-loud quasar PKS 1217 + 023 
    Ghosh, K. K; Soundararajaperumal, S (EDP Sciences, 1991-12)
    A study of the X-ray (0.1-10 keV) spectrum from the radio-loud quasar, PKS 1217 + 023 is presented. This quasar was observed with Exosat on two epochs in January 29 and May 14, 1984. The data were obtained from the Exosat ...
  • The X-ray spectrum of the superluminal quasar 1928 + 73 
    Ghosh, K. K; Soundararajaperumal, S (Blackwell Publishing, 1992-02)
    Exosat observations (0.1-10 keV) of the radio-loud quasar 1928 + 73, which displays superluminal motion, were made at four epochs between 1983/283 and 1984/009, and spectra of this source are obtained from the Exosat ...

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