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Browsing by Author "Ghosh, K. K"

Browsing by Author "Ghosh, K. K"

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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 ...
  • Flare-like activity in Be stars HR 7403 and .8762 
    Ghosh, K. K (D. Reidel Publishing Co., 1989-05)
    Results are presented from rapid spectrophotometric observations of the Be stars HR 7403 and HR 8762. The observations were conducted between November, 1984 and December, 1985. No ultrarapid variations were detected in the ...
  • Further spectroscopic observations of SN 1987A 
    Anupama, G. C; Prabhu, T. P; Ghosh, K. K; Ashoka, B. N; Giridhar, S (Elsevier, 1988)
    Spectroscopic observations of SN 1987a obtained during 1987 August 30 – September 8 from Vainu Bappu Observatory, Kavalur, are presented; the spectrum is compared and contrasted with the spectra recorded at earlier epochs. ...
  • Gravitational instability of interstellar magnetic clouds 
    Ghosh, K. K; Bhattacharyya, J. C (D. Reidel Publishing Co.,, 1985-12)
    The gravitational instability of a nonrotating isothermal gaseous disk permeated by a uniform frozen-in magnetic field is investigated using a fourth-order perturbation technique. From the results it is found that the disk ...
  • Identification of emission bands in P/Halley 
    Bhattacharyya, J. C; Babu, G. S. D; Ghosh, K. K; Jayakumar, K; Appakutty, M (Indian Academy of Sciences, 1986)
    Spectrophotometric studies of P /Halley (r = 1.98 AU, Δ= 1.19AU, r = 1.97, Δ = 1.16 AU and r = 1.95 AU, Δ. = 1.13 AU) in the spectral range 3900 A - 6450 A were made on three nights and identifications of emission features ...
  • Interstellar shocked region chemistry - certain reactions between interstellar molecules and O and N atoms 
    Ghosh, K. K; Saleem, S. S; Kutty, K. N (International Astronomical Union, 1987)
    The reactions between O and N atoms and certain interstellar molecules (H/sub2S, NH/sub3, H/sub2CO, CH/sub3OH, C/sub2H/sub5OH) are studied using the dynamical flowing after glow method. It is found that NH and OH radicals ...
  • Line profile variations in γ Doradus 
    Balona, L. A; Böhm, T; Foing, B. H; Ghosh, K. K; Janot-Pacheco, E; Krisciunas, K; Lagrange, A. M; Lawson, W. A; James, S. D; Baudrand, J; Catala, C; Dreux, M; Felenbok, P; Hearnshaw, J. B (Royal Astronomical Society, 1996-08)
    We present data from high-dispersion echelle spectra and simultaneous uvby photometry for γ Doradus. These data were obtained from several sites during 1994 November as part of the MUSICOS-94 campaign. The star has two ...
  • 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 ...
  • Multisite observations of surface structures on AB Doradus in 1994 November 
    Collier Cameron, A; Walter, F. M; Vilhu, O; Böhm, T; Catala, C; Char, S; Clarke, F. J; Felenbok, P; Foing, B. H; Ghosh, K. K; Hao, J; Huang, L; Jackson, D. A; Janot-Pacheco, E; Jiang, S; Lagrange, A. M; Suntzeff, N; Zhai, D. S (The Royal Astronomical Society, 1999-09)
    We present time-resolved optical spectroscopy and broad-band photometry of the rapidly rotating southern K0 dwarf star AB Doradus, obtained during 1994 November. The data were obtained as part of a collaboration dedicated ...
  • Nova Herculis 1991 
    Iijima, T; Gehrz, R. D; Jones, T. J; Lawrence, G; Sivaraman, K. R; Prabhu, T. P; Ghosh, K. K; Anupama, G. C; Selvakumar, G (Smithsonian Astrophysical Observatory, 1991-04)
  • Observation of an H-alpha outburst in the Be star HR 4123 
    Ghosh, K. K; Apparao, K. M. V; Tarafdar, S. P (American Astronomical Society, 1989-09)
    During routine monitoring of the Be star HR 4123 during the year 1987-1988, a burst of H-alpha emission was observed on May 11, 1987. The increase was observed on May 9 and lasted until June 7, peaking to an equivalent ...
  • Observations of BN and AN stars: New Be stars 
    Ghosh, K. K; Apparao, K. M. V; Pukalenthi, S (The European Southern Observatory, 1999-01)
    From a survey of spectra of Bn/An stars, we have detected seven new Be stars: HR 1056 (A0Vn), 1544 (A1Vn), 2191 (A0Vnn), 2300 (B8Vn), 3134 (B9.5 Vn), 3878 (B0.5 IIIn) and 4552 (B9IIIpSi). H_alpha profiles of these stars ...
  • 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 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 ...
  • Origin of MeV gamma-ray emissions from blazars 
    Ghosh, K. K; Ramsey, B. D; Sivaram, C (Elsevier Science B. V, 1999-06)
    We have developed a model for MeV emission from blazars that involves the production of MeV gamma-rays through Inverse Compton (IC) scattering of electrons in the blob of a jet, with the UV photons of the accretion disk. ...
  • Physics of the phase changes of Be stars 
    Ghosh, K. K (International Astronomical Union, 1994)
    Based on Spectrosopic observations of more than 100 Be stars, we present the reuslts of the phase changes of Be stars.
  • Probability for the formation of complex ring molecules in interstellar medium and their detection proposal 
    Ghosh, K. K (International Astronomical Union, 1987)
    The pathways for the formation and destruction processes of ring molecules in the interstellar medium are proposed and their abundances are calculated under steady state conditions. The calculated abundances are of the ...
  • Quenching of NO2 continuum by NO, H2O & CH4 
    Ghosh, K. K (Publications & Information Directorate, CSIR, 1984-10)
    The K/A ratio, where K is the quenching rate coefficient of NO2 continuum by NO2, H2O and CH4 and A is the transition probability of NO2 continuum, has been measured using flowing afterglow method. The obtained values are ...
  • Rapid continuum level variability in Be stars earlier than B2 
    Ghosh, K. K (American Astronomical Society, 1990-05)
    H-alpha profiles for 12 Be stars and four standard stars were obtained on six nights in January and February, 1988, in order to search for rapid spectral variability in these stars. The results show that the Be stars earlier ...

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