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Browsing by Author "Gupta, A. C"

Browsing by Author "Gupta, A. C"

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  • A complete photometric study of the open cluster NGC 7790 containing Cepheid variables 
    Gupta, A. C; Subramaniam, A; Sagar, R; Griffiths, W. K (EDP Sciences, 2000-09)
    CCD photometry of the northern open star cluster NGC 7790 has been carried out in BVI photometric passbands down to V ~ 21 mag for 1150 stars of which for ~ 700 stars, the data is obtained for the first time. We derive the ...
  • Core shift effect in blazars 
    Agarwal, A; Mohan, P; Gupta, A. C; Mangalam, A; Volvach, A. E; Aller, M. F; Aller, H. D; Gu, M. F; Lahteenmaki, A; Tornikoski, M; Volvach, L. N (Oxford University Press on behalf of the Royal Astronomical Society, 2017-07)
    We studied the pc-scale core shift effect using radio light curves for three blazars, S5 0716+714, 3C 279 and BL Lacertae, which were monitored at five frequencies (ν) between 4.8 and 36.8 GHz using the University of ...
  • Equilibria of self-gravitating gaseous disks 
    Pandey, U. S; Gupta, A. C (Astronomical Society of India, 1998-12)
  • Frequency-dependent core shifts and parameter estimation for the blazar 3C 454.3 
    Mohan, Prashanth; Agarwal, A; Mangalam, A; Gupta, A. C; Wiita, P. J; Volvach, A. E; Aller, M. F; Aller, H. D; Gu, M. F; Lahteenmaki, A; Tornikoski, M; Volvach, L. N (Oxford University Press on behalf of the Royal Astronomical Society, 2015-09-11)
    We study the core shift effect in the parsec-scale jet of the blazar 3C 454.3 using the 4.8– 36.8 GHz radio light curves obtained from three decades of continuous monitoring. From a piecewise Gaussian fit to each flare, ...
  • Multiwavelength intraday variability of the BL Lacertae S5 0716+714 
    Gupta, A. C; Krichbaum, T. P; Wiita, P. J; Rani, B; Sokolovsky, K. V; Mohan, Prashanth; Mangalam, A; Marchili, N; Fuhrmann, L; Agudo, I; Bach, U; Bachev, R; Böttcher, M; Gabanyi, K. E; Gaur, H; Hawkins, K; Kimeridze, G. N; Kurtanidze, O. M; Kurtanidze, S. O; Lee, C.-U; Liu, X; McBreen, B; Nesci, R; Nestoras, G; Nikolashvili, M. G; Ohlert, J. M; Palma, N; Peneva, S; Pursimo, T; Semkov, E; Strigachev, A; Webb, J. R; Wiesemeyer, H; Zensus, J. A (Wiley-Blackwell, 2012-09)
    We report results from a one-week multiwavelength campaign to monitor the BL Lacertae object (BL Lac) S5 0716+714 (on 2009 December 9–16). Nine ground-based telescopes at widely separated longitudes and one space-based ...
  • Observations of AGNs using PACT 
    Bose, D; Chitnis, V. R; Vishwanath, P. R; Majumdar, P; Rahman, M. A; Singh, B. B; Gupta, A. C; Acharya, B. S (Springer Netherlands, 2007-06)
    We report our observations on 4 AGNs viz, Mkn 421, Mkn 501, 1ES1426+428 and ON231 belonging to a sub-class called blazars. The observations were carried out using the Pachmarhi Array of Cherenkov Telescopes and span about ...
  • A peculiar multiwavelength flare in the blazar 3C 454.3 
    Gupta, A. C; Mangalam, A; Wiita, J. Paul; Kushwaha, P; Gaur, H; Zhang, H; Gu, M. F; Liao, M; Dewangan, G. C; Ho, L. C; Mohan, P; Umeura, M; Sasada, M; Volvach, A. E; Agarwal, A; Aller, M. F; Aller, H. D; Bachev, R; Lahteenmaki, A; Semkov, E; Strigachev, A; Tornikoski, M; Volvach, L. N (Oxford University Press on behalf of the Royal Astronomical Society, 2017-11)
    The blazar 3C 454.3 exhibited a strong flare seen in γ -rays, X-rays and optical/near-infrared bands during 2009 December 3–12. Emission in the V and J bands rose more gradually than did the γ -rays and soft X-rays, ...
  • Re-Analysis of QPO in 3C 273 Light Curve 
    Mohan, Prashanth; Mangalam, A; Chand, H; Gupta, A. C (Indian Academy of Sciences, 2011-06)
    We have developed analysis tools to search for quasi periodic oscillations in light curves from active galactic nuclei, using the following time series techniques: Wavelets, periodogram, Lomb–Scargle periodogram, structure ...
  • Site characterization for the UPSO-TIFR telescope 
    Sagar, R; Uddin, W; Pandey, A. K; Stalin, C. S; Mohan, V; Sanwal, B. B; Gupta, S. K; Yadav, R. K. S; Durgapal, A. K; Joshi, S; Kumar, B; Gupta, A. C; Joshi, Y; Srivastava, J. B; Chaubey, U. S; Singh, M; Pant, P; Gupta, K. G; Padalia, T. D (Astronomical Society of India, 2000)
    The Uttar Pradesh State Observatory, Naini Tal and Tata Institute of Fundamental Research, Mumbai plan to install jointly a 3 metre size optical telescope at Devasthal located east of Naini Tal about 50 km by road. The ...

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