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  • Optical studies of a bright Type Iax supernova SN 2020rea 
    Singh, Mridweeka; Misra, Kuntal; Sahu, D. K; Ailawadhi, Bhavya; Dutta, Anirban; Howell, D. Andrew; Anupama, G. C; Bostroem, K. Azalee; Burke, Jamison; Dastidar, Raya; Gangopadhyay, Anjasha; Hiramatsu, Daichi; Im, Hyobin; McCully, Curtis; Pellegrino, Craig; Srivastav, Shubham; Teja, Rishabh Singh (Oxford University Press on behalf of Royal Astronomical Society, 2022-12)
    We present optical photometric and spectroscopic analysis of a Type Iax supernova (SN) 2020rea situated at the brighter luminosity end of Type Iax supernovae (SNe). The light curve decline rate of SN 2020rea is m15(g) = ...
  • Optical studies of novae 
    Anupama, G. C; Kamath, U. S (Astronomical Society of India, 2012-09)
    We review the observational characteristics of classical and recurrent novae in the optical region, in the context of observational programmes carried out using telescopes at the Vainu Bappu Observatory (VBO) and the ...
  • Optical studies of SN 2009jf: a Type Ib supernova with an extremely slow decline and aspherical signature 
    Sahu, D. K; Gurugubelli, U. K; Anupama, G. C; Nomoto, K (Wiley-Blackwell, 2011-06)
    Optical UBVRI photometry and medium-resolution spectroscopy of the Type Ib supernova SN 2009jf, during the period from ∼ −15 to +250 d, with respect to the B maximum are reported. The light curves are broad, with an extremely ...
  • Optical Studies of the Low Velocity Gradient Type Ia Supernovae 2009an and 2009ig 
    Sahu, D. K; Anupama, G. C; Anto, P; Gurugubelli, U. K (Cambridge University Press, 2013-01)
    UBVRI photometry and medium resolution spectroscopy of two Type Ia supernovae, SN 2009an and SN 2009ig, are presented. Their Δm15(B) indicate these two SNe marginally deviate from “normal” Type Ia events. Spectroscopically, ...
  • Optical studies of two stripped envelope supernovae − SN 2015ap (Type Ib) and SN 2016P (Type Ic) 
    Gangopadhyay, A; Misra, K; Sahu, D. K; Wang, Shan-Qin; Kumar, Brajesh; Li, Long; Anupama, G. C; Dastidar, R; Elias-Rosa, N; Kumar, Brijesh; Singh, Mridweeka; Pandey, S. B; Sanwal, Pankaj; Singh, A; Srivastav, S; Tartaglia, L; Tomasella, L (Oxford University Press on behalf of the Royal Astronomical Society, 2020-09)
    We present the photometric and spectroscopic studies of a Type Ib SN 2015ap and a Type Ic SN 2016P. SN 2015ap is one of the bright (MV = −18.04 mag) Type Ib while SN 2016P lies at an average value among the Type Ic SNe (MV ...
  • Optical studies of Type IIb SN 2011dh 
    Sahu, D. K; Anupama, G. C; Chakradhari, N. K (Cambridge University Press, 2014-01)
    UBVRI photometry and low resolution optical spectroscopy of the type IIb SN 2011dh in M51 are presented, covering the first year after the explosion. The peak absolute magnitude in V-band of −17.12±0.18 mag indicates SN ...
  • Optical Studies of V4332 Sagittarii: Detection of Unusually Strong K I and Na I Lines in Emission 
    Banerjee, D. P. K; Ashok, N. M (University of Chicago Press, 2004)
    We present optical observations of the enigmatic nova-like variable V4332 Sgr. The importance of this object should not be understated since it is considered to be the possible prototype of a new class of eruptive variables. ...
  • Optical telescopes in India 
    Bhattacharyya, J. C (National Institute of Science Communication and Information Resources, 1989-08)
    Fabrication and use of optical telescopes for astronomical observations in India have been reviewed. Evolution of telescopes, their optics, mounting and drive system leading to large aperture instruments of today has been ...
  • Optical testing of a gamma-ray telescope mirror 
    Udupa, D. V; Shukla, R. P; Saksena, G. D (Astronomical Society of India, 1993)
    A large size concave mirror for use in the gamma-ray telescope TACTIC was tested. Focal length of the concave spherical mirror of diameter 600 mm was measured to be 401.2 cm using the Ronchi test. The surface accuracy of ...
  • 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 Tracking of Artificial Satellites 
    Bappu, M. K. V (NISCAIR, 1958)
  • Optical Transmission Spectra of Hot Jupiters: Effects of Scattering 
    Sengupta, S; Chakrabarty, Aritra; Tinetti, Giovanna (IOP Publishing, 2020-02-01)
    We present new grids of transmission spectra for hot Jupiters by solving the multiple-scattering radiative transfer equations with non-zero scattering albedo instead of using the Beer–Bouguer–Lambert law for the change in ...
  • 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 ...
  • Optical variability of narrow-line and broad-line Seyfert 1 galaxies 
    Rakshit, S; Stalin, C. S (IOP Publishing, 2017-05)
    We studied the optical variability ( OV ) of a large sample of narrow-line Seyfert 1 ( NLSy1 ) and broad-line Seyfert 1 ( BLSy1 ) galaxies with z  <  0.8 to investigate any differences in their OV ...
  • Optical variability of radio-intermediate quasars 
    Goyal, Arti; Gopal-Krishna; Joshi, S; Sagar, R; Wiita, Paul J; Anupama, G. C; Sahu, D. K (Blackwell Publishing, 2010-02)
    We report the results of our intensive intranight optical monitoring of eight optically bright `radio-intermediate quasars' (RIQs) having flat or inverted radio spectra. The monitoring was carried out in R band on 25 nights ...
  • An Optical, Dual-Beam, Automated Medium Resolution Spectropolarimeter for the Vainu Bappu Telescope 
    Chakraborty, P; Vasundhara, R (Springer, 2003-03)
    Fabrication of an optical dual-beam spectropolarimeter as an add-on facility to an existing astronomical spectrograph at the Vainu Bappu Telescope is described. The polarimetric optics consists of a superachromatic ...
  • The optical-GeV connection in fermi blazars 
    Bhoomika (Indian Institute of Astrophysics, 2020-07)
    Blazars are a class of active galactic nuclei (AGN) that have relativistic jets that are oriented close to the observers line of sight. They display ux variability across the en- tire accessible electromagnetic spectrum ...
  • Optical/IR studies of Be stars in NGC 6834 with emphasis on two specific stars 
    Mathew, B; Varricatt, W. P; Subramaniam, A; Ashok, N. M; Banerjee, D. P. K (IOP Publishing, 2014-09)
  • Optimization of existing centroiding algorithms for Shack Hartmann sensor 
    Vyas, A; Roopashree, M. B; Prasad, B. R (2009)
    Three centroiding techniques to estimate the position of the spots in a Shack Hartmann sensor: Normalized Centre of Gravity (CoG), Iteratively Weighted Centre of Gravity (IWCoG) and Intensity Weighted (IWC) centroiding are ...

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