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Browsing by Author "Mohan, V"

Browsing by Author "Mohan, V"

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  • Field star contamination in open star cluster NGC 2301 
    Mohan, V; Sagar, R (Astronomical Society of Indian, 1988-12)
    Photographic photometry of about 900 stars down to V = 17 mag has been carried out in the region of the open cluster NGC 2301. The cluster region seems to be severely contaminated by field stars. Statistical criteria yield ...
  • GRB 000301C with peculiar afterglow emission 
    Sagar, R; Mohan, V; Pandey, S. B; Pandey, A. K; Stalin, C. S; Castro-Tirado, A. J (Astronomical Society of India, 2000)
    The CCD magnitudes in Johnson V and Cousins R and I photometric passbands are determined for GRB 000301C afterglow starting ~ 1.5 day after the γ - ray burst. In fact we provide the earliest optical observations for this ...
  • GRB 000926 and its optical afterglow : Another possible evidence for non-isotropic emission 
    Sagar, R; Pandey, S. B; Mohan, V; Bhattacharya, D; Castro-Tirado, A. J (Astronomical Society of India, 2001)
    The CCD Johnson BV and Cousins RI photomertric magnitudes are determined for 20 stars in the field of GRB 000926. They are used to calibrate the present R as well as published BVRI photometric magnitudes of the GRB 000926 ...
  • Integrated photometric characteristics of galactic open star clusters 
    Lata, S; Pandey, A. K; Sagar, R; Mohan, V (E D P Sciences, 2002-06)
    Integrated UBVRI photometric parameters of 140 galactic open clusters have been computed. Integrated I(V-R)0 and I(V-I)0 colours as well as integrated parameters for 71 star clusters have been obtained for the first time. ...
  • Low resolution spectroscopy of selected Algol systems 
    Shanti Priya Devarapalli; Rukmini Jagirdar; Parthasarathy, M; Sahu, D. K; Mohan, V; Bhatt, B. C; Thomas, V. S (Springer, 2018-04)
    The analysis of spectroscopic data for 30 Algol-type binaries is presented. All these systems are short period Algols having primaries with spectral types B and A. Dominant spectral lines were identified for the spectra ...
  • Multi-colour optical monitoring of the intra-day variable blazar S5 0716+71 
    Sagar, R; Gopal-Krishna; Mohan, V; Pandey, A. K; Bhatt, B. C; Wagner, S. J (The European Southern Observatory, 1999-02)
    We report multi-colour optical monitoring of the intra-day variable blazar S5 0716+71 with a dense temporal coverage over a total duration of 4 weeks in February/March 1994. Four filters (BV Johnson and RI Cousins) were ...
  • The Occulatation of Hyd - 20/sup0/51695 by Uranus on 1982 May 1 
    Pandey, A. K; Mahra, H. S; Mohan, V (Astronomical Society of India, 1984-09)
  • The Occultation of BD - 19 4222 by Uranus on 1981 April 26 
    Mahra, H. S; Pandey, A. K; Joshi, U. C; Mohan, V (Astronomical Society of India, 1983-06)
    From the observations of the occultation of BD - 194222 by Uranus on 1981 April 26 the temperature profiles of the Uranian upper atmosphere have been obtained. The mean temperature of the upper atmosphere of Uranus in the ...
  • Optical and radio observations of the bright GRB 010222 afterglow: evidence for rapid synchrotron cooling ? 
    Sagar, R; Stalin, C. S; Bhattacharya, D; Pandey, S. B; Mohan, V; Castro-Tirado, A. J; Pramesh Rao, A; Trushkin, S. A; Nizhelskij, N. A; Bremer, M; Castro Ceron, J. M (Astronomical Society of India, 2001)
    We report photometric observations of the optical afterglow of GRB 010222 in V, R and I passbands carried out between 22-27 February 2001 at Nainital. We determine the CCD Johnson BV and Cousins RI photometric magnitudes ...
  • Optical follow up of the GRB 990123 sources from UPSO, Naini Tal 
    Sagar, R; Pandey, A. K; Mohan, V; Yadav, R. K. S; Nilakshi; Bhattacharya, D; Castro-Tirado, A. J (Astronomical Society of India, 1999)
    The CCD magnitudes in Johnson $BV$ and Cousins $R$ photometric passbands are determined for the optical transient of GRB 990123. These observations have been taken approximately 12 hours after trigger of the gamma-ray ...
  • Optical follow-up of GRB afterglows from UPSO, Naini Tal 
    Pandey, S. B; Sagar, R; Mohan, V; Pandey, A. K; Bhattacharya, D; Castro-Tirado, A. J (Astronomical Society of India, 2001)
    Successful optical photometric observations of five GRB afterglows namely GRB 990123, GRB 991208, GRB 991216, GRB 000301c and GRB 000926 have been carried out from State Observatory Naini Tal till 2000. The results and ...
  • Optical observations of the bright long duration peculiar GRB 021004 afterglow. 
    Pandey, S. B; Sahu, D. K; Resmi, L; Sagar, R; Anupama, G. C; Bhattacharya, D; Mohan, V; Prabhu, T. P; Bhatt, B. C; Pandey, J. C; Parihar, P. S; Castro-Tirado, A. J (Astronomical Society of India, 2003)
    The CCD magnitudes in Johnson B,V and Cousins R and I photometric passbands are determined for the bright long duration GRB 021004 afterglow from 2002 October 4 to 16 starting ~ 3 hours after the γ - ray burst. Light curves ...
  • The outburst and nature of young eruptive low mass stars in dark clouds 
    Ninan, J. P; Ojha, D. K; Bhatt, B. C; Mallick, K. K; Tej, A; Sahu, D. K; Ghosh, S. K; Mohan, V (Astronomical Society of India, 2012)
    The FU Orionis (FUor) or EX Orionis (EXor) phenomenon has attracted increasing attention in recent years and is now accepted as a crucial element in the early evolution of low-mass stars. FUor and EXor eruptions of young ...
  • Performance of the IIA mosaic CCD camera system 
    Naidu, B. N; Srinivasan, R; Mohan, V; Sagar, R (Astronomical Society of India, 2001)
    We evaluate performance of the 4K x 4K mosaic CCD camera system developed at the Indian Institute of Astrophysics using four Thomson CCDs in a buttable configuration. The camera system consists of a mosaic CCD dewar developed ...
  • Photometric performance of UPSO CCD system 
    Mohan, V; Paliwal, D. C; Mahra, H. S (Astronomical Society of India, 1991)
    The photometrics CCD system obtained by the Uttar Pradesh State Observatory is discussed. The calibration of the system is described and its photometric performance is evaluated based on photometric transformation coefficients
  • A photometric study of the open cluster King 7 
    Durgapal, A. K; Mohan, V; Pandey, A. K; Mahra, H. S (Astronomical Society of India, 1996)
  • Photometry of open cluster King 21 
    Mohan, V; Pandey, A. K (Astronomical Society of India, 1984-09)
    Photoelectric magnitudes of 26 stars in the field of King 21 have been obtained. The reddening is variable across the cluster. A distance of 1.91 kpc has been estimated for the cluster. It is concluded that the age of the ...
  • Possible Detection of a Ring System in Saturn's Magnetosphere 
    Vasundhara, R; Bhattacharyya, J. C; Santhanam, P; Pande, A. K; Mohan, V; Mahra, H (Nature Publishing Group, 1984-12)
    The region of the magnetosphere of Saturn around 14 radii and 19 radii has been of special interest since the detection of anomalous dips in the low-energy plasma ion-density in these regions by the Voyager 1, Voyager 2 ...
  • Post-outburst phase of LDN 1415 nebula (IRAS 04376+5413) 
    Pawad, V. S; Ojha, D. K; Ninan, J. P; Tej, A; Bhatt, B. C; Sahu, D. K; Ghosh, S. K; Kaurav, S. S; Mohan, V (Astronomical Society of India, 2010)
    LDN 1415 nebula was first detected by Stecklum (2006) in early April 2006 in the vicinity of lRAS 04376+5413. In this paper, we present a study of the post-outburst phase of LDN 1415 nebula using optical (V, R, J) and ...
  • Reappearance of McNeil’s Nebula (V1647 Orionis) and its Outburst Environment 
    Ninan, J. P; Ojha, D. K; Bhatt, B. C; Ghosh, S. K; Mohan, V; Mallick, K. K; Tamura, M; Henning, T (IOP Publishing, 2013-12-01)
    We present a detailed study of McNeil's nebula (V1647 Ori) in its ongoing outburst phase starting from 2008 September to 2013 March. Our 124 nights of photometric observations were carried out in optical V, R, I, and ...

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