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Browsing by Author "Sagar, R"

Browsing by Author "Sagar, R"

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  • Star clusters in the magellanic clouds-1: parameterisation and classification of 1072 clusters in the LMC 
    Nayak, P. K; Subramaniam, A; Choudhury, S; Indu, G; Sagar, R (Oxford University Press on behalf of the Royal Astronomical Society, 2016-12-01)
    We have introduced a semi-automated quantitative method to estimate the age and reddening of 1072 star clusters in the Large Magellanic Cloud (LMC) using the Optical Gravitational Lensing Experiment III survey data. This ...
  • Star Formation in the Dwarf Seyfert Galaxy NGC 4395: Evidence for Both AGN and SN Feedback? 
    Nandi, Payel; Stalin, C. S; Saikia, D. J; Muneer, S; Mountrichas, George; Wylezalek, D; Sagar, R; Patig, M. K (American Astronomical Society, 2023-06-20)
    We present a detailed multiwavelength study of star formation in the dwarf galaxy NGC 4395, which hosts an active galactic nucleus (AGN). From our observations with the Ultra-Violet Imaging Telescope, we have compiled a ...
  • Star formation in young cluster NGC 1893 
    Sharma, S; Pandey, A. K; Ojha, D. K; Chen, W. P; Ghosh, S. K; Bhatt, B. C; Maheswar, G; Sagar, R (International Astronomical Union, 2008-05)
    We have carried out a multi-wavelength study of the star forming region NGC 1893 to make a comprehensive exploration of the effects of massive stars on low mass star formation. Using deep optical U BV RI broad band, Hα ...
  • Star formation in young star cluster NGC1893 
    Sharma, S; Pandey, A. K; Ojha, D. K; Chen, W. P; Ghosh, S. K; Bhatt, B. C; Maheswar, G; Sagar, R (Blackwell Publishing, 2007-09)
    We present a comprehensive multiwavelength study of the star-forming region NGC 1893 to explore the effects of massive stars on low-mass star formation. Using near-infrared colours, slitless spectroscopy and narrow-band ...
  • Star-clusters in the magellanic clouds and their mass functions 
    Sagar, R (Indian Academy of Sciences, 1993-03-10)
  • Stellar contents of two young open clusters: NGC 663 and 654 
    Pandey, A. K; Upadhyay, K; Ogura, K; Sagar, R; Mohan, V; Mito, H; Bhatt, H. C; Bhatt, B. C (Royal Astronomical Society, 2005-04)
    UBVRI CCD photometry in a wide field around two young open clusters, NGC 663 and 654, has been carried out. Hα and polarimetric observations for the cluster NGC 654 have also been obtained. We use the photometric data to ...
  • Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. 6: Variability of NGC 3783 from ground-based data 
    Stirpe, G. M; Winge, C; Altieri, B; Alloin, D; Aguero, E. L; Anupama, G. C; Ashley, R; Bertram, R; Calderon, J. H; Catchpole, R. M; Corradi, R. L. M; Covino, E; Dottori, H. A; Feast, M. W; Ghosh, K. K; Hutton, R. Gil; Glass, I. S; Grebel, E. K; Jorda, L; Koen, C; Laney, C. D; Maia, M; Marang, F; Mayya, Y. D; Morrell, N; Nakada, Y; Pastoriza, M. G; Pati, A. K; Pelat, D; Peterson, B. M; Prabhu, T. P; Roberts, G; Sagar, R; Salamanca, I; Sekiguchi, K; Storchi-Bergmann, T; Subramaniam, A; Van Winckel, H; Van Wyk, F; Villada, M; Wagner, R. M; Whitelock, P. A; Winkler, H; Clavel, J; Dietrich, M; Kollatschny, W; O'Brien, P. T; Perola, G. C; Recondo-Gonzalez, M. C; Rodriguez-Pascual, P; Santos-Lleo, M (The American Astronomical Society, 1994-04)
    The Seyfert 1 galaxy NGC 3783 was intensely monitored in several bands between 1991 December and 1992 August. This paper presents the results from the ground-based observations in the optical and near-IR bands, which ...
  • Study of interstellar extinction in some young open clusters 
    Sagar, R (Royal Astronomical Society, 1987-09)
    Interstellar extinction has been studied in 15 open clusters, based on reliable cluster members and precise observational data. Out of these, 10 show nonuniform extinction across the cluster region. Most of these show ...
  • A study of spatial structure of galactic open star clusters 
    Nilakshi; Sagar, R; Pandey, A. K; Mohan, V (E D P Sciences, 2002-02)
    In order to study the relation between the core and corona in galactic star clusters, the spatial structure of 38 rich open star clusters has been studied using radial density profiles derived from the photometric data of ...
  • Study of the Galactic Cluster NGC 581 
    Sagar, R; Joshi, U. C (Astronomical Society of India, 1978-03)
    Photoelectric magnitudes and colours in the UBV system have been determined for 73 stars in NGC 581. The value of the interstellar reddening is 0m.38. The distance modules to the cluster is estimated at 12m.16 plus or ...
  • A study of the old galactic star cluster Berkeley 32 
    Richtler, T; Sagar, R (Astronomical Society of India, 2001)
    We present new CCD photometry of the distant old open star cluster Berkeley 32 in Johnson V and Cousins I passbands. A total of ~ 3200 stars have been observed in a field of about 13? x 13?. The colour-magnitude diagram ...
  • A study of the spatial stellar mass distribution in some young open clusters 
    Sagar, R; Miakutin, V. I; Piskunov, A. E; Dluzhnevskaia, O. B (Royal Astronomical Society, 1988-10)
    The stellar spatial distribution is studied as a function of mass in 11 young open clusters. In seven of these clusters, mass segregation is observed. The possibility of two cluster centers for NGC 2264 is discussed. It ...
  • A study of the spatial variation of mass functions in some young open clusters 
    Pandey, A. K; Mahra, H. S; Sagar, R (Astronomical Society of the Pacific, 1991)
    The effect of mass segregation on cluster mass functions has been studied and it is found that the slope of the mass function is steeper in the outer parts of open dusters. Since dynamical relaxation time is always larger ...
  • Supernova 2012aw – a high-energy clone of archetypal Type IIP SN 1999em 
    Bose, Subhash; Kumar, Brijesh; Sutaria, F. K; Kumar, Brajesh; Roy, Rupak; Bhatt, V. K; Pandey, S. B; Chandola, H. C; Sagar, R; Misra, Kuntal; Chakraborti, Sayan (Oxford University Press, 2013-08-11)
    We present densely sampled UBVRI/griz photometric and low-resolution (6–10 Å) optical spectroscopic observations from 4 to 270 d after explosion of a newly discovered Type II SN 2012aw in a nearby (∼9.9 Mpc) galaxy M95. ...
  • Survey for roAp stars in the northern sky from Naini Tal 
    Ashoka, B. N; Seetha, S; Raj, E; Chaubey, U. S; Gupta, S. K; Joshi, S; Martinez, P; Kurtz, D. W; Sagar, R; Kasturirangan, K (Astronomical Society of India, 2000)
    Of the 31 known rapidly oscillating Ap (roAp) stars, 28 are in the southern sky and majority of them were discovered at SAAO indicating that a systematic survey also is needed in the northern sky. Therefore, a project has ...
  • Temporal behaviour of emissions from gamma-ray bursts and optical/near-IR afterglows of GRB 991208 and GRB 991216 
    Sagar, R; Mohan, V; Pandey, A. K; Pandey, S. B; Castro-Tirado, A. J (Astronomical Society of India, 2000)
    The CCD magnitudes in Cousins R and I photometric passbands are determined for GRB 991216 and GRB 991208 afterglows respectively ~ 1 and ~ 3 day after trigger of the corresponding gamma-ray bursts. Light curves of the ...
  • Testing the mechanisms for optical micro-variability of powerful active galactic nuclei 
    Gopal-Krishna; Sagar, R; Wiita, P. J (Astronomical Society of India, 1993)
    We present the first results of a new type of observational program being carried out using the 2.34m Vainu Bappu Telescope at Kavalur. This program involves intra-night optical monitoring of radio quiet but optically ...
  • UBV photoelectric photometry of the open cluster NGC 2539 
    Joshi, U. C; Sagar, R (Astronomical Society of Indian, 1986-06)
    UBV photometric observations of 135 stars near NGC 2539, obtained using the 104-cm Sampurnanand reflector at Uttar Pradesh State Observatory during 1975-1978, are reported. The data are presented in tables and graphs and ...
  • UBVRI CCD photometry of the OB associations Bochum 1 and Bochum 6 
    Yadav, R. K. S; Sagar, R (Astronomical Society of India, 2003)
    We report the first deep $UBVRI$ CCD photometry of 2460 stars in the field of two poorly studied OB associations Bochum 1 and Bochum 6. We selected 15 and 14 probable members in Bochum 1 and Bochum 6 respectively using ...
  • UBVRI CCD photometry of the two southern galactic star clusters Berkeley 79 and Trumpler 11 
    Sagar, R; Cannon, R. D (Astronomical Society of India, 1994)

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