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Browsing by Author "Chitnis, V. R"

Browsing by Author "Chitnis, V. R"

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  • Fluctuations in Čerenkov photon density in extensive air showers 
    Chitnis, V. R; Bhat, P. N (Astronomical Society of India, 1999)
    In the absence of a standard source of γ-rays or hadrons of known energy one has to study the details of production of Cerenkov light at the observation level only through detailed simulation studies. Recently such studies ...
  • Gamma ray and hadron generated Cverenkov photon spectra at various observation altitudes 
    Rahman, M. A; Bhat, P. N; Acharya, B. S; Chitnis, V. R; Majumdar, P; Vishwanath, P. R (Astronomical Society of India, 2002)
    We have studied the propagation of Cverenkov photons generated by Very High Energy gamma-rays and hadrons in the atmosphere. Photon production height distributions derived from semi-empirical methods agree with those ...
  • Gamma-hadron separation using Cverenkov photon density fluctuations 
    Chitnis, V. R; Bhat, P. N (Astronomical Society of India, 2002)
    In atmospheric Cverenkov technique gamma-rays are detected against abundant background produced by hadronic showers. In order to improve signal to noise ratio of the experiment, it is necessary to reject a significant ...
  • Gamma-ray source observations with the HAGAR telescope system at Hanle in the Himalayas 
    Britto, R. J; Acharya, B. S; Chitnis, V. R; Cowsik, R; Dorji, N; Duhan, S. K; Gothe, K. S; Kamath, P. U; Mahesh, P. K; Nagesh, B. K; Naidu, A; Parmar, N. K; Prabhu, T. P; Rao, S. K; Saha, L; Saleem, F; Saxena, A. K; Sharma, S. K; Shukla, A; Singh, B. B; Srinivasan, R; Srinivasulu, G; Sudersanan, P. V; Tsewang, D; Upadhya, S. S; Vishwanath, P. R (Societe Francaise d’Astronomie et dAstrophysique, 2009-11)
    We have observed Crab nebula using the recently commissioned wavefront sampling high alti- tude (4270 m) array, HAGAR, at Hanle in the Ladakh region of the Himalayas. Regular source observations have begun with the ...
  • Hard X-ray spectra of some X-ray binaries from balloon-borne observations 
    Chitnis, V. R; Agrawal, P. C; Manchanda, R. K; Rao, A. R (Astronomical Society of India, 1993)
    We have studied X-ray binaries 4U1907 + 09, GX1 + 4 and Cygnus X-1 in the energy range 20-100 keV, using balloon-borne xenon-filled multilayer proportional counters flown from Hyderabad, India. Results of these observations ...
  • High altitude gamma ray observatory at Hanle 
    Sripathi Acharya, B; Cowsik, R; Bhat, P. N; Chitnis, V. R; Vishwanath, P. R; Prabhu, T. P; Srinivasan, R (International Union of Pure and Applied Physics, 2003-07)
    We have carried out Monte Carlo simulations to study the nature of Cherenkov light pool generated by γ -ray and proton primaries for the altitude of Hanle(4515m amsl) in the Himalayas, the site of proposed HAGAR experiment. ...
  • The Himalayan gamma ­ ray observatory at Hanle 
    Koul, R; Kaul, R. K; Mitra, A. K; Rannot, R. C; Acharya, B. S; Chitnis, V. R; Cowsik, R; Prabhu, T. P; Srinivasan, R; Srivatsan, R; Vishwanath, P (Tata Institute of Fundamental Research, 2005)
    A new gamma ray observatory comprising a large stereo imaging cherenkov telescope and an array of wave front sampling telescopes is being set up at the high altitude astronomical site at Hanle in the Ladakh region of ...
  • Long-term study of Mkn 421 with the HAGAR array of telescopes 
    Sinha, A; Shukla, A; Saha, L; Acharya, B. S; Anupama, G. C; Bhattacharjee, P; Britto, R. J; Chitnis, V. R; Prabhu, T. P; Singh, B. B; Vishwanath, P. R (EDP Sciences, 2016-07)
    Context. The HAGAR Telescope Array at Hanle, Ladakh has been regularly monitoring the nearby blazar Mkn 421 for the past seven years. Aims. Blazars show flux variability in all timescales across the electromagnetic ...
  • Longitudinal shower development and its signature at observation level 
    Chitnis, V. R; Bhat, P. N (Astronomical Society of India, 2002)
    From a study of Cverenkov photon arrival times at various core distances at the observation level it has already been established that the photon front is well fitted with a spherical surface traveling at the speed of light ...
  • A mini ACT experiment at low and high altitudes 
    Vishwanath, P. R; Acharya, B. S; Bhat, P. N; Chitnis, V. R (Tata Institute of Fundamental Research, 2005)
    A simple experimental apparatus was used to measure rate of cosmic ray events due to Atmospheric Cerenkov Radiation at two mountain altitude sites with the height difference of 3.5 km. The event rates at Hanle (altitude ...
  • Multi-frequency, multi-epoch study of MrK 501: hints for a two-component nature of the emission 
    Shukla, A; Chitnis, V. R; Singh, B. B; Acharya, B. S; Anupama, G. C; Bhattacharjee, P; Britto, R. J; Mannheim, K; Prabhu, T. P; Saha, L; Vishwanath, P. R (IOP Publishing, 2015-01-01)
    Since the detection of very high energy (VHE) γ -rays from Mrk 501, its broadband emission of radiation was mostly and quite effectively modeled using the one zone emission scenario. However, broadband spectral and flux ...
  • Multiwavelength study of the TeV blazar Mrk 421 during a giant flare 
    Shukla, A; Chitnis, V. R; Vishwanath, P. R; Acharya, B. S; Anupama, G. C; Bhattacharjee, P; Britto, R. J; Prabhu, T. P; Saha, L; Singh, B. B (EDP Sciences, 2012-05)
    Aims. The nearby (z = 0.031) TeV blazar Mrk 421 was reported to be in a high state of flux activity since November, 2009. We aim to investigate possible changes in the physical parameters of Mrk 421 during its high state ...
  • 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 ...
  • Observations with the High Altitude GAmma Ray (HAGAR) telescope array in the Indian Himalayas 
    Britto, R. J; Acharya, B. S; Anupama, G. C; Bhatt, N; Bhattacharjee, P; Bhattacharya, S. S; Chitnis, V. R; Cowsik, R; Dorji, N; Duhan, S. K; Gothe, K. S; Kamath, P. U; Koul, R; Mahesh, P. K; Mitra, A; Nagesh, B. K; Parmar, N. K; Prabhu, T. P; Rannot, R. C; Rao, S. K; Saha, L; Saleem, F; Saxena, A. K; Sharma, S. K; Shukla, A; Singh, B. B; Srinivasan, R; Srinivasulu, G; Sudersanan, P. V; Tickoo, A. K; Tsewang, D; Upadhya, S; Vishwanath, P. R; Yadav, K. K (French Society of Astronomy and Astrophysics, 2010-12)
    For several decades, it was thought that astrophysical sources emit high energy photons within the energy range of the gamma-ray region of the lectromagnetic spectrum also. These photons originate from interactions of high ...
  • Observations with the High Altitude GAmma-Ray (HAGAR) telescope array in the Indian Himalayas 
    Britto, R. J; Acharya, B. S; Anupama, G. C; Bhatt, N; Bhattacharjee, P; Bhattacharya, S; Chitnis, V. R; Cowsik, R; Dorji, N; Duhan, S. K; Gothe, K. S; Kamath, P. U; Koul, R; Manoharan, J; Mahesh, P. K; Mitra, A; Nagesh, B. K; Parmar, N. K; Prabhu, T. P; Rannot, R. C; Rao, S. K; Saha, L; Saleem, F; Saxena, A. K; Sharma, S. K; Shukla, A; Singh, B. B; Srinivasan, R; Srinivasulu, G; Sudersanan, P. V; Tickoo, A. K; Tsewang, D; Upadhya, S. S; Vishwanath, P. R; Yadav, K. K (Copernicus Publications, 2011-11)
    The High Altitude GAmma-Ray (HAGAR) array is a wavefront sampling array of 7 telescopes, set-up at Hanle, at 4270 m amsl, in the Ladakh region of the Himalayas (Northern India). It constitutes the first phase of the HImalayan ...
  • On the Spectral Curvature of VHE Blazar 1ES 1011 + 496: Effect of Spatial Particle Diffusion 
    Sinha, A; Sahayanathan, S; Acharya, B. S; Anupama, G. C; Chitnis, V. R; Singh, B. B (IOP Publishing, 2017-02-10)
    The American Astronomical Society, find out more The Institute of Physics, find out more On the Spectral Curvature of VHE Blazar 1ES 1011+496: Effect of Spatial Particle Diffusion Atreyee Sinha1, S. ...
  • Pachmarhi array of Cerenkov telescopes 
    Bhat, P. N; Acharya, B. S; Chitnis, V. R; D'Souza, A. I; Francis, P. J; Gothe, K. S; John, A. V; Mazumdar, P; Nagesh, B. K; Purohit, P. N; Rahman, M. A; Rao, S. K; Rao, K. K; Sharma, S. K; Stanislaus, A. J; Sudershanan, P. V; Swamy, M. R. K; Upadhyaya, S. S; Murty, B. L. V (Astronomical Society of India, 2000)
    Pachmarhi Array of Cerenkov Telescopes (PACT) consisting of 25 telescopes has been installed at Pachmarhi (longitude : 76d 26' E, latitude : 22d 28' N and altitude : 1075m) recently. The telescopes are deployed in the form ...
  • PACT results on very high energy g-ray emission from CRAB pulsar 
    Sripathi Acharya, B; Vishwanath, P. R; Bhat, P. N; Chitnis, V. R; Majumdar, P; Rahman, M. A; Singh, B. B (International Union of Pure and Applied Physics, 2003-07)
    The data taken on the Crab pulsar by the recently commissioned array of ˇ Cerenkov telescopes at Pachmarhi using the wave front sampling technique have been analyzed. The phasograms show significant excess of events at the ...
  • Performance studies of the PACT experiment 
    Vishwanath, P. R; Acharya, B. S; Bhat, P. N; Chitnis, V. R; Majumdar, P; Rahman, M. A; Singh, B. B (Astronomical Society of India, 2002)
    Monte Carlo calculations have been done to understand various characteristics like the energy threshold, collection area etc of the recently commissioned PACT. The energy threshold of the array for gamma rays is found to ...
  • Pointing of HAGAR telescope mirrors 
    Gothe, K. S; Prabhu, T. P; Vishwanath, P. R; Acharya, B. S; Srinivasan, R; Chitnis, V. R; Kamath, P. U; Srinivasulu, G; Saleem, F; Kemkar, P. M. M; Mahesh, P. K; Gabriel, F; Manoharan, J; Dorji, N; Dorjai, T; Angchuk, D; D'souza, A. I; Duhan, S. K; Nagesh, B. K; Rao, S. K; Sharma, S. K; Singh, B. B; Sudersanan, P. V; Thsering, M. T; Upadhya, S. S; Anupama, G. C; Britto, R. J; Cowsik, R; Saha, L; Shukla, A (Springer, 2013-04)
    An array of seven atmospheric Cherenkov telescopes was commissioned at a high altitude site in Hanle in the Ladakh region of the Himalayas. The array called HAGAR has been designed to observe celestial γ-rays of energy ...

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