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Browsing by Author "Bhat, P. N"

Browsing by Author "Bhat, P. N"

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  • Estimation of vital shower parameters in wavefront sampling technique 
    Chitnis, V. R; Bhat, P. N (Astronomical Society of India, 2002)
    Wavefront sampling experiments record arrival times of Cverenkov photons with high precision at various locations in Cverenkov pool using a distributed array of telescopes. It was shown earlier that this photon front can ...
  • 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 ...
  • Ground-based Very High Energy Gamma-Ray Astronomy at Pachmarhi 
    Acharya, B. S; Bhat, P. N; D'Souza, A. I; Francis, J; Gothe, K. S; John, A. V; Joshi, S. R; Krishnaswamy, M. R; Mehta, S; Nagesh, B. K; Pereira, M. P; Purohit, P. N; Rao, K. S; Rao, M. V. S; Satyanarayana, G. P; Sudershanan, P. V; Upadhyaya, S. S; Venkateshamurthy, B. L; Vishwanath, P. R (Astronomical Society of India, 1996)
  • 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. ...
  • Ionized Gas in Elliptical Galaxies 
    Singh, K. P; Prabhu, T. P; Kembhavi, A. K; Bhat, P. N (Indian Academy of Sciences, 1995-06)
    We report observations of H alpha nebulosities in the X-ray bright elliptical galaxies which are members of nearby groups of galaxies or clusters. Our sample includes NGC 1399, NGC 1600, NGC 2563, NGC 3607, NGC 4203, ...
  • 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 ...
  • Morphological properties of short duration Gamma Ray Bursts 
    Gupta, V; Gupta, P. D; Bhat, P. N (Astronomical Society of India, 2000)
    In this paper, we study a sample of short duration bursts contained in the 3B BATSE catalogue. We fit the time profiles of these GRBs with lognormal functions and study various temporal properties of these objects. In most ...
  • Multicolour broadband study of a lenticular galaxy : NGC 4753 
    Dewangan, G. C; Singh, K. P; Bhat, P. N (Astronomical Society of India, 2000)
    Based on VBT observations, we report multicolour broadband study of a lenticular galaxy, NGC 4753 with prominent dust lanes. The extinction curve derived for NGC 4753 is similar to the Galactic extinction curve. The dust ...
  • Optical counter-parts of Gamma Ray Bursts 
    Bhat, P. N (Astronomical Society of India, 2000)
    Gamma Ray Bursts (GRB'S) being the most energetic astronomical phenomena known to date still pose a formidable challenge to astronomers. The BATSE on board the Compton Observatory (CGRO) launched in 1991, has shown that ...
  • 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 ...
  • Photometry of X-ray selected quasars from Einstein Medium Sensitivity Survey 
    Singh, K. P; Bhat, P. N; Prabhu, T. P (Astronomical Society of India, 1993)
    We present a few photometric measurements of quasars in the Einstein Medium Sensitivity Survey (EMSS). The measurements are a part of an ongoing program of CCD photometry of quasars in the southern sky and are based on ...
  • A possible high altitude high energy gamma ray observatory in India 
    Cowsik, R; Bhat, P. N; Chitnis, V. R; Acharya, B. S; Vishwanath, P. R (Copernicus Gesellschaft, 2001-08)
    Recently an Indian Astronomical Observatory has been set up at Hanle (32° 46 4 6 N , 78° 57 5 1 E , 4515m amsl) situated in the high altitude cold desert in the Himalayas. The Observatory has 2-m aperture optical-infrared ...
  • Preliminary results on the flux of TeV g-rays from crab system obtained with the PACT at Pachmarhi 
    Sripathi Acharya, B; Bhat, P. N; Chitnis, V. R; Majumdar, P; Rahman, M. A; Singh, B. B; Vishwanath, P. R (International Union of Pure and Applied Physics, 2003-07)
    We have observed the Crab system (Nebula and Pulsar) and the corresponding background regions during many clear nights in the years 1999-2002 ˇ using the atmospheric Cerenkov array at Pachmarhi, PACT. Preliminary results ...
  • Status of HAGAR, the high altitude gamma ray observatory at Hanle 
    Chitnis, V. R; Acharya, B. S; Bhat, P. N; Cowsik, R; Prabhu, T. P; Srinivasan, R; Srivatsan, R; Vishwanath, P. R (Tata Institute of Fundamental Research, 2005)
    A 7 telescope array is planned to be constructed at Hanle in the Himalayas at an altitude of about 4200m above mean sea level for detecting celestial gamma-rays. The atmospheric Cerenkov light pool created by the ...
  • Surface photometry of ellipticals: Radio and cluster galaxies 
    Singh, K. P; Bhat, P. N; Prabhu, T. P; Kembhavi, A. K (Astronomical Society of India, 1993)
    Broad-band surface photometry in V, R and I colors is presented for three elliptical galaxies immersed in hot intracluster gas emitting X-rays due to thermal bremsstrahlung. The galaxies are (1) a cD galaxy, and (2) a radio ...

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