IIA Institutional Repository

Browsing by Author "Bhattacharyya, S"

Browsing by Author "Bhattacharyya, S"

Sort by: Order: Results:

  • Adiabatic cooling and nonthermal spectrum of blazars 
    Sahayanathan, S; Bhattacharyya, S; Kaul, C. L; Bhat, C. L (Astronomical Society of India, 2001)
    Here we study the effect of adiabatic cooling on the non-thermal synchrotron spectra of blazars from radio to X-ray region resulting when blazars are in the flaring state.
  • ASTROSAT mission 
    Singh, Kulinder Pal; Tandon, S. N; Agrawal, P. C; Antia, H. M; Manchanda, R. K; Yadav, J. S; Seetha, S; Ramadevi, M. C; Rao, A. R; Bhattacharya, D; Paul, B; Sreekumar, P; Bhattacharyya, S; Stewart, G. C; Hutchings, J; Subramaniam, A; Ghosh, S. K; Murthy, J; Pati, A. K; Kameswara Rao, N; Stalin, C. S; Girish, V; Sankarasubramanian, K; Vadawale, S; Bhalerao, V. B; Dewangan, G. C; Dedhia, D. K; Hingar, M. K; Katoch, T. B; Kothare, A. T; Mirza, I; Mukerjee, K; Shah, H; Shah, P; Mohan, Rekhesh; Sangal, A. K; Nagabhusana, S; Sriram, S; Malkar, J. P; Sreekumar, S; Abbey, A. F; Hansford, G. M; Beardmore, A. P; Sharma, M. R; Murthy, S; Kulkarni, R; Meena, G; Babu, V. C; Postma, J (SPIE--The International Society for Optical Engineering, 2014-07)
    ASTROSAT is India’s first astronomy satellite that will carry an array of instruments capable of simultaneous observations in a broad range of wavelengths: from the visible, near ultraviolet (NUV), far-UV (FUV), soft X-rays ...
  • Coordinated TeV gamma-ray and optical polarization study of BL Lac object Mkn 501 
    Joshi, U. C; Baliyan, K. S; Ganesh, S; Deshpande, M. R; Bhattacharyya, S; Kaul, R. K; Kaul, C. L; Bhat, C. L (Astronomical Society of India, 2000)
    Coordinated TeV gamma-ray and optical polarization observations of the BL Lac object Mkn 501, carried out during 1997 with the TACTIC imaging Cerenkov telescope of the BARC and the 1.2 m Gurushikhar optical/IR telescope ...
  • Correlated X-ray timing and spectral behavior in GX 349+2 
    Agrawal, V. K; Bhattacharyya, S (The European Southern Observatory, 2003-01)
    We present a detailed and systematic investigation of correlated spectral and timing properties of the Z source GX 349+2, using extensive data ( ~ 221 ks) obtained from the Proportional-Counter-Array on-board RXTE satellite, ...
  • Development of a large-area, wide-angle Cerenkov radiation detector for the MYSTIQUE gamma-ray telescope 
    Dhar, V. K; Yadav, K. K; Bhattacharyya, S; Kaul, R. K; Bhat, C. L; Koul, R; Kaul, S. R; Kaul, S. K (Astronomical Society of India, 1999)
    An ultra-sensitive, multi-detector gamma-ray telescope array is being setup at Mt. Abu for cosmic gamma-ray studies in the tens of TeV energy region. Here, we present the essential design features of the Cerenkov radiation ...
  • The Effect of Non-thermal Protons on the High Energy Spectra of Black Hole Binaries 
    Bhattacharyya, S; Bhatt, N; Misra, R; Kaul, C. L (Astronomical Society of India, 2003)
    We investigate here the effect on the emitted spectrum of a black hole binary due to the presence of accelerated protons in the inner region of the accretion disk. Our study shows that e-e+ pairs and high energy -rays ...
  • Emission line star catalogues post-Gaia DR3: A validation of Gaia DR3 data using the LAMOST OBA emission catalogue 
    Shridharan, B; Mathew, B; Bhattacharyya, S; Robin, T; Arun, R; Kartha, S. S; Manoj, P; Nidhi, S; Maheswar, G; Paul, K. T; Narang, M; Himanshu, T (EDP Sciences, 2022-12)
    Aims. Gaia Data Release 3 (DR3) and further releases have the potential to identify and categorise new emission-line stars in the Galaxy. We perform a comprehensive validation of astrophysical parameters from Gaia DR3 ...
  • Energy Sensitive Search for Pulsed Photons from Crab Pulsar using the TACTIC Imaging Element 
    Rannot, R. C; Yadav, K. K; Dhar, V. K; Tickoo, A. K; Bhatt, N; Bhattacharyya, S; Chandra, P; Goyal, H. C; Kaul, C. L; Kaul, R. K; Kothari, M; Kotwal, S; Koul, R; Sahayanathan, S; Sapru, M. L; Sharma, M; Venugopal, K; Bhat, C. L (Astronomical Society of India, 2003)
    The Imaging Element (IE) of the 4-element TACTIC array of atmospheric Cherenkov telescopes is in operation at Mt. Abu Rajasthan, in Western India. We have successfully detected a steady signal from the Crab Nebula at a ...
  • General relativistic spectra of accretion discs around rapidly rotating neutron stars: effect of light bending 
    Bhattacharyya, S; Bhattacharya, D; Thampan, A. V (Royal Astronomical Society, 2001-08)
    We present computed spectra, as seen by a distant observer, from the accretion disc around a rapidly rotating neutron star. Our calculations are carried out in a fully general relativistic framework, with an exact treatment ...
  • General Relativistic Spectra of Accretion Disks around Rotating Neutron Stars 
    Bhattacharyya, S; Misra, R; Thampan, A. V (The American Astronomical Society, 2001-04)
    General relativistic spectra from accretion disks around rotating neutron stars in the appropriate spacetime geometry for several different equations of state, spin rates, and masses of the compact object have been computed. ...
  • Large-Area Wide Angle (LAWA) cerenkov detector for MYSTIQUE array 
    Kamath, K; Bhattacharyya, S; Dhar, V. K; Darzi, M. A; Kaul, S. R; Kaul, R. K; Koul, R; Sahayanathan, S; Tickoo, A. K; Wani, A. M; Bhat, C. L (Astronomical Society of India, 2002)
    An ultra-sensitive, multidetector wide angle atmospheric Cerenkov telescope array is being set up at Mt. Abu for cosnic gamma-ray studies in tens of TeV energy region. The design features of the Cerenkov light detector, ...
  • Limits to the Mass and the Radius of the Compact Star in SAX J1808.4-3658 and Their Implications 
    Bhattacharyya, S (American Astronomical Society, 2001-06)
    We show that a survey of equations of state and observations of X-ray pulsations from SAX J1808.4-3658 give 2.27 Msolar as the upper limit of the compact star mass. The corresponding upper limit of the radius comes out to ...
  • Multiwavelength study of different flaring and low-activity states of blazar 4C+21.35 
    Bhattacharya, D; Krishna Mohana, A; Bhattacharyya, S; Bhatt, N; Stalin, C. S (Oxford University Press on behalf of the Royal Astronomical Society, 2021-01)
    Blazars, a class of active galactic nuclei, emit over the entire accessible electromagnetic spectrum and modelling of their broad-band spectral energy distribution (SED) is the key to constrain the underlying emission ...
  • Neutron star physics in the square kilometre array era: an Indian perspective 
    Konar, S; Bagchi, Manjari; Bandyopadhyay, Debades; Banik, Sarmistha; Bhattacharya, D; Bhattacharyya, S; Gangadhara, R. T; Gopakumar, A; Gupta, Y; Joshi, B. C; Maan, Yogesh; Maitra, Chandreyee; Mukherjee, D; Pai, Archana; Paul, B; Ray, A; Sutaria, F. K (Indian Academy of Sciences, 2016-12)
    It is an exceptionally opportune time for astrophysics when a number of next-generation mega-instruments are poised to observe the Universe across the entire electromagnetic spectrum with unprecedented data quality. The ...
  • Optical spectroscopy of Galactic field classical Be stars 
    Banerjee, G; Mathew, B; Paul, K. T; Subramaniam, A; Bhattacharyya, S; Anusha, R (Oxford University Press on behalf of the Royal Astronomical Society, 2021-01)
    In this study, we analyse the emission lines of different species present in 118 Galactic field classical Be stars in the wavelength range of 3800–9000 Å. We re-estimated the extinction parameter (AV) for our sample stars ...
  • Recent observations of lES2344+514 and PSR 0355+54 with TACTIC Imaging Element 
    Tickoo, A. K; Dhar, V. K; Yadav, K. K; Rannot, R. C; Bhattacharyya, S; Chandra, P; Goyal, H. C; Kaul, C. L; Kaul, R. K; Kothari, M; Kotwal, S; Koul, R; Sahayanathan, S; Sapru, M. L; Sharma, M; Venugopal, K; Bhatt, N; Bhatt, C. L (Astronomical Society of India, 2002-09)
    The TACTIC Imaging Element has observed the active galaxy 1ES 2344+514 and the pulsar PSR 0355+54 during Oct-Nov, 2001. Analysis of the recorded events, collected for a period of 70 hours on both these sources reveals ...
  • Search for pulsed Te V gamma- rays from Crab pulsar with the TACTIC Imaging gamma-ray Telescope 
    Rannot, R. C; Yadav, K. K; Dhar, V. K; Tickoo, A. K; Bhatt, N; Bhattacharyya, S; Chandra, P; Goyal, H. C; Kaul, C. L; Kaul, R. K; Kothari, M; Kotwal, S; Koul, R; Sahayanathan, S; Sapru, M. L; Sharma, M; Venugopal, K; Bhat, C. L (Astronomical Society of India, 2002-09)
    The TACTIC Imaging Element has observed Crab Nebula/pulsar for a total. of about 40 hours during Jan.- Mar. 2001. Preliminary results do not show any evidence of the 33 ms pulsations from the pulsar direction at an energy ...
  • A study of accretion discs around rapidly rotating neutron stars in general relativity and its applications to four low mass X-ray binaries 
    Bhattacharyya, S (E D P Sciences, 2002-02)
    We calculate the accretion disc temperature profiles, disc luminosities and boundary layer luminosities for rapidly rotating neutron stars considering the full effect of general relativity. We compare the theoretical values ...
  • Temperature profiles of accretion discs around rapidly rotating strange stars in general relativity: A comparison with neutron stars 
    Bhattacharyya, S; Thampan, A. V; Bombaci, I (EDP Sciences, 2001-06)
    We compute the temperature profiles of accretion discs around rapidly rotating strange stars, using constant gravitational mass equilibrium sequences of these objects, considering the full effect of general relativity. ...
  • Temperature Profiles of Accretion Disks around Rapidly Rotating Neutron Stars in General Relativity and the Implications for Cygnus X-2 
    Bhattacharyya, S; Thampan, A. V; Misra, R; Datta, B (The American Astronomical Society, 2000-10)
    We calculate the temperature profiles of (thin) accretion disks around rapidly rotating neutron stars (with low surface magnetic fields), taking into account the full effects of general relativity. We then consider a model ...

Search DSpace

Browse

My Account