IIA Institutional Repository

Browsing by Author "Bhattacharjee, P"

Browsing by Author "Bhattacharjee, P"

Sort by: Order: Results:

  • A common origin of the highest energy cosmic rays and baryon asymmetry of the universe? 
    Bhattacharjee, P (Tata Institute of Fundamental Research, 2005)
  • Constraints on dark matter models from the observation of Triangulum-II with the Fermi Large Area Telescope 
    Biswas, Sayan; Bhattacharjee, P; Majumdar, P; Das, Subinoy; Mousumi Das; Joarder, P. S (IOP Publishing, 2017-11)
    Triangulum-II, a newly discovered dwarf spheroidal galaxy, is a strong candidate for the indirect search of dark matter through the detection of γ -ray emission that could originate from the pair- annihilation ...
  • Cosmic rays from cosmic strings and other topological defects 
    Bhattacharjee, P (World Scientific, 1995)
    The model of origin of ultrahigh energy (UHE) (i.e., energy E~> 10sup/8 eV) cosmic rays from cosmic topological defects such as cosmic strings, magnetic monopoles, etc., is discussed. We discuss the general nature of the ...
  • Cosmic relics from the microsecond epoch 
    Bhattacharjee, P (Saha Institute of Nuclear Physics, 1995)
    "A phase transition from quark-gluon plasma to hadronic matter may have ocurred in the early universe when the universe was about 10 ~sec old and the temperature was about 100-200 MeV. Is there any relic from that microsecond ...
  • Cosmic Topological Defects, Highest Energy Cosmic Rays, and the Baryon Asymmetry of the Universe 
    Bhattacharjee, P (The American Physical Society, 1998-07)
    It is pointed out that the observed extremely high energy cosmic rays (EHECR) above 1011 GeV and the observed baryon asymmetry of the Universe (BAU) may have a common origin in baryon number violating decays of supermassive ...
  • Cosmological QCD phase transition and dark matter 
    Bhattacharyya, A; Alam, J; Sarkar, S; Roy, P; Sinha, B; Raha, S; Bhattacharjee, P (Elsevier, 1999-12)
    The authors calculate the size distribution of quark nuggets, which could be formed due to first order QCD phase transition in the early universe. They find that there are a large number of stable quark nuggets which could ...
  • Data analysis method for the search of point sources of gamma rays with the HAGAR telescope array 
    Britto, R. J; Acharya, B. S; Anupama, G. C; Bhattacharjee, P; Chitnis, V. R; Cowsik, R; Dorji, N; Duhan, S. K; Gothe, K. S; Kamath, P. U; Mahesh, P. K; Manoharan, J; Nagesh, B. K; 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 (French Society of Astronomy and Astrophysics, 2011-12)
    The High Altitude GAmma-Ray (HAGAR) experiment is the highest altitude atmospheric Cherenkov sampling array, set up at 4300 m amsl in the Himalayas (Northern India). It constitutes 7 telescopes, each one with seven 90 ...
  • Detection of dark matter in the galactic halo 
    Bhattacharjee, P (Indian Academy of Sciences, 1994-02)
  • Dispersion Velocity of Galactic Dark Matter Particles 
    Cowsik, R; Ratnam, C; Bhattacharjee, P (The American Physical Society, 1996-05)
    The self-consistent spatial distribution of particles of galactic dark matter is derived including their own gravitational potential, as also of that of the visible matter of the Galaxy. In order to reproduce the observed ...
  • Dispersion velocity of Galactic dark matter particles- Reply 
    Cowsik, R; Ratnam, C; Bhattacharjee, P (The American Physical Society, 1997-03)
    A Reply to the Comment by N. W. Evans. Also, Evalyn Gates, Marc Kamionkowski, and Michael S. Turner.
  • Dynamics of dwarf-spheroidals and the dark matter halo of the galaxy 
    Cowsik, R; Ratnam, C; Bhattacharjee, P; Majumdar, S (Elsevier B. V., 2007-08)
    The dynamics of the dwarf-spheroidal (dSph) galaxies in the gravitational field of the Galaxy is investigated with particular reference to their susceptibility to tidal break-up. Based on the observed paucity of the dSphs ...
  • Extreme-energy cosmic rays: hints to new physics beyond the standard model? 
    Bhattacharjee, P; Sigl, G (Springer, 2001)
    The observed extreme energy cosmic ray (EECR) events above 10(20) eV are difficult to explain within tile standard scenario of origin of cosmic rays in which charged particles are accelerated in magnetized shocks in powerful ...
  • A Gap in the Highest Energy Cosmic Ray Spectrum as a Signature of Unification Scale Physics 
    Sigl, G; Lee, S; Schramm, D. N; Bhattacharjee, P (American Association for the Advancement of Science, 1995-12)
    Recent experimental data seem to indicate that there is significant structure in the cosmic ray spectrum above 1018 electron volts (eV). Besides a dip at ~5 x 1018 eV, two events above 2 x 1020 eV have been observed. The ...
  • Injection spectrum of ultrahigh energy cosmic rays in the top-down scenario 
    Basu, R; Bhattacharjee, P (The American Physical Society, 2004-07)
    We analyze the uncertainties involved in obtaining the injection spectra of UHECR particles in the top-down scenario of their origin. We show that the Dokshizer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) Q/Sup2 evolution 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 ...
  • Monopole annihilation and highest energy cosmic rays 
    Bhattacharjee, P; Sigl, G (The American Physical Society, 1995-04)
    Cosmic rays with energies exceeding 1020 eV have been detected. The origin of these highest energy cosmic rays remains unknown. Established astrophysical acceleration mechanisms encounter severe difficulties in accelerating ...
  • 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 analysis of low surface brightness galaxies to study possible dark matter signature 
    Bhattacharjee, P; Majumdar, P; Mousumi Das; Das, Subinoy; Joarder, P. S; Biswas, Sayan (Oxford University Press on behalf of the Royal Astronomical Society, 2021-03)
    Low surface brightness (LSB) galaxies have very diffuse, low surface density stellar discs that appear faint in optical images. They are very rich in neutral hydrogen (H I) gas, which extends well beyond the stellar discs. ...
  • 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 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 ...

Search DSpace

Browse

My Account