IIAP Publications: Recent submissions

  • On the Weakening of the Chromospheric Magnetic Field in Active Regions 
    Nagaraju, K; Sankarasubramanian, K; Rangarajan, K. E (The American Astronomical Society, 2008-05)
    Simultaneous measurement of line-of-sight (LOS) magnetic and velocity fields at the photosphere and chromosphere are presented. The Fe i line at λ6569 and Hα at λ6563 are used for deriving the physical parameters at ...
  • RACE-OC project: rotation and variability in the open cluster NGC 2099 (M 37) 
    Messina, S; Distefano, E; Parihar, P. S; Kang, Y. B; Kim, S. -L; Rey, S. -C; Lee, C. -U (EDP Sciences, 2008-05)
    Context. Rotation and solar-type magnetic activity are closely related to each other in main-sequence stars of G or later spectral types. The presence and level of magnetic activity depend on star's rotation, and rotation ...
  • Crustal stress patterns: Analysis of Ps splitting for seismic anisotropy 
    Rai, Abhishek; Rai, S. S; Gaur, V. K (Indian Academy of Sciences, 2008-04)
  • Relativistic unitary coupled cluster theory and applications 
    Sur, C; Chaudhuri, R. K; Sahoo, B. K; Das, B. P; Mukherjee, D (Institute of Physics, 2008-03)
    We present the formulation and application of relativistic unitary coupled cluster theory to atomic properties. The remarkable features of this theory are highlighted, and it is used to calculate the lifetimes of 5d2D3/2 ...
  • Recent onset of an outburst in mu centauri 
    Ghosh, K. K; Velu, C; Kuppuswamy, K; Jaykumar, K; Rosario, M. J (Konkoly Observatory, 1987-08)
  • X-ray observations of the Seyfert 1 galaxy MCG 2-58-22 
    Ghosh, K. K; Soundararajaperumal, S (University of Chicago Press, 1992-10)
    Results of the detailed X-ray (0.1-10 keV) spectral analysis of the Seyfert 1 galaxy, MGC 2-58-22, are presented based on the Exosat observations on 1984 November 16-26. X-ray spectra of this source were obtained from the ...
  • X-ray spectra of Seyfert galaxies 
    Ghosh, K. K; Soundararajaperumal, S (Blackwell Publishing, 1992-11)
    A spectra analysis of eight Seyfert galaxies shows that while seven have soft excesses in their spectra, with no low-energy absorption, ESO 140-G43 exhibits low energy absorption, and may have weak soft excess that is ...
  • On the role of reverse current on the hard X-ray production in solar flares and time-lags between high- and low-energy photons 
    Bakaya, R; Chasti, S. A; Rausaria, R. R (Springer Netherlands, 1992-09)
    The evolution of energy and angular distributions of electrons has been studied accounting for the reverse current effect by combining analytically treated small angle multiple scatterings with large angle Monte-Carlo ...
  • On the triggering of a spotless double-ribbon flare 
    Rausaria, R. R; Aleem, S. M; Sundararaman, K (Springer Netherlands, 1992-11)
    We have studied the evolution of the double-ribbon, spotless flare of 21 February, 1992, using Kodaikanal Hagr and Kf1 observations. The analysis of the data shows that the Hagr filament underwent a large change in shear ...
  • First X-ray spectrum of the most luminous quasar PKS 2126 - 158 
    Ghosh, K. K; Soundararajaperumal, S (EDP Sciences, 1992-11)
    For the first time the detailed results of the spectral analysis of the X-ray (0.1 - 10 keV) spectrum of the luminous radio-loud quasar PKS 2126 - 158 are presented. Power law and fixed absorption model fits well with the ...
  • Possible young stellar objects in the region of the Cygnus OB2 (VI Cygni) association from IRAS observations 
    Parthasarathy, M; Jain, S. K; Bhatt, H. C (EDP Sciences, 1992-12)
    Several massive young stellar objects are found from an analysis of the 12- to 100-micron flux data of IRAS sources in the region of the Cyg OB2 association. Sixty-four sources with positive spectral indices and steeply ...
  • Pressure structure of solar coronal loops. III 
    Sreedharan, T. D; Sasidharan, K; Satya Narayanan, A; Krishan, V (Springer Netherlands, 1992-12)
    The theory of ideal magnetohydrodynamic turbulence in cylindrical geometry is used to study the steady-state structure of a coronal loop. The pressure profile is derived from MHD equations by representing the velocity and ...
  • High Resolution Spectroscopy of the Semi-Regular Variable LR Sco 
    Giridhar, S; Kameswara Rao, N; Lambert, D. L (Indian Academy of Sciences, 1992)
    A detailed spectroscopic investigation of LR Sco which was earlier misclassified as R CrB star is made. Atmospheric parameters and elemental abundances are determined using detailed depth-dependent model atmospheres and ...
  • VRI Photometry of M67 for CCD Standardization at 2.3m VBT 
    Bhat, P. N; Singh, K. P; Prabhu, T. P; Kembhavi, A. K (Indian Academy of Sciences, 1992)
    We present the results from CCD photometry in the V, R and I bands, of the ‘Dipper Asterism’ region of the open cluster Μ67 based on observations carried out at the prime focus of the 2.3 m Vainu Bappu Telescope of the ...
  • B-L cosmic strings and baryogenesis 
    Bhattacharjee, P; Sahu, N; Yajnik, U.A (American Physical Society, 2004-10)
    Cosmic strings arising from breaking of the $U(1)_{B-L}$ gauge symmetry that occurs in a wide variety of unified models can carry zero modes of heavy Majorana neutrinos. Decaying and/or repeatedly self-interacting closed ...
  • Enhanced role of electron correlation in the hyperfine interactions in D5/22 states in alkaline-earth-metal ions 
    Sahoo, B. K; Sur, C; Beier, T; Das, B. P; Chaudhuri, R. K; Mukherjee, D (The American Physical Society, 2007-04)
    The low-lying n(=3,4,5)d 2D5/2 states of alkaline-earth-metal ions are of vital importance in a number of different physical applications. The hyperfine structure constants of these states are characterized by unusually ...
  • 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 ...
  • Age Sequence in Small Clusters Associated with Bright-Rimmed Clouds 
    Ogura, K; Chauhan, N; Pandey, A. K; Bhatt, B. C; Ojha, D; Itoh, Y (Astronomical Society of Japan, 2007-02)
    Bright-rimmed clouds (BRCs) found in HII regions are probable sites of triggered star formation due to compression by ionization/shock fronts, and it is hypothesized that star formation proceeds from the exciting star(s) ...
  • Measurement of Kodaikanal White-Light Images: Relaxation of Tilts of Spot Groups as Indicator of Subsurface Dynamics of Parent Flux Loops 
    Sivaraman, K. R; Gokhale, M. H; Sivaraman, H; Gupta, S. S; Howard, R. F (The American Astronomical Society, 2007-03)
    We reexamine the evolution of the observed tilts θ of spot groups with life spans 2–7 days in the two latitude belts <13° and >13°. Using an iterative procedure, we refine the linear fit between θ and the daily tilt angle ...
  • Investigations of the Morphology of Dust Shells of Comet C/2001 Q4 (NEAT) 
    Vasundhara, R; Chakraborty, P; Muneer, S; Masi, G; Rondi, S (The American Astronomical Society, 2007-02)
    The morphology of the dust fans and shells in the images of comet C/2001 Q4 (NEAT) showed significant changes between 2004 April and June due to rapid changes in the Earth viewing and solar illumination geometry. We model ...

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