IIA Institutional Repository: Recent submissions

  • Radio observations of a coronal mass ejection induced depletion in the outer solar corona 
    Ramesh, R; Sastry, Ch. V (European Southern Observatory, 2000-06)
    We report the first low frequency radio observations of a depletion that occurred in the outer solar corona in the aftermath of the CME event of 1986 June 5, with the large E-W one dimensional grating interferometer at the ...
  • Line formation in the Atmosphere of brown dwarf Gliese 229B : CH_4 at 2.3 mu m 
    Sengupta, S; Krishan, V (European Southern Observatory, 2000-06)
    We investigate the formation of methane line at 2.3 μm in Brown Dwarf Gliese 229B. Two sets of model parameters with (a) T_eff=940 K and log (g) =5.0, (b) T_eff=1030 K and log (g)=5.5 are adopted both of which provide ...
  • Origin of quantum-mechanical complementarity without momentum back action in atom-interferometry experiments 
    Unnikrishnan, C. S (The American Physical Society, 2000-07)
    We identify the physical origin of the loss of interference pattern in the which-path atom-interferometery experiments that have been discussed widely. The origin of complementarity between the which-path information and ...
  • Chemical composition of HD 179821 (IRAS 19114+0002) 
    Thévenin, F; Parthasarathy, M; Jasniewicz, G (European Southern Observatory, 2000-07)
    A LTE analysis of medium resolution spectra of HD 179821 has been made. Derived atmospheric parameters of HD 179821 are K, and [Fe/H]=-0.5. The position of the star in the H-R diagram, its high radial velocity (Vr=100 ...
  • Possible signatures for strange stars in stellar X-ray binaries 
    Datta, B; Thampan, A. V; Bombaci, I (European Southern Observatory, 2000-03)
    Kilohertz quasi-periodic brightness oscillations (kHz QPOs) observed in certain X-ray burst sources may represent Keplerian frequencies in the inner regions of the accretion disk in such systems. If this assumption is ...
  • New limits on the gravitational Majorana screening from the Zürich G experiment 
    Unnikrishnan, C. S; Gillies, G. T (The American Physical Society, 2000-05)
    We analyze the results from an experiment being conducted at the Physik-Institut, Universität Zürich to measure the gravitational constant, and obtain a tight constraint on the Majorana gravitational shielding factor. The ...
  • Optical Variability of Blazars 
    Ghosh, K. K; Ramsey, B. D; Sadun, A. C; Soundararajaperumal, S (The American Astronomical Society, 2000-03)
    In this paper we show the results of our monitoring the flux variability of 15 blazars, within the redshift range of 0.07-2.06, all with a visual magnitude range between 14 and 20 mag. Because blazars have displayed ...
  • Binary pulsar PSR B1913+16 constrains the electron-proton charge asymmetry 
    Sengupta, S (Elsevier, 2000-07)
    A binary stellar system loses its orbital rotational energy by the emission of gravity wave. If there exists a charge asymmetry between electron and proton then the system would also lose its orbital rotational energy due ...
  • Some Further Effects of Discrete Scale Transformations 
    Sivaram, C (Springer, 2000-05)
    Some further consequences of the notion of discrete scale transformations invoked earlier to suggest strong links between fundamental interactions and cosmology are developed.
  • Oscillations In Galaxies 
    Namboodiri, P. M. S (Springer, 2000-02)
    Oscillations in galaxies have been investigated by numerical simulations. The various models used have density distributions corresponding to that of polytrope of index n in the range 0 ≤ n ≤ 4 and their evolution has been ...
  • Abundance evolution of intermediate mass elements (C to Zn) in the Milky Way halo and disk 
    Goswami, A; Prantzos, N (European Southern Observatory, 2000-07)
    We present a comprehensive study of the evolution of the abundances of intermediate mass elements, from C to Zn, in the Milky Way halo and in the local disk. We use a consistent model to describe the evolution of those two ...
  • Distribution of Supergranular Sizes 
    Srikanth, R; Singh, J; Raju, K. P (The American Astronomical Society, 2000-05)
    A gradient-based method of tessellation was applied to SOHO Dopplergrams and to Ca II K filtergrams in order to study the cellular pattern of the solar surface, in specific the geometric relationship between the tessellation ...
  • Effects of nuclear structure on parity nonconservation in atomic cesium in relativistic mean field theory 
    Panda, P. K; Das, B. P (The American Physical Society, 2000-12)
    We use relativistic mean field theory, which includes scalar and vector mesons, to calculate the binding energy and charge radii in 125Cs-139Cs. We then evaluate the nuclear structure corrections to the weak charges for a ...
  • The Chemical Compositions of the SRD Variable Stars. III. KK Aquilae, AG Aurigae, Z Aurigae, W Leo Minoris, and WW Tauri 
    Giridhar, S; Lambert, D. L; Gonzalez, G (The Astronomical Society of the Pacific, 2000-12)
    Chemical compositions are derived from high-resolution spectra for five field SRd variables. These supergiants not previously analyzed are shown to be metal poor: KK Aql with [Fe/H]=-1.2, AG Aur with [Fe/H]=-1.8, Z Aur ...
  • Radiative Transfer Effects and the Dynamics of Small-Scale Magnetic Structures on the Sun 
    Rajaguru, S. P; Hasan, S. S (The American Astronomical Society, 2000-11)
    The dynamical consequences of radiative energy transport on the evolution of gas confined to small-scale magnetic structures on the Sun are studied. Convective collapse, which transforms weak-field structures into intense ...
  • Results from a revisit to the K2V bright points 
    Sivaraman, K. R; Gupta, S. S; Livingston, W. C; Damé, L; Kalkofen, W; Keller, C. U; Smartt, R; Hasan, S. S (European Southern Observatory, 2000-11)
    We have used pairs of temporally simultaneous CaII K-line spectroheliograms and magnetic area scans to search for spatial correlation between the CaII K2V bright points in the interior of the network and corresponding ...
  • Changing molecular gas properties in the bar and center of NGC 7479 
    Hüttemeister, S; Aalto, S; Das, M; Wall, W. F (European Southern Observatory, 2000-11)
    We present sensitive interferometric 12/supCO, 13/supCO and HCN observations of the barred spiral galaxy NGC 7479, one of the few barred galaxies known to have a continuous gas-filled bar. We focus on the investigation and ...
  • Ionization potentials of beryllium-like ions from the relativistic coupled-cluster-based linear response theory 
    Chaudhuri, R. K; Panda, P. K; Merlitz, H; Das, B. P; Mahapatra, U. S; Mukherjee, D (Institute of Physics, 2000-11)
    We first test our recently developed relativistic coupled-cluster-based linear response theory (RCCLRT) by computing the principal and the shake-up ionization potentials (IP) of highly stripped atoms. Comparison is made ...
  • Non-radial Oscillations in an Axisymmetric MHD Incompressible Fluid 
    Satya Narayanan, A (Indian Academy of Sciences, 2000-12)
    It is well known from Helioseismology that the Sun exhibits oscillations on a global scale, most of which are non_radial in nature. These oscillations help us to get a clear picture of the internal structure of the Sun as ...
  • High energy universe -- Satellite missions 
    Krishan, V (Indian Academy of Sciences, 2000-12)
    A variety of satellite missions to observe the high energy universe are currently operating and some more with more versatility and capability are on the anvil. In this paper, after giving a brief introduction to the ...

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