IIA Institutional Repository: Recent submissions

  • Solar flare effects on the geomagnetic elements during normal and counter electrojet periods 
    Rastogi, R. G; Pathan, B. M; Rao, D. R. K; Sastry, T. S; Sastri, J. H (Terra Scientific Publishers, 1999-09)
    During a strong and normal electrojet event time, sfeconsists of a positive impulse in Hat all stations, the amplitude of Hfollowing the latitudinal variation similar to that of the quiet day monthly mean, Sq(H). The sfein ...
  • On the existence of interfacial waves with inclined magnetic fields 
    Satya Narayanan, A (European Southern Observatory, 1997-08)
    The dispersive characteristics of interfacial waves in low β plasma is studied. The condition for the existence of these waves is derived. It is assumed that the magnetic field and the propagation vector are inclined at ...
  • Nighttime thermospheric meridional winds at Cachoeira Paulista (23°S, 45°W): Evidence for effects of the equatorial midnight pressure bulge 
    Batista, I. S; Sastri, J. H; de Medeiros, R. T; Abdu, M. A (American Geophysical Union, 1997-08)
    We have studied the local time and seasonal variations of thermospheric nighttime meridional winds at the low-latitude station, Cachoeira Paulista, Brazil, corresponding to quiet geomagnetic conditions of high solar activity ...
  • A comparison of synthetic and observed spectra for G-K dwarfs using artificial neural networks 
    Gulati, R. K; Gupta, R; Kameswara Rao, N (European Southern Observatory, 1997-06)
    A library of synthetic spectra, based on Kurucz model atmospheres, has been used to compare the spectroscopic observations in the wavelength range 4850-5384 Å by using statistical and supervised artificial neural network ...
  • An operator perturbation method for polarized line transfer. I. Non-magnetic regime in 1D media. 
    Faurobert-Scholl, M; Frisch, H; Nagendra, K. N (European Southern Observatory, 1997-06)
    In this paper we generalize an Approximate Lambda Iteration (ALI) technique developed for scalar transfer problems to a vectorial transfer problem for polarized radiation. Scalar ALI techniques are based on a suitable ...
  • Radiative neutrino decay in hot media 
    Nieves, J. F; Pal, P. B (The American Physical Society, 1997-07)
    We calculate the rate for the radiative neutrino decay in a thermal background of electrons and photons, taking into account the effect of the stimulated emission of photons in the thermal bath. We show that the rate is ...
  • Effect of Newtonian Cooling on Waves in a Magnetized Isothermal Atmosphere 
    Banerjee, D; Hasan, S. S; Christensen-Dalsgaard, J (Springer, 1997-05)
    We examine the influence of nonadiabatic effects on the modes of an isothermal stratified magnetic atmosphere. The present investigation is a continuation of earlier work by Hasan and Christensen-Dalsgaard (1992) and ...
  • Far-infrared and radio continuum properties of spiral galaxies in clusters 
    Rengarajan, T. N; Karnik, A. D; Iyengar, K. V. K (The Royal Astronomical Society, 1997-09)
    Data on the far-infrared (FIR) and radio continuum properties of spiral galaxies in several clusters have been collected from the literature. To assess the effect of the cluster environment on the FIR and radio continuum ...
  • Elemental Abundances and Atmospheric Parameters of Seven F-G Supergiants 
    Giridhar, S; Ferro, A; Parrao, L (Astronomical Society of the Pacific, 1997-10)
    Spectroscopic abundance determinations for a sample of seven F-G stars have been carried out. The majority of them have large galactic latitudes. One objective in deriving spectroscopic abundances is to differentiate evolved ...
  • Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. X. Variability of Fairall 9 from Optical Data 
    Santos-Lleo, M; Chatzichristou, E; de Oliveira, C. M; Winge, C; Alloin, D; Peterson, B. M; Rodriguez-Pascual, P. M; Stirpe, G. M; Beers, T; Bragaglia, A; Claeskens, J. F; Federspiel, M; Giannuzzo, E; Gregorio-Hetem, J; Mathys, G; Salamanca, I; Stein, P; Stenholm, B; Wilhelm, R; Zanin, C; Albrecht, P; Calderon, J; Caretta, C. A; Carranza, G; da Costa, R. D. D; Diaz, R; Dietrich, M; Dottori, H; Elizalde, F; Goldes, G; Ghosh, K. K; Maia, M. A. G; Paolantonio, S; de Oliveira Filho, R. I; Rodriguez-Ardila, A; Schmitt, H. R; Soundararajaperumal, S; de Souza, R. E; Willmer, C. N. A; Zheng, W (American Astronomical Society, 1997-10)
    The results of an optical monitoring campaign on the active nucleus in the luminous Seyfert 1 galaxy Fairall 9 are presented. This campaign was undertaken in parallel with ultraviolet spectroscopic monitoring with the IUE ...
  • Lithium abundance and mass 
    Mallik, S. G. V (The European Southern Observatory, 1999-12)
    Observations of cool giants have shown that there exists a large range in their lithium abundances even for apparently similar stars. The depletions are large in a majority of them, far in excess of the predictions of the ...
  • On the hydrogen-deficient nature of Z Ursae Minoris 
    Goswami, A; Kameswara Rao, N; Lambert, D. L; Gonzalez, G (The Astronomical Society of the Pacific, 1997-05)
    Z Ursa Minoris was classified by Benson et al. (1994) a a R Coronae Borealis (RCB) variable star from its light variations. Hydrogen deficiency, which is a defining feature of RCB stars, was not established. To investigate ...
  • Computation of correlation effects on the parity-nonconserving electric-dipole transition in atomic ytterbium 
    Das, B. P (The American Physical Society, 1997-08)
    A high-precision experiment to measure parity-nonconservation in atomic Yb has been proposed recently [D. De Mille, Phys. Rev. Lett. 74, 4165 (1995)]. We use a relativistic configuration-interaction approach to highlight ...
  • Fast Plasma Processes in Active Galactic Nuclei 
    Krishan, V (Springer, 1997-05)
    The physics of active galactic nuclei (AGN) and related objects is one of the most actively pursued areas in astrophysics. Their large luminosities over the entire electromagnetic spectrum combined with extremely short-time ...
  • Rotation curves of galaxies: missing mass or missing physics 
    Krishan, V (Indian Academy of Science, 1997-07)
    The rotation curves of galaxies are modelled using very special properties of an hydrodynamically turbulent fluid possessing helicity fluctuations. The development of correlations among these fluctuations leads to the ...
  • A multiwavelength study of LS II+34 26: a hot post-AGB star in the process of becoming a planetary nebula 
    Garcia-Lario, P; Parthasarathy, M; de Martino, D; Sanz Fernandez de Cordoba, L; Monier, R; Manchado, A; Pottasch, S. R (European Southern Observatory, 1997-10)
    We present the results from a multiwavelength analysis of LS II+34 26, recently identified as a low mass post-AGB star and not a massive population I B-type star, as previously thought. We confirm that the central star is ...
  • Optical Spectra of Recent Supernovae of Type Ia: SN1995AL, SN1997Y, SN 1997BP 
    Anupama, G. C (American Astronomical Society, 1997-11)
    Optical spectra of three recent supernovae of type Ia: SN1995al in NGC 3021, SN1997Y in NGC 4675, and SN 1997bp in NGC 4680 are presented. Comparing the spectra with those of other normal type a supernovae, the epoch since ...
  • IRAS 17395-0841: A New Young Low Excitation Planetary Nebula 
    Vijapurkar, J; Drilling, J. S; Parthasarathy, M (American Astronomical Society, 1997-10)
    We report here the discovery of a new young low excitation planetary nebula IRAS 17395-0841.
  • The ultraviolet variations of the post-AGB star HD 89353 
    Monier, R; Parthasarathy, M (The European Southern Observatory, 1999-01)
    Based on an analysis of all low resolution spectra of HD 89353 (HR 4049) obtained with the International Ultraviolet Explorer (IUE) over several years and uniformly reprocessed, we report on large ultraviolet variations ...
  • Observations of BN and AN stars: New Be stars 
    Ghosh, K. K; Apparao, K. M. V; Pukalenthi, S (The European Southern Observatory, 1999-01)
    From a survey of spectra of Bn/An stars, we have detected seven new Be stars: HR 1056 (A0Vn), 1544 (A1Vn), 2191 (A0Vnn), 2300 (B8Vn), 3134 (B9.5 Vn), 3878 (B0.5 IIIn) and 4552 (B9IIIpSi). H_alpha profiles of these stars ...

Search DSpace

Browse

My Account