IIA Institutional Repository: Recent submissions

  • Scattering of light by a periodic structure in the presence of randomness VII: Application of statistical detection test 
    Vani, V. C; Chatterjee, S (Indian Academy of Sciences, 2008-05)
    Detection of periodic structures, hidden in random surfaces has been addressed by us for some time and the `extended matched filter' method, developed by us, has been shown to be effective in detecting the ...
  • The Evolution of the Peculiar Type Ia Supernova SN 2005hk over 400 Days 
    Sahu, D. K; Tanaka, M; Anupama, G. C; Kawabata, K. S; Maeda, K; Tominaga, N; Nomoto, K; Mazzali, P. A; Prabhu, T. P (The American Astronomical Society, 2008-06-10)
    UBVRI photometry and medium-resolution optical spectroscopy of the peculiar Type Ia supernova SN 2005hk are presented and analyzed, covering the premaximum phase to around 400 days after explosion. The supernova is found ...
  • Stellar contents and star formation in the young open cluster Stock 8 
    Jose, J; Pandey, A. K; Ojha, D. K; Ogura, K; Chen, W. P; Bhatt, B. C; Ghosh, S. K; Mito, H; Maheswar, G; Sharma, S (Blackwell Publishing, 2008-03)
    We present UBVIc CCD photometry of the young open cluster Stock 8 with the aim of studying its basic properties such as the amount of interstellar extinction, distance, age, stellar contents and initial mass function (IMF). ...
  • Clustering of Galaxies by the Alpha-Effect 
    Krishan, V (Royal Astronomical Society, 1993-09-01)
    The development of large-scale flows from the stresses generated by small-scale flows in a Navier-Stokes system is studied in order to model the large-scale structure of the Universe. This process is an analogue of the ...
  • Polarization Maps for the Dark Clouds B:227 and L:121 
    Bhatt, H. C; Jain, S. K (European Southern Observatory, 1993-09)
    Optical linear polarization measurements for stars in the regions of the molecular clouds B 227 and L 121 are presented. The magnetic field geometry in the clouds as indicated by the polarization maps is discussed in ...
  • BV Photometry and Hα Spectroscopy of the Rs-Canum Binary II-Pegasi 
    Mohin, S; Raveendran, A. V (European Southern Observatory, 1993-09)
    Differential BV photometry of II Peg obtained on a total of 57 nights during the years 1986-1991 and Hα spectroscopy obtained on 12 nights during the 1990-1991 observing season are presented. From an analysis of the available ...
  • Polarization Changes of Radiation through Stimulated Raman Scattering 
    Gangadhara, R. T; Krishan, V (The American Astronomical Society, 1993-10)
    We study change in the polarization of electromagnetic waves due to the stimulated Raman scattering in a plasma. In this process an electromagnetic wave undergoes coherent scattering off an electron plasma wave. It is found ...
  • Nebular emission lines in IRAS 10215-5916 
    Garcia-Lario, P; Manchado, A; Parthasarathy, M; Pottasch, S. R (European Southern Observatory, 1994-05)
    From low and high resolution spectroscopic observations of IRAS 10215-5916 we have discovered the presence of nebular emission lines in this G-type supergiant star in the post-AGB stage. From its high resolution spectrum ...
  • Star Formation in Giant Extragalactic H II Regions 
    Mayya, Y. Divakara (Astronomical Society of the Pacific, 1994-04)
    Star formation properties in Giant Extragalactic H II Regions (GEHRs) are investigated using optical photometry and evolutionary population synthesis models. Photometric data in $BVR$ bands and in the emission line of ...
  • The R Coronae Borealis stars - A few mere facts 
    Lambert, D. L; Kameswara Rao, N (Indian Academy of Sciences, 1994-03)
    This review presents a selection of recent highlights of observations of R Coronae Borealis (RCB) variables. Emphasis is placed on an abundance analysis of a complete sample (18 stars) of the warm galactic RCBs. It is shown ...
  • High speed photometry of PG 1012-029 
    Ashoka, B. N; Seetha, S; Marar, T. M. K; Kasturirangan, K; Rao, U. R; Bhattacharyya, J. C (European Southern Observatory, 1994-03)
    High speed optical photometric observations of PG 1012 - 029, conducted during 1990-1991, confirm the nova-like classification of the object. Several eclipses observed by us have been used to refine the orbital period of ...
  • Rapid searches for counterparts of GRB 930131 
    Schaefer, Bradley. E; Barthelmy, Scott. D; Palmer, David. M; Cline, Thomas. L; Hurley, Kevin. C; Sommer, Michael; Boer, Michel; Niel, Michel; Fishman, Gerald. J; Kouveliotou, Chryssa; Meegan, Charles. A; Coe, M. J; Elmegreen, Bruce. G; McNamara, Bernard. J; Harrison, Thomas; Owens, Alan; Sollee, Neyle; Stull, John; Palermiti, Michael; Schwartz, Richard; Brooks, Jack; Vanderspek, Roland; Ricker, George. R; Krimm, Hans. A; Wenzel, Wolfgang; Greiner, Jochen; Hudec, Rene; Novak, Miroslav; Borovicka, Jiri; Predota, Miroslav; Bailyn, Charles. D; Hanlon, Lorraine. O; Bennett, K; Spoelstra, Titus. A. Th; Smette, Alain; Pedersen, Holger; Florentin, Ralph; Pollas, Christian; Steinle, Helmut; Schramm, K. J; Iyengar, K. V. K; Prabhu, T. P (American Astronomical Society, 1994-02)
    A fading counterpart to a gamma-ray burst (GRB) would appear as a point source inside a GRB error region soon after the burst which dims on a timescale from minutes to days. The favorable circumstances of the burst GRB ...
  • Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. 6: Variability of NGC 3783 from ground-based data 
    Stirpe, G. M; Winge, C; Altieri, B; Alloin, D; Aguero, E. L; Anupama, G. C; Ashley, R; Bertram, R; Calderon, J. H; Catchpole, R. M; Corradi, R. L. M; Covino, E; Dottori, H. A; Feast, M. W; Ghosh, K. K; Hutton, R. Gil; Glass, I. S; Grebel, E. K; Jorda, L; Koen, C; Laney, C. D; Maia, M; Marang, F; Mayya, Y. D; Morrell, N; Nakada, Y; Pastoriza, M. G; Pati, A. K; Pelat, D; Peterson, B. M; Prabhu, T. P; Roberts, G; Sagar, R; Salamanca, I; Sekiguchi, K; Storchi-Bergmann, T; Subramaniam, A; Van Winckel, H; Van Wyk, F; Villada, M; Wagner, R. M; Whitelock, P. A; Winkler, H; Clavel, J; Dietrich, M; Kollatschny, W; O'Brien, P. T; Perola, G. C; Recondo-Gonzalez, M. C; Rodriguez-Pascual, P; Santos-Lleo, M (The American Astronomical Society, 1994-04)
    The Seyfert 1 galaxy NGC 3783 was intensely monitored in several bands between 1991 December and 1992 August. This paper presents the results from the ground-based observations in the optical and near-IR bands, which ...
  • Embedded clusters in giant extragalactic H II regions, 1: BVRH-alpha photometry 
    Mayya, Y. D (The American Astronomical Society, 1994-10)
    Photometry in BVR continuum bands and in the emission line of H-alpha+(N II) are presented for a sample of H II complexes in disk, spiral arm and nuclear regions of galaxies NGC 1365, 1566, 2366, 2903, 2997, 3351, 4303, ...
  • Time variability of the He I 10830 A line profile 
    Singh, J; Jain, S. K; Venkatakrishnan, P (Springer, 1994-03)
    We have studied the time-dependent behavior of the He I 10830 A line. These studies show that (1) the fluctuations of the line width are uncorrelated with the equivalent-width fluctuations and (2) the autocorrelation curves ...
  • Vlasov-Maxwell equilibria of solar coronal loops 
    Krishan, V; Sreedharan, T. D; Mahajan, Swadesh M (Royal Astronomical Society, 1991-04)
    A Vlasov-Maxwell description of the ubiquitous solar coronal structures is presented. It is found that an equilibrium plasma configuration can live with spatial gradients in density, temperature, current and drift speeds ...
  • A new discussion on the M(v) - W(O I 7774 A) relationship for F-G stars in the light of high-resolution data 
    Arellano Ferro, A; Giridhar, S; Goswami, A (Royal Astronomical Society, 1991-05)
    High-resolution CCD data and a large group of F-G stars of fundamentally determined distances are used here to investigate the intrinsic nature of the M(v) - W(O I) relation and the effect of other atmospheric parameters ...
  • H-alpha flare of 14 March, 1984 -- Evidence for reconnection? 
    Sundararaman, K; Aleem, S. M; Singh, J; Selvendran, R; Thiagarajan, R (Springer, 1994-01)
    Kodaikanal H-alpha monochromatic and white-light observations are used to study the circular flare of 14 March, 1984. We report here the dynamic activity of the H-alpha filament, which attained a severe twist before erupting ...
  • A model of solar granulation through inverse cascade 
    Krishan, V (Royal Astronomical Society, 1991-05)
    Nonlinear interactions between small fluid elements in an energetically open system facilitate the formation of large coherent stable structures. This is known as self-organization. Solar granulation on all scales is ...
  • Clustering of galaxies by inverse cascade in a turbulent medium 
    Krishan, V; Sivaram, C (Royal Astronomical Society, 1991-05)
    A definite physical mechanism based in inverse cascading is suggested which quite naturally yields a bottom-up hierarchical structure for galactic clustering. In this mechanism, nonlinear interactions between small fluid ...

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