IIA Institutional Repository: Recent submissions

  • Temporal and spatial variations of the quiet upper chromosphere from SOHO/SUMER observations of hydrogen Lyman lines 
    Kariyappa, R; Varghese, B. A; Curdt, W (EDP Sciences, 2001-08)
    We have analyzed a time series of spectra in the hydrogen Lyman lines and the Lyman continuum obtained by the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on the SOlar Heliospheric Observatory ...
  • SiO maser survey of AGB stars in the North Galactic Cap 
    Ita, Y; Deguchi, S; Fujii, T; Kameya, O; Miyoshi, M; Nakada, Y; Nakashima, J; Parthasarathy, M (EDP Sciences, 2001-09)
    A SiO maser survey in the J=1-0, v=1 and 2 transitions has been made for IRAS sources in the North Galactic Cap b > 30o) with the Nobeyama 45 m radio telescope. The sources were selected on the basis of their IRAS 12/25-μm ...
  • Luminosity function of GRBs 
    Sethi, S; Bhargavi, S. G (EDP Sciences, 2001-09)
    A SiO maser survey in the J=1-0, v=1 and 2 transitions has been made for IRAS sources in the North Galactic Cap b > 30o) with the Nobeyama 45 m radio telescope. The sources were selected on the basis of their IRAS 12/25-μm ...
  • Upper Limits on O VI Emission From Voyager Observations 
    Murthy, J; Henry, R. C; Shelton, R. L; Holberg, J. B (American Astronomical Society, 2001-08)
    We have examined 426 Voyager fields distributed across the sky for O VI λλ1032, 1038 emission from the Galactic diffuse interstellar medium. No such emission was detected in any of our observed fields. Our most constraining ...
  • General relativistic spectra of accretion discs around rapidly rotating neutron stars: effect of light bending 
    Bhattacharyya, S; Bhattacharya, D; Thampan, A. V (Royal Astronomical Society, 2001-08)
    We present computed spectra, as seen by a distant observer, from the accretion disc around a rapidly rotating neutron star. Our calculations are carried out in a fully general relativistic framework, with an exact treatment ...
  • A Study of the Emission-Line Spectra and the Stellar Populations of Starburst Galaxies 
    Ravindranath, S; Prabhu, T. P (Springer, 2001-03)
    Based on optical-NIR spectra, we discuss the nebular properties and stellar populations of starburst nuclei. Starbursts are found to have higher electron densities and higher excitations than HII nuclei. The emission lines ...
  • The Luminosity Function and Size Distribution of HII Regions in NGC 1365 
    Ravindranath, S; Prabhu, T. P (Springer, 2001-03)
    We present the HII region luminosity function and size distribution obtained for the HII regions in NGC 1365. The diameters were corrected for the effects of seeing using a Wiener image restoration procedure. The luminosities ...
  • Does the Poleward Migration Rate of the Magnetic Fields Depend on the Strength of the Solar Cycle? 
    Makarov, V. I; Tlatov, A. G; Sivaraman, K. R (Springer, 2001)
    We present the pattern of the polar magnetic reversal for cycle 23 derived from Hα synoptic charts and have also included the reversals of the earlier cycles 18-22 for comparison. At the beginning of a new cycle (i.e., ...
  • IUE and ISO observations of the bipolar proto-planetary nebula Hen 401 (IRAS 10178-5958) 
    Parthasarathy, M; García-Lario, P; Gauba, G; de Martino, D; Nakada, Y; Fujii, T; Pottasch, S. R; de Cordoba, L. S. F (EDP Sciences, 2001-09)
    We present ultraviolet (IUE) and infrared (ISO) observations of the bipolar proto-planetary nebula Hen 401 which, combined with previously available optical and near infrared data, are used to reconstruct the overall ...
  • Decameter Wavelength Observations of an Absorption Burst from the Sun and Its Association with an X2.0/3B Flare and the Onset of a ``Halo'' Coronal Mass Ejection 
    Ramesh, R; Ebenezer, E (The American Astronomical Society, 2001-09)
    We report a transient intensity reduction/absorption burst observed at decameter wavelengths in close temporal association with an X2.0/3B flare near the disk center and the onset of a ``halo'' coronal mass ejection. The ...
  • Dynamics of embedded protostar clusters in clouds 
    Gorti, U; Bhatt, H. C (Royal Astronomical Society, 1996-01)
    The dynamics of clumps and protostars in a young protocluster system embedded in its parent molecular cloud are studied here through numerical simulations. It is found that the presence of massive clumps and their dynamics ...
  • A Dust Lane in the Radio Galaxy 3C 270 
    Mahabal, A; Kembhavi, A; Singh, K. P; Bhat, P. N; Prabhu, T. P (American Astronomical Society, 1996-02)
    We present the broad band surface photometry of the radio galaxy 3C 270 (NGC 4261). We find a distinct dust lane in the V - R image of the galaxy and determine its oriantation and size. We use the major axis profile of the ...
  • Spectral line radiation from solar small-scale magnetic flux tubes 
    Kneer, F; Hasan, S. S; Kalkofen, W (European Southern Observatory, 1996-01)
    We consider spectral line radiation from small-scale magnetic model flux tubes in the solar atmosphere. The structure of the tube is determined from the magnetostatic equations in the thin flux tube approximation. We assume ...
  • Spectrophotometry of the comets C /2000 WM 1(LINEAR) and C /2002 C1 (Ikeya-Zhang) 
    Sanwal, B. B; Kumar, B; Singh, M (Astronomical Society of India, 2002-12)
    Spectrophotometric observations of the coma of the comets Cj2000 WM1 (LINEAR) and Cj2002 C1 (Ikeya-Zhang) were taken during Nov, Dec 2001 and Mar, Apr 2002 respectively with 104-cm telescope of the State Observatory, ...
  • On mass and velocity distributions in members of star clusters: An analytical approach 
    Chatterjee, S; Kumar, B; Sagar, R (Astronomical Society of India, 2002-12)
    Dynamical evolution of stellar mass distribution in star clusters is analysed by considering simultaneously the effects of dynamical friction, stochastic heating and the gravitational potential due to mass distribution ...
  • Photometric Catalogs of Four EMSS Poor Clusters of Galaxies 
    Sharma, M; Prabhu, T. P (Astronomical Society of India, 2002-12)
    We have used the 2.3-meter Vainu Bappu Telescope to perform CCD imaging of X-ray-selected poor clusters of galaxies. Our sample consists of four X-ray luminous clusters in the Einstein Observatory Extended Medium ...
  • Axial oscillation of a planetoid in Restricted Three Body Problem : The circular Sitnikov problem 
    Faruque, S. B (Astronomical Society of India, 2002-12)
    Two equally massive primaries are assumed to be moving in circular orbits in Cartesian x-y plane. A planetoid is assumed to be on the z-axis. This is a particular case of the restricted three body problem with mass ratio ...
  • Evaluation of Lijiang Gaomeigu site for astrophysical observation 
    Tan, H; Cen, X; Qian, T; Wang, J (Astronomical Society of India, 2002-12)
    The work on the site testing at the Gaomeigu village Lijiang country in the northwest of Yunnan province, was started in 1994 after the completion of the investigation on optical astronomical observatory site survey over ...
  • The Distribution of the Quiet Sun Photospheric Magnetic Flux 
    Srikanth, R; Singh, J; Bagare, S. P (Astronomical Society of India, 2002-12)
    A gradient-based tessellating algorithm is used to study the magnetic field structure of the quiet Sun photosphere using SoRO full disk magnetograms. We find that the field is not uniformly distributed, but parcelled ...
  • Geomagnetic storms with H ≥ 400nT during 1979-99 
    Kumar, S; Yadav, M. P (Astronomical Society of India, 2002-12)
    The effect of solar features on geospheric conditions leading to ninety nine geomagnetic storms (OMSs) with H~400 nT and Ap;::;:20 have been investigated using interplanetary magnetic field (IMF) , solar wind plasma (SWP) ...

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