IIA Institutional Repository: Recent submissions

  • The Decameter and Meter Wave Radiotelescopes in India and Mauritius 
    Sastry, Ch. V (Springer, 1995-05)
    The Indian Institute of Astrophysics and the Raman Research Institute in a joint collaboration program operate the Gauribidanur radio observatory. Details of the various radiotelescopes available at the observatory are ...
  • A comparative study of finite-difference methods for radiative transfer problems. 
    Mohan Rao, D; Varghese, B. A; Srinivasa Rao, M (Elsevier, 1995-06)
    We have compared the numerical results of two widely used difference methods for the radiative transfer equation in plane-parallel medium. The Discrete Space theory (DS) is based on the direct first-order differential ...
  • Near-infrared and optical imaging of Q2345+007: The largest gravitationally lensed QSO system? 
    Gopal-Krishna; Yates, M; Wiita, P. J; Smette, A; Pati, A. K; Altieri, B (The European Southern Observatory, 1993-12)
    We have taken K, R, V, and B band images of Q 2345+007, which has been claimed to be the gravitationally lensed quasar with the widest separation between the two images (approximately equal 7 arcsec), although the lens ...
  • Scale transformations and evolution of the early universe 
    Sivaram, C (Springer, 1993-09)
    The notion of discrete scale transformations is invoked to suggest strong links between fundamental interactions and cosmology giving rise to a hierarchy of cosmic scales.
  • "Steady" and "Fluctuating" Parts of the Sun's Internal Magnetic Field: Improved Model 
    Hiremath, K. M; Gokhale, M. H (The American Astronomical Society, 1995-07)
    Using reasonable assumptions and approximations it is shown that the poloidal component part of the magnetic field in the Sun's radiative core (RC) and convection zone (CE) can be modeled as in an analytical solution of ...
  • Detection of additional absorption in the post-outburst spectra of MU Centauri 
    Ghosh, K. K; Kuppuswamy, K; Pukalenthi, S; Selvakumar, G (The American Astronomical Society, 1991-09)
    A large number of photographic (92) and CCD (27) spectra of the pole-on Be star, Mu Cen, were obtained between February 1987 and May 1990. From the results of the above-mentioned spectra a weak outburst was detected in ...
  • X-ray spectrum (0.1-10 keV) of the broad line radio galaxy - 3C 390.3 
    Ghosh, K. K; Sondararajaperumal, S (The American Astronomical Society, 1991-10)
    Results are presented of observations of the broad-line radio galaxy, 3C 390.3 that were made with Exosat on several occasions between 1984 and 1986 using low- (LE) and medium-energy (ME) detectors. Detailed findings of ...
  • Coronal heating and chromospheric energy density: An observational association 
    Venkatakrishnan, P (Springer, 1993-12)
    The time-averaged equivalent width of the He 1 10830 Angstrom line is seen to be correlated with the time-averaged line width. This correlation is interpreted as evidence for the association of the chromospheric energy ...
  • A photoionization model of the nebula around the WC11 star M4-18 
    Surendiranath, R; Kameswara Rao, N (Blackwell Publishing, 1995-08)
    A photoionization code has been developed incorporating provision for the presence of dust mixed with gas. M4-18 has been modelled utilizing optical CCD spectra and other observations ranging from UV to radio wavelengths. ...
  • Frenet-Serret description of gyroscopic precession 
    Iyer, B. R; Vishveshwara, C. V (The American Physical Society, 1993)
    The phenomenon of gyroscopic precession is studied within the framework of the Frenet-Serret formalism adapted to quasi-Killing trajectories. Its relation to the congruence vorticity is highlighted with particular reference ...
  • Simultaneous infrared and H-alpha measurements of Be stars 
    Apparao, K. M. V; Tarafdar, S. P; Verma, R. P; Iyengar, K. V. K; Ghosh, K. K (Indian Academy of Sciences, 1993)
    The observed infrared excess in Be stars is usually interpreted as free-free and free-bound emission from a hot gas envelope around the Be star. This hot gas should also emit H-alpha line radiation. Earlier observations ...
  • Torsion, massive electrodynamics and primordial magnetic fields in the Early Universe 
    de Andrade, L. C. G; Sivaram, C (Springer, 1993)
    A recent model of torsion-modified electrodynamics which breaks the electromagnetic conformal invariance is shown to lead to the generation of magnetic fields in the Early Universe.
  • SN 1993J in M 81: Optical photometry and spectrophotometry during the first two months 
    Prabhu, T. P; Mayya, Y. D; Singh, K. P; Kameswara Rao, N; Ghosh, K. K; Mekkaden, M. V; Pati, A. K; Raveendran, A. V; Reddy, B. E; Sagar, R; Subramaniam, A; Surendiranath, R (The European Southern Observatory, 1995-03)
    CCD photometric and spectrophotometric data on the type IIb supernova 1993J in M 81 (NGC 3031) obtained from Vainu Bappu Observatory, Kavalur, during the first two months since the outburst are reported. The evolution of ...
  • Photometric elements, absolute dimensions and evolutionary status of the eclipsing binary HU Tauri (HR 1471) 
    Parthasarathy, M; Sarma, M. B. K; Vivekananda, Rao P (The European Southern Observatory, 1995-05)
    The photometric elements of HU Tauri are derived from an analysis of its blue and visual light curves using the Wilson & Devinney (1971) light curve synthesis method. The photometric elements suggest that HU Tauri is a ...
  • Young LMC star clusters as a test for stellar evolutionary models. 
    Subramaniam, A; Sagar, R (The European Southern Observatory, 1995-05)
    We compare the observed colour-magnitude diagrams (CMD) and the main sequence luminosity functions (LFs) of four Large Magellanic Cloud (LMC) star clusters namely, NGC 1711, NGC 2004, NGC 2164 and NGC 2214 with the synthetic ...
  • Detection of optical pulsations from RX J0558.0+5353 
    Ashoka, B. N; Marar, T. M. K; Seetha, S; Kasturirangan, K; Bhattacharyya, J. C (The European Southern Observatory, 1995-05)
    We report the detection of optical pulsations at a period of 272.785+-0.003s from the newly discovered intermediate polar RX J0558.0+5353. This period nearly coincides with the X-ray period reported by Haberl et al. (1994). ...
  • Effects of aberration and advection on line formation 
    Peraiah, A (University of Chicago Press, 1991-10)
    The effects of inclusion of the aberration and advection terms in the equation of the line transfer are studied. Spherical shells whose ratios of outer (B) to inner (A) radii (B/A) are 2, 5, and 10 and with line-center ...
  • Thermal self-energies at zero momentum 
    Nieves, Jose. F; Palash, B. Pal (The American Physical Society, 1995-05)
    In general the zero momentum limit of thermal self-energies calculated in perturbation theory depends on the order in which the time and the space components of the momentum are taken to zero. We show that this is an ...
  • Strong-CP question in SU(3)c×SU(3)L×U(1)N models 
    Palash, B. Pal (The American Physical Society, 1995-08)
    We analyze two recent models based on the gauge group SU(3)c×SU(3)L×U(1)N where each generation is not anomaly-free but the anomaly cancels when three generations are taken into account. We show that the most general Yukawa ...
  • VLA observations of solar active regions at 6 and 20 CM 
    Alissandrakis, C. E; Kundu, M. R; Shevgaonkar, R. K (The European Southern Observatory, 1991-11)
    High-resolution observations are presented of two active regions at 6 and 20 cm over a period of 5 days, together with H-alpha and photospheric magnetic fields. The large-scale emission at 20 cm is associated with the ...

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