IIAP Publications: Recent submissions

  • Embedded Clusters in Giant Extragalactic HII Regions.III.Extinction and Star Formation 
    Mayya, Y. D; Prabhu, T. P (American Astronomical Society, 1996-03)
    A study of star formation is carried out on 35 giant extragalactic H II regions (GEHRs) in seven galaxies using optical photometric data in BVR broad bands and in the emission line of Hα. Interstellar extinction, metallicity ...
  • Influence of Rotation on Pulsar Radiation Characteristics 
    Ahmadi, P; Gangadhara, R. T (The American Astronomical Society, 2002-02)
    We present a relativistic model for pulsar radio emission by including the effect of rotation on coherent curvature radiation by bunches. We find that rotation broadens the width of the leading component compared to the ...
  • Morphologies in megaparsec-size powerful radio galaxies 
    Subrahmanyan, R; Saripalli, L; Hunstead, R. W (Royal Astronomical Society, 1996-03)
    We present radio images with the Australia Telescope of a sample of powerful radio galaxies. The observations were designed to be sensitive to the largest-scale structures in the radio sources. The morphologies are ...
  • CCD observations of the H-alpha line in late G and K supergiants and their interpretation 
    Mallik, S. G. V (American Astronomical Society, 1993-01-01)
    CCD echelle spectra of the H-alpha line at 6563 A have been obtained for a sample of 30 G and K supergiants with a spectral resolution of about 0.24 A. The data clearly indicate that the observed H-alpha profile is a deep ...
  • On the evaluation of magnetic shear from H-alpha pictures 
    Venkatakrishnan, P (Kluwer Academic Publishers, 1993-01-10)
    It is shown that pre-flare activity in H-alpha filaments is unrelated to changes in magnetic shear. Changes in the shear angle are found to be related to either redeployment of the sources of magnetic flux relative to the ...
  • SAO 244567 - A post-AGB star which has turned into a planetary nebula within the last 40 years 
    Parthasarathy, M; Garcia-Lario, P; Pottasch, S. R; Manchando, A; Clavel, J; de Martino, D; Van de Steene, G. C. M; Sahu, K. C (European Sothern Observatory, 1993-01)
    SAO 244567 (Hen 1357 = CPD -59 deg 6926 = IRAS 17119-5926) is an IRAS source with far infrared colors and flux distribution similar to those of planetary nebulae. The IUE ultraviolet spectra obtained in July 1988 and April ...
  • Magnetic fields in cometary globules. I. CG 22 
    Sridharan, T. K; Bhatt, H. C; Rajagopal, J (Royal Astronomical Society, 1996-04)
    We report first results from a program to study magnetic fields in cometary globules (CGs). These are clouds near massive stars showing a head-tail morphology. Linear optical polarization measurements on stars seen projected ...
  • A new investigation of microbursts at meter-decameter wavelengths 
    Subramanian, K. R; Gopalswamy, N; Sastry, Ch. V (Kluwer Academic Publishers, 1993-02)
    The results of a new investigation of microbursts at meter-decameter wavelengths are reported. Several properties of microbursts reported earlier are confirmed, and some new properties, such as time profile characteristics, ...
  • Dispersion Velocity of Galactic Dark Matter Particles 
    Cowsik, R; Ratnam, C; Bhattacharjee, P (The American Physical Society, 1996-05)
    The self-consistent spatial distribution of particles of galactic dark matter is derived including their own gravitational potential, as also of that of the visible matter of the Galaxy. In order to reproduce the observed ...
  • Transient 1/f noise 
    Sinha, S (The American Physical Society, 1996-05)
    We provide examples of transient (nonasymptotic) ``1/f noise,'' occurring over reasonably long time scales, in extended nonlinear systems modeling complex spatiotemporal phenomena. These studies contribute towards establishing ...
  • Near Infrared Observations of Sakurai's Object during 1998-99 
    Kamath, U. S; Ashok, N. M (Springer, 2002-03)
    We present new near-infrared observations of Sakurai's Object obtained during 1998-99 when this final helium shell flash object was in the dust condensation phase. The infrared colours have reddened compared to earlier ...
  • Correlation between magnetic shear and magnetic tension in a solar active region 
    Venkatakrishnan, P; Narayanan, R. S; Prasad, N. D. N (Kluwer Academic Publishers, 1993-04)
    The difference between the magnetic tension and magnetic shear was calculated for four vector magnetograms of NOAA AR 4474. It was seen that this difference between the two independent angular measures of magnetic stress ...
  • Anomalous dust in the environment of Herbig Ae/Be stars 
    Gorti, U; Bhatt, H. C (European Southern Observatory, 1993-04)
    Photometric data in the UBVRI bands of Herbig Ae/Be stars have been analyzed to study the wavelength dependence of extinction to these objects. The color excess ratios E(U-B)/E(B-V), E(V-R)/E(B-V), E(V-I)/E(B-V) and ...
  • Filament activity in a quiet region flare 
    Sundararaman, K; Gupta, S. S; Selvendran, R (Indian Academy of Sciences, 1993-03)
    We have taken the case of a circular H-alpha filament observed on May 9, 1979 erupting into a double-ribbon flare associated with a nonspot region. The plage motions are responsible for the filament reorientation and, here ...
  • The Density Structure of a Galaxy Influenced by a Massive Companion 
    Namboodiri, P. M. S; Kochhar, R. K (Royal Astronomical Society, 1993-04-15)
    The tidal influence of a massive galaxy on a non-rotating spherical companion is studied using numerical simulations. The simulations use various values of mass ratio and velocity of collision while the pericentric distance ...
  • Alfvén vortices in nonuniform dusty magnetoplasmas 
    Shukla, P. K; Varma, R. K; Krishan, V; Mckenzie, J. F (The American Physical Society, 1993-01)
    The Alfvén waves are shown to be linearly coupled with finite-frequency convective cell modes in a nonuniform cold dusty magnetoplasma. The dynamics of weakly interacting finite-amplitude electromagnetic oscillations is ...
  • Characteristics of synchrotron Čerenkov radiation 
    Pratap, R; Sasidharan, K; Krishan, V (The American physical Society, 1993-01)
    A diagrammatic technique has been worked out in the framework of nonequilibrium statistical mechanics as developed by Prigogine and co-workers to tackle the problem of radiation emission from a relativistic electron in an ...
  • Onset of Hydrodynamic Non-Equilibrium in Helmet Streamers 
    Venkatakrishnan, P (Kluwer Academic Publishers, 1996-06)
    The steady-state solar wind solution is examined for different geometries of the flow tube that mimics a helmet streamer. Onset of non-equilibrium is seen whenever the spatial variation of the flow geometry crosses critical ...
  • Ellipsometry of Coelostat Coatings Using a Babinet Compensator: Simulation of the Experimental Accuracy 
    Sankarasubramanian, K; Venkatakrishnan, P (Kluwer Academic Publishers, 1996-08)
    The precise measurement of solar magnetic fields requires an accurate measurement of the Muller matrix of the optical components in the path of the light beam, which again requires a careful measurement of the optical ...
  • Spectral Variations of DY Cen 
    Giridhar, S; Kameswara Rao, N; Lambert, D. L (Indaian Academy of Sciences, 1996-06)
    Two high resolution spectra of the hot RCrB star DY Cen in the red region are compared. The photospheric absorption lines show a radial velocity variation of 12 km s(sup -1) between 1989 July and 1992 May. Emission components ...

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