IIA Institutional Repository: Recent submissions

  • Dither-based sensor for improved consistency of adaptive optics system 
    Vyas, A; Roopashree, M. B; Prasad, B. R (SPIE--The International Society for Optical Engineering, 2010-07)
    The wavefront reconstruction accuracy in Shack Hartmann sensor based adaptive optics system depends on accurate centroiding and phase estimation from measured slope values. Monte Carlo simulations of vector matrix multiply ...
  • Optimizing the modal index of Zernike polynomials for regulated phase screen simulation 
    Vyas, A; Roopashree, M. B; Prasad, B. R (SPIE--The International Society for Optical Engineering, 2010-07)
    Simulations of optical wavefronts propagating through the atmosphere are widely used in the design and testing of adaptive optics systems. Phase screens are defined by their spatial and temporal statistics. In many ...
  • Seismic and spectroscopic characterization of the solar-like pulsating CoRoT target HD 49385 
    Deheuvels, S; Bruntt, H; Michel, E; Barban, C; Verner, G; Régulo, C; Mosser, B; Mathur, S; Gaulme, P; Garcia, R. A; Boumier, P; Appourchaux, T; Samadi, R; Catala, C; Baudin, F; Baglin, A; Auvergne, M; Roxburgh, I. W; Pérez Hernández, F (EDP Science, 2010-06-11)
    Context. The star HD 49385 is the first G-type solar-like pulsator observed in the seismology field of the space telescope CoRoT. The satellite collected 137 days of high-precision photometric data on this star, confirming ...
  • On the rotational temperature of AlH in Sunspots 
    Karthikeyan, B; Rajamanickam, N; Bagare, S. P (Springer, 2010-07)
    A search has been carried out for the presence of rotational lines of two bands of the (0, 0) and (1, 1) A 1Π – X 1Σ+ system of the AlH molecule in the high resolution Fourier Transform Spectra of sunspots observed at the ...
  • Multilayered temporally evolving phase screens based on statistical interpolation 
    Roopashree, M. B; Vyas, A; Prasad, B. R (SPIE--The International Society for Optical Engineering, 2010-07)
    Simulation of the dynamic effects of atmospheric turbulence assists in understanding, testing and effective implementation of adaptive optics systems. Statistical interpolation technique helps in retaining the spatial ...
  • Noise reduction in the centroiding of laser guide star spot pattern using thresholded Zernike reconstructor 
    Vyas, A; Roopashree, M. B; Prasad, B. R (SPIE--The International Society for Optical Engineering., 2010-07)
    Centroiding inaccuracies contribute to most of the wavefront reconstruction error in a Shack Hartmann sensor based adaptive optics system. These errors primarily occur due to the presence of photon noise, readout noise, ...
  • Radio observations of weak energy releases in the solar corona 
    Ramesh, R; Kathiravan, C; Barve, Indrajit V; Beeharry, G. K; Rajasekara, G. N (IOP Science, 2010-08-10)
    We report observations of weak, circularly polarized, structureless type III bursts from the solar corona in the absence of Hα/X-ray flares and other related activity, during the minimum between the sunspot cycles 23 and ...
  • Phase variability of Sq (H) on normal quiet days in the equatorial electrojet region 
    Sastri, J. H (Royal Astronomical Society, 1982-10)
    From a study of ‘abnormal quiet days’ (AQDs) at equatorial latitudes it was found earlier (Sastri) that the occurrence of an abnormal Sq(H) phase confined to the equatorial electrojet belt is closely associated with the ...
  • Physical process at super-high energies 
    Datta, B (Einstein Foundation International, 1983)
  • Two-wave mixing and light-induced absorption dynamics in photorefractive BaTiO3 crystals 
    Banyal, R. K; Prasad, B. R (Indian Institute of Science, 2003-08)
    Steady-state and temporal measurements of TWM and LIA have been carried out in PR BaTiO3 crystals at different wavelengths and intensities of laser light. The observed behavior is interpreted in terms of two-center charge ...
  • Alfred Wegener –From Continental Drift to Plate Tectonics 
    Saigeetha, A. J; Banyal, R. K (Indian Academy of Sciences, 2005-06)
  • A new probable Be Star Alpha Leo 
    Singh, M (Konkoly Observatory, 1982-08-16)
  • Migrating from Informal to Formal Consortium - ”COSTLI” issues 
    Birdie, C; Patil, Y. M (Astronomical Society of the Pacific, 2010)
    There are many models of library consortia which came into existence due to various reasons and compulsions. FORSA (Forum for Resource Sharing in Astronomy) is an informal consortium borne from institutional linkages of ...
  • Managing the contents of Indian Institute of Astrophysics (IIA) Archives - Copyright Issues 
    Birdie, C; Vagiswari, A (Astronomical Society of the Pacific, 2010)
    Archives and museums all over the world face challenges in facilitating the access to their contents and also protecting the rights of the author, more so, in the case of unpublished works. At the Indian Institute of ...
  • Magnetic transport on the solar atmosphere by turbulent ambipolar diffusion 
    Krishan, V; Masuda, S (Anita Publications, 2008-12)
    The lower solar atmosphere consists of partially ionized turbulent plasmas harboring velocity field, magnetic field and current density fluctuations. The correlations amongst these small scale fluctuations give rise to ...
  • The hydrogen-deficient irregular variable star V348 SGR 
    Kameswara Rao, N; Nandy, K (1984-07)
    The distribution of the reddening material around V 348 Sgr was studied using the IUE low resolution spectra. The nebula surrounding the star has a reddening of E(B-V) = 0.3 caused mainly by the foreground interstellar ...
  • Rotation and H-alpha emission activity in F8-G3 dwarfs 
    Mekkaden, M. V (Kluwer Academic Publishers, 1985-12)
    The dependence of H-alpha emission strength on rotational period and spectral type in late-type stars is studied using published data. The emission strength shows strong correlation with rotation irrespective of age and ...
  • Evolution of coronal helicity in a twisted emerging active region 
    Ravindra, B; Longcope, D. W (Springer, 2010)
    Active-region magnetic fields are believed to be generated near the shear layer of the convection zone by dynamo processes. These magnetic fields are concentrated into fluxtubes, which rise, due to buoyancy, through the ...
  • Long-term variations in meridional flows 
    Javaraiah, J (Springer, 2010)
    Using sunspot group data from Greenwich and from the Solar Optical Observation Network during 1879–2008, we find that the mean meridional motion of the observed spot groups varies considerably on a time scale of about 10–20 ...
  • Low-frequency radio observations of coronal magnetic fields 
    Ramesh, R; Sonnett, S. M; Kathiravan, C (Springer, 2010)
    We report observations of circularly polarized noise storm emission from the solar corona at 77 and 109MHz during the period 11–18 August 2006 (Carrington Rotation 2046) with the recently commissioned East-West one-dimensional ...

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