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Browsing IIAP Publications by Title

Browsing IIAP Publications by Title

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  • Long-term variations in the north–south asymmetry of solar activity and solar cycle prediction, III: prediction for the amplitude of solar cycle 25 
    Javaraiah, J (Elsevier B.V, 2015-01)
    The combined Greenwich and Solar Optical Observing Network (SOON) sunspot group data during 1874–2013 are analysed and studied the relatively long-term variations in the annual sums of the areas of sunspot groups in 0°–10°, ...
  • Long-Term Variations in the Solar Differential Rotation 
    Javaraiah, J (Springer, 2003-01)
    Using Greenwich data (1879 1976) and SOON/NOAA data (1977 2002) on sunspot groups we found the following results: (i) The Sun's mean (over all the concerned cycles during 1879 1975) equatorial rotation rate (A) is significantly ...
  • Long-Wavelength Observations of Jets from Polar Regions of the Sun 
    Ramesh, R (Kluwer Academic Publishers, 1999-10)
    We report radio observations of enhanced emission associated with the extreme-ultraviolet (EUV) jets from polar coronal hole regions of the Sun, with the Gauribidanur radioheliograph (GRH). We have estimated the brightness ...
  • Longitudinal dependence of equatorial F region vertical plasma drifts in the dusk sector 
    Sastri, J. H (American Geophysical Union, 1996-02)
    The effect of solar activity on the postsunset peak of F region vertical plasma drift at Kodaikanal (77°28'E, dip 3°N) is determined as a function of season and for two levels of magnetic activity using extensive HF phase ...
  • Longitudinal flows in stellar magnetic flux tubes 
    Gokhale, M. H; Hiremath, K. M (Elsevier, 1986)
    It is shown that if a thin, isolated and untwisted magnetic flux tube, consisting of a current-free core bounded by a thin current sheath, is in an ‘overall’ equilibrium in a stratified atmosphere, then there is, in general, ...
  • Longterm Photometry of Variables at ESO - Part Two - the Second Data Catalogue 1986-1990 
    Sterken, C; Manfroid, J; Anton, K; Barzewski, A; Bibo, E; Bruch, A; Burger, M; Duerbeck, H. W; Duemmler, R; Heck, A; Hensberge, H; Hiesgen, M; Inklaar, F; Jorissen, A; Juettner, A; Kinkel, U; Zongli, L; Mekkaden, M. V; Ng, Y. K; Niarchos, P; Puttmann, M; Szeifert, T; Spiller, F; Vandijk, R; Vogt, N; Wanders, I (European Southern Observatory, 1993-11)
    In this paper we present the second catalogue of photometric data in the Stromgren system obtained during the period October 1986 - September 1990 in the framework of the Long-Term Photometry of Variables (LTPV)program at ...
  • Loss of magnetic tension in pre-flare magnetic configurations 
    Venkatakrishnan, P (Kluwer Academic Publishers, 1990-08)
    We demonstrate that magnetic tension vanishes at regions of large magnetic shear on the polarity inversion line. The characteristics of these tension-free fields depend on the density of the medium and, therefore, change ...
  • Low cost method for subarcsecond testing of a right angle prism 
    Saxena, A. K; Yeswanth, L (SPIE, 1990-12)
    This paper describes a method for testing a right angle prism, or any other optical component having a right angle, to subarcsecond accuracy. The method makes use of Haidinger fringes and is simple to use. Unlike autocollimation ...
  • A low cost steerable radio-telescope 
    Sawant, H. S; Neri, J. A. C. F; Fernandes, F. C. R; Cecatto, J. R; Sankararaman, M. R; Faria, C; Stephany, S; Rosa, R. R; Andrade, M. C; Alonso, E. M. B; Ludke, E; Subramanian, K. R; Ramesh, R; Sundararajan, M. S; Ananthakrishnan, S; Swarup, G; Boas, J. W. V; Botti, L. C. L; Moron, C. E; Saito, J. H (Elsevier B. V., 2003)
    We present the technical characteristics of a low-cost radio telescope for solar/non solar observations at decimetric (1200–1700 MHz) and centimetric (2700 and 5000 MHz) wavelengths known as Brazilian Decimetric Array ...
  • Low frequency (30-110 MHz) radio imaging observations of solar coronal mass ejections 
    Ramesh, R (Cambridge University Press, 2005)
    Ground based radio imaging observations play an useful role in the study of mass ejections from the solar corona since they do not have the limitation of an occulter and both the disk/limb events can be detected early in ...
  • Low frequency (< 100 MHz) thermal radio emission from the solar corona and the effect of radial magnetic field 
    Ramesh, R; Sastry, Ch. V (Astronomical Society of the Pacific, 2005-12)
    We measured the degree of circular polarization of the thermal radiation from discrete structures in the solar corona at a frequency of 77 MHz and attempted to derive the magnetic field strength of these regions.
  • Low frequency radio emission from seyfert galaxies 
    Singh, V; Shastri, P; Athreya, R (Astronomical Society of the Pacific, 2009-09)
    Seyfert galaxies are low-luminosity, radio-quiet, nearby active galaxies. The high-frequency radio observations of several Seyfert galaxies show jet-like features, which tend to be confined within the host galaxy, whereas ...
  • Low Frequency Radio Emission from the 'Quiet Sun' 
    Ramesh, R (Indian Academy of Sciences, 2000-12)
    We present observations of the 'quiet' Sun close to the recent solar minimum (Cycle 22), with the Gauribidanur radioheliograph. Our main conclusion is that coronal streamers also influence the observed radio brightness ...
  • Low frequency radio observations of the solar corona prior to the onset of a mass ejection event 
    Ramesh, R; Subramanian, K. R; Sastry, Ch. V (European Space Agency, 1999-10)
    It is well known that the halo CMEs originating on the visible hemisphere of the Sun could give rise to the severest terrestrial consequences. Recent studies carried out with the YOHKOH soft X-ray data by various authors ...
  • A low frequency radio telescope at Mauritius for a southern sky survey. 
    Golap, K; Shankar, N. U; Sachdev, S; Dodson, R; Sastry, Ch. V (Indian Academy of Sciences, 1998-06)
    A new, meter-wave radio telescope has been built in the north-east of Mauritius, an island in the Indian Ocean, at a latitude of -20.14°. The Maritius Radio Telescope is a Fourier Synthesis T-shaped array, consisting of a ...
  • Low frequency solar radio astronomy at the Indian Institute of Astrophysics (IIA) 
    Ramesh, R (Astronomical Society of India, 2011)
    IIA is presently involved in the expansion of its existing radioheliograph operating in the frequency 120-40 MHz at the Gauribidanur radio observatory located about 80 km north of Bangalore. Once completed, the expanded ...
  • Low frequency view of GRB 190114C reveals time varying shock micro-physics 
    Misra, K; Resmi, L; Kann, D. A; Marongiu, M; Moin, A; Klose, S; Bernardi, G; de Ugarte Postigo, A; Jaiswal, V. K; Schulze, S; Perley, D. A; Ghosh, A; Dimple; Kumar, H; Gupta, R; Michałowski, M. J; Martin, S; Cockeram, A; Cherukuri, S. V; Bhalerao, V; Anderson, G. E; Pandey, S. B; Anupama, G. C; Thone, C. C; Barway, Sudhanshu; Wieringa, M. H; Fynbo, J. P. U; Habeeb, N (Oxford University Press on behalf of the Royal Astronomical Society, 2021-07)
    We present radio and optical afterglow observations of the TeV-bright long gamma-ray burst 190114C at a redshift of z = 0.425, which was detected by the Major Atmospheric Gamma Imaging Cherenkov telescope. Our observations ...
  • Low resolution spectroscopy of hot post-AGB candidates 
    Parthasarathy, M; Vijapurkar, J; Drilling, J. S (EDP Sciences, 2000-08)
    Spectral types are determined from low resolution optical spectra of 40 IRAS sources with far-infrared colours similar to planetary nebulae. The presence of circumstellar dust, high galactic latitude, and early supergiant ...
  • Low resolution spectroscopy of ISOGAL sources: Search for early-type stars with infrared excess 
    Schultheis, M; Parthasarathy, M; Omont, A; Cohen, M; Ganesh, S; Sevre, F; Simon, G (E D P Sciences, 2002-05)
    An analysis of low resolution spectra and infrared data of 29 ISOGAL-DENIS sources with mid-IR excess is presented. Eight ISOGAL sources from our sample with 7-15 mu m excesses are found to be B and A-type stars, some of ...
  • Low resolution spectroscopy of selected Algol systems 
    Shanti Priya Devarapalli; Rukmini Jagirdar; Parthasarathy, M; Sahu, D. K; Mohan, V; Bhatt, B. C; Thomas, V. S (Springer, 2018-04)
    The analysis of spectroscopic data for 30 Algol-type binaries is presented. All these systems are short period Algols having primaries with spectral types B and A. Dominant spectral lines were identified for the spectra ...

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