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  • On the nature of substorm-related transient electric field disturbances in the equatorial ionosphere 
    Sastri, J. H; Ramesh, K. B; Karunakaran, D (Elsevier, 1992-01)
    Results are presented of a study of h-prime F data derived from interval ionograms recorded on the night of August 29-30, 1957 at Kodaikanal (10 deg 14 min N, 77 deg 29 min E, geomag. lat. 0.6 deg N) during a geomagnetic ...
  • On the nature of the compact condensations at the centre of galaxies 
    Mitra, A (Astronomical Society of India, 2002)
    There are many observational evidences for the existence of massive compact condensations in the range 106 - 1010 M? at the core of various galaxies and in particular in the core of High Energy Gamma Ray emitting galaxies. ...
  • On the Neutrino Emissivity of Degenerate Strange Quark Matter 
    Datta, B; Raha, S; Sinha, B (World Scientific Publishing Company, 1988-10)
    We examine the neutrino emissivity of a system of degenerate three-component (u, d, s) strange quark matter using improved expressions for the quark chemical potentials in a self-consistent manner, and obtain tighter bounds ...
  • On the non-acceleration origin of the highest energy cosmic rays 
    Sivaram, C (University of Calgary, 1993)
    The Hawking radiation from primordial black holes in their near terminal stages of evaporation can produce ultra high energy (UHE) particles spontaneously. The contribution from such objects to the highest energy cosmic ...
  • On the observational behaviour of the highly polarized Type IIn supernova SN 2017hcc 
    Brajesh Kumar; Eswaraiah, C; Singh, A; Sahu, D. K; Anupama, G. C; Kawabata, K. S; Yamanaka, Masayuki; Otsubo, Ikki; Pandey, S. B; Nakaoka, Tatsuya; Kawabata, Miho; Aryan, Amar; Akitaya, Hiroshi (Oxford University Press on behalf of the Royal Astronomical Society, 2019-09)
    We present the results based on photometric (Swift UVOT), broad-band polarimetric (V and Rbands) and optical spectroscopic observations of the Type IIn supernova (SN) 2017hcc. Our study is supplemented with spectropolarimetric ...
  • On the occurrence and vertical movement of kink at Kodaikanal 
    Narayana Iyer, K; Rastogi, R. G (American Geophysical Union, 1974)
    The occurrence of ionospheric irregularities observed as sharp discontinuities (kinks) on the ionograms and moving upward with time at Kodaikanal have been studied for a period covering high, medium, and low solar activity ...
  • On the occurrence of AQDs at Kodaikanal 
    Sastri, J. H; Murthy, B. S (The Council of Scientific and Industrial Research, 1978-02)
    A study is made of the occurrence of 'abnormal quiet days' (AQDs) at Kodaikanal (10 deg 14 min N, 77 deg 28 min E; dip 3.5 deg N) using H-field data over a 26-yr period (1950-1975). The results show distinctive differences ...
  • On the orbital periods of the eclipsing binaries CM Lacertae, AB Andromedae and YY Eridani 
    Panchatsaram, T; Abhyankar, K. D (Astronomical Society of India, 1981-09)
    A study of all the available photoelectric times of minima of CM Lac, AB And and YY Eri does not reveal any changes in their orbital periods.
  • On the orientation of the pulsar space velocity vector relative to the spin axis 
    Kochhar, R. K (Nature Publishing Group, 1977-05)
    It is noted that the angle between the space velocity vector and the spin axis projected on the plane of the sky has a value close to zero deg for three pulsars, close to 90 deg for six others, and between zero and 90 deg ...
  • On the origin of core radio emissions from black hole sources in the realm of relativistic shocked accretion flow 
    Das, Santabrata; Nandi, Anuj; Stalin, C. S; Rakshit, Suvendu; Dihingia, Indu Kalpa; Singh, Swapnil; Aktar, Ramiz; Mitra, Samik (Oxford University Press on behalf of Royal Astronomical Society, 2022-08)
    We study the relativistic, inviscid, advective accretion flow around the black holes and investigate a key feature of the accretion flow, namely the shock waves. We observe that the shock-induced accretion solutions are ...
  • On the Origin of Gamma-Ray Flares from Bright Fermi Blazars 
    Paliya, Vaidehi S; Böttcher, M; Gurwell, Mark; Stalin, C. S (IOP Publishing, 2021-12)
    The origin of γ-ray flares observed from blazars is one of the major mysteries in jet physics. We have attempted to address this problem following a novel spectral energy distribution (SED) fitting technique that explored ...
  • On the origin of highest energy cosmic rays 
    Sigl, G; Schramm, D. N; Bhattacharjee, P (Elsevier, 1994-09)
    In this paper we show that the conventional diffusive shock acceleration mechanism for cosmic rays associated with relativistic astrophysical shocks in active galactic nuclei (AGNs) has severe difficulties to explain the ...
  • On the oscillator strength and the dissociation energy of CN molecules 
    Sinha, K; Tripathi, B. M (Astronomical Society of Indian, 1986-03)
    Equivalent widths of the CN red system in the solar spectrum are determined and compared with previous observational data in order to evaluate various published values for oscillator strength and dissociation energy. The ...
  • On the Oscillator strengths of the Phillips bands 
    Sinha, K (Astronomical Society of India, 1984-03)
    The recently published values of oscillator strengths for the Phillips bands were checked with those obtainable from the solar spectrum. The results of (1982) Erman et al. based on the assumption of a varying electronic ...
  • On the Out of Phase Appearance of Large-Scale Diffuse Magnetic Field of the Sun with Respect to Sunspots 
    Dikpati, M; Choudhuri, A. R (Kluwer Academic Publishers, 1996-03)
    We assume the large-scale diffuse magnetic field of the Sun to originate from the poloidal component of a dynamo operating at the base of the convection zone, whereas the sunspots are due to the toroidal component. The ...
  • On the p-mode Asymmetry between Velocity and Intensity from the GONG+ Data 
    Tripathy, S. C; Jain, K; Hill, F; Toner, C. G (Astronomical Society of India, 2003)
    We have analyzed the local acoustic spectra of small regions over the solar surface at different locations from disk center to limb via the technique of ring diagrams. The analysis suggest that the frequency shifts between ...
  • On the parallax of α Herculis 
    Jacob, W. S (Royal Astronomical Society, 1853-06)
  • On the performance of a dual-beam polarimeter at Kodaikanal tower telescope 
    Nagaraju, K; Sankarasubramanian, K; Rangarajan, K. E; Ramesh, K. B; Singh, J; Devendran, P; Hariharan (Astronomical Society of India, 2008-09)
    Calibration and characterization of a dual-beam polarimeter installed at Kodaikanal Tower Telescope (KTT) for spectropolarimetric observations are presented in this paper. It was found that a slit width of 48 μ is optimum ...
  • On the Period of Delta Ceti 
    Mohan, Vijay (Astronomical Society of India, 1979-12)
    A period analysis of delts Ceti has been carried out. It has been found that the period of delta Ceti has undergone a sudden decrease somewhere after 1976. The average period between 1976 and 1978 has been found to be 0d.1611335
  • On the periodicity of solar great hard X-ray bursts, energic solar radio bursts and sunspot data 
    Verma, V. K; Joshi, G. C (Indian Institute of Astrophysics, Bangalore, 1988)
    In the last solar maximum period (cycle 21) the 152-158 day periodicity was found in the occurrence rate of solar flares through solar gamma ray, microwave, soft X-ray, hard X-ray and H-alpha flares. In the present, brief ...

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