IIA Institutional Repository

Browsing by Author "Shevgaonkar, R. K"

Browsing by Author "Shevgaonkar, R. K"

Sort by: Order: Results:

  • Deconvolution and self-calibration in radio astronomy using MEM 
    Shevgaonkar, R. K (Tata Institute of Fundamental Reserach, 1988)
    Aperture synthesis technique is the most powerful indirect imaging technique used in radio astronomy for obtainIng high resolution images. The technique, instead of measuring the image directly, measures its Fourier ...
  • Diffuse radio emission from the coma cluster of galaxies at decametre wavelengths 
    Sastry, Ch. V; Shevgaonkar, R. K (Indian Academy of Sciences, 1983-03)
    We have observed the region of the Coma cluster at 34.5 MHz with a resolution of 26 arcmin × 40 arcmin. A map of the diffuse halo (Coma C) is presented. The size of the halo is found to be 54 arcmin × 30 arcmin. The position ...
  • Dual frequency observations of solar microwave bursts using the VLA 
    Shevgaonkar, R. K; Kundu, M. R (The American Astronomical Society, 1985-05)
    Simultaneous VLA observations of microwave bursts at 6 and 2 cm in a solar active region are presented and discussed. Using the full-day synthesis, I and V maps of the active region are produced. The radiation mechanisms ...
  • Maximum entropy method for phase-unstable aperture synthesis 
    Shevgaonkar, R. K (European Southern Observatory, 1986-07)
    An application of the Maximum Entropy Method (MEM) to the closure data is described. It is shown that although the basic principle of the method is to obtain a brightness distribution which has highest entropy, the closure ...
  • Maximum entropy method for phase-unstable aperture synthesis 
    Shevgaonkar, R. K (European Southern Observatory, 1986-07)
    An application of the Maximum Entropy Method (MEM) to the closure data is described. It is shown that although the basic principle of the method is to obtain a brightness distribution which has highest entropy, the closure ...
  • Maximum Entropy Method for Polarized Images 
    Shevgaonkar, R. K (The European Southern Observatory, 1987-04)
    A simple maximum entropy method algorithm for deconvolving polarized images obtained from synthesis observations has been described here. A general purpose Fortran program is also developed. it demonstrated that although ...
  • Microwave emission from late-type dwarf stars UV Ceti and YZ Canis Minoris 
    Kundu, M. R; Shevgaonkar, R. K (The University of Chicago Press, 1985-10-15)
    Simultaneous high-resolution observations of two late-type dwarf stars, UV Cet and YZ CMi, at 6 and 20 cm are presented. These observations put sufficient constraints on existing interpretations to conclude that the quiescent ...
  • Minimum Relative Entropy Method - Solution to Missing Short Baseline Problem 
    Shevgaonkar, R. K (Indian Academy of Sciences, 1986-12)
    The minimum-relative-entropy method (MREM) is proposed as a solution to the missing short-baseline problem in radio synthesis observations. It is shown that a measure of distance between the prior model and the image in ...
  • Multiwavelength observations of a preflare solar active region using the VLA 
    Kundu, M. R; Shevgaonkar, R. K (The University of Chicago Press, 1985-04)
    A preflare active region was studied using the Very Large Array at 2, 6, and 20 cm. At 2 cm the region is composed of two components located in regions of opposite polarity. Both components are preheated prior to the ...
  • Observations and interpretation of the slowly varying component of solar radio emission at decameter wavelengths 
    Sastry, Ch. V; Dwarakanath, K. S; Shevgaonkar, R. K; Krishan, V (D. Reidel Publishing Co., 1981-10)
    We have observed the slowly varying component of solar radio emission at a frequency of 34.5 MHz with half power beam widths of 26/40 in the east-west and north-south directions, respectively. It is found that the observed ...
  • Observations of the Rosette Nebula using the Decameter Wave Radio Telescope at Gauribidanur 
    Deshpande, A. A; Shevgaonkar, R. K; Sastry, Ch. V (D. Reidel Publishing Co., 1984-07)
    A map of Rosette Nebula in continuum absorption is made at 34.5 MHz using the Decameter Wave Radio Telescoe at Gauribidanur, India, with a resolution of 26×40, is presented. These observations are combined with the 2700 ...
  • Observations of the supernova remnants HB 9 and IC 443 at 34.5 MHz 
    Dwarakanath, K. S; Shevgaonkar, R. K; Sastry, Ch. V (Indian Academy of Sciences, 1982-06)
    The results of observations of the two SNRs HB 9 and IC 443 are discussed. A map of HB 9 is presented whose main features are an elongation in the northerly direction and a strong region at the center of the map. The ...
  • Observations on the slowly varying component of solar radio emission at decameter wavelengths 
    Sastry, Ch. V; Shevgaonkar, R. K; Ramanuja, M. N (Springer, 1983-09)
    The authors have made two-dimensional maps of the slowly varying component (SVC) of solar radio emission at a frequency of 34.5 MHz with half power beam width of 26'/40'. It is found that a majority of SVC sources have ...
  • Simultaneous dual wavelength observations of an impulsive microwave burst using the V.L.A. 
    Shevgaonkar, R. K; Kundu, M. R (Elsevier B.V., 1984)
    Simultaneous observations of a microwave burst at 2 and 6 cm wavelengths were carried out with the Very Large Array (VLA). The 6 cm burst source is located close to a magnetic neutral line, presumably near the top of a ...
  • Simultaneous microwave observations of solar flares at 6 and 20 CM wavelengths using the VLA 
    Melozzi, M; Kundu, M. R; Shevgaonkar, R. K (Kluwer Academic Publishers, 1985-06)
    Using the Very Large Array, solar burst observations have been carried out simultaneously at 6 and 20 cm. Structural changes and preheating have been observed in the flaring regions on time scales of minutes to tens of ...
  • Solar coronal bright points observed with the VLA 
    Habbal, S. R; Ronan, R. S; Withbroe, G. L; Shevgaonkar, R. K; Kundu, M. R (The American Astronomical Society, 1986-07)
    The first observations of solar coronal bright points made at 20-cm wavelength with the VLA are reported. The brightness temperature of the sources observed varies between 1 and 5 x 10 to the 5th K. The observations indicate ...
  • Speckle interferometry at IIA and elsewhere: An overview 
    Venkatakrishnan, P; Saha, S. K; Shevgaonkar, R. K (Tata Institute of Fundamental Reserach, 1988)
    The technique of speckle interferometry, used for compensating the blurring effects of the earth's atmosphere, is briefly outlined. The achievements of this technique by different groups in the world are listed. We then ...
  • The structure of the Cygnus Loop at 34.5 MHz 
    Sastry, Ch. V; Shevgaonkar, R. K; Dwarakanath, K. S (Indian Academy of Sciences, 1981-09)
    The large supernova remnant Cygnus Loop was observed at 34.5 MHz with a low-frequency radio telescope at Gauribidanur, India. The structure of the object is presented on a radio map with a resolution of 26 arcmin x 40 ...
  • Three-dimensional structures of two solar active regions from VLA observations at 2, 6, and 20 centimeter wavelengths 
    Shevgaonkar, R. K; Kundu, M. R (The American Astronomical Society, 1984-08)
    Three-dimensional structures of two active region groups are determined from observations with the Very Large Array (VLA) at 2, 6, and 20 cm. One of the groups exhibits a single magnetic loop of length approximately 10 to ...
  • 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 ...

Search DSpace

Browse

My Account