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Browsing IIAP Publications by Title

Browsing IIAP Publications by Title

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  • Radiative transfer with Compton scattering in spherically symmetric shells 
    Peraiah, A; Varghese, B. A (Astronomical Society of Japan, 1990)
    The radiative transfer equation with Compton scattering is solved for spherically symmetric shells. The purpose of the study is to determine how gamma rays or X-rays change their energies and how they become reflected and ...
  • Radiative transfer with J-state interference in a two-term atom Partial frequency redistribution in the non-magnetic case 
    Smitha, H. N; Nagendra, K. N; Sampoorna, M; Stenflo, J. O (EDP Sciences, 2011-11)
    Context. Quantum interference phenomena play a fundamental role in the formation of linear polarization that arises from scattering processes in multiplets of the solar spectrum. In particular, the J-state interference ...
  • Radio and EUV measurements of the equatorial coronal hole of February 25, 1999 
    Subramanian, K. R; Sundaram, G. A. S (Astronomical Society of the Pacific, 2005)
    We present here the observations of the equatorial coronal hole made at 109 MHz on February 25, 1999 with the Gauribidanur Radioheliograph. The brightness temperature of this coronal hole is about 1:7£105 K.We compare our ...
  • Radio and X-ray Emission from Low-Luminosity AGNs: Testing Unification Hypothesis 
    Singh, V; Shastri, P; Risaliti, G; Athreya, R (Astronomical Society of the Pacific, 2010-10)
    We investigate the low-frequency radio properties and the X-ray spectral properties of a sample of Seyfert galaxies in order to compare the two subtypes of Seyferts and rigorously test the predictions of Seyfert unification.
  • The radio brightness of the undisturbed outer solar corona in the presence of a radial magnetic field 
    Golap, K; Sastry, Ch. V (Springer, 1994-03)
    The radio brightness of the quiet outer solar corona at a frequency of 35 MHz in the presence of a radial magnetic field is computed. It is found that the brightness temperature of the ordinary radiation increases ...
  • Radio Continuum and H I Study of Blue Compact Dwarf Galaxies 
    Ramya, S; Kantharia, N. G; Prabhu, T. P (IOP Publishing, 2011-02)
    The multifrequency radio continuum and 21 cm H I observations of five blue compact dwarf (BCD) galaxies, Mrk 104, Mrk 108, Mrk 1039, Mrk 1069, and I Zw 97, using the Giant Meterwave Radio Telescope (GMRT) are presented ...
  • A radio continuum and H I study of optically selected blue compact dwarf galaxies: Mrk 1039 and Mrk 0104 
    Ramya, S; Kantharia, N. G; Prabhu, T. P (Astronomical Society of the Pacific, 2009-09)
    We present a GMRT radio continuum and H I study of two Blue Compact Dwarf (BCD) galaxies Mrk 1039 and Mrk 0104. GMRT 610 MHz observations of Mrk 1039 show that the emission is coincident with a bright intense star forming ...
  • Radio emission by parallel acceleration mechanism 
    Krishan, V; Sivaram, C (Springer, 1983-04)
    The equations describing the linear-acceleration mechanism of radiation emission are generalized and applied to type III and IIIb solar radio bursts. A general expression for the power emitted by an electron in a spatially ...
  • Radio emission by particles due to pulsar spin 
    Thomas, R. M. C; Gangadhara, R. T (EDP Sciences, 2005-07)
    We present a relativistic model for the motion of charged particles in rotating magnetic field lines projected onto a plane perpendicular to the rotation axis. By making an approximation that the projected field lines are ...
  • Radio emission from a helical electron beam-plasma system in a twisted magnetic field 
    Krishan, V (Institute of Physics, 1982-01)
    The excitation of electromagnetic radiation near the harmonics of electron plasma frequency from a helical electron beam travelling parallel to a helical magnetic field through a stationary inhomogeneous plasma is studied. ...
  • Radio emission from an intense electromagnetic beam-plasma system 
    Krishan, V (D. Reidel Publishing Co., 1979-06)
    Interaction of a high-intensity and low-frequency electromagnetic beam with a plasma is investigated. The dynamics of plasma particles under this strong electromagnetic field is calculated without using the perturbation ...
  • Radio emission from pulsars due to relativistic plasma 
    Roy, Tridib; Gangadhara, R. T. (IOP Publishing, 2019-07)
    Pulsar radio emission is not well understood because of a lack of knowledge about the emission geometry and the plasma process involved. We develop a mechanism for pulsar radio emission that takes into account the ...
  • Radio Emission From The Quiet Sun and Active Regions at Decametric Wavelengths 
    Sastry, Ch. V (Indian Institute of Astrophysics, Bangalore, 1986)
    The Continuum emission from the Quiet Sun and active regions is the radiation from the solar atmosphere when there is no transient burst activity. At decametric wavelengths this radiation originates in the outer corona. A ...
  • Radio emission from the Solar Corona due to shock waves 
    Thejappa, G (Indian Institute of Astrophysics, Bangalore, 1988)
    The slowly drifting solar type II radio bursts are believed to be due to the flare associated shock waves propagating radially outward in the corona. The main observational characteristics of these bursts show that the ...
  • Radio emission of coronal shock waves 
    Benz, A. O; Thejappa, G (European Southern Observatory, 1988-08)
    The "backbone" emission of shock initiated coronal (metric) type II solar radio bursts is considered. The source has extremely narrow bandwidth and appears to be stationary in relation to the shock. The increasingly complete ...
  • Radio Emission Processes: Part I 
    Subramanian, K. R (Springer, 2010)
    This chapter provides an overview of the radio emission mechanisms in the Solar atmosphere. Incoherent (free - free emission and gyro - emission) and coherent (plasma emission and electron cyclotron maser emission) emission ...
  • Radio Evolution of a Type IIb Supernova SN 2016gkg 
    Nayana, A. J; Chandra, Poonam; Krishna, Anoop; Anupama, G. C (American Astronomical Society, 2022-08-01)
    We present extensive radio monitoring of a Type IIb supernova (SN IIb), SN 2016gkg during t ∼ 8−1429 days postexplosion at frequencies ν ∼ 0.33−25 GHz. The detailed radio light curves and spectra are broadly consistent with ...
  • Radio frequency emission in electron beam-plasma and beam-beam interaction 
    Krishan, V; Sinha, K. P; Krishan, S (D.Reidel Publishing Co.,, 1978-01)
    A linear excitation of electromagnetic modes at frequencies ~_ (n+1/2)ωce , in a plasma through which two electron beams are contra-streaming along the magnetic field is investigated. This may be a source of the observed ...
  • Radio interferometric observations of the Sun using commercial dish TV antennas 
    Gireesh, G. V. S; Kathiravan, C; Barve, Indrajit V; Ramesh, R (Springer, 2021-08)
    The radio astronomy group in the Indian Institute of Astrophysics (IIA) has been carrying out routine observations of radio emission from the solar corona at low frequencies (≈40 – 440 MHz) at the Gauribidanur observatory, ...
  • Radio noise-bursts from solar M-regions 
    Das, A. K; Bhargava, B. N (Nature Publishing Group, 1953-11)
    In 1932, Bartels put forward the hypothesis that moderate geomagnetic storms with gradual commencements were associated with certain active regions on the sun which he called M-regions. Solar and geomagnetic studies in ...

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