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Browsing IIAP Publications by Title

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  • Polarimetric observations of comet P/Halley on 19 March 1986 
    Sen, A. K; Joshi, U. C; Deshpande, M. R; Babu, G. S. D; Kulshrestha, A. K (European Southern Observatory, 1988-10)
    Optical linear polarization data are presented for the coma and tail region of comet P/Halley observed on 19 March 1986. Polarization in the continuum has been found to increase with wavelength while the position angle ...
  • Polarimetric observations of hydrogen deficient stars 
    Raveendran, A. V; Kameswara Rao, N; Deshpande, M. R; Joshi, U. C; Kulshrestha, A. K (Reidel Publishing Company, 1986)
    Polarimetric observations of HD 30353, SU Tau, XX Cam, R CrB, UV Cas, BD +13°3224, BD +10°2179 and HD 124448 are presented. The linear polarization of HD 30353 is found to vary appreciably at Hα over a time scale as short ...
  • Polarimetric observations of the RV Tauri star AR Puppis 
    Raveendran, A. V; Kameswara Rao, N (European Southern Observatory, 1988-03)
    UBVRI polarimetry of AR Pup is presented. Large variations are seen both in the amount and direction of polarization. On one occasion, the polarization in U was found to be as high as 14.6 percent. Polarization level ...
  • Polarimetric studies of carbon stars at high galactic latitude 
    Goswami, A; Drisya, K (EDP Sciences, 2013-01)
    Context. Very little is known about the polarimetric properties of CH stars and carbon-enhanced metal-poor (CEMP) stars, although many of these objects have been studied in detail both photometrically and spectroscopically. Aims. ...
  • Polarimetry of Comet P/Halley - Properties of dust 
    Sen, A. K; Deshpande, M. R; Joshi, U. C; Kameswara Rao, N; Raveendran, A. V (European Southern Observatory, 1991-02)
    Comet P/Halley was observed polarimetrically for seven nights in IHW and other continuum filters, during its pre- and postpreihelion passages. These polarimetric observations have been combined with the observations taken ...
  • Polarimetry of Supernova SN 1987A - A Dust Shell Model 
    Joshi, U. C; Sen, A. K; Deshpande, M. R; Jain, Rekha (Indian Institute of Astrophysics, 1988)
    Polarimetric measurements of SN1987A in BVR bands were made on March 6 and 7. These observations along with the polarimetric data reported by various other authors within first 30 days of explosion have been discussed. ...
  • Polarisation in A-type stars with circumstellar shells 
    Bhatt, H. C (European Southern Observatory, 1996-12)
    We present the results of optical linear polarisation measurements of about 30 A-type stars that are known to be either Ae/A shell stars or have shown anomalous emission in the infrared. Compared with the general population ...
  • Polarization : proving ground for methods in radiative transfer 
    Nagendra, K. N; Anusha, L. S; Sampoorna, M (Societa Astronomica Italiana, 2009)
    Polarization of solar lines arises due to illumination of radiating atom by anisotropic (limb darkened/brightened) radiation. Modelling the polarized spectra of the Sun and stars requires solution of the line radiative ...
  • Polarization and QPOs from jets in black hole systems 
    Mangalam, A (Indian Academy of Sciences, 2018-12)
    The historical observations of polarized jet emission for Blazars are reviewed and previous models are discussed. Motivated by this, a model for polarization of both steady and transient behavior using a helical magnetic ...
  • Polarization Changes of Radiation through Stimulated Raman Scattering 
    Gangadhara, R. T; Krishan, V (The American Astronomical Society, 1993-10)
    We study change in the polarization of electromagnetic waves due to the stimulated Raman scattering in a plasma. In this process an electromagnetic wave undergoes coherent scattering off an electron plasma wave. It is found ...
  • Polarization line radiative transfer in the atmospheres of magnetic white dwarfs 
    Nagendra, K. N (Akademie verlag GmbH, 1987)
    Some physical mechanisms which can affect the Zeeman line profiles of magnetic white dwarfs are studied. The pure absorption polarization transfer equation is solved including these mechanisms. The broadening of lines in ...
  • Polarization Maps for the Dark Clouds B:227 and L:121 
    Bhatt, H. C; Jain, S. K (European Southern Observatory, 1993-09)
    Optical linear polarization measurements for stars in the regions of the molecular clouds B 227 and L 121 are presented. The magnetic field geometry in the clouds as indicated by the polarization maps is discussed in ...
  • Polarization Measurements of Post-Asymptotic Giant Branch Candidates and Related Stars 
    Parthasarathy, M; Jain, S. K; Sarkar, G (The American Astronomical Society, 2005-05)
    We have obtained UBVRI polarization measurements of 26 post-asymptotic giant branch (post-AGB) candidates and related stars. The extremely metal-poor post-AGB star HR 4049 has been observed several times. In most cases we ...
  • Polarization Measurements of Some Herbig Ae / Be-Stars 
    Jain, S. K; Bhatt, H. C; Sagar, R (International Astronomical Union, 1990)
    We have measured the linear polarization of 8 bright Herbing Ae/ Be starsin UBVRI bands. No unique wavelength dependence of magnitude as well as direction is found on these measurements.
  • Polarization measurements of stars in the region of the nearby molecular cloud MBM 12 
    Bhatt, H. C; Jain, S. K (Blackwell Publishing, 1992-07)
    Linear polarization measurements of stars in the region of the nearby high-latitude molecular cloud MBM 12 are presented. Stars behind the cloud show a polarization of about 2-3 percent, while stars that are in front of ...
  • Polarization measurements of the luminous blue variable HR Carinae 
    Parthasarathy, M; Jain, S. K; Bhatt, H. C (European Southern Observatory, 2000-03)
    We have made BVRI polarization measurements of HR Car on ten occasions during the period JD 2447919 to JD 2449014. All our observations are on the rising part of the light curve. We find the presence of intrinsic variable ...
  • Polarization measurements of Vega-like stars 
    Bhatt, H. C; Manoj, P (European Southern Observatory, 2000-10)
    Optical linear polarization measurements are presented for about 30 Vega-like stars. These are then compared with the polarization observed for normal field stars. A significant fraction of the Vega-like stars are found ...
  • Polarization Observations of a Split-band Type II Radio Burst from the Solar Corona 
    Ramesh, R; Kathiravan, C (American Astronomical Society, 2022-11-20)
    Using temporal observations of circular polarized harmonic plasma emission from a split-band type II solar radio burst at 80 MHz, we separately estimated the coronal magnetic field strengths (B) associated with the lower ...
  • Polarization of coherent curvature radiation in pulsars 
    Thomas, R. M. C; Gangadhara, R. T (Springer Netherlands, 2008)
    We consider the coherent curvature radiation by relativistic plasma in pulsar magnetosphere. The radiation emitted by relativistic particle bunches is beamed in the direction of field line tangents. For the first time, we ...
  • Polarization of continuum radiation in magnetic atmospheres 
    Nagendra, K. N; Peraiah, A (Kluwer Academic Publishers, 1984-09)
    A numerical solution is presented for the problem of continuum radiative transfer in a magnetoactive medium. The continuum opacities are calculated in the presence of a strong magnetic field (H = 10 MG) typical of magnetic ...

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