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Browsing Kodaikanal Observatory Bulletins (1905 - 1997 ) by Author "Peraiah, A"

Browsing Kodaikanal Observatory Bulletins (1905 - 1997 ) by Author "Peraiah, A"

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  • Comoving frame calculations with Lorentz profiles in radially expanding media 
    Peraiah, A; Raghunath, G (Indian Institute of Astrophysics, 1979-11)
    A computationally simple method for solving the line transfer in comoving frame has been described for radially expanding spherical medium. We have assumed a radially increasing velocity distribution and a non-LTE (where ...
  • Compton Broadening Due To Electron Scattering 
    Peraiah, A; Srinivasa Rao, M (Indian Institute of Astrophysics, Bangalore, 1993)
    We have investigated the effects of Compton broadening due to electron scattering in the hot stellar atmosphere, quasars, AGN's etc. We considered a purely electron scattering media. The Compton effect scattering function ...
  • Discretization of the equation of Radiative Transfer with Compton Scattering 
    Peraiah, A (Indian Institute of Astrophysics, Bangalore, 1986-05)
    We have attempted to solve the equation of radiative transfer by including Compton and inverse Compton scattering. We expanded the specific intensity by Taylor series at about v/sup1/ = v/sub0/. The resulting equation has ...
  • Effects of aberration and advection on partial frequency redistribution of photon in spectral line formation 
    Peraiah, A (Indian Institute of Astrophysics, Bangalore, 1989)
    A formal solution of equation transfer with aberration and advection terms is developed for spectral lines taking into consideration partial redistribution of photon in a spherical medium which is expanding with a radial ...
  • Effects of partial frequency redistribution with dipole scattering on the formation of spectral lines in expanding media 
    Peraiah, A (Indian Institute of Astrophysics, 1978)
    Line formation in expanding spherical atmospheres using partial frequency redistribution with dipole scattering has been studied by using a non LTE two level atom model. Lines with zero natural line widths are treated by ...
  • Effects of Velocities on Ca II H and K Lines 
    Rangarajan, K. E; Mohan Rao, D; Peraiah, A (Indian Institute of Astrophysics, Bangalore, 1981)
    Ca II H and K (3968, 3933) and infrared triplet lines lamda lamda lamda 8498, 8662, 8542 were calculated in a very slowly expanding medium. Five level atom with continuum was considered. Radiative transfer equation and ...
  • Fluxvector Splitting of the Inviscid Radiation Gas Dynamic Equations 
    Peraiah, A (Indian Institute of Astrophysics, Bangalore, 1980)
    We have analysed various schemes for the iterative simultaneous solution of the inviscid gas dynamic equations. We have considered the problem from the point of view of the stellar atmospheres. The difference between ...
  • Formation of Spectral Lines with the Redistribution Function R1 along the line of Sight 
    Peraiah, A (Indian Institute of Astrophysics, Bangalore, 1981)
    We studied the formation of spectral lines at infinity with the redistribution function R1. The radial optical depths considered are 5, 5, 10, 50 and 100. A linear law of velocity is assumed in these calculations. Profiles ...
  • Integral Operator Technique of Line Transfer 
    Peraiah, A (Indian Institute of Astrophysics, Bangalore, 1986-05)
    We present details of a new technique of obtaining a numerical solution of the radiative transfer equation in spherical symmetry in a polychromatic system. We employed the integral operators together with an interpolation ...
  • Limb Darkening due to the Incidence of a Parallel Beam of Radiation 
    Peraiah, A (Indian Institute of Astrophysics, Bangalore, 1983)
    We have investigated how the radiation is distributed from the centre to the limb when the atmosphere receives a parallel beam of radiation from infinity. We have considered a purely reflecting surface at the bottom of the ...
  • Line Profiles in an Expanding Spherical Medium 
    Peraiah, A; Srinivasa Rao, M; Varghese, B. A (Indian Institute of Astrophysics, Bangalore, 1986)
    We have applied the discrete space theory of radiative with the integral operator technique to calculate the spectral line profiles formed in a spherically symmetric expanding stellar atmospheres. We calculated the source ...
  • Lines Formed in Slowly Expanding Thin Spherical Shell 
    Peraiah, A; Raghunath, G; Nagendra, K. N (Indian Institute of Astrophysics, Bangalore, 1980)
    We have investigated how an optically thin spherical shell with small velocities change the profiles and equivalent widths of the lines. We have employed several types of variations in density, velocity of expansion and ...
  • On negative intensities in discrete space theory in spherical medium 
    Peraiah, A (Indian Institute of Astrophysics, 1978)
    The reasons for the occurrence of negative intensities are discussed. A method is described to obtain positive solution of radiative transfer equation in spherical symmetry in distance space theory by using frequency ...
  • P Cygni type profiles 
    Peraiah, A; Srinivasa Rao, M (Indian Institute of Astrophysics, Bangalore, 1985-11)
    We have presented a series of P Cygni type profiles of special lines computed by employing different velocity laws of expansion in a spherically atmosphere. A comparison has been made with those of Beals classification. ...
  • Radiation pressure in resonance lines 
    Peraiah, A (Indian Institute of Astrophysics, 1979-11)
    The effects of large scales gas motions on the radiation pressure in a resonance lines are investigated. We have assumed a medium with pure scattering together with emission in the continuum. A linear velocity law is ...
  • Relativistic effects on Radiative Transfer Equation: Order of Magnitude study 
    Peraiah, A (Indian Institute of Astrophysics, Banglore, 1986-05)
    We have analyzed how the high gas velocities which are observed in the objects such as the atmospheres of supergiant stars, novae, supernovae, accretion discs around high density objects (like black holes, neutron stars ...
  • RII partial frequency redistribution function and its effects on the formation of lines in expanding spherical atmospheres 
    Peraiah, A (Indian Institute of Astrophysics, 1979-11)
    The redistribution in frequency in lines formed in atmospheres in which the matter is moving radially outwards with velocity gradients is studied in the rest frame of the star. We velocity gradients is studied in the rest ...
  • Rotational Effects on line Source Function 
    Peraiah, A; Raghunath, G (Indian Institute of Astrophysics, Bangalore, 1980)
    The effects of rotation are investigated on the source functions in an expanding atmosphere. We have considered a non-LTE two-level atom in an extended atmosphere. We have also made use of von Zeipel`s theorem in giving ...
  • Simultaneous Solution of Radiative Transfer Equation in the Comoving Frame and the Statistical Equilibrium Equation with Complete Redisribution 
    Peraiah, A (Indian Institute of Astrophysics, Bangalore, 1980)
    Complete redistribution with Voigt profile function has been employed in obtaining the simultaneous solution of line transfer and the statistical equilibrium equation for a non-LTE two level atom in an extended stellar ...
  • Solution of radiative transfer equation in spherically symmetric media with spherical harmonic approximation 
    Peraiah, A (Indian Institute of Astrophysics, 1979-11)
    A numerical method for obtaining solution of radiative transfer equation in spherically symmetric media with spherical harmonic approximation is presented. The angle derivative is approximated by an orthonormal polynomial ...

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