Browsing by Author "Mitra, D."

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    Scatter broadening of pulsars in the direction of the gum nebula
    (2001-07-05) Mitra, D.; Ramachandran, R.
    We have measured the scatter broadening of pulsars in the direction of the Gum nebula. For the rst time, our observations show clear variations of scattering properties across the Gum nebula. The IRAS-Vela shell is shown to be a high scattering region. Our revised estimations of distances to these pulsars are consistently less by a factor of 2{3, which has very important consequences for the deduced values of radio luminosity and transverse velocity of pulsars.
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    Tracking pulsar dispersion measures using the GMRT
    (2011-07-06) Ahuja, A. L.; Gupta, Y.; Mitra, D.; et al.
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    Vacuum gaps in pulsars and PSR J2144-3933
    (2000-12-20) Gil, Janusz; Mitra, D.
    In this paper we revisit the radio pulsar death line problem within the framework of curvature radiation and/or inverse compton scattering induced vacuum gap model above neutron star polar caps. Our special interest is in the recently detected pulsar PSR J2144−3933 with extremal period 8.5 seconds, which lies far beyond conventional death lines. We argue, that formation of vacuum gaps requires a complicated multi- polar surface magnetic field, with a strenght Bs much higher than the surface dipolar component Bd, and radii of curvature R much smaller than the neutron star radius R = 106 cm. Such a multipolar surface field is also consistent with death lines including the extremal pulsar PSR J2144−3933. Since vacuum gap models produce sparks, our paper naturally supports the spark related models of subpulse drift phenomenon as well as to the spark associated models of coherent pulsar radio emission.