Open AccessOn the subpulse modulation, polarization and sub‐beam carousel configuration of pulsar B1857−26
Author(s) -
Mitra Dipanjan,
Rankin Joanna M.
Publication year - 2008
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2008.12838.x
Subject(s) - physics , pulsar , polarization (electrochemistry) , traverse , radio telescope , astrophysics , modulation (music) , longitude , optics , stokes parameters , astronomy , scattering , geodesy , acoustics , latitude , chemistry , geography
New Giant Metre‐Wave Radio Telescope (GMRT) observations of the five‐component pulsar B1857−26 provide detailed insight into its pulse‐sequence modulation phenomena for the first time. The outer conal components exhibit a 7.4‐rotation period, longitude‐stationary modulation. Several lines of evidence indicate a carousel circulation time of about 147 stellar rotations, characteristic of a pattern with 20 beamlets. The pulsar nulls some 20 per cent of the time, usually for only a single pulse, and these nulls show no discernible order or periodicity. Finally, the pulsar's polarization‐angle traverse raises interesting issues: if most of its emission comprises a single polarization mode, the full traverse exceeds 180°; or if both polarization modes are present, then the leading and the trailing halves of the profiles exhibit two different modes. In either case, the rotating‐vector model fails to fit the polarization‐angle traverse of the core component.