DSpace
 

RRI Digital Repository >
04. Astronomy and Astrophysics >
Research Papers (A&A) >

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/4984

Title: Pulsar polar-cap emission mapping: ``sparks'', modes, geometry, ``absorption'', and theoretical implications
Authors: Rankin, J.M.
Deshpande, A.A.
Issue Date: 1998
Publisher: American Astronomical Society
Citation: Bulletin of the American Astronomical Society, 1998, Vol.30, p1309
Abstract: A nearly coherent sequence of ``drifting" pulses from PSR B0943+10 has led us to develop a technique for mapping the pattern of polar-cap ``storms" or ``sparks" responsible for its emission. We have developed procedures which compute both this ``cartographic" transform and its inverse, in order first to study the character of the polar-cap emission ``map" and then to confirm that this ``map" in turn reproduces the observed pulse sequence. The application of this technique to pulsar 0943+10 and to other pulsars with regular patterns of subpulse emission provides a basis for assessing the physical origins of ``drifting" subpulse emission---which in turn is one of the most carefully articulated aspects of the Ruderman & Sutherland (1975) theory. We have studied 0943+10 pulse sequences in both the bright ``B" (profile) mode and ``quiescent" ``Q" mode, and our accurate polarimetric observations at both 430 and 111.5 MHz show that the pulse train is comprised of different polarization-modal contributions. On this basis, we have computed polar-cap emission ``maps" corresponding to these different observations and modal sequences. We find that, strangely, most of the emission comes from the part of the polar cap prior to the magnetic axis, and this circumstance raises the possibility of propagation effects (absorption and/or refraction) within the pulsar magnetosphere which may be responsible for the ``absorption" phenomenon. We further find that pulsar 0943+10 is an ``antipulsar", contrary to the expectations of Ruderman & Sutherland, but has an inside (poleward) sight-line traverse as favored by Arons & Scharlemann (1979). A number of other pulsars are known with highly regular patterns of subpulse modulation, and this number is likely to increase as the interrupting effect of pulse nulling is better understood. Pulsars with central sight-line traverses, such as B1237+25 or B1919+21, also provide illuminating objects of study.
Description: Restricted Access
URI: http://hdl.handle.net/2289/4984
ISSN: 0002-7537
Alternative Location: http://adsabs.harvard.edu/abs/1998AAS...193.4108R
Copyright: 1998 American Astronomical Society
Appears in Collections:Research Papers (A&A)

Files in This Item:

File Description SizeFormat
1998_BAAS_Vol.30_p1309.pdfRestricted Access58.61 kBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

    RRI Library DSpace