Differential frequency-dependent delay from the pulsar magnetosphere
Artikel i vetenskaplig tidskrift, 2013

Some radio pulsars show clear "drifting subpulses", in which subpulses are seen to drift in pulse longitude in a systematic pattern. Here we examine how the drifting subpulses of PSR B0809+74 evolve with time and observing frequency. We show that the subpulse period (P-3) is constant on timescales of days, months and years, and between 14-5100 MHz. Despite this, the shapes of the driftbands change radically with frequency. Previous studies have concluded that, while the subpulses appear to move through the pulse window approximately linearly at low frequencies (<500 MHz), a discrete step of similar to 180 degrees in subpulse phase is observed at higher frequencies (>820 MHz) near to the peak of the average pulse profile. We use LOFAR, GMRT, GBT, WSRT and Effelsberg 100-m data to explore the frequency-dependence of this phase step. We show that the size of the subpulse phase step increases gradually, and is observable even at low frequencies. We attribute the subpulse phase step to the presence of two separate driftbands, whose relative arrival times vary with frequency - one driftband arriving 30 pulses earlier at 20 MHz than it does at 1380 MHz, whilst the other arrives simultaneously at all frequencies. The drifting pattern which is observed here cannot be explained by either the rotating carousel model or the surface oscillation model, and could provide new insight into the physical processes happening within the pulsar magnetosphere.

telescope

drifting subpulses

radio pulsars

stability

radiation

polarization

psr b0809+74

emission

model

telescopes

profiles

pulsars: general

pulsars: individual: PSR B0809+74

Författare

T. E. Hassall

University of Southampton

B. W. Stappers

University of Manchester

P. Weltevrede

University of Manchester

J. W. T. Hessels

Netherlands Institute for Radio Astronomy (ASTRON)

Anton Pannekoek Institute for Astronomy

A. Alexov

Space Telescope Science Institute (STScI)

Anton Pannekoek Institute for Astronomy

T. Coenen

Anton Pannekoek Institute for Astronomy

A. Karastergiou

University of Oxford

M. Kramer

University of Manchester

Max Planck-institutet

E. F. Keane

Max Planck-institutet

V. I. Kondratiev

Netherlands Institute for Radio Astronomy (ASTRON)

J. van Leeuwen

Anton Pannekoek Institute for Astronomy

Netherlands Institute for Radio Astronomy (ASTRON)

A. Noutsos

Max Planck-institutet

M. Pilia

Netherlands Institute for Radio Astronomy (ASTRON)

M. Serylak

Institut National des Sciences de l'Univers

Centre national de la recherche scientifique (CNRS)

C. Sobey

Max Planck-institutet

K. Zagkouris

University of Oxford

R. Fender

University of Southampton

M. E. Bell

The University of Sydney

University of Southampton

J. Broderick

University of Southampton

J. Eisloffel

H. Falcke

Netherlands Institute for Radio Astronomy (ASTRON)

Radboud Universiteit

J. M. Griessmeier

Centre national de la recherche scientifique (CNRS)

Institut National des Sciences de l'Univers

M. Kuniyoshi

Max Planck-institutet

J. C. A. Miller-Jones

Curtin University

Anton Pannekoek Institute for Astronomy

M. W. Wise

Netherlands Institute for Radio Astronomy (ASTRON)

Anton Pannekoek Institute for Astronomy

O. Wucknitz

Universität Bonn

Max Planck-institutet

P. Zarka

GEPI - Galaxies, Etoiles, Physique, Instrumentation

A. Asgekar

Netherlands Institute for Radio Astronomy (ASTRON)

Fabien Batejat

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

M. J. Bentum

Netherlands Institute for Radio Astronomy (ASTRON)

G. Bernardi

Rijksuniversiteit Groningen

P. Best

University of Edinburgh

A. Bonafede

Jacobs University Bremen

Universität Hamburg

F. Breitling

Astrophysikalisches Institut Potsdam

M. Brüggen

Universität Hamburg

H. R. Butcher

Australian National University

Netherlands Institute for Radio Astronomy (ASTRON)

B. Ciardi

Max Planck-institutet

F. De Gasperin

Max Planck-institutet

Universität Hamburg

J. P. de Reijer

Netherlands Institute for Radio Astronomy (ASTRON)

S. Duscha

Netherlands Institute for Radio Astronomy (ASTRON)

R. A. Fallows

Netherlands Institute for Radio Astronomy (ASTRON)

C. Ferrari

Université Nice Sophia Antipolis (UNS)

W. Frieswijk

Netherlands Institute for Radio Astronomy (ASTRON)

M. A. Garrett

Universiteit Leiden

Netherlands Institute for Radio Astronomy (ASTRON)

A. W. Gunst

Netherlands Institute for Radio Astronomy (ASTRON)

G. Heald

Netherlands Institute for Radio Astronomy (ASTRON)

M. Hoeft

E. Juette

Ruhr-Universität Bochum

P. Maat

Netherlands Institute for Radio Astronomy (ASTRON)

J. P. McKean

Netherlands Institute for Radio Astronomy (ASTRON)

M. J. Norden

Netherlands Institute for Radio Astronomy (ASTRON)

M. Pandey-Pommier

Universiteit Leiden

Observatoire de Lyon

R. Pizzo

Netherlands Institute for Radio Astronomy (ASTRON)

A. G. Polatidis

Netherlands Institute for Radio Astronomy (ASTRON)

W. Reich

Max Planck-institutet

H. Rottgering

Universiteit Leiden

J. Sluman

Netherlands Institute for Radio Astronomy (ASTRON)

Y. Tang

Netherlands Institute for Radio Astronomy (ASTRON)

C. Tasse

GEPI - Galaxies, Etoiles, Physique, Instrumentation

R. Vermeulen

Netherlands Institute for Radio Astronomy (ASTRON)

R. J. van Weeren

Netherlands Institute for Radio Astronomy (ASTRON)

Universiteit Leiden

Harvard-Smithsonian Center for Astrophysics

S. J. Wijnholds

Netherlands Institute for Radio Astronomy (ASTRON)

S. Yatawatta

Netherlands Institute for Radio Astronomy (ASTRON)

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 552

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1051/0004-6361/201220764