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.

profiles

emission

telescopes

drifting subpulses

radiation

pulsars: general

psr b0809+74

pulsars: individual: PSR B0809+74

polarization

model

radio pulsars

stability

telescope

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)

Astronomical Institute Anton Pannekoek

A. Alexov

STScI

Astronomical Institute Anton Pannekoek

T. Coenen

Astronomical Institute Anton Pannekoek

A. Karastergiou

University of Oxford

M. Kramer

Max Planck-institutet

University of Manchester

E. F. Keane

Max Planck-institutet

V. I. Kondratiev

Netherlands Institute for Radio Astronomy (ASTRON)

J. van Leeuwen

Astronomical Institute Anton Pannekoek

Netherlands Institute for Radio Astronomy (ASTRON)

A. Noutsos

Max Planck-institutet

M. Pilia

Netherlands Institute for Radio Astronomy (ASTRON)

M. Serylak

UMR 7328 CNRS

Institut National des Sciences de l'Univers

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

Radboud Universiteit

Netherlands Institute for Radio Astronomy (ASTRON)

J. M. Griessmeier

UMR 7328 CNRS

Institut National des Sciences de l'Univers

M. Kuniyoshi

Max Planck-institutet

J. C. A. Miller-Jones

Astronomical Institute Anton Pannekoek

Curtin University

M. W. Wise

Astronomical Institute Anton Pannekoek

Netherlands Institute for Radio Astronomy (ASTRON)

O. Wucknitz

Max Planck-institutet

Universität Bonn

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

University of Groningen, Kapteyn Astronomical Institute

P. Best

University of Edinburgh

A. Bonafede

Jacobs University Bremen

Universität Hamburg

F. Breitling

Astrophysikalisches Institut Potsdam

M. Brüggen

Universität Hamburg

H. R. Butcher

Netherlands Institute for Radio Astronomy (ASTRON)

Australian National University

B. Ciardi

Max Planck-institutet

F. De Gasperin

Universität Hamburg

Max Planck-institutet

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

Universite Nice Sophia Antipolis

W. Frieswijk

Netherlands Institute for Radio Astronomy (ASTRON)

M. A. Garrett

Netherlands Institute for Radio Astronomy (ASTRON)

Leiden University

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

Observatoire de Lyon

Leiden University

R. Pizzo

Netherlands Institute for Radio Astronomy (ASTRON)

A. G. Polatidis

Netherlands Institute for Radio Astronomy (ASTRON)

W. Reich

Max Planck-institutet

H. Rottgering

Leiden University

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

Harvard-Smithsonian Center for Astrophysics

Leiden University

Netherlands Institute for Radio Astronomy (ASTRON)

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