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|Title:||Single-pulse and profile-variability study of PSR J1022+1001||Authors:||Liu, K.
Lee, K. J.
Stappers, B. W.
Purver, M. B.
Janssen, G. H.
|Issue Date:||2015||Journal:||MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY||Number:||449||Issue:||1||First Page:||1158||Abstract:||Millisecond pulsars (MSPs) are known as highly stable celestial clocks. Nevertheless, recent studies have revealed the unstable nature of their integrated pulse profiles, which may limit the achievable pulsar timing precision. In this article, we present a case study on the pulse-profile variability of PSR J1022+1001. We have detected approximately 14 000 subpulses (components of single pulses) in 35-h long observations, mostly located in the trailing component of the integrated profile. Their flux densities and fractional polarization suggest that they represent the bright end of the energy distribution in ordinary emission mode and are not giant pulses. The occurrence of subpulses in the leading and trailing components of the integrated profile is shown to be correlated. For subpulses from the latter, a preferred pulse width of approximately 0.25 ms has been found. Using simultaneous observations from the Effelsberg 100-m telescope and the Westerbork Synthesis Radio Telescope, we have found that the integrated profile varies on a time-scale of a few tens of minutes. We show that improper polarization calibration and diffractive scintillation cannot be the sole reason for the observed instability. In addition, we demonstrate that timing residuals generated from averages of the detected subpulses are dominated by phase jitter and we place an upper limit of ̃700 ns on jitter noise, based on continuous 1-min integrations.||Acknowledgments:||We thank J. P. W. Verbiest for sharing the ephemeris for our timing analysis and are grateful to A. Jessner and L. Guillemot for valuable discussions. We would also like to thank the anonymous referee, who provided constructive suggestions to improve the article. KL is supported by the ERC Advanced Grant ‘LEAP’, Grant Agreement Number 227947 (PI M. Kramer). This work was carried out based on observations with the 100-m telescope of the Max-Planck-Institut für Radioastronomie at Effelsberg. The Westerbork Synthesis Radio Telescope is operated by the Netherlands Foundation for Radio Astronomy, ASTRON, with support from The Netherlands Foundation for Scientific Research (NWO).||URI:||http://hdl.handle.net/20.500.12386/24486||URL:||https://academic.oup.com/mnras/article/449/1/1158/1333417||ISSN:||0035-8711||DOI:||10.1093/mnras/stv397||Bibcode ADS:||2015MNRAS.449.1158L||Fulltext:||open|
|Appears in Collections:||1.01 Articoli in rivista|
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