Measuring pulse times of arrival from broad-band pulsar observations

K Liu (1, 2) , G. Desvignes (3) , Ismaël Cognard (2, 1) , B.W. Stappers (4) , J.P W. Verbiest (3, 5) , K.J. Lee (3, 6) , D.J. Champion (3) , M Kramer (3, 4) , P.C.C. Freire (3) , R Karuppusamy (3)

1 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
2 USN - Unité Scientifique de la Station de Nançay
3 MPIFR - Max-Planck-Institut für Radioastronomie
4 University of Manchester [Manchester]
5 Universitat Bielefeld
6 KIAA, Peking University

In recent years, instrumentation enabling pulsar observations with unprecedentedly high frac-tional bandwidth has been under development which can be used to substantially improve the precision of pulsar timing experiments. The traditional template-matching method used to calculate pulse times of arrival (ToAs) may not function effectively on these broad-band data due to a variety of effects such as diffractive scintillation in the interstellar medium, profile variation as a function of frequency, dispersion measure (DM) evolution, and so forth. In this paper, we describe the channelized discrete Fourier transform method that can greatly mitigate the influence of the aforementioned effects when measuring ToAs from broad-band timing data. The method is tested on simulated data, and its potential in improving timing precision is shown. We further apply the method to PSR J1909−3744 data collected at the Nançay Radio Telescope with the Nançay Ultimate Pulsar Processing Instrument. We demonstrate removal of systematics due to the scintillation effect as well as improvement on ToA measurement uncertainties. Our method also determines temporal variations in DM, which are consistent with multichannel timing approaches used earlier.

Keywords: methods: data analysis – pulsars: general – pulsars: individual (PSR J1909−3744).

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]

K Liu, G. Desvignes, Ismaël Cognard, B.W. Stappers, J.P W. Verbiest, et al.. Measuring pulse times of arrival from broad-band pulsar observations. Monthly Notices of the Royal Astronomical Society, 2014, 443, pp.3752 - 3760. ⟨10.1093/mnras/stu1420⟩. ⟨insu-01111454⟩