Optical polarization of the Crab pulsar: precision measurements and comparison to the radio emission

Słowikowska, A.; Kanbach, G.; Krämer, M.; Stefanescu, A.

doi:10.1111/j.1365-2966.2009.14935.x

Cited by 94 publications

(110 citation statements)

References 55 publications

(87 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, from this work we see that a simple synchrotron model gives good agreement with observation. The linear polarisation peaks on the rising edge of the main pulse, in agreement with Smith et al (1988) andS lowikowska et al 2009. We find that, for the most part, the radiation is circularly polarised, with an interplay between circular and linear polarisation occurring on the rising edge of the main peak.…”

Section: Discussionsupporting

confidence: 78%

Inverse Mapping of Pulsar Magnetospheres: Optical Emission Comes From 300 km Above the Surface

et al. 2011

View full text Add to dashboard Cite

Abstract. In order to determine the emission height of the optical photons from pulsars we present an inverse mapping approach, which is directly constrained by empirical data. The model discussed is for the case of the Crab pulsar. Our method, which uses the optical Stokes parameters, determines the most likely geometry for emission including the magnetic-field inclination angle (α), the observer's line-of-sight angle (χ) and emission height. We discuss the computational implementation of the approach, and the physical assumptions made. We find that the most likely emission altitude is at 20% of the light-cylinder radius above the stellar surface in the open field region.

show abstract

Section: Discussionsupporting

confidence: 78%

Inverse Mapping of Pulsar Magnetospheres: Optical Emission Comes From 300 km Above the Surface

et al. 2011

View full text Add to dashboard Cite

show abstract

“…The Q and U variations in AR Sco are qualitatively similar to that seen in the optical polarimetry of the Crab pulsar [6], although for the Crab p and θ variations show somewhat different morphologies, with more abrupt θ "swings", possibly a consequence of the lower phase resolution of the AR Sco data. The polarized flux for the Crab shows a duty cycle of ∼30%, less that the minimum duty cycle estimated for AR Sco of ∼60%.…”

Section: Polarization Discovery and Behavioursupporting

confidence: 52%

Polarimetric Evidence of the First White Dwarf Pulsar: The Binary System AR Scorpii

et al. 2018

View full text Add to dashboard Cite

Abstract:The binary star AR Scorpii was recently discovered to exhibit high amplitude coherent variability across the electromagnetic spectrum (ultraviolet to radio) at two closely spaced ∼2 min periods, attributed to the spin period of a white dwarf and the beat period. There is strong evidence (low X-ray luminosity, lack of flickering and absense of broad emission lines) that AR Sco is a detached non-accreting system whose luminosity is dominated by the spin-down power of a white dwarf, due to magnetohydrodynamical (MHD) interactions with its M5 companion. Optical polarimetry has revealed highly pulsed linear polarization on the same periods, reaching a maximum of 40%, consistent with a pulsar-like dipole, with the Stokes Q and U variations reminiscent of the Crab pulsar. These observations, coupled with the spectral energy distribution (SED) which is dominated by non-thermal emission, characteristic of synchrotron emission, support the notion that a strongly magnetic (∼200 MG) white dwarf is behaving like a pulsar, whose magnetic field interacts with the secondary star's photosphere and magnetosphere. Radio synchrotron emission is produced from the pumping action of the white dwarf's magnetic field on coronal loops from the M-star companion, while emission at high frequencies (UV/optical/X-ray) comes from the particle wind, driven by large electric potential, again reminiscent of processes seen in neutron star pulsars.

show abstract

“…Słowikowska et al 2009). The pulse shape is characterized by a double-peak profile, separated in phase by ∼140 • .…”

Section: Introductionmentioning

confidence: 99%

Aqueye optical observations of the Crab Nebula pulsar

Germanà

Zampieri

Barbieri

et al. 2012

A&A

View full text Add to dashboard Cite

Context. We observed the Crab pulsar in October 2008 at the Copernico Telescope in Asiago -Cima Ekar with the optical photon counter Aqueye (the Asiago Quantum Eye), which has the best temporal resolution and accuracy ever achieved in the optical domain (hundreds of picoseconds). Aims. Our goal was to perform a detailed analysis of the optical period and phase drift of the main peak of the Crab pulsar and compare it with the Jodrell Bank ephemerides. Methods. We determined the position of the main peak using the steepest zero of the cross-correlation function between the pulsar signal and an accurate optical template. Results. The pulsar rotational period and period derivative have been measured with great accuracy using observations covering only a two day time interval. The error on the period is 1.7 ps, limited only by the statistical uncertainty. Both the rotational frequency and its first derivative agree with those from the Jodrell Bank radio ephemerides archive. We also found evidence that the optical peak precedes the radio peak by ∼230 μs. The distribution of phase residuals of the whole dataset is slightly more scattered than that of a synthetic signal generated as a sequence of pulses distributed in time with the probability proportional to the pulse shape. Conclusions. The counting statistics and quality of the data allowed us to determine the pulsar period and period derivative with great accuracy in two days only. The time of arrival of the optical peak of the Crab pulsar precedes the radio peak in agreement with what was recently reported in the literature. The distribution of the phase residuals can be approximated with a Gaussian and is consistent with being completely caused by photon noise (for the best data sets).

show abstract

Optical polarization of the Crab pulsar: precision measurements and comparison to the radio emission

Cited by 94 publications

References 55 publications

Inverse Mapping of Pulsar Magnetospheres: Optical Emission Comes From 300 km Above the Surface

Inverse Mapping of Pulsar Magnetospheres: Optical Emission Comes From 300 km Above the Surface

Polarimetric Evidence of the First White Dwarf Pulsar: The Binary System AR Scorpii

Aqueye optical observations of the Crab Nebula pulsar

Contact Info

Product

Resources

About