Crab Nebula Pulsar NP 0532

The Crab Nebula is the brightest TeV gamma-ray source in the sky and has been used for the past 25 years as a reference source in TeV astronomy, for calibration and verification of new TeV instruments. The High Altitude Water Cherenkov Observatory (HAWC), completed in early 2015, has been used to observe the Crab Nebula at high significance across nearly the full spectrum of energies to which HAWC is sensitive. HAWC is unique for its wide field-of-view, nearly 2 sr at any instant, and its high-energy reach, up to 100 TeV. HAWC's sensitivity improves with the gamma-ray energy. Above ∼1 TeV the sensitivity is driven by the best background rejection and angular resolution ever achieved for a wide-field ground array.We present a time-integrated analysis of the Crab using 507 live days of HAWC data from 2014 November to 2016 June. The spectrum of the Crab is fit to a function of the form φ(E) = φ 0 (E/E 0 ) −α−β·ln(E/E0) . The data is well-fit with values of α = 2.63 ± 0.03, β = 0.15 ± 0.03, and log 10 (φ 0 cm 2 s TeV) = −12.60 ± 0.02 when E 0 is fixed at 7 TeV and the fit applies between 1 and 37 TeV. Study of the systematic errors in this HAWC measurement is discussed and estimated to be ±50% in the photon flux between 1 and 37 TeV.Confirmation of the Crab flux serves to establish the HAWC instrument's sensitivity for surveys of the sky. The HAWC survey will exceed sensitivity of current-generation observatories and open a new view of 2/3 of the sky above 10 TeV.

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“…While the pulsar position is known more precisely (e.g. Comella et al (1969)), this precision is sufficient for use in HAWC. Table 2.…”

Section: Calibrationmentioning

confidence: 99%

Observation of the Crab Nebula with the HAWC Gamma-Ray Observatory

Abeysekara

Albert

Alfaro

et al. 2017

ApJ

306

387

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“…As an example, we apply this method to the Crab pulsar, which has been studied from radio, optical, X-ray to γ-ray wavelength since its discovery [83,84]. Its period and period derivative are P = 33.…”

Section: Traditional Outer-gap Modelsmentioning

confidence: 99%

High-Energy Emission From Pulsar Magnetospheres

Hirotani

2006

Mod. Phys. Lett. A

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A synthesis of the present knowledge on gamma-ray emission from the magnetosphere of a rapidly rotating neutron star is presented, focusing on the electrodynamics of particle accelerators. The combined curvature, synchrotron, and inverse-Compton emission from ultra-relativistic positrons and electrons, which are created by two-photon and/or one-photon pair creation processes, or emitted from the neutron-star surface, provide us with essential information on the properties of the accelerator -electric potential drop along the magnetic field lines. A new accelerator model, which is a mixture of traditional inner-gap and outer gap models, is also proposed, by solving the Poisson equation for the electrostatic potential together with the Boltzmann equations for particles and gamma-rays in the two-dimensional configuration and twodimensional momentum spaces.

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“…Since its discovery (Staelin & Reifenstein 1968;Comella et al 1969), the pulsar in the Crab nebula has been one of the most often targeted objects in the sky at all wavelengths, from radio to very high energy rays, serving as a test bed for pulsar theories as well as for studying astrophysical non-thermal processes. Optical pulsations were discovered more than 40 years ago (Cocke et al 1969;Lynds et al 1969) and the Crab pulsar was indeed the first celestial object to be detected as a pulsating source in the optical band.…”

Section: Introductionmentioning

confidence: 99%

Aqueye optical observations of the Crab Nebula pulsar

Germanà

Zampieri

Barbieri

et al. 2012

A&A

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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).

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Crab Nebula Pulsar NP 0532

Cited by 106 publications

References 4 publications

Observation of the Crab Nebula with the HAWC Gamma-Ray Observatory

Observation of the Crab Nebula with the HAWC Gamma-Ray Observatory

High-Energy Emission From Pulsar Magnetospheres

Aqueye optical observations of the Crab Nebula pulsar

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