Particle acceleration model for the broad-band baseline spectrum of the Crab nebula

Fraschetti, Federico; Pohl, Martin

doi:10.1093/mnras/stx1833

Cited by 17 publications

(18 citation statements)

References 36 publications

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“…The morphology of the Nebula, revealed by the optical and X-ray data, is non-trivial. Nonetheless, its broad-band spectral energy distribution (SED) is reasonably well described even by one-zone models, involving diverse electron distributions (Meyer et al 2010) and/or A158, page 1 of 10 A&A 635, A158 (2020) propagation and cooling effects (Martín et al 2012;Fraschetti & Pohl 2017).…”

Section: Introductionmentioning

confidence: 99%

MAGIC very large zenith angle observations of the Crab Nebula up to 100 TeV

Acciari

Ansoldi

Antonelli

et al. 2020

A&A

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Aims. We measure the Crab Nebula γ-ray spectral energy distribution in the ~100 TeV energy domain and test the validity of existing leptonic emission models at these high energies. Methods. We used the novel very large zenith angle observations with the MAGIC telescope system to increase the collection area above 10 TeV. We also developed an auxiliary procedure of monitoring atmospheric transmission in order to assure proper calibration of the accumulated data. This employs recording optical images of the stellar field next to the source position, which provides a better than 10% accuracy for the transmission measurements. Results. We demonstrate that MAGIC very large zenith angle observations yield a collection area larger than a square kilometer. In only ~ 56 h of observations, we detect the γ-ray emission from the Crab Nebula up to 100 TeV, thus providing the highest energy measurement of this source to date with Imaging Atmospheric Cherenkov Telescopes. Comparing accumulated and archival MAGIC and Fermi/LAT data with some of the existing emission models, we find that none of them provides an accurate description of the 1 GeV to 100 TeV γ-ray signal.

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Section: Introductionmentioning

confidence: 99%

MAGIC very large zenith angle observations of the Crab Nebula up to 100 TeV

Acciari

Ansoldi

Antonelli

et al. 2020

A&A

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“…Other IC models agree within a factor of two, with more recent models producing more flux. The Fraschetti and Pohl model [11] considers a single electron population with a log-parabola momentum distribution, plus synchrotron self-Compton and and cosmic microwave background as target photons, and produces similar results to Meyer above 1 TeV, but differs at lower energies. Next we consider various experiments' fits to their own VHE data.…”

Section: Fits To Crab Spectrummentioning

confidence: 99%

“…In this section we study the highest energy photons in the Crab spectrum and in other Galactic PoS(ICRC2019)723 Figure 2: Here are ratios of various fits to dN/dE, divided (for reference) by the Inverse Compton fit from Meyer [9]. The other theory fits include de Jager [10], Aharonian [8], and Fraschetti [11]. Experimental references include HAWC [1,2], HEGRA [8], HESS [3,12], MAGIC [13], and VER-ITAS [4].…”

Section: Analysis Of High Energy Photonsmentioning

confidence: 99%

The Spectrum of the Crab Nebula and Highest Energy Photons Measured by HAWC

Linnemann

Harding

Lundeen

et al. 2019

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019)

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HAWC has developed new energy algorithms using an artificial neural network for event-by-event reconstruction of Very High Energy (VHE) primary gamma ray energies. Unlike previous estimation methods for HAWC photons, these estimate photon energies with good energy precision and accuracy in a range from 1 TeV to greater than 100 TeV. Photon emission at the highest energies is of interest in understanding acceleration mechanisms of astrophysical sources and where the acceleration might cut off. We apply the new HAWC reconstruction to present the preliminary measurement of the highest energies at which photons are emitted by the Crab Nebula and by six additional sources in the galactic plane which emit above 50 TeV. We have observed photons above 200 TeV at 95% confidence. We also compare fits to the HAWC Crab spectrum with other measurements and theoretical models of the Crab spectrum.

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“…Both the Crab and Vela PWNe have well studied pulsars (PSR B0531+21 and PSR B0833-45, respectively) which allow the broadband emission to be modeled and measured within the context of the pulsar-nebula system (Seward & Wang 1988;Bühler & Giomi 2016). Studies of the Crab have indicated Lorentz factors of electrons reaching γ ≈ 10 6 (Fraschetti & Pohl 2017), emphasizing the importance of PWNe as astrophysical laboratories for relativistic processes. This is particularly important when considering the contribution of nearby PWNe to the cosmic ray positron population Grasso et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Multiwavelength Investigation of Pulsar Wind Nebula DA 495 with HAWC, VERITAS, and NuSTAR

Coerver

Wilcox

Zhang

et al. 2019

ApJ

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Pulsar Wind Nebula (PWN) DA 495 (G65.7+1.2) was detected in TeV gamma-rays by the High Altitude Water Cherenkov Observatory (HAWC) in 2017 (2HWC J1953+294). Follow-up observations by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) confirmed the association between 2HWC J1953+294 and DA 495 and found the TeV emission to be spatially coincident with the radio emission first reported in 1968. The detection of TeV gamma-rays from DA 495, along with past X-ray detection up to 10 keV, prompted high energy X-ray observations as part of the NuSTAR Galactic Legacy Survey. We present the results of these NuSTAR observations, combined with archival Chandra and XMM-Newton observations, and confirm the previous X-ray photon index of Γ 2−20 keV = 2.0 ± 0.1. We find no spectral cutoff up to 20 keV. With the spectral information for DA 495 extended to TeV gamma-rays, we were able to perform analytical modeling to test leptonic and hadronic emission scenarios. The leptonic models can explain the broadband emission, but also imply a diffuse X-ray nebula of similar extent to the radio and TeV nebulae, which cannot be confirmed by our observations. The hadronic models can simultaneously explain the spectrum and the spatial extent in all wavelengths; however, we need a very high magnetic field strength pervading the radio and TeV nebulae and a surprisingly high particle kinetic energy. These requirements deepen the mystery of the physical nature of DA 495. Future observations in radio to infrared bands and spatially resolved γ-rays can further constrain the physical conditions and radiation mechanisms in DA 495.

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Particle acceleration model for the broad-band baseline spectrum of the Crab nebula

Cited by 17 publications

References 36 publications

MAGIC very large zenith angle observations of the Crab Nebula up to 100 TeV

MAGIC very large zenith angle observations of the Crab Nebula up to 100 TeV

The Spectrum of the Crab Nebula and Highest Energy Photons Measured by HAWC

Multiwavelength Investigation of Pulsar Wind Nebula DA 495 with HAWC, VERITAS, and NuSTAR

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