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The Crab Nebula and Pulsar between 500 GeV and 80 TeV: Observations with the HEGRA stereoscopic air Cherenkov telescopes
Astrophysics · Submitted 6 Jul 2004
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim The spectrum extends up to energies of 80 TeV and is well matched by model calculations in the framework of inverse Compton scattering of various seed photons in the nebula including for the first time a recently detected compact emission region at mm-wavelengths.
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The abstract, sentence by sentence
The Crab supernova remnant has been observed regularly with the stereoscopic system of 5 imaging air Cherenkov telescopes that was part of the High Energy Gamma Ray Astronomy (HEGRA) experiment. In total, close to 400 hours of useful data have been collected from 1997 until 2002. The spectrum extends up to energies of 80 TeV and is well matched by model calculations in the framework of inverse Compton scattering of various seed photons in the nebula including for the first time a recently detected compact emission region at mm-wavelengths. The observed indications for a gradual steepening of the energy spectrum in data is expected in the inverse Compton emission model.The average magnetic field in the emitting volume is determined to be $(161.6\pm0.8mathrm{stat}\pm18_\mathrm{sys}) \mu$G. The presence of protons in the nebula is not required to explain the observed flux and upper limits on the injected power of protons are calculated being as low as 20 % of the total spin down luminosity for bulk Lorentz factors of the wind in the range of $10^4-10^6$.The position and size of the emission region have been studied over a wide range of energies. The position is shifted by 13\arcsec to the west of the pulsar with a systematic uncertainty of 25\arcsec. No significant shift in the position with energy is observed. The size of the emission region is constrained to be less than 2\arcmin at energies between 1 and 10 TeV. Above 30 TeV the size is constrained to be less than 3\arcmin.No indications for pulsed emission has been found and upper limits in differential bins of energy have been calculated reaching typically 1-3 % of the unpulsed component.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | The Crab supernova remnant has been observed regularly with the stereoscopic system of 5 imaging air Cherenkov telescopes that was part of the High Energy Gamma Ray Astronomy (HEGRA) experiment. | method 0.90 | 0.77 | 0.03 | asserted 1.00 |
| s1 | In total, close to 400 hours of useful data have been collected from 1997 until 2002. | method 0.99 | 0.90 | 0.02 | asserted 1.00 |
| s2 | The spectrum extends up to energies of 80 TeV and is well matched by model calculations in the framework of inverse Compton scattering of various seed photons in the nebula including for the first time a recently detected compact emission region at mm-wavelengths. | result 0.98 | 0.86 | 0.37 | asserted 0.99 |
| s3 | The observed indications for a gradual steepening of the energy spectrum in data is expected in the inverse Compton emission model.The average magnetic field in the emitting volume is determined to be $(161.6\pm0.8mathrm{stat}\pm18_\mathrm{sys}) \mu$G. | result 0.84 | 0.90 | 0.19 | asserted 0.89 |
| s4 | The presence of protons in the nebula is not required to explain the observed flux and upper limits on the injected power of protons are calculated being as low as 20 % of the total spin down luminosity for bulk Lorentz factors of the wind in the range of $10^4-10^6$.The position and size of the emission region have been studied over a wide range of energies. | result 0.96 | 0.92 | 0.22 | asserted 0.90 |
| s5 | The position is shifted by 13\arcsec to the west of the pulsar with a systematic uncertainty of 25\arcsec. | result 1.00 | 0.92 | 0.04 | asserted 1.00 |
| s6 | No significant shift in the position with energy is observed. | result 1.00 | 0.94 | 0.06 | asserted 0.99 |
| s7 | The size of the emission region is constrained to be less than 2\arcmin at energies between 1 and 10 TeV. | result 1.00 | 0.94 | 0.05 | asserted 1.00 |
| s8 | Above 30 TeV the size is constrained to be less than 3\arcmin.No indications for pulsed emission has been found and upper limits in differential bins of energy have been calculated reaching typically 1-3 % of the unpulsed component. | result 1.00 | 0.95 | 0.08 | asserted 0.99 |
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The paper
Original abstract
The Crab supernova remnant has been observed regularly with the stereoscopic system of 5 imaging air Cherenkov telescopes that was part of the High Energy Gamma Ray Astronomy (HEGRA) experiment. In total, close to 400 hours of useful data have been collected from 1997 until 2002. The spectrum extends up to energies of 80 TeV and is well matched by model calculations in the framework of inverse Compton scattering of various seed photons in the nebula including for the first time a recently detected compact emission region at mm-wavelengths. The observed indications for a gradual steepening of the energy spectrum in data is expected in the inverse Compton emission model.The average magnetic field in the emitting volume is determined to be $(161.6\pm0.8mathrm{stat}\pm18_\mathrm{sys}) \mu$G. The presence of protons in the nebula is not required to explain the observed flux and upper limits on the injected power of protons are calculated being as low as 20 % of the total spin down luminosity for bulk Lorentz factors of the wind in the range of $10^4-10^6$.The position and size of the emission region have been studied over a wide range of energies. The position is shifted by 13\arcsec to the west of the pulsar with a systematic uncertainty of 25\arcsec. No significant shift in the position with energy is observed. The size of the emission region is constrained to be less than 2\arcmin at energies between 1 and 10 TeV. Above 30 TeV the size is constrained to be less than 3\arcmin.No indications for pulsed emission has been found and upper limits in differential bins of energy have been calculated reaching typically 1-3 % of the unpulsed component.
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References
How the literature uses it
9 arXiv papers cite this in 14 sentences
Papers citing it · 6 sentences without a confident label
Uses its data or values 5 papers
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To constrain oscillation effects we consider a combination of the recent 100+ TeV gamma ray data from Tibet AS$γ$ [ref] and HAWC [ref] , together with previous measurements from HEGRA [ref] and MAGIC [ref] .
Axion and dark photon limits from Crab Nebula high energy gamma-rays · Fits to Gamma Rays · 1.00
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This constraint has been tightened to $|η_±| 0.05$, thanks to observations of 80 TeV photons by HEGRA [ref] .
New constraints on Planck-scale Lorentz Violation in QED from the Crab Nebula · Photon decay · 0.82
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Thus, when we consider the 80 TeV photons observed by HEGRA [ref] we have $|η_+|<0.05$.
Loop Quantum Gravity Phenomenology: Linking Loops to Observational Physics · Dynamical constraints arising from photon stability · 0.98
Cites it as background 2 papers
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Very high energy $γ$-rays from the CN were detected in the pioneering observations by Whipple [ref] , and, since then, by several Imaging Atmospheric Čerenkov Telescopes (IACT) (see, for example, [ref] ) and Extensive Air Shower (EAS) detectors.
New constraints on Planck-scale Lorentz Violation in QED from the Crab Nebula · The Crab Nebula · 0.81
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In case of the Crab Nebula, the extended cloud of non-thermal plasma is radiating in multi-wavelength, from radio to gamma-ray [ref] .
Fermi Large Area Telescope Observations of the Fast-dimming Crab Nebula in 60-600 MeV · Introduction · 0.99
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