The Crab Nebula as a standard candle in very high-energy astrophysics

By M. Meyer, D. Horns, H. Zechlin. 2010

163 citations recorded by the source corpus.

The continuum high-energy gamma-ray emission between 1 GeV and 100 TeV from the Crab Nebula has been measured for the first time in overlapping energy bands by the Fermi large-area telescope (Fermi/LAT) below ~ 100 GeV and by ground-based imaging air Cherenkov telescopes (IACTs) above ~ 60 GeV. To follow up on the phenomenological approach suggested by Hillas et al. (1998), the broad band spectral and spatial measurement (from radio to low-energy gamma-rays < 1 GeV) is used to extract the shape of the electron spectrum. While this model per construction provides an excellent description of the data at energies < 1 GeV, the predicted inverse Compton component matches the combined Fermi/LAT and IACT measurements remarkably well after including all relevant seed photon fields and fitting the average magnetic field to B = (124 +/- 6 (stat.) +15 / -6 (sys.)) {\mu}G. The close match of the resulting broad band inverse Compton component with the combined Fermi/LAT and IACTs data is used to derive instrument specific energy-calibration factors. These factors can be used to combine data from Fermi/LAT and IACTs without suffering from systematic uncertainties on the common energy scale. As a first application of the cross calibration, we derive an upper limit to the diffuse gamma-ray emission between 250 GeV and 1 TeV based upon the combined measurements of Fermi/LAT and the H.E.S.S. ground-based Cherenkov telescopes. Finally, the predictions of the magneto-hydrodynamic flow model of Kennel & Coroniti (1984) are compared to the measured SED.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/47acf02ab6fc6db6466767ad943c0fa9972b5fc9

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. J. Biteau
2. David A. Williams
3. E. Orlando
4. M. Meyer
5. D. Horns
6. Anna Franckowiak
7. B. Cerutti
8. A. Spitkovsky

In Nuclear and High Energy Physics

1. J. Biteau
2. David A. Williams
3. E. Orlando
4. D. Horns
5. M. Meyer
6. Anna Franckowiak
7. B. Cerutti
8. I. Grenier

Citations in the corpus

• Measurement of the Crab Nebula Spectrum Past 100 TeV with HAWC (2019, methodology): “Compared to the Inverse Compton model in Meyer et al. (2010), which has been used as a reference spectrum to compare the energy scale of IACTs, both methods presented here have a 20% higher flux at 7 TeV.”
• Indications for a pair-production anomaly from the propagation of VHE gamma-rays (2012, methodology): “In a recent study [72], the flux normalization of the Crab nebula between the different Cherenkov telescopes has been compared among each other in order to estimate systematic differences between the energy calibration of HESS, MAGIC, and HEGRA.”
• SIMULATIONS OF PARTICLE ACCELERATION BEYOND THE CLASSICAL SYNCHROTRON BURNOFF LIMIT IN MAGNETIC RECONNECTION: AN EXPLANATION OF THE CRAB FLARES (2013, background): “The initial −2 powerlaw of the electrons approximately represents the purely non-thermal background particles emitting the quiescent emission of the Crab Nebula, inferred from spectral modeling (Horns &Aharonian 2004; Meyer et al. 2010).”
• THE EXTRAGALACTIC BACKGROUND LIGHT, THE HUBBLE CONSTANT, AND ANOMALIES: CONCLUSIONS FROM 20 YEARS OF TeV GAMMA-RAY OBSERVATIONS (2015, result): “A systematic energy bias of ±10% is a conservative estimate with respect to the value half as large as that found in Meyer et al. (2010) by studying the marginal mismatch between HE and VHE observations of the Crab Nebula, but is comparable to the systematic error typically quoted by the observers.”
• The Search for Spatial Extension in High-latitude Sources Detected by the Fermi Large Area Telescope (2018, methodology): “This is commonly assumed to be on the order of ±15%, but a cross-calibration between the FermiLAT and IACTs, using the spectrum of the Crab Nebula, found the uncertainty to be on the order of 5% (Meyer et al. 2010).”
• Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S. (2012, background): “4 Meyer et al. (2010) have even shown that a precision of 5% on the energy scale can be achieved with atmospheric Cherenkov telescopes.”