Pith. sign in

REVIEW 2 cited by

Measurement of the Crab Nebula Spectrum Past 100 TeV with HAWC

Not yet reviewed by Pith; the record is open.

This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.

SPECIMEN: schema-true, not a live event

T0 review · schema-true

One-sentence machine reading of the paper's core claim.

pith:XXXXXXXX · record.json · timestamp

arxiv 1905.12518 v3 pith:B3FPNMXO submitted 2019-05-29 astro-ph.HE astro-ph.IM

classification astro-ph.HEastro-ph.IM
keywords energygamma-rayshowerhawcbetacrabdistributionleft
verification ladder T0 review T1 audit T2 compute T3 formal
0 comments
abstract

We present TeV gamma-ray observations of the Crab Nebula, the standard reference source in ground-based gamma-ray astronomy, using data from the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory. In this analysis we use two independent energy-estimation methods that utilize extensive air shower variables such as the core position, shower angle, and shower lateral energy distribution. In contrast, the previously published HAWC energy spectrum roughly estimated the shower energy with only the number of photomultipliers triggered. This new methodology yields a much improved energy resolution over the previous analysis and extends HAWC's ability to accurately measure gamma-ray energies well beyond 100 TeV. The energy spectrum of the Crab Nebula is well fit to a log parabola shape $\left(\frac{dN}{dE} = \phi_0 \left(E/\textrm{7 TeV}\right)^{-\alpha-\beta\ln\left(E/\textrm{7 TeV}\right)}\right)$ with emission up to at least 100 TeV. For the first estimator, a ground parameter that utilizes fits to the lateral distribution function to measure the charge density 40 meters from the shower axis, the best-fit values are $\phi_o$=(2.35$\pm$0.04$^{+0.20}_{-0.21}$)$\times$10$^{-13}$ (TeV cm$^2$ s)$^{-1}$, $\alpha$=2.79$\pm$0.02$^{+0.01}_{-0.03}$, and $\beta$=0.10$\pm$0.01$^{+0.01}_{-0.03}$. For the second estimator, a neural network which uses the charge distribution in annuli around the core and other variables, these values are $\phi_o$=(2.31$\pm$0.02$^{+0.32}_{-0.17}$)$\times$10$^{-13}$ (TeV cm$^2$ s)$^{-1}$, $\alpha$=2.73$\pm$0.02$^{+0.03}_{-0.02}$, and $\beta$=0.06$\pm$0.01$\pm$0.02. The first set of uncertainties are statistical; the second set are systematic. Both methods yield compatible results. These measurements are the highest-energy observation of a gamma-ray source to date.

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 2 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. The Galactic Neutrino Sky: Predictions from Gamma-ray Source Populations

    astro-ph.HE 2026-08 conditional novelty 6.0 of 10

    A template of resolved and unresolved gamma-ray sources, added to an unmodified diffuse model, reproduces the shape and spectrum of IceCube's inner-Galaxy neutrino excess.

  2. Dissecting the Diffuse Emission of the Galaxy with the HAWC Observatory

    astro-ph.HE 2025-09 conditional novelty 6.0 of 10

    HAWC's Pass 5 analysis of 8 years of data yields new TeV diffuse galactic emission profiles with tails beyond 3 degrees latitude and a galactic-center excess relative to standard cosmic-ray propagation models.

Pith tools