Measurement of the Iron Spectrum in Cosmic Rays by VERITAS

Abstract

We present a new measurement of the energy spectrum of iron nuclei in cosmic rays from 20 to 500 TeV. The measurement makes use of a template-based analysis method, which, for the first time, is applied to the energy reconstruction of iron-induced air showers recorded by the VERITAS array of imaging atmospheric Cherenkov telescopes. The event selection makes use of the direct Cherenkov light which is emitted by charged particles before the first interaction, as well as other parameters related to the shape of the recorded air shower images. The measured spectrum is well described by a power law $\frac{\mathrm{d}F}{\mathrm{d}E}=f_0\cdot {\left(\frac{E}{E_0}\right)}^{-\gamma }$ over the full energy range, with $\gamma =2.82\pm 0.30{(stat.)}_{-0.27}^{+0.24}(syst.)$ and $f_0=\left(4.82\pm 0.98{(stat.)}_{-2.70}^{+2.12}(syst.)\right)\cdot 10^{-7}$m${}^{-2}$s${}^{-1}$sr${}^{-1}$TeV${}^{-1}$ at $E_0=50$TeV, with no indication of a cutoff or spectral break. The measured differential flux is compatible with previous results, with improved statistical uncertainty at the highest energies.

arXiv comment16 pages, 5 figures, submitted to Phys. Rev. D

References in corpus (27)

• Big-Bang Nucleosynthesis
• PAMELA Measurements of Cosmic-ray Proton and Helium Spectra
• Detection of the Characteristic Pion-Decay Signature in Supernova Remnants
• Cosmic ray event generator Sibyll 2.1
• On the knee in the energy spectrum of cosmic rays
• QGSJET-II: towards reliable description of very high energy hadronic interactions
• Discrepant hardening observed in cosmic-ray elemental spectra
• Background Modelling in Very-High-Energy gamma-ray Astronomy
• Cosmic-Ray Proton and Helium Spectra from the First CREAM Flight
• A high performance likelihood reconstruction of gamma-rays for Imaging Atmospheric Cherenkov Telescopes
• Non-linear screening effects in high energy hadronic interactions
• Implementation of the Random Forest Method for the Imaging Atmospheric Cherenkov Telescope MAGIC
• A Monte Carlo Template based analysis for Air-Cherenkov Arrays
• Energy spectra of cosmic-ray nuclei at high energies
• Origin of the Cosmic Ray Spectral Hardening
• Energy spectra of primary and secondary cosmic-ray nuclei measured with TRACER
• On the re-summation of enhanced Pomeron diagrams
• Spectra of Cosmic Ray Protons and Helium Produced in Supernova Remnants
• Composition of Primary Cosmic-Ray Nuclei at High Energies
• A new analysis method for very high definition Imaging Atmospheric Cherenkov Telescopes as applied to the CAT telescope
• First ground based measurement of atmospheric Cherenkov light from cosmic rays
• TeV cosmic-ray proton and helium spectra in the myriad model
• Status of the VERITAS Observatory
• A new template background estimate for source searching in TeV gamma-ray astronomy
• Cosmic rays from the knee to the second knee: 10^14 to 10^18 eV
• Measurement of the cosmic ray energy spectrum using hybrid events of the Pierre Auger Observatory
• A High Resolution Method for Measuring Cosmic Ray Composition beyond 10 TeV

Cited by in corpus (5)

• Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers
• Cosmic-ray database update: ultra-high energy, ultra-heavy, and anti-nuclei cosmic-ray data (CRDB v4.0)
• Effect of the uncertainty in the hadronic interaction models on the estimation of the sensitivity of the Cherenkov Telescope Array
• Potential for measuring the longitudinal and lateral profile of muons in TeV air showers with IACTs
• The Very Energetic Radiation Imaging Telescope Array System (VERITAS)