All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

Alfaro, R.; Álvarez, C.; Álvarez, José David Ruiz; Arceo, R.; Arteaga‐Velázquez, J. C.; Rojas, D. Avila; Solares, H. A. Ayala; Barber, Ahron S.; Becerril, A.; Belmont‐Moreno, E.; BenZvi, S.; Brisbois, C.; Caballero-Mora, K. S.; Capistrán, T.; Carramiñana, A.; Casanova, S.; Castillo, M.; Cotti, U.; Cotzomi, J.; León, S. Coutińo de; León, C. De; Fuente, Eduardo de la; Hernández, R. Díaz; Dichiara, S.; Dingus, B. L.; DuVernois, Michael; Díaz–Vélez, Juan Carlos; Ellsworth, R. W.; Enríquez‐Rivera, O.; Fiorino, D. W.; Fleischhack, Henrike; Fraija, N.; García-González, J. A.; Muñoz, A. González; González, M. M.; Goodman, J. A.; Hampel-Arias, Z.; Harding, J. Patrick; Hernández-Almada, A.; Hinton, J. A.; Hueyotl-Zahuantitla, F.; Hui, C. M.; Hüntemeyer, P.; Iriarte, A.; Jardin-Blicq, A.; Joshi, Vikas; Kaufmann, S.; Lara, A.; Lauer, R.; Lennarz, D.; Vargas, H. León; Linnemann, J.; Longinotti, A. L.; Raya, Gabriel; Luna-García, R.; López-Cámara, Diego; López-Coto, R.; Malone, K.; Marinelli, S. S.; Martı́nez, O.; Martínez-Castellanos, I.; Martínez-Castro, J.; Martínez-Huerta, H.; Matthews, John; Miranda-Romagnoli, P.; Moreno, E.; Mostafá, M.; Nellen, L.; Newbold, M.; Nisa, Mehr; Noriega-Papaqui, R.; Pelayo, R.; Pretz, J.; Pérez-Pérez, E. G.; Ren, Z.; Rho, Chang Dong; Rivière, C.; Rosa-González, D.; Rosenberg, M.; Ruiz-Velasco, E.; Greus, F. Salesa; Sandoval, A.; Schneider, M.; Schoorlemmer, H.; Sinnis, G.; Smith, A. J.; Springer, R. W.; Surajbali, P.; Taboada, I.; Tibolla, O.; Tollefson, K.; Torres, I.; Ukwatta, T. N.; Villaseñor, L.; Weisgarber, T.; Westerhoff, S.; Wood, J.; Yapici, T.; Zepeda, A.; Zhou, H.

doi:10.1103/physrevd.96.122001

Cited by 80 publications

(91 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is also interesting to note that the HAWC measurement of the all-particle spectrum [23] in the 10-500 TeV energy range shows a spectral break at the energy 45.7 ± 0.1 TeV where the index is oberved to change from 2.49 ± 0.01 to 2.71 ± 0.01 (with a step of approximately the same size as the one observed for the proton flux). Evidence for a strong break in the all-particle spectrum at a rigidity 7-17 TV has also been reported by the NUCLEON experiment [8,9].…”

Section: Discussionmentioning

confidence: 68%

The shape of the cosmic ray proton spectrum

Lipari

Vernetto

2020

Astroparticle Physics

View full text Add to dashboard Cite

Recent observations of cosmic ray protons in the energy range 10 2 -10 5 GeV have revealed that the spectrum cannot be described by a simple power law. A hardening of the spectrum around an energy of order few hundred GeV, first observed by the magnetic spectrometers PAMELA and AMS02, has now been confirmed by several calorimeter detectors (ATIC, CREAM, CALET, NUCLEON and DAMPE). These new measurements reach higher energy and indicate that the hardening corresponds to a larger step in spectral index than what estimated by the magnetic spectrometers. Data at still higher energy (by CREAM, NUCLEON and DAMPE) show that the proton spectrum undergoes a marked softening at E ≈ 10 4 GeV. Understanding the origin of these unexpected spectral features is a significant challenge for models of the Galactic cosmic rays. An important open question is whether additional features are present in the proton spectrum between the softening and the "Knee". Extensive Air Shower detectors, using unfolding procedures that require the modeling of cosmic ray showers in the atmosphere, estimated the proton flux below and around the Knee (at E 3 PeV). These results however have large systematic uncertainties and are in poor agreement with each other. The measurement in the PeV energy range, recently presented by IceTop/IceCube, indicates a proton flux higher than extrapolations of the direct measurements calculated assuming a constant slope, and therefore requires the existence of an additional spectral hardening below the Knee. A clarification of this point is very important for an understanding of the origin of the Galactic cosmic rays, and is also essential for a precise calculation of the spectra of atmospheric neutrinos in the energy range (E 10 TeV) where they constitute the foreground for the emerging astrophysical ν signal.

show abstract

Section: Discussionmentioning

confidence: 68%

The shape of the cosmic ray proton spectrum

Lipari

Vernetto

2020

Astroparticle Physics

View full text Add to dashboard Cite

show abstract

“…With high background rejection and an angular resolution approaching 0.2 • at the highest energies, HAWC has been measuring very-high-energy gamma-ray emission from point and extended sources since commencing full operations in 2014 [62]. At the same time HAWC has also analyzed TeV cosmic rays through studies of the Moon and Sun Shadows [63][64][65]. In the following section, we review the analysis of the Sun in cosmic rays and extend it further to search for TeV gamma rays.…”

Section: The Hawc Gamma-ray Observatorymentioning

confidence: 99%

“…The evolution of the shadow size with energy is also an illustration of the angular resolution of the detector to cosmic rays, which has been modeled and verified in Refs. [20,61,63]. The presence of the shadow can bias the search for gamma rays in two ways:…”

Section: Sky Maps and Background Estimationmentioning

confidence: 99%

First HAWC observations of the Sun constrain steady TeV gamma-ray emission

Albert¹,

Alfaro²,

Álvarez³

et al. 2018

Phys. Rev. D

Self Cite

View full text Add to dashboard Cite

Steady gamma-ray emission up to at least 200 GeV has been detected from the solar disk in the Fermi-LAT data, with the brightest, hardest emission occurring during solar minimum. The likely cause is hadronic cosmic rays undergoing collisions in the Sun's atmosphere after being redirected from ingoing to outgoing in magnetic fields, though the exact mechanism is not understood. An important new test of the gamma-ray production mechanism will follow from observations at higher energies. Only the High Altitude Water Cherenkov (HAWC) Observatory has the required sensitivity

show abstract

“…At higher γ-ray energies the resulting spectrum is predicted to become flatter due to the emergence of the polar-cap component with E −2 in wind-SN-CRs (CR-IV [39]). Other new data can also be used for further tests, e.g., from AMS (Alpha Magnetic Spectrometer on the ISS) or HAWC, such as the spectra of various elements and secondary and primary contributions to Ni in cosmic rays (ASR18, Alfaro et al 2017, Aguilar et al 2017, 2018a).…”

Section: The Origin Of High Energy Galactic Cosmic Raysmentioning

confidence: 99%

The Origin of the Most Energetic Galactic Cosmic Rays: Supernova Explosions into Massive Star Plasma Winds

et al. 2019

View full text Add to dashboard Cite

We propose that the high energy Cosmic Ray particles up to the upturn commonly called the ankle, from around the spectral turn-down commonly called the knee, mostly come from Blue Supergiant star explosions. At the upturn, i.e., the ankle, Cosmic Rays probably switch to another source class, most likely extragalactic sources. To show this we recently compiled a set of Radio Supernova data where we compute the magnetic field, shock speed and shock radius. This list included both Blue and Red Supergiant star explosions; both data show the same magnetic field strength for these two classes of stars despite very different wind densities and velocities. Using particle acceleration theory at shocks, those numbers can be transformed into characteristic ankle and knee energies. Without adjusting any free parameters both of these observed energies are directly indicated by the supernova data. In the next step in the argument, we use the Supernova Remnant data of the starburst galaxy M82. We apply this analysis to Blue Supergiant star explosions: The shock will race to their outer edge with a magnetic field that is observed to follow over several orders of magnitude B ( r ) × r ∼ c o n s t . , with in fact the same magnetic field strength for such stellar explosions in our Galaxy, and other galaxies including M82. The speed is observed to be ∼0.1 c out to about 10 16 cm radius in the plasma wind. The Supernova shock can run through the entire magnetic plasma wind region at full speed all the way out to the wind-shell, which is of order parsec scale in M82. We compare and identify the Cosmic Ray spectrum in other galaxies, in the starburst galaxy M82 and in our Galaxy with each other; we suggest how Blue Supergiant star explosions can provide the Cosmic Ray particles across the knee and up to the ankle energy range. The data from the ISS-CREAM (Cosmic Ray Energetics and Mass Experiment at the International Space Station) mission will test this cosmic ray concept which is reasonably well grounded in two independent radio supernova data sets. The next step in developing our understanding will be to obtain future more accurate Cosmic Ray data near to the knee, and to use unstable isotopes of Cosmic Ray nuclei at high energy to probe the “piston” driving the explosion. We plan to incorporate these data with the physics of the budding black hole which is probably forming in each of these stars.

show abstract

All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

Cited by 80 publications

References 39 publications

The shape of the cosmic ray proton spectrum

The shape of the cosmic ray proton spectrum

First HAWC observations of the Sun constrain steady TeV gamma-ray emission

The Origin of the Most Energetic Galactic Cosmic Rays: Supernova Explosions into Massive Star Plasma Winds

Contact Info

Product

Resources

About