Evidence of 200 TeV Photons from HAWC J1825-134

Journal Article · Thu Jan 28 00:00:00 EST 2021 · The Astrophysical Journal. Letters (Online)

DOI:https://doi.org/10.3847/2041-8213/abd77b· OSTI ID:1804419

Albert, Andrea ^[1]; Alfaro, R.; Alvarez, C.; Camacho, J. Angeles; Arteaga-Velázquez, J. C.; Arunbabu, K. P.; Rojas, D. Avila; Ayala Solares, H. A.; Baghmanyan, V.; Belmont-Moreno, E.; BenZvi, S. Y.; Brisbois, Chad ^[1]; Capistrán, T.; Carramiñana, A.; Casanova, Sabrina; Cotti, U.; Cotzomi, J.; Fuente, E. la; Hernandez, R. Diaz; Dingus, Brenda L. ^[1] ; DuVernois, M. A.; Durocher, Mora ^[1]; Díaz-Vélez, J. C.; Engel, K.; Espinoza, C.; Fang, K.; Fleischhack, H.; Fraija, N.; Galván-Gámez, A.; Garcia, D.; García-González, J. A.; Garfias, F.; Giacinti, G.; González, M. M.; Goodman, J. A.; Harding, James Patrick ^[1]; Hona, B.; Huang, Dezhi; Hueyotl-Zahuantitla, F.; Hüntemeyer, P.; Iriarte, A.; Jardin-Blicq, A.; Joshi, V.; Kunde, Gerd Joachim ^[1]; Lara, A.; Lee, W. H.; Vargas, H. León; Linnemann, J. T.; Longinotti, A. L.; Luis-Raya, G.; Lundeen, J.; Malone, Kelly Anne ^[1]; Marandon, V.; Martinez, O.; Martínez-Castro, J.; Matthews, J. A.; Miranda-Romagnoli, P.; Moreno, E.; Mostafá, M.; Nayerhoda, A.; Nellen, L.; Newbold, M.; Nisa, M. U.; Noriega-Papaqui, R.; Omodei, N.; Peisker, A.; Araujo, Y. Pérez; Pérez-Pérez, E. G.; Rho, C. D.; Rosa-González, D.; Salazar, H.; Greus, Francisco Salesa; Sandoval, A.; Schneider, M.; Serna, F.; Springer, R. W.; Tollefson, K.; Torres, I.; Torres-Escobedo, R.; Ureña-Mena, F.; Villaseñor, L.; Willox, E.; Zhou, Hao; León, C. de

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

The Earth is bombarded by ultrarelativistic particles, known as cosmic rays (CRs). CRs with energies up to a few PeV (=10¹⁵ eV), the knee in the particle spectrum, are believed to have a Galactic origin. One or more factories of PeV CRs, or PeVatrons, must thus be active within our Galaxy. The direct detection of PeV protons from their sources is not possible since they are deflected in the Galactic magnetic fields. Hundred TeV γ-rays from decaying π⁰, produced when PeV CRs collide with the ambient gas, can provide the decisive evidence of proton acceleration up to the knee. Here we report the discovery by the High Altitude Water Cerenkov (HAWC) observatory of the γ-ray source, HAWC J1825-134, whose energy spectrum extends well beyond 200 TeV without a break or cutoff. The source is found to be coincident with a giant molecular cloud. Further, the ambient gas density is as high as 700 protons cm^–3. While the nature of this extreme accelerator remains unclear, CRs accelerated to energies of several PeV colliding with the ambient gas likely produce the observed radiation.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), High Energy Physics (HEP)
• Contributing Organization: HAWC Collaboration
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1804419
• Alternate ID(s): OSTI ID: 23154057
• Report Number(s): LA-UR--20-28703
• Journal Information: The Astrophysical Journal. Letters (Online), Journal Name: The Astrophysical Journal. Letters (Online) Journal Issue: 2 Vol. 907; ISSN 2041-8213
• Publisher: Institute of Physics (IOP)
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
Astronomy and Astrophysics
Gamma-ray astronomy
Gamma-ray observatories
Gamma-ray sources
Gamma-rays