Abstract
We report an observation of ultrahigh-energy (UHE) gamma rays from the Galactic center (GC) region, using 7 yr of data collected by the High-Altitude Water Cherenkov (HAWC) Observatory. The HAWC data are best described as a point-like source (HAWC J1746-2856) with a power-law spectrum ( d N / d E = ϕ E / 26 TeV γ ), where γ = −2.88 ± 0.15stat − 0.1sys and ϕ = 1.5 x 10−15 (TeV cm2 s)−1 ± 0.3 stat − 0.13 sys + 0.08 sys extending from 6 to 114 TeV. We find no evidence of a spectral cutoff up to 100 TeV using HAWC data. Two known point-like gamma-ray sources are spatially coincident with the HAWC gamma-ray excess: Sgr A* (HESS J1745-290) and the Arc (HESS J1746-285). We subtract the known flux contribution of these point sources from the measured flux of HAWC J1746-2856 to exclude their contamination and show that the excess observed by HAWC remains significant (>5σ), with the spectrum extending to >100 TeV. Our result supports that these detected UHE gamma rays can originate via hadronic interaction of PeV cosmic-ray protons with the dense ambient gas and confirms the presence of a proton PeVatron at the GC.
Recommended Citation
A. Albert and R. Alfaro and C. Alvarez and A. Andrés and J. C. Arteaga-Velázquez and D. Avila Rojas and H. A. Ayala Solares and R. Babu and E. Belmont-Moreno and A. Bernal and K. S. Caballero-Mora and T. Capistrán and A. Carramiñana and S. Casanova and U. Cotti and J. Cotzomi and S. Coutiño de León and E. De la Fuente and C. de Leon and D. Depaoli and N. Di Lalla and R. Diaz Hernandez and B. L. Dingus and M. A. DuVernois and J. C. Diaz-Velez and K. Engel and T. Ergin and C. Espinoza and K. L. Fan and K. Fang and N. Fraija and S. Fraija and J. A. Garcia-Gonzalez and F. Garfias and H. Goksu and M. M. Gonzalez and J. A. Goodman and S. Groetsch and J. P. Harding and S. Hernandez-Cadena and I. Herzog and J. Hinton and D. Huang and F. Hueyotl-Zahuantitla and T. B. Humensky and P. Huntemeyer and A. Iriarte and S. Kaufmann and D. Kieda and A. Lara and W. H. Lee and J. Lee and H. Leon Vargas and J. T. Linnemann and A. L. Longinotti and G. Luis-Raya and K. Malone and O. Martinez and J. Martinez-Castro and J. A. Matthews and P. Miranda-Romagnoli and J. A. Montes and J. A. Morales-Soto and E. Moreno and M. Mostafa and M. Najafi and L. Nellen and M. Newbold and M. U. Nisa and R. Noriega-Papaqui and L. Olivera-Nieto and N. Omodei and M. Osorio-Archila and Y. Perez Araujo and E. G. Perez-Perez and C. D. Rho and D. Rosa-Gonzalez and E. Ruiz-Velasco and H. Salazar and D. Salazar-Gallegos and A. Sandoval and M. Schneider and G. Schwefer and J. Serna-Franco and A. J. Smith and Y. Son and R. W. Springer and O. Tibolla and K. Tollefson and I. Torres and R. Torres-Escobedo and R. Turner and F. Urena-Mena and E. Valera and X. Wang and Z. Wang and I. J. Watson and E. Willox and H. Wu and S. Yu and S. Yun-Carcamo and H. Zhou, "Observation Of The Galactic Center PeVatron Beyond 100 TeV With HAWC," Astrophysical Journal Letters, vol. 973, no. 1, article no. L34, American Astronomical Society; IOP Publishing, Sep 2024.
The definitive version is available at https://doi.org/10.3847/2041-8213/ad772e
Department(s)
Physics
Publication Status
Open Access
International Standard Serial Number (ISSN)
2041-8213; 2041-8205
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2025 The Authors, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution 4.0 License.
Publication Date
01 Sep 2024
Comments
National Science Foundation, Grant B16F630069