Abstract
The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory surveys the very high-energy sky in the 300 GeV to >100 TeV energy range. HAWC has detected two blazars above 11σ, Markarian 421 (Mrk 421) and Markarian 501 (Mrk 501). The observations are comprised of data taken in the period between 2015 June and 2018 July, resulting in ∼1038 days of exposure. In this work, we report the time-averaged spectral analyses for both sources, above 0.5 TeV. Taking into account the flux attenuation due to the extragalactic background light, the intrinsic spectrum of Mrk 421 is described by a power law with an exponential energy cutoff with index α=2.26±0.12stat-0.2+0.17sys and energy cutoff Ec=5.1±1.6stat-2.5+1.4sys TeV, while the intrinsic spectrum of Mrk 501 is better described by a simple power law with index α=2.61±0.11stat-0.07+0.01sys . The maximum energies at which the Mrk 421 and Mrk 501 signals are detected are 9 and 12 TeV, respectively. This makes these some of the highest energy detections to date for spectra averaged over years-long timescales. Since the observation of gamma radiation from blazars provides information about the physical processes that take place in their relativistic jets, it is important to study the broadband spectral energy distributions (SEDs) of these objects. For this purpose, contemporaneous data in the gamma-ray band to the X-ray range, and literature data in the radio to UV range, were used to build time-averaged SEDs that were modeled within a synchrotron-self Compton leptonic scenario.
Recommended Citation
A. Albert et al., "Long-term Spectra Of The Blazars Mrk 421 And Mrk 501 At TeV Energies Seen By HAWC," Astrophysical Journal, vol. 929, no. 2, article no. 125, American Astronomical Society; IOP Publishing, Apr 2022.
The definitive version is available at https://doi.org/10.3847/1538-4357/ac58f6
Department(s)
Physics
Publication Status
Open Access
International Standard Serial Number (ISSN)
1538-4357; 0004-637X
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 Apr 2022
Comments
National Science Foundation, Grant DEC-2017/27/B/ST9/02272