https://doi.org/10.1140/epjc/s10052-026-15580-9
Regular Article - Theoretical Physics
Temporary EHBL-like behavior of Markarian 501 during July 2014 VHE flaring
1
Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior S/N, C.U., A.P. 70-543, 04510, Mexico, CDMX, Mexico
2
Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados del IPN, Unidad Mérida. A.P. 73, Cordemex, 97310, Mérida, Yucatán, Mexico
3
Department of Physics and Astronomy, California State University, 1250 Bellflower Boulevard, 90840, Long Beach, CA, USA
4
Instituto Universitario de Matemática Pura y Aplicada, Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain
5
Dipartimento di Fisica “E.R. Caianiello”, Università di Salerno, Via Giovanni Paolo II, 84084, Fisciano, SA, Italy
6
INFN, Gruppo collegato di Salerno, Via Giovanni Paolo II, 84084, Fisciano, SA, Italy
a
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Received:
12
December
2025
Accepted:
14
March
2026
Published online:
6
April
2026
Abstract
Markarian 501, a BL Lac object well-known as a high energy gamma-ray source, has exhibited several epochs of very high energy (VHE) gamma-ray flaring events when its synchrotron peak frequency shifted above 
Hz, a signature of extreme behavior. From July 16 to July 31, 2014 such flaring events were observed for 15 days by various telescopes. On July 19 (MJD 56857.98), the X-ray outburst from the source was at its highest and on the same day an intriguing narrow peak-like feature around 3 TeV was observed by the MAGIC telescopes, a feature inconsistent with standard interpretations. Using the well-known two-zone photohadronic model, we study these VHE gamma-ray spectra on a day-by-day basis and offer explanation. Our two-zone photohadronic scenario shows that, on MJD 56857.98, the peak-like feature appears at a cutoff energy of 
TeV. Below this energy the VHE spectrum increases slowly and is in high emission state. However, for 
TeV, the spectrum falls faster, resulting in a mild peak-like feature, not prominent enough as claimed by the MAGIC collaboration.
© The Author(s) 2026
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