Upper limits on the isotropic diffuse flux of cosmic PeV photons from Carpet-2 observations

Isotropic diffuse gamma-ray flux in the PeV energy band is an important tool for multimessenger tests of models of the origin of high-energy astrophysical neutrinos and for new-physics searches. So far, this flux has not yet been observed. Carpet-2 is an air-shower experiment capable of detecting astrophysical gamma rays with energies above 0.1 PeV. Here we report the upper limits on the isotropic gamma-ray flux from Carpet-2 data obtained in 1999-2011 and 2018-2022. These results, obtained with the new statistical method based on the shape of the muon-number distribution, summarize Carpet-2 observations as the upgraded installation, Carpet-3, starts its operation.Comment: 5 pages, 3 figures, JETPL.cls; V2: references added, version accepted by JETP Letter

Search for astrophysical PeV gamma rays from point sources with Carpet-2

Early results of the search for Eγ > 1 PeV cosmic photons from point sources with the data of Carpet–2, an air-shower array equipped with a 175 m2 muon detector, are presented. They include 95% CL upper limits on PeV photon fluxes from stacked directions of high-energy IceCube neutrino events and from four predefined sources, Crab, Cyg X-3, Mrk 421 and Mrk 501. An insignificant excess of events from Mrk 421 will be further monitored. Prospects of the use of the upgraded installation, Carpet–3 (410 m2 muon detector), scheduled to start data taking in 2019, for searches of Eγ > 100 TeV photons, are briefly discussed

Search for astrophysical PeV gamma rays from point sources with

Early results of the search for Eγ > 1 PeV cosmic photons from point sources with the data of Carpet–2, an air-shower array equipped with a 175 m2 muon detector, are presented. They include 95% CL upper limits on PeV photon fluxes from stacked directions of high-energy IceCube neutrino events and from four predefined sources, Crab, Cyg X-3, Mrk 421 and Mrk 501. An insignificant excess of events from Mrk 421 will be further monitored. Prospects of the use of the upgraded installation, Carpet–3 (410 m2 muon detector), scheduled to start data taking in 2019, for searches of Eγ > 100 TeV photons, are briefly discussed