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| Main Authors: | , , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2412.13804 |
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| _version_ | 1866917872460103680 |
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| author | Stasielak, J. Borodai, N. Góra, D. Niechciol, M. |
| author_facet | Stasielak, J. Borodai, N. Góra, D. Niechciol, M. |
| contents | Flares produced by certain classes of astrophysical objects may be sources of some ultra-high-energy particles, which, if they are photons, would group into clusters of events correlated in space and time. Identification of such clustering in cosmic-ray data would provide important evidence for possible existence of ultra-high-energy (UHE) photons and could potentially help identify their sources. We present an analysis method to search for space-time clustering of ultra-high-energy extensive air showers, namely the stacking method, which combines a time-clustering algorithm with an unbinned likelihood study. In addition, to enhance the capability to discriminate between signal (photon-initiated events) and background (hadron-initiated) events, we apply a photon tag. This involves using relevant probability distribution functions to classify each event as more likely to be either a photon or a hadron. We demonstrate that the stacking method can effectively distinguish between events initiated by photons and those initiated by hadrons (background). The number of photon events in a data sample, as well as the flare(s) duration can also be retrieved correctly. The stacking method with a photon tag requires only a few events to identify a photon flare. This method can be used to search for the cosmic ray sources and/or improve limits on the fluxes of UHE photons. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2412_13804 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | An improved method to search for flares from point sources of ultra-high-energy photons Stasielak, J. Borodai, N. Góra, D. Niechciol, M. High Energy Astrophysical Phenomena Flares produced by certain classes of astrophysical objects may be sources of some ultra-high-energy particles, which, if they are photons, would group into clusters of events correlated in space and time. Identification of such clustering in cosmic-ray data would provide important evidence for possible existence of ultra-high-energy (UHE) photons and could potentially help identify their sources. We present an analysis method to search for space-time clustering of ultra-high-energy extensive air showers, namely the stacking method, which combines a time-clustering algorithm with an unbinned likelihood study. In addition, to enhance the capability to discriminate between signal (photon-initiated events) and background (hadron-initiated) events, we apply a photon tag. This involves using relevant probability distribution functions to classify each event as more likely to be either a photon or a hadron. We demonstrate that the stacking method can effectively distinguish between events initiated by photons and those initiated by hadrons (background). The number of photon events in a data sample, as well as the flare(s) duration can also be retrieved correctly. The stacking method with a photon tag requires only a few events to identify a photon flare. This method can be used to search for the cosmic ray sources and/or improve limits on the fluxes of UHE photons. |
| title | An improved method to search for flares from point sources of ultra-high-energy photons |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2412.13804 |