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| Main Authors: | , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2512.03192 |
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| _version_ | 1866912745667952640 |
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| author | Stern, Boris Tkachev, Igor |
| author_facet | Stern, Boris Tkachev, Igor |
| contents | The extragalactic magnetic field could be detected by searching for signatures of the electromagnetic cascade initiated by high-energy photons on the intergalactic radiation and deflected by the field. This process produces a time delay and an extended gamma-ray halo around the source, which are looked for. We propose a new signature of electromagnetic echoes: the asymmetry of the gamma-ray distribution around blazars. As a measure of asymmetry, we use the offset of the gamma-ray distribution to the location of the blazar. This offset is due to the tilt of the jet of the blazar relative to the line of sight. Using a subsample of the 10 brightest BL Lacs, we exclude the range of extragalactic magnetic fields from $10^{-16}$ to $10^{-14}$ G, assuming that these objects have maintained a constant average luminosity over hundreds of thousands of years. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_03192 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | New Method for Investigating the Presence of Extragalactic Magnetic Fields Stern, Boris Tkachev, Igor Cosmology and Nongalactic Astrophysics The extragalactic magnetic field could be detected by searching for signatures of the electromagnetic cascade initiated by high-energy photons on the intergalactic radiation and deflected by the field. This process produces a time delay and an extended gamma-ray halo around the source, which are looked for. We propose a new signature of electromagnetic echoes: the asymmetry of the gamma-ray distribution around blazars. As a measure of asymmetry, we use the offset of the gamma-ray distribution to the location of the blazar. This offset is due to the tilt of the jet of the blazar relative to the line of sight. Using a subsample of the 10 brightest BL Lacs, we exclude the range of extragalactic magnetic fields from $10^{-16}$ to $10^{-14}$ G, assuming that these objects have maintained a constant average luminosity over hundreds of thousands of years. |
| title | New Method for Investigating the Presence of Extragalactic Magnetic Fields |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2512.03192 |