H.E.S.S. follow-up observations of GRB 221009A
GRB 221009A is the brightest gamma-ray burst (GRB) ever detected. To probe the very-high-energy (VHE; >100 GeV) emission, the High Energy Stereoscopic System (H.E.S.S.) began observations 53 hr after the triggering event, when the brightness of the moonlight no longer precluded observations....
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Journal article |
| Language: | English |
| Published: |
American Astronomical Society
2023
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| _version_ | 1797110639352610816 |
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| author | Aharonian, F Benkhali, FA Aschersleben, J Cotter, G |
| author2 | H.E.S.S. Collaboration |
| author_facet | H.E.S.S. Collaboration Aharonian, F Benkhali, FA Aschersleben, J Cotter, G |
| author_sort | Aharonian, F |
| collection | OXFORD |
| description | GRB 221009A is the brightest gamma-ray burst (GRB) ever detected. To probe the very-high-energy (VHE; >100 GeV) emission, the High Energy Stereoscopic System (H.E.S.S.) began observations 53 hr after the triggering event, when the brightness of the moonlight no longer precluded observations. We derive differential and integral upper limits using H.E.S.S. data from the third, fourth, and ninth nights after the initial GRB detection, after applying atmospheric corrections. The combined observations yield an integral energy flux upper limit of Φ UL 95 % = 9.7 × 10 − 12 erg cm − 2 s − 1 above E thr = 650 GeV. The constraints derived from the H.E.S.S. observations complement the available multiwavelength data. The radio to X-ray data are consistent with synchrotron emission from a single electron population, with the peak in the spectral energy distribution occurring above the X-ray band. Compared to the VHE-bright GRB 190829A, the upper limits for GRB 221009A imply a smaller gamma-ray to X-ray flux ratio in the afterglow. Even in the absence of a detection, the H.E.S.S. upper limits thus contribute to the multiwavelength picture of GRB 221009A, effectively ruling out an IC-dominated scenario. |
| first_indexed | 2024-03-07T07:57:39Z |
| format | Journal article |
| id | oxford-uuid:8635a923-42fa-4fb3-a74c-e11c024adf9b |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:57:39Z |
| publishDate | 2023 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | oxford-uuid:8635a923-42fa-4fb3-a74c-e11c024adf9b2023-08-24T15:50:08ZH.E.S.S. follow-up observations of GRB 221009AJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:8635a923-42fa-4fb3-a74c-e11c024adf9bEnglishSymplectic ElementsAmerican Astronomical Society2023Aharonian, FBenkhali, FAAschersleben, JCotter, GH.E.S.S. CollaborationGRB 221009A is the brightest gamma-ray burst (GRB) ever detected. To probe the very-high-energy (VHE; >100 GeV) emission, the High Energy Stereoscopic System (H.E.S.S.) began observations 53 hr after the triggering event, when the brightness of the moonlight no longer precluded observations. We derive differential and integral upper limits using H.E.S.S. data from the third, fourth, and ninth nights after the initial GRB detection, after applying atmospheric corrections. The combined observations yield an integral energy flux upper limit of Φ UL 95 % = 9.7 × 10 − 12 erg cm − 2 s − 1 above E thr = 650 GeV. The constraints derived from the H.E.S.S. observations complement the available multiwavelength data. The radio to X-ray data are consistent with synchrotron emission from a single electron population, with the peak in the spectral energy distribution occurring above the X-ray band. Compared to the VHE-bright GRB 190829A, the upper limits for GRB 221009A imply a smaller gamma-ray to X-ray flux ratio in the afterglow. Even in the absence of a detection, the H.E.S.S. upper limits thus contribute to the multiwavelength picture of GRB 221009A, effectively ruling out an IC-dominated scenario. |
| spellingShingle | Aharonian, F Benkhali, FA Aschersleben, J Cotter, G H.E.S.S. follow-up observations of GRB 221009A |
| title | H.E.S.S. follow-up observations of GRB 221009A |
| title_full | H.E.S.S. follow-up observations of GRB 221009A |
| title_fullStr | H.E.S.S. follow-up observations of GRB 221009A |
| title_full_unstemmed | H.E.S.S. follow-up observations of GRB 221009A |
| title_short | H.E.S.S. follow-up observations of GRB 221009A |
| title_sort | h e s s follow up observations of grb 221009a |
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