Fermi Constraints on the Ejecta Speed and Prompt Emission Region of the Distant GRB 220101A
At redshift z = 4.618, GRB 220101A is the most distant gamma-ray burst (GRB) detected by Fermi/LAT to date. It is also a very energetic event, with an equivalent isotropic energy of 3.6 × 10 ^54 erg. We jointly analyzed the Fermi/GBM and LAT observations of GRB 220101A with two independent approache...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2023-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/acf4fe |
| _version_ | 1797661001790783488 |
|---|---|
| author | Lorenzo Scotton Frédéric Piron Nicola Omodei Niccolò Di Lalla Elisabetta Bissaldi |
| author_facet | Lorenzo Scotton Frédéric Piron Nicola Omodei Niccolò Di Lalla Elisabetta Bissaldi |
| author_sort | Lorenzo Scotton |
| collection | DOAJ |
| description | At redshift z = 4.618, GRB 220101A is the most distant gamma-ray burst (GRB) detected by Fermi/LAT to date. It is also a very energetic event, with an equivalent isotropic energy of 3.6 × 10 ^54 erg. We jointly analyzed the Fermi/GBM and LAT observations of GRB 220101A with two independent approaches and found a significant spectral break at sub-100 MeV energies during the prompt emission. The fast variability of the emission suggests that this spectral attenuation is caused by internal opacity to pair creation. Regardless of the nature of the emission processes assumed in the spectral analysis, we infer a moderate value for the jet Lorentz factor, Γ ∼ 110, and find that all of the high-energy emission was produced above and near the photosphere, at a distance of ∼10 ^14 cm from the central engine. We compare these results with the four other LAT-detected GRBs with similar properties. |
| first_indexed | 2024-03-11T18:39:05Z |
| format | Article |
| id | doaj.art-b45c47e584744a22955be47e5d8e7375 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-11T18:39:05Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-b45c47e584744a22955be47e5d8e73752023-10-12T13:50:37ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01956210110.3847/1538-4357/acf4feFermi Constraints on the Ejecta Speed and Prompt Emission Region of the Distant GRB 220101ALorenzo Scotton0https://orcid.org/0000-0002-0602-0235Frédéric Piron1https://orcid.org/0000-0001-6885-7156Nicola Omodei2https://orcid.org/0000-0002-5448-7577Niccolò Di Lalla3https://orcid.org/0000-0002-7574-1298Elisabetta Bissaldi4https://orcid.org/0000-0001-9935-8106Laboratoire Universe et Particules de Montpellier , CNRS/IN2P3, Place Eugène Bataillon—CC 72, Montpellier, France ; lorenzoscotton@live.itLaboratoire Universe et Particules de Montpellier , CNRS/IN2P3, Place Eugène Bataillon—CC 72, Montpellier, France ; lorenzoscotton@live.itHansen Experimental Physics Lab, Stanford University , 452 Lomita Mall, Stanford, CA, USAHansen Experimental Physics Lab, Stanford University , 452 Lomita Mall, Stanford, CA, USADipartimento di Fisica “M. Merlin” dell’Università e del Politecnico di Bari , via Amendola 173, I-70126 Bari, ItalyAt redshift z = 4.618, GRB 220101A is the most distant gamma-ray burst (GRB) detected by Fermi/LAT to date. It is also a very energetic event, with an equivalent isotropic energy of 3.6 × 10 ^54 erg. We jointly analyzed the Fermi/GBM and LAT observations of GRB 220101A with two independent approaches and found a significant spectral break at sub-100 MeV energies during the prompt emission. The fast variability of the emission suggests that this spectral attenuation is caused by internal opacity to pair creation. Regardless of the nature of the emission processes assumed in the spectral analysis, we infer a moderate value for the jet Lorentz factor, Γ ∼ 110, and find that all of the high-energy emission was produced above and near the photosphere, at a distance of ∼10 ^14 cm from the central engine. We compare these results with the four other LAT-detected GRBs with similar properties.https://doi.org/10.3847/1538-4357/acf4feGamma-ray burstsHigh energy astrophysics |
| spellingShingle | Lorenzo Scotton Frédéric Piron Nicola Omodei Niccolò Di Lalla Elisabetta Bissaldi Fermi Constraints on the Ejecta Speed and Prompt Emission Region of the Distant GRB 220101A The Astrophysical Journal Gamma-ray bursts High energy astrophysics |
| title | Fermi Constraints on the Ejecta Speed and Prompt Emission Region of the Distant GRB 220101A |
| title_full | Fermi Constraints on the Ejecta Speed and Prompt Emission Region of the Distant GRB 220101A |
| title_fullStr | Fermi Constraints on the Ejecta Speed and Prompt Emission Region of the Distant GRB 220101A |
| title_full_unstemmed | Fermi Constraints on the Ejecta Speed and Prompt Emission Region of the Distant GRB 220101A |
| title_short | Fermi Constraints on the Ejecta Speed and Prompt Emission Region of the Distant GRB 220101A |
| title_sort | fermi constraints on the ejecta speed and prompt emission region of the distant grb 220101a |
| topic | Gamma-ray bursts High energy astrophysics |
| url | https://doi.org/10.3847/1538-4357/acf4fe |
| work_keys_str_mv | AT lorenzoscotton fermiconstraintsontheejectaspeedandpromptemissionregionofthedistantgrb220101a AT fredericpiron fermiconstraintsontheejectaspeedandpromptemissionregionofthedistantgrb220101a AT nicolaomodei fermiconstraintsontheejectaspeedandpromptemissionregionofthedistantgrb220101a AT niccolodilalla fermiconstraintsontheejectaspeedandpromptemissionregionofthedistantgrb220101a AT elisabettabissaldi fermiconstraintsontheejectaspeedandpromptemissionregionofthedistantgrb220101a |