A Comprehensive Analysis of Text-Book-Version Afterglow Light curves of Gamma-Ray Bursts and Implication for Universal Radiation Physics of Baryonic Jets
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| Autores principales: | , , , |
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| Formato: | Preprint |
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2024
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| _version_ | 1866929457725440000 |
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| author | Zhang, Lu-Lu Zhong, Shu-Qing Xin, Li-Ping Liang, En-Wei |
| author_facet | Zhang, Lu-Lu Zhong, Shu-Qing Xin, Li-Ping Liang, En-Wei |
| contents | The standard external shock model in the thin-shell scenario predicts an onset bump in the early optical afterglow light curves of gamma-ray bursts (GRBs). We collect such a textbook-version light curve sample of $30$ GRBs, and derive the jet properties from our joint fit to their X-ray and optical afterglow light curves. It is found that the distributions of the isotropic initial Lorentz factors ($Γ_0$), the deceleration radii ($R_{\rm dec}$), and the magnetic field strength ($B_0$) are log-normal, but the distributions of the isotropic kinetic energy ($E_{\rm k, iso}$), medium density ($n_{0}$), and the magnetization parameter ($σ_{B}\equivε_B/ε_e$) are tentatively bimodal. A tight $R_{\rm dec}\mbox{-}B_{0}\mbox{-}σ_{B}$ relation is found. It infers a universal $ε_e E_{\rm k,iso}$ among bursts, plausibly supporting the previous argument of a universal GRB radiation energy among GRBs. A jet break is required for modeling the light curves of $26$ GRBs. The distributions of the jet opening angles and the jet-corrected kinetic energies log-normally center at $\log θ_{\rm j,c}/{\rm rad}=-1.51$ (standard deviation $σ=0.27$) and $\log (E_{\rm k, j,c}/{\rm erg})=51.78$ ($σ=0.54$), respectively. Those GRBs ($19$ GRBs), whose prompt gamma-ray emission is well estimated with broad energy-band observations, satisfy the previously discovered $L_{\rm γ, p, iso}-E_{\rm p,z}-Γ_{0}$ relation, and their gamma-ray radiation efficiencies log-normally distribute in the range from $0.04\%$ to $10\%$ with a central value of $0.42\%$. Such a low efficiency favors the baryonic fireball model, and the distribution of their baryon mass loading in the GRB ejecta log-normally centers at $\log (M_{\rm fb,c}/M_{\rm sun})=-5$ ($σ=0.75$). |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2408_06694 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | A Comprehensive Analysis of Text-Book-Version Afterglow Light curves of Gamma-Ray Bursts and Implication for Universal Radiation Physics of Baryonic Jets Zhang, Lu-Lu Zhong, Shu-Qing Xin, Li-Ping Liang, En-Wei High Energy Astrophysical Phenomena The standard external shock model in the thin-shell scenario predicts an onset bump in the early optical afterglow light curves of gamma-ray bursts (GRBs). We collect such a textbook-version light curve sample of $30$ GRBs, and derive the jet properties from our joint fit to their X-ray and optical afterglow light curves. It is found that the distributions of the isotropic initial Lorentz factors ($Γ_0$), the deceleration radii ($R_{\rm dec}$), and the magnetic field strength ($B_0$) are log-normal, but the distributions of the isotropic kinetic energy ($E_{\rm k, iso}$), medium density ($n_{0}$), and the magnetization parameter ($σ_{B}\equivε_B/ε_e$) are tentatively bimodal. A tight $R_{\rm dec}\mbox{-}B_{0}\mbox{-}σ_{B}$ relation is found. It infers a universal $ε_e E_{\rm k,iso}$ among bursts, plausibly supporting the previous argument of a universal GRB radiation energy among GRBs. A jet break is required for modeling the light curves of $26$ GRBs. The distributions of the jet opening angles and the jet-corrected kinetic energies log-normally center at $\log θ_{\rm j,c}/{\rm rad}=-1.51$ (standard deviation $σ=0.27$) and $\log (E_{\rm k, j,c}/{\rm erg})=51.78$ ($σ=0.54$), respectively. Those GRBs ($19$ GRBs), whose prompt gamma-ray emission is well estimated with broad energy-band observations, satisfy the previously discovered $L_{\rm γ, p, iso}-E_{\rm p,z}-Γ_{0}$ relation, and their gamma-ray radiation efficiencies log-normally distribute in the range from $0.04\%$ to $10\%$ with a central value of $0.42\%$. Such a low efficiency favors the baryonic fireball model, and the distribution of their baryon mass loading in the GRB ejecta log-normally centers at $\log (M_{\rm fb,c}/M_{\rm sun})=-5$ ($σ=0.75$). |
| title | A Comprehensive Analysis of Text-Book-Version Afterglow Light curves of Gamma-Ray Bursts and Implication for Universal Radiation Physics of Baryonic Jets |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2408.06694 |