Rapid fading of optical afterglows as evidence for beaming in gamma-ray bursts
| dc.creator | Huang, Y. F. | |
| dc.creator | Dai, Z. G. | |
| dc.creator | Lu, T. | |
| dc.date | 2000-02-23 | |
| dc.date.accessioned | 2026-07-07T01:52:27Z | |
| dc.date.available | 2026-07-07T01:52:27Z | |
| dc.description | Based on the refined dynamical model proposed by us earlier for beamed $γ$-ray burst ejecta, we carry out detailed numerical procedure to study those $γ$-ray bursts with rapidly fading afterglows (i.e., $\sim t^{-2}$). It is found that optical afterglows from GRB 970228, 980326, 980519, 990123, 990510 and 991208 can be satisfactorily fitted if the $γ$-ray burst ejecta are highly collimated, with a universal initial half opening angle $θ_0 \sim 0.1$. The obvious light curve break observed in GRB 990123 is due to the relativistic-Newtonian transition of the beamed ejecta, and the rapidly fading optical afterglows come from synchrotron emissions during the mildly relativistic and non-relativistic phases. We strongly suggest that the rapid fading of afterglows currently observed in some $γ$-ray bursts is evidence for beaming in these cases. | |
| dc.description | 5 pages, 4 embedded figures, l-aa style Latex, A&A Lett submitted | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0002433 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0002433 | |
| dc.identifier | A&A, 355 (2000), L43 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/625 | |
| dc.subject | Astrophysics | |
| dc.title | Rapid fading of optical afterglows as evidence for beaming in gamma-ray bursts | |
| dc.type | text |