Testing Two-Component Jet Models of GRBs with Orphan Afterglows

Abstract

Abstract In the Swift era, two-component jet models were introduced to explain the complex temporal profiles and the diversity of early afterglows. In this paper, we concentrate on the two-component jet model: the first component is the conventional afterglow, and second is emission due to late internal dissipation, such as late-prompt emission. We suggest herein that the two-component jet model can be probed by the existence of two optical peaks for orphan GRB afterglows. Each peak is caused by its respective jet as its relativistic beaming cone widens to encompass the off-axis line of sight. Typically, the first peak appears at 10$^{4}$–10$^{5}\ $s, and the second at 10$^{5}\ $–10$^{6}\ $s. Furthermore, we expect to observe a single, bright X-ray peak at the same time as the first optical peak. Because orphan afterglows do not have prompt emission, it is necessary to monitor the entire sky every 10$^{4}$s in the X-ray regime. We can test the model with orphan afterglows through the X-ray all-sky survey collaboration, and by using ground-based optical telescopes.