Daily Image
29-04-2020
Predictions for prompt low-frequency radio emission from gamma-ray bursts
| Submitter: | Rhaana L.C. Starling |
| Description: | Gamma-ray bursts (GRBs) are the explosive end states of massive stars and some compact binary mergers. The prompt pulses (Fig 1, UK Swift Science Data Centre) arise in a relativistic jet, but whether this jet is matter- or magnetically-dominated remains a central outstanding question. Some magnetic models predict low-frequency radio emission alongside the initial high energy pulses. We suggest a test for the magnetically-dominated wind model of Usov & Katz (2000) using the LOFAR rapid-response mode, on-target within 5 minutes. Fig 2 (Starling et al. 2020) shows the predicted detections as green stars for a sample of Swift GRB X-ray flares from Yi et al. (2016). We find LOFAR could have detected 44% of the flares at 144 MHz, adopting this model and negligible absorption and scattering effects. Several such detections could be accessible to LOFAR each year, enabling triggered LF observations to play a key role in establishing the mechanism responsible for GRB prompt emission. This work was made possible by an ASTRON Helena Kluyver visiting fellowship during the summer of 2019, and appears in ”LOFAR detectability of prompt low-frequency radio emission during gamma-ray burst X-ray flares”, 2020, Starling, Rowlinson, van der Horst & Wijers, MNRAS in press, https://arxiv.org/abs/2004.11209 |
| Copyright: | Starling et al. 2020 (MNRAS in press) |
| Tweet |  |