The early radio afterglow of short GRB 230217A

Fuente: arXiv
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Main Authors: Anderson, G. E., Schroeder, G., van der Horst, A. J., Rhodes, L., Rowlinson, A., Bahramian, A., Chastain, S. I., Gompertz, B. P., Hancock, P. J., Laskar, T., Leung, J. K., Wijers, R. A. M. J.
Format: Preprint
Published: 2024
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author Anderson, G. E.
Schroeder, G.
van der Horst, A. J.
Rhodes, L.
Rowlinson, A.
Bahramian, A.
Chastain, S. I.
Gompertz, B. P.
Hancock, P. J.
Laskar, T.
Leung, J. K.
Wijers, R. A. M. J.
author_facet Anderson, G. E.
Schroeder, G.
van der Horst, A. J.
Rhodes, L.
Rowlinson, A.
Bahramian, A.
Chastain, S. I.
Gompertz, B. P.
Hancock, P. J.
Laskar, T.
Leung, J. K.
Wijers, R. A. M. J.
contents We present the radio afterglow of short gamma-ray burst (GRB) 230217A, which was detected less than 1 day after the gamma-ray prompt emission with the Australia Telescope Compact Array (ATCA) and the Karl G. Jansky Very Large Array (VLA). The ATCA rapid-response system automatically triggered an observation of GRB 230217A following its detection by the Neil Gehrels Swift Observatory and began observing the event just 32 minutes post-burst at 5.5 and 9 GHz for 7 hours. Dividing the 7-hour observation into three time-binned images allowed us to obtain radio detections with logarithmic central times of 1, 2.8 and 5.2 hours post-burst, the first of which represents the earliest radio detection of any GRB to date. The decline of the light curve is consistent with reverse shock emission if the observing bands are below the spectral peak and not affected by synchrotron self-absorption. This makes GRB 230217A the fifth short GRB with radio detections attributed to a reverse shock at early times ($<1$ day post-burst). Following brightness temperature arguments, we have used our early radio detections to place the highest minimum Lorentz factor ($Γ_{min} > 50$ at $\sim1$ hour) constraints on a GRB in the radio band. Our results demonstrate the importance of rapid radio follow-up observations with long integrations and good sensitivity for detecting the fast-evolving radio emission from short GRBs and probing their reverse shocks.
format Preprint
id arxiv_https___arxiv_org_abs_2409_07686
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The early radio afterglow of short GRB 230217A
Anderson, G. E.
Schroeder, G.
van der Horst, A. J.
Rhodes, L.
Rowlinson, A.
Bahramian, A.
Chastain, S. I.
Gompertz, B. P.
Hancock, P. J.
Laskar, T.
Leung, J. K.
Wijers, R. A. M. J.
High Energy Astrophysical Phenomena
We present the radio afterglow of short gamma-ray burst (GRB) 230217A, which was detected less than 1 day after the gamma-ray prompt emission with the Australia Telescope Compact Array (ATCA) and the Karl G. Jansky Very Large Array (VLA). The ATCA rapid-response system automatically triggered an observation of GRB 230217A following its detection by the Neil Gehrels Swift Observatory and began observing the event just 32 minutes post-burst at 5.5 and 9 GHz for 7 hours. Dividing the 7-hour observation into three time-binned images allowed us to obtain radio detections with logarithmic central times of 1, 2.8 and 5.2 hours post-burst, the first of which represents the earliest radio detection of any GRB to date. The decline of the light curve is consistent with reverse shock emission if the observing bands are below the spectral peak and not affected by synchrotron self-absorption. This makes GRB 230217A the fifth short GRB with radio detections attributed to a reverse shock at early times ($<1$ day post-burst). Following brightness temperature arguments, we have used our early radio detections to place the highest minimum Lorentz factor ($Γ_{min} > 50$ at $\sim1$ hour) constraints on a GRB in the radio band. Our results demonstrate the importance of rapid radio follow-up observations with long integrations and good sensitivity for detecting the fast-evolving radio emission from short GRBs and probing their reverse shocks.
title The early radio afterglow of short GRB 230217A
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2409.07686