Dataset Open Access
This repository includes the final datasets derived from Murchison Widefield Array (MWA) rapid-response observations of gamma-ray burst (GRB) 180805A used for analysis in the paper "Murchison Widefield Array rapid-response observations of the short GRB 1808085A". All raw MWA data for this observation can be obtained from the Murchison Widefield Array All-sky Virtual Observatory (https://asvo.mwatelescope.org/), and include observation identification (ObsID) numbers 1217495184, 1217495304, 1217495424, 1217495544, 1217495664, 1217495784, 1217495904, 1217496024, 1217496144, 1217496264, 1217496384, 1217496504, 1217496624, 1217496744, 1217496864 under project code D0009. These 15 observations are referred to as snapshots in the following.
The files attached files to this repository are described below.
Calibration solutions (1217495544_infield_solutions.bin): The calibration solutions applied to all ObsIDs, which were derived from an infield calibration of ObsID 1217495544 using the GLEAM model (Hurley-Walker et al. 2017).
Light curves (GRB180805A_2m_lc.csv, GRB180805A_30s_lc.csv, GRB180805A_5s_lc.csv, GRB180805A_05s_lc.csv): All observations were imaged on 2 minutes, 30 seconds, 5 seconds, and 0.5 seconds timescales. Priorized fitting was performed at the position of the GRB to obtain monitoring light curves. These csv files list the resulting flux density as a function of time for these four different timescales.
Dynamic spectrum: This is the dynamic spectrum created at the pixel position of GRB 180805A by splitting the full 30-minute MWA integration (15 snapshot observations) into the 0.5-second coarse channel (1.28 MHz frequency resolution) images. The first 4s and last 5.5s of each individual snapshot observation are flagged due to instrumental reasons. The axes are Frequency (MHz) vs Time post-GRB (seconds) with the greyscale showing Jy/beam. This dynamic spectrum was used to create a dedispersed time series, for which we search from prompt, dispersed signals.
Dedispersed time series: The mean flux density (Jy/beam) for the path swept across the dynamic spectrum (see above) for every dispersion measure (DM) trial ranging from 100-3000 pc cm-3 at 1.0 pc cm-3 intervals for all time steps at a resolution of 0.1s following the GRB detection. This dedispersed time series was searched for evidence of prompt signals but there were no significant signals (above signal-to-noise ratio of 6) for DM > 200 pc cm-3, which is the lowest DM that we expect short GRBs to be detected (corresponding to a minimum redshift of z~0.1).
Hurley-Walker, N., et al., 2017, MNRAS, 464, 1146