J.P. Osborne (U. Leicester) and N.P.M. Kuin (MSSL/UCL) for the Swift team
Bissaldi et al. (GCN Circ. 18065) reported the GRB detection. At 18:45:36.71 on 2015-07-24, Fermi-LAT detected high-energy emission from GRB 150724B, which was also detected by Fermi-GBM (trigger 459456340/150724782). Table 1 contains the best reported positions from Swift.
Kuin (GCN Circ. 18075) reported the detection with UVOT of an optical afterglow. Watson et al. (GCN Circ. 18078) reported the position from RATIR for the optical afterglow of this GRB. Table 2 is a summary of GCN Circulars about this GRB from observatories other than Swift.
BAT did not observe this burst.
XRT results are not available.
The Swift/UVOT began settled observations
(Kuin GCN Circ. 18075) of the field of GRB 150724B 88.6ks after the LAT trigger (Bissaldi et al., GCN Circ. 18065), which was also observed at high energy by Fermi-GBM (Veres et al., GCN Circ. 18066) and Konus-Wind (Golenetskii et al. GCN Circ. 18074).
Five UVOT exposures were obtained of which the first two show a weak detection at the XRT position (Osborne et al., GCN Circ. 18069).
Table 3 gives preliminary
magnitudes using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc., 1358, 373).
No correction has been made for the expected extinction in the Milky Way
corresponding to a reddening of
Figure 1. The BAT light curve is not available.
Figure 2. The XRT light curve.
Any data from a crosshatched region are not included in the fit.
RA (J2000) | Dec (J2000) | Error | Note | Reference |
---|---|---|---|---|
2 |
+03°49'06.2" | 2.3" | XRT-final | UKSSDC |
2 |
+03°49'05.2" | 4.1" | XRT | Osborne et al. GCN Circ. 18101 |
Band | Authors | GCN Circ. | Subject | Observatory | Notes |
---|---|---|---|---|---|
Optical | Butler et al. | 18072 | RATIR Optical Observations | RATIR | detection |
Optical | Ivanov et al. | 18077 | MASTER upper limit | MASTER | upper limits |
Optical | Watson et al. | 18078 | Continued RATIR Optical Observations | RATIR | detection |
Gamma-ray | Bissaldi et al. | 18065 | Fermi-LAT detection | Fermi LAT | |
Gamma-ray | Veres et al. | 18066 | Fermi GBM detection | Fermi GBM | Fluence=3.55±0.04x1 (9 |
Gamma-ray | Golenetskii et al. | 18074 | Konus-Wind observation | Konus-Wind | Fluence=3.63(-0.29,+0.69)x1 |
Filter | Exp(s) | Mag | ||
---|---|---|---|---|
white | 88619 | 88799 | 178 | 19.64± 0.12 |
white | 88802 | 90608 | 1765 | 20.99± 0.14 |
white | 90614 | 90748 | 60 | >19.53 |
white | 94379 | 94558 | 176 | >20.82 |
white | 94562 | 96236 | 1648 | >22.01 |
Table 3. UVOT observations reported by Kuin (GCN Circ. 18075). The start and stop times of the exposures are given in seconds since the BAT trigger. The preliminary detections and 3-σ upper limits are given. No correction has been made for extinction in the Milky Way.
August 2, 2015