J.R. Cummings (NASA/UMBC), K.L. Page (U. Leicester) and L.M.Z. Hagen (PSU) for the Swift team
At2014-07-16T10:27:57.3 Swift-BAT rate-triggered on the first episode of GRB 140716 (Cummings GCN Circ. 16596). Table 1 contains the best reported positions from Swift.
Knust et al. (GCN Circ. 16601) reported the position from GROND for the optical afterglow of this GRB. Table 2 is a summary of GCN Circulars about this GRB from observatories other than Swift.
The burst had three peaks with similar maximum flux, the first 2 seconds long, the second 4 seconds long at T+90, and the third about 8 seconds long at T+100.
The emission was undetectable between the first and second peaks, while there was a slight overlap between peaks 2 and 3.
The total
The average spectrum from 15 to 150 keV is best fit by a simple power law function with a photon index of 1.61 ± 0.33.
The total fluence was (5.9 ± 1.2) x 1
We have analysed 10 ks of XRT data for the Swift/BAT-detected burst: GRB 140716A, from 34.1 ks to 478.7 ks after the Swift/BAT trigger. The data are entirely in Photon Counting (PC) mode. An X-ray source is detected within the Swift/BAT error circle.
The light curve (Figure 2) can be modelled with a power-law decay with a decay index of α=1.19 (+0.36, -0.25).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.58 (+0.58, -0.22). The best-fitting absorption column is consistent with the Galactic value of 1.3 x 1
A summary of the PC-mode spectrum is thus:
Total column: 1.3 ± 1.6 x 1
Galactic foreground: 1.3 x 1
Excess significance: <1.6 σ
Photon index: 1.58 (+0.58, -0.22)
The results of the XRT team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020390.
The Swift/UVOT began settled observations of the field of GRB 140716A 34072 s after the BAT trigger
(Hagen and Page GCN Circ. 16604).
No optical afterglow consistent with the XRT candidate (Page, GCN Circ. 16600) or GROND candidate (Knust et al., GCN Circ. 16601) is detected in the initial UVOT exposures.
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 |
---|---|---|---|---|
0 |
-60°10'31.3" | 2.4" | XRT-final | UKSSDC |
0 |
-60°10'32.7" | 4.7" | XRT | Page GCN Circ. 16600 |
0 |
-60°08'59" | 1.5' | BAT-refined | Cummings et al. GCN Circ. 16598 |
Band | Authors | GCN Circ. | Subject | Observatory | Notes |
---|---|---|---|---|---|
Optical | Knust et al. | 16601 | GROND afterglow candidate | GROND | detection |
Optical | Bolmer et al. | 16614 | GROND confirmation of the afterglow | GROND | detection |
Gamma-ray | Jenke and Yu | 16599 | A Fermi GBM Detection | Fermi GBM | Fluence=1.03±0.04x1 (7 |
Gamma-ray | Golenetskii et al. | 16605 | Konus-Wind observation | Konus-Wind | Fluence=9.4(-1.6,+2.2)x1 |
Filter | Exp(s) | Mag | ||
---|---|---|---|---|
u (fc) | 34072 | 34367 | 291 | >19.17 |
u | 40452 | 56904 | 1860 | >20.20 |
v | 40559 | 57641 | 1125 | >19.52 |
Table 3. UVOT observations reported by Hagen and Page (GCN Circ. 16604). The start and stop times of the exposures are given in seconds since the BAT trigger. The preliminary 3-σ upper limits are given. No correction has been made for extinction in the Milky Way.
July 22, 2014