Swift Observations of GRB 131110A

1. Introduction

At 11:53:11 Swift was slewing (Cummings GCN Circ. 15483). Table 1 contains the best reported positions from Swift.

Table 2 is a summary of GCN Circulars about this GRB from observatories other than Swift.

2. BAT Observations and Analysis

The BAT mask-weighted lightcurve (Figure 1) shows a single broad peak with a slow rise to a plateau at T+25 seconds, lasting about 70 seconds, and a slow decay. T₉₀ is about 100 ± 10 seconds.

The average spectrum from T₀ to T+90 (after which the source had a low mask coding factor in BAT) is best fit by a simple power law function with a photon index of 1.61 ± 0.09. The fluence from 15-150 keV during this interval was (3.53 ± 0.10) x 10^-6 ergs/cm² s^-1. Errors are 90% confidence.

3. XRT Observations and Analysis

We have analysed xx ks of XRT data for the Swift/BAT-detected burst: GRB 131110A, from 0 s to 0 s after the Swift/BAT trigger. The data are entirely in Photon Counting (PC) mode. We cannot determine at the present time whether the source is fading.

4. UVOT Observations and Analysis

UVOT results are not available.

Figure 1. The BAT light curve is not available.

RA (J2000)	Dec (J2000)	Error	Note	Reference
04h37m04.4s	-17°15'34"	0.8'	BAT-refined	Cummings et al. GCN Circ. 15487

Table 1. Positions from the Swift instruments.

Band	Authors	GCN Circ.	Subject	Observatory	Notes

Table 2. No GCN Circulars from other observatories were found.

Filter	Tstart(s)	Tstop(s)	Exp(s)	Mag
white	397556	409058	892	>20.2
v	398095	409489	938	>18.6
u	397018	408678	892	>19.2

Table 3. UVOT observations reported by Page et al. (GCN Circ. 15488). 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.