Swift Observations of GRB 140623A

V. D'Elia (ASDC) for the Swift team

1. Introduction

von Kienlin (GCN Circ. 16450) reported the GRB detection. At 05:22:06.60 UT on 23 June 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 140623A (trigger 425193729 / 140623224), which was observed by the intermediate Palomar Transient Factory beginning 11 minutes after trigger time, and was reported in GCN Circ. 16425 (Bhalerao et al. 2014) as iPTF14cvb. 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

BAT did not observe this burst.

3. XRT Observations and Analysis

We have analysed 8.1 ks of XRT data for the Fermi/GBM-detected burst: GRB 140623A, from 38.7 ks to 315.1 ks after the Fermi/GBM trigger. The data are entirely in Photon Counting (PC) mode. An X-ray source is detected within the Fermi/GBM error circle. We cannot determine at the present time whether the source is fading.

The results of the XRT team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020388.

4. UVOT Observations and Analysis

The Swift/UVOT began settled observations of the field of GRB 140423A 38708 s after the GBM trigger (D'Elia et al. GCN Circ. 16451). No optical afterglow consistent with the optical position (Bhalerao et al. GCN Circ. 16442) 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 EB-V of 0.037 mag. in the direction of the GRB (Schlegel et al. 1998).

Figure 1. The BAT light curve is not available.

XRT light curve

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
15h01m55.02s +81°11'25.7" 5.8" XRT-final UKSSDC
15h01m55.02s +81°11'25.7" 5.8" XRT D'Elia et al. GCN Circ. 16451

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes
Gamma-ray von Kienlin 16450 iPTF14cyb: Fermi GBM detection Fermi GBM Epeak=350 (+220/-100) keV
T90=110 seconds
Fluence=6.8±0.6x10-6erg cm-2
(66th percentile for long GRBs)

Table 2. Summary of GCN Circulars from other observatories sorted by band and then circular number.

Filter Tstart(s) Tstop(s) Exp(s) Mag
u 38708 44173 925 >22.0
white 38926 44863 851 >21.9

Table 3. UVOT observations reported by D'Elia et al. (GCN Circ. 16451). 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.

June 28, 2014