Swift Observations of GRB 140606B

V. Mangano (PSU) and M.M. Chester (PSU) for the Swift team

1. Introduction

Burns (GCN Circ. 16363) reported the GRB detection. At 03:11:51.86 UT on 06 June 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 140606B (trigger 423717114 / 140606133). Table 1 contains the best reported positions from Swift, and the latest XRT position can be viewed at http://www.swift.ac.uk/xrt_positions.

Perley et al. (GCN Circ. 16387) reported the position from MOSFIRE/Keck for the optical afterglow of this GRB. Perley et al. (GCN Circ. 16365) determined a redshift of 0.384 from Keck. 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

Analysis of the initial XRT data was reported by Mangano and Burrows (GCN Circ. 16373). We have analysed 18 ks of XRT data for the Fermi/GBM-detected burst: GRB 140606B, from 184.4 ks to 870.8 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.

The light curve (Figure 2) can be modelled with a power-law decay with a decay index of α=1.0 (+0.7, -0.6).

The results of the XRT team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020384.

4. UVOT Observations and Analysis

The Swift/UVOT observed the field of the Fermi/GBM-detected burst GRB 140606B beginning 184.4 ks after the Fermi/GBM trigger (Burns et al. GCN Circ. 16363) (Chester and Mangano GCN Circ. 16368). No source consistent with iPTF14bfu, the optical counterpart proposed by Singer et al. (GCN Circ. 16360) and Perley et al. (GCN Circ. 16365), 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 0.12 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
21h52m30.00s +32°00'52.5" 2.3" XRT-final UKSSDC
21h52m30.00s +32°00'52.5" 2.3" XRT Mangano et al. GCN Circ. 16366

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes
Optical Singer et al. 16360 Fermi423717114: iPTF optical transient
candidates		 iPTF detection
Optical Perley et al. 16365 Fermi 432717114 / iPTF 14bfu: Keck
redshift		 Keck redshift
Optical Toy et al. 16367 iPTF14bfu: Discovery Channel Telescope
Optical Detection		 Discovery Channel detection
Optical Toy et al. 16377 DCT time of observation correction Discovery Channel
Optical Perley et al. 16387 iPTF 14bfu: MOSFIRE NIR imaging MOSFIRE/Keck
Optical Volnova et al. 16398 iPTF 14bfu: AAO optical observations Abastumani Obs. detection
Optical Volnova et al. 16403 iPTF 14bfu: Mondy optical observations Mondy detection
Optical Moskvitin et al. 16431 iPTF 14bfu: SAO RAS optical observations iPTF
Optical Perley et al. 16454 iPTF14bfu: Keck detection of an
associated supernova		 Keck
Gamma-ray Burns 16363 Fermi GBM detection Fermi GBM Epeak=473.00 (9.018 ± 0.369) keV
T90=23.6 seconds
Fluence=9.018±0.369x10-6erg cm-2
(73rd percentile for long GRBs)
Gamma-ray Hurley et al. 16369 IPN Triangulation IPN
Gamma-ray Golenetskii et al. 16374 Konus-Wind observation Konus-Wind Epeak=254 (-27,+33) keV
Fluence=6.6(-0.5,+0.5)x10-6erg cm-2

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 185271 191914 1693 >21.1
b 186146 192611 1495 >20.9
v 184395 191055 1693 >20.6

Table 3. UVOT observations reported by Chester and Mangano (GCN Circ. 16368). 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 26, 2014