Swift Observations of GRB 160910A

A. D'Aì (INAF-IASFPA) and L.M.Z. Hagen (PSU) for the Swift team

1. Introduction

Racusin and Kocevski (GCN Circ. 19902) reported the GRB detection. At 17:19:39 on September 10, 2016 Fermi-LAT detected high-energy emission from GRB 160910A, which was also detected by Fermi-GBM (trigger 495220782/160910722; Veres et al. GCN Circ. 19901). Table 1 contains the best reported positions from Swift.

Malesani et al. (GCN Circ. 19908) reported the position from NOT for the optical afterglow of this GRB. Hagen and Cummings (GCN Circ. 19923) reported the detection with UVOT of an optical afterglow. 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

XRT refined results are not available.

4. UVOT Observations and Analysis

The Swift/UVOT began settled observations (Hagen and Cummings GCN Circ. 19923) of the field of GRB 160910A 196954 s after the Fermi/GBM (Veres et al., GCN Circ. 19901) and Fermi/LAT (Racusin et al., GCN Circ. 19902) triggers. We detect a fading source consistent with the XRT position (D'Ai et al., GCN Circ. 19904) and optical detections (de Ugarte Postigo et al., GCN Circ. 19907; Malesani et al., GCN Circ. 19908; Lipunov et al., GCN Circ. 19914; Mazaeva et al., GCN Circ. 19919). 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 0.01 mag. in the direction of the GRB (Schlegel et al. 1998).

Figure 1. The BAT light curve is not available.

RA (J2000) Dec (J2000) Error Note Reference
14h45m46.16s +39°04'00.64" 4.3" XRT D'Aì et al. GCN Circ. 19904

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes
Optical de Ugarte Postigo et al. 19907 Afterglow detection from OSN Obs.de Sierra Nevada detection
Optical Malesani et al. 19908 NOT afterglow confirmation NOT detection
Optical Lipunov et al. 19914 Global MASTER Net OT detection before
LAT alert		 MASTER detection
Optical Mazaeva et al. 19919 Mondy optical observations Mondy detection
Optical Mazaeva et al. 19925 Maidanak optical observations Maidanak detection
Optical Mazaeva et al. 19935 TSHAO optical observations Zeiss-1000 detection
Radio Mooley et al. 19937 15 GHz detection from AMI AMI detection
Radio Nayana and Chandra 19966 Possible radio detection of GRB
160910A with the GMRT		 GMRT possible detection
Gamma-ray Veres and Meegan 19901 Fermi GBM observation Fermi GBM Epeak=347±9 keV
T90=24.3 seconds
Fluence=8.41±0.06x10-5erg cm-2
(97.1 percentile for long GRBs)
Gamma-ray Racusin and Kocevski 19902 Fermi-LAT detection Fermi LAT Emax=500 MeV
Gamma-ray Kawakubo et al. 19909 CALET Gamma-Ray Burst Monitor detection CALET T90=20.7±1.5 seconds
Gamma-ray Tsvetkova et al. 19913 Konus-Wind observation Konus-Wind Epeak=315 (-29,+31) keV
Fluence=1.36(-0.09,+0.10)x10-4erg cm-2
Gamma-ray Bhalerao et al. 19949 AstroSat CZTI detection CZTI T90=9.44 seconds

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

Filter Tstart(s) Tstop(s) Exp(s) Mag
white 196954 267060 1620 20.61± 0.14
white 267064 318724 2326 20.95± 0.14

Table 3. UVOT observations reported by Hagen and Cummings (GCN Circ. 19923). 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.

October 3, 2016