Swift Observations of GRB 201116A

A. Tohuvavohu (U. Toronto) for the Swift team

1. Introduction

Axelsson et al. (GCN Circ. 28907) reported the GRB detection. 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

Analysis of the initial XRT data was reported by Tohuvavohu et al. (GCN Circ. 28916). Four uncatalogued X-ray sources are detected, of which one ("Source 3") is above the RASS 3-sigma upper limit at this position, and shows signes of fading, and is therefore likely the GRB afterglow.

The light curve (Figure 2) is consistent with a constant source of mean count rate 5.2 x 10-2 ct s-1, however fading also cannot be ruled out. A power-law fit gives an index of 1.6 (+1.4, -2.0), thus the large uncertainties hinder a confident statement about fading.

A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.9 (+0.6, -0.5). The best-fitting absorption column is 2.7 (+2.5, -1.9) x 1021 cm-2, in excess of the Galactic value of 2.8 x 1020 cm-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.2 x 10-11 (4.4 x 10-11) erg cm-2 count-1.

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
09h57m17.98s +00°16'33.1" 2.5" XRT Tohuvavohu et al. GCN Circ. 28916

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes
Optical Lipunov et al. 28905 LAT GRB201116.03: Global MASTER-Net
observations report 		MASTER
Optical de Ugarte Postigo et al. 28915 OSN Afterglow Candidate Obs.de Sierra Nevada detection
Optical Zhu et al. 28917 NOT optical observations NOT
Gamma-ray Fermi 28897 Fermi GBM Final Real-time Localization Fermi GBM
Gamma-ray Kunzweiler et al. 28898 BALROG localization (Fermi Trigger
627180592 / GRB 201116035)		 BALROG
Gamma-ray Axelsson et al. 28907 Fermi-LAT detection Fermi LAT Emax=2.4 GeV
Gamma-ray Ridnaia et al. 28920 Konus-Wind detection Konus-Wind Epeak=220 (-28,+40) keV
Duration=~9.5 seconds
Fluence=2.46(-0.34,+0.33)x10-5erg cm-2
Gamma-ray Cannady et al. 28923 CALET Gamma-Ray Burst Monitor detection CALET

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

November 20, 2020