Swift Observations of GRB 220831A

S. Dichiara (PSU) and N.J. Klingler (NASA-GSFC/UMBC/CRESST II) for the Swift team

1. Introduction

Tohuvavohu et al. (GCN Circ. 32506) reported the GRB detection. Swift/BAT did not successfully trigger on GRB 220831A (T0: 2022-08-31 13:56:33 UTC). Table 1 contains the best reported positions from Swift.

Freeburn et al. (GCN Circ. 32516) reported the position from Dark Energy Camera for the optical afterglow of this GRB. Table 2 is a summary of GCN Circulars about this GRB from observatories other than Swift.

2. BAT Observations and Analysis

BAT refined results are not available.

3. XRT Observations and Analysis

Analysis of the initial XRT data was reported by Dichiara et al. (GCN Circ. 32510).

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

01^h37^m00.86^s -41°35'35.7" 6.8" XRT GCN Circ. 32510

01^h37^m01.2^s -41°34'54.5" 2' BAT-GUANO Tohuvavohu et al. GCN Circ. 32506

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes

Optical D'Avanzo et al. 32513 VLT/HAWK-I near-infrared observations VLT

Optical Freeburn et al. 32516 DECam detection of a possible optical
counterpart Dark Energy Camera possible detection

Optical Gordon et al. 32535 Gemini-South/GMOS detection of
potential optical counterpart Gemini detection

Optical O'Connor et al. 32542 Gemini-South Infrared Observations Gemini

Optical Freeburn et al. 32548 DECam optical counterpart follow-up Dark Energy Camera detection

Radio Anderson et al. 32529 ATCA 5/9 GHz radio observations ATCA

Gamma-ray Wood and Meegan 32511 Fermi GBM observation Fermi GBM E_peak=46±8 keV
T₉₀=1.7 seconds
Fluence=5.0±0.5x10^-7erg cm^-2
(brighter than 65% of short GRBs)

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

Filter T_start(s) T_stop(s) Exp(s) Mag

white 51227 78844 4712 >23.39

RA (J2000)	Dec (J2000)	Error	Note	Reference
01^h37^m00.86^s	-41°35'35.7"	6.8"	XRT	GCN Circ. 32510
01^h37^m01.2^s	-41°34'54.5"	2'	BAT-GUANO	Tohuvavohu et al. GCN Circ. 32506

Band	Authors	GCN Circ.	Subject	Observatory	Notes
Optical	D'Avanzo et al.	32513	VLT/HAWK-I near-infrared observations	VLT
Optical	Freeburn et al.	32516	DECam detection of a possible optical counterpart	Dark Energy Camera	possible detection
Optical	Gordon et al.	32535	Gemini-South/GMOS detection of potential optical counterpart	Gemini	detection
Optical	O'Connor et al.	32542	Gemini-South Infrared Observations	Gemini
Optical	Freeburn et al.	32548	DECam optical counterpart follow-up	Dark Energy Camera	detection
Radio	Anderson et al.	32529	ATCA 5/9 GHz radio observations	ATCA
Gamma-ray	Wood and Meegan	32511	Fermi GBM observation	Fermi GBM	E_peak=46±8 keV T₉₀=1.7 seconds Fluence=5.0±0.5x10^-7erg cm^-2 (brighter than 65% of short GRBs)

Filter	T_start(s)	T_stop(s)	Exp(s)	Mag
white	51227	78844	4712	>23.39

Table 3. UVOT observation reported by Klingler (GCN Circ. 32521). The start and stop time of the exposure are given in seconds since the BAT trigger. The preliminary 3-σ upper limit is given. No correction has been made for extinction in the Milky Way.

September 13, 2022