Swift Observations of GRB 221006A

B. Sbarufatti (INAF-OAB) for the Swift team

1. Introduction

Mihara et al. (GCN Circ. 32626) reported the GRB detection. The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray transient source at 2022-10-06T00:57:09 UT. Table 1 contains the best reported positions from Swift.

Cunha et al. (GCN Circ. 32742) determined a redshift of 0.731. 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 Sbarufatti et al. (GCN Circ. 32731). Of the sources reported by Sbarufatti et al. (GCN Circ. 32628), "Source 2" is fading with >3-sigma significance, and is therefore likely the GRB afterglow.

The light curve (Figure 2) can be modelled with a power-law decay with a decay index of α=1.01 (+0.34, -0.25).

4. UVOT Observations and Analysis

UVOT results are not available.

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
22h28m58.99s +15°42'49.6" 3.2" XRT Sbarufatti et al. GCN Circ. 32731

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes
X-ray Mihara et al. 32626 MAXI/GSC detection MAXI detection
X-ray Cunha et al. 32742 MAXI GRB 221006A: Redshifts of the
possible host galaxies		 MAXI redshift
Gamma-ray Cannady et al. 32674 CALET Gamma-Ray Burst Monitor detection CALET
Other Brogan et al. 32710 Afterglow limits of GRB 221006A from
OHP		 upper limits

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

October 14, 2022