Swift Observations of GRB 220107B

J.D. Gropp (PSU) for the Swift team

1. Introduction

Arimoto et al. (GCN Circ. 31409) 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 Gropp et al. (GCN Circ. 31411). The source has a mean count rate of 1.3 x 10-1 ct s-1; while we cannot determine at the present time whether it is fading, the fact that the source is well above RASS limit strongly suggests it is the X-ray afterglow of GRB 220107B.

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
14h25m37.56s +20°10'14.3" 3.4" XRT Gropp et al. GCN Circ. 31411

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes
Optical Jiang et al. 31417 Nanshan/NEXT optical upper limits and
host galaxy candidate		 Xinjiang Astro. Obs. upper limits
Optical Niwano et al. 31418 MITSuME Akeno optical upper limits MITSuME Akeno upper limits
Gamma-ray Arimoto et al. 31409 Fermi-LAT detection Fermi LAT Emax=2.4 GeV
Gamma-ray Suresh et al. 31412 AstroSat CZTI detection CZTI
Gamma-ray Veres and Meegan 31414 Fermi GBM observations Fermi GBM Epeak=391±21 keV
T90=25 seconds
Fluence=2.68±0.03x10-5erg cm-2
(brighter than 90% of long GRBs)
Gamma-ray Ridnaia et al. 31430 Konus-Wind detection Konus-Wind Epeak=309 (-65,+72) keV
Duration=~26.4 seconds
Fluence=4.20(-0.78,+0.91)x10-5erg cm-2

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

January 11, 2022