Swift Observations of GRB 200715A

A. D'Ai (INAF-IASFPA) for the Swift team

1. Introduction

Mereghetti et al. (GCN Circ. 28110) reported the GRB detection. A gamma ray burst lasting about 160 s has been detected by IBAS in the IBIS/ISGRI data at 23:51:40 UT of July 15, 2020. 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 D'Ai et al. (GCN Circ. 28115).

The light curve (Figure 2) can be modelled with a power-law decay with a decay index of α=1.06 (+0.32, -0.27).

A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.1 ± 0.5. The best-fitting absorption column is 1.06 (+0.60, -0.29) x 1022 cm-2, consistent with the Galactic value of 7.6 x 1021 cm-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.8 x 10-11 (9.4 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.

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
16h34m09.14s -51°50'18.2" 7.2" XRT-final UKSSDC
16h34m09.04s -51°50'08.0" 3.7" XRT D'Ai et al. GCN Circ. 28115

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes
Gamma-ray Mereghetti et al. 28110 A long GRB detected by INTEGRAL INTEGRAL

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

July 17, 2020