Swift Observations of GRB 180809A

V. D'Elia (SSDC) for the Swift team

1. Introduction

Yatabe et al. (GCN Circ. 23103) reported the GRB detection. The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 11:38:25 UT on 9 August 2018. 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'Elia (GCN Circ. 23141). Swift performed a second visit to the field of the MAXI-detected burst GRB 180809A (Yatabe et al. GCN Circ. 23103). The XRT data comprise 3700 s of exposure time, acquired ~5 days after the GRB trigger and entirely in PC mode.

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
19h51m36.65s	-34°47'07.6"	2.3"	XRT	D'Elia et al. GCN Circ. 23106

Table 1. Positions from the Swift instruments.

Band	Authors	GCN Circ.	Subject	Observatory	Notes
Optical	Kong	23107	iTelescope optical limit	iTelescope	upper limits
X-ray	Yatabe et al.	23103	MAXI/GSC detection	MAXI	detection
Gamma-ray	Ricciarini et al.	23117	CALET Gamma-Ray Burst Monitor detection	CALET
Gamma-ray	Bissaldi	23118	Fermi GBM observation	Fermi GBM	Epeak=620±230 keV T90=220 seconds Fluence=6.8±0.4x10-6erg cm-2 (66th percentile for long GRBs)

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

August 17, 2018