Swift Observations of GRB 180914B

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

1. Introduction

Bissaldi and Longo (GCN Circ. 23232) reported the GRB detection. At 18:23:02 UT on September 14, 2018 Fermi-LAT detected high-energy emission from GRB 180914B, which was also detected by AGILE/MCAL (Ursi et al., GCN Circ. 23226) and by AGILE/GRID (Verrecchia et al., GCN Circ. 23231). Table 1 contains the best reported positions from Swift.

Zheng and Filippenko (GCN Circ. 23237) reported the position from KAIT for the optical afterglow of this GRB. Paul (GCN Circ. 23241) reported the detection with UVOT of an optical afterglow. D'Avanzo et al. (GCN Circ. 23246) determined a redshift of 1.096 from VLT. 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. 23236). The source has a mean count rate of 6.2 x 10-2 ct s-1; we cannot determine at the present time whether it is fading.

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
22h09m25.54s +25°03'43.9" 1.0" UVOT GCN Circ. 23241
22h09m25.56s +25°03'47.3" 3.4" XRT D'Ai et al. GCN Circ. 23236

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes
Optical Zheng and Filippenko 23237 KAIT Optical Afterglow Candidate KAIT detection
Optical Troja et al. 23238 RATIR Optical and NIR Observations RATIR
Optical de Ugarte Postigo et al. 23239 Optical counterpart observation from OAJ Obs. Astro. de Javalambre detection
Optical Troja et al. 23243 Continued RATIR Optical and NIR
Observations		 RATIR
Optical Mazaeva et al. 23244 TSHAO optical observations Zeiss-1000
Optical Lipunov et al. 23245 MASTER OT automatic dtection MASTER
Optical D'Avanzo et al. 23246 VLT/X-shooter spectroscopic redshift VLT redshift
Optical Mazaeva et al. 23249 continued TSHAO optical observations Zeiss-1000
Optical Ramsay et al. 23252 GOTO optical detection Gravitational-wave Optical Transient Observer detection
Optical Izzo et al. 23255 OAJ multi-color follow-up Obs. Astro. de Javalambre detection
Optical Kann et al. 23256 OSN Detection and light curve/SED
analysis		 Obs.de Sierra Nevada light curve
Optical Lyapin et al. 23287 RTT150 optical observations RTT150 detection
Optical Irtuganov et al. 23288 RTT150 optical observations RTT150 detection
Gamma-ray Ursi et al. 23226 AGILE/MCAL detection of a burst AGILE
Gamma-ray Verrecchia et al. 23231 AGILE/GRID detection AGILE
Gamma-ray Bissaldi and Longo 23232 Fermi-LAT detection Fermi LAT Emax=12.6 GeV
Gamma-ray Frederiks et al. 23240 Konus-Wind of the very bright GRB
180914B		 Konus-Wind Epeak=466 (-27,+29) keV
Gamma-ray Ursi et al. 23242 AGILE/MCAL refined analysis AGILE
Gamma-ray Khanam et al. 23250 AstroSat CZTI detection CZTI T90=146.8 seconds
Gamma-ray Rodi et al. 23278 INTEGRAL detections of the prompt
gamma-ray emission		 INTEGRAL
Other Watson et al. 23253 DDOTI/OAN Detection and Confirmation of
Fading 		detection

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

Table 3. Found no UVOT observations.

October 2, 2018