Swift Observations of GRB 190501A

P. Evans (U. Leicester) for the Swift team

1. Introduction

Hurley et al. (GCN Circ. 24372) 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 Evans and Marshall (GCN Circ. 24419).

4. UVOT Observations and Analysis

The Swift/UVOT began settled observations of the field of GRB 190501A 146672 s after the AGILE trigger (Evans and Marshall GCN Circ. 24419). No optical afterglow consistent with the AGILE/GRID position is detected in the initial UVOT exposures. Table 3 gives preliminary magnitudes using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc., 1358, 373). No correction has been made for the expected extinction in the Milky Way corresponding to a reddening of EB-V of 0.03 mag. in the direction of the GRB (Schlegel et al. 1998).

Figure 1. The BAT light curve is not available.

RA (J2000) Dec (J2000) Error Note Reference

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes
Optical Lipunov et al. 24364 Fermi GRB190501.79 Global MASTER-Net
observations report 		MASTER
Optical Lyman et al. 24370 GOTO optical counterpart search Gravitational-wave Optical Transient Observer detection
Gamma-ray Ursi et al. 24360 AGILE/MCAL and scientific ratemeters
detection of a burst		 AGILE
Gamma-ray Lucarelli et al. 24361 AGILE/GRID detection AGILE
Gamma-ray Verrecchia et al. 24363 refined position from AGILE/GRID
analysis		 AGILE
Gamma-ray Hurley et al. 24372 IPN Triangulation of GRB 190501A
(long/bright)		 IPN
Gamma-ray Ricciarini et al. 24406 CALET Gamma-Ray Burst Monitor detection CALET

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

Filter Tstart(s) Tstop(s) Exp(s) Mag
white 147234 153893 933 >21.8
v 147796 154103 761 >20.0
u 146672 157636 1167 >20.7

Table 3. UVOT observations reported by Evans and Marshall (GCN Circ. 24419). The start and stop times of the exposures are given in seconds since the BAT trigger. The preliminary 3-σ upper limits are given. No correction has been made for extinction in the Milky Way.

May 8, 2019