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GCN Circular 31079

GRB 211106A: Swift/UVOT upper limits
2021-11-12T22:27:08Z (2 years ago)
Paul Kuin at MSSL <>
N Paul Kuin (UCL-MSSL) and Aaron Tohuvavohu (U Toronto) report on
behalf of the Swift/UVOT team:

The Swift/UVOT observed the field of the Swift/BAT-GUANO localisation (
Tohuvavohu et al, GCN Circ. 31049) of the INTEGRAL/SPI-ACS #9504 discovery
of the short GRB211106A  using the white filter. The GRB was also reported
by Fermi GBM (Fletcher, GCN Circ. 31055), Konus-Wind (Ridnaia et al.,
GCN Circ. 31054). Ground-based follow up on XRT Source 2 by MeerLicht
(de Wet et al, GCN Circ. 31063) at 17 hours past trigger found an upper
limit of q = 21.90; GROND around seventy hours after the trigger while
mounted on the 2.2m MPG telescope find upper limits only ranging from
g' > 24.8 to K > 19.8 (GCN Circ. 31069); Malesani et al used the VLT
UT1/FORS2 also at 70 hours after triggger to place a limit R > 26.2.

Here we report on upper limits for the XRT Source number 2 (see D'Elia et
al, GCN Circ. 31051) which is the candidate afterglow (D'Elia et al, GCN
Circ. 31068).

Swift UVOT observed discontinuously starting day 0.45-0.67d, then day
1.45-1.97, 2.6-3.7, 4.6-5.0 for a total of 19.5 ks. For these periods, the
3-sigma UVOT upper limits are white > 23.2, 22.4, 22.7, 22.9 mag (Vega,
Breeveld et al. 2011).

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).
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