NOTE: uvot_fluxes_wget.pl vrs. 2024-08-27 fem at 251018d18h47m43s379003usUT
NOTE: Source region spec. is: 282.04183 -37.02840 3"
NOTE: Used archived uvot source position of 282.04183 -37.02840  3.00
NOTE: position reference is GCN_Circ_42343
NOTE: A UVOT position was reported in GCN_Circ_42343
NOTE: Possible detection in wh at T+83.7

=========== Draft Upper Limit Circular ========

GRB 251018A: Swift/UVOT Upper Limits

***UBS*** (***INSTITUTION***) and Gupta (NASA GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 251018A
84 s after the BAT trigger (Gupta et al., GCN Circ. 42343).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Notice ***
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC            84          233          147         >18.0
u_FC               296          546          246         >19.8
white               84         4988          363         >19.1
v                  626         5303          121         >18.6
b                  551         4783          216         >20.4
u                  296         4578          442         >19.9
w1                4173         4373          197         >20.0
m2                 650          670           19         >18.3
w2                 602         5195          216         >19.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.101 in the direction of the burst
(Schlegel et al. 1998).


=========== Draft Detection Circular ========

GRB 251018A: Swift/UVOT Detection

***UBS*** (***INSTITUTION***) and Gupta (NASA GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 251018A
84 s after the BAT trigger (Gupta et al., GCN Circ. 42343).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Notice ***
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  18:48:10.03 = 282.04180 (deg.)
    Dec (J2000) = -37:01:42.4  = -37.02845 (deg.)
with an estimated uncertainty of 0.45 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white               84          233          147         18.16 +/- 0.05
v                  626         5303          121        >18.6
b                  551         4783          216        >20.4
u                  296         4578          442        >19.9
w1                4173         4373          197        >20.0
m2                 650          670           19        >18.3
w2                 602         5195          216        >19.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.101 in the direction of the burst
(Schlegel et al. 1998).