NOTE: uvot_fluxes_wget.pl vrs. 2023-03-23 fem at 230427d15h18m21s525946usUT
NOTE: Source region spec. is: 153.31270 48.20400 3"
NOTE: Used archived uvot source position of 153.31270  48.20400  3.00
NOTE: position reference is GCN_Circ_33687
NOTE: A UVOT position was reported in GCN_Circ_33687
NOTE: Possible detection in wh at T+98.3

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

GRB 230427A: Swift/UVOT Upper Limits

N. J. Klingler (GSFC/UMBC/CRESTII) and E. Troja (UToV)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 230427A
98 s after the BAT trigger (Troja et al., GCN Circ. 33687).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-33688 ***
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            98          248          147         >19.8
u_FC               256          506          246         >20.4
white               98         1182          353         >20.6
v                  586         4999          255         >19.3
b                  512         1158           58         >19.6
u                  256          854          265         >20.5
w1                 810         5404          231         >20.0
m2                5004         5204          197         >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.007 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 230427A: Swift/UVOT Detection

N. J. Klingler (GSFC/UMBC/CRESTII) and E. Troja (UToV)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 230427A
98 s after the BAT trigger (Troja et al., GCN Circ. 33687).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-33688 ***
is detected in the initial UVOT exposures.

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               98          248          147         20.19 +/- 0.15
v                  586         4999          255        >19.3
b                  512         1158           58        >19.6
u                  256          854          265        >20.5
w1                 810         5404          231        >20.0
m2                5004         5204          197        >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.007 in the direction of the burst
(Schlegel et al. 1998).