NOTE: Possible detection in uu at T+37636.2

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

GRB 140420A: Swift/UVOT Upper Limits

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

The Swift/UVOT began settled observations of the field of GRB 140420A
37636 s after the GBM trigger (***Author*** et al., GCN Circ. ????).
No optical afterglow consistent with the optical position
*** POSITION REFERENCE is GCN_Circ-16425 ***
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 initial exposures are:

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

u                37636        43876         1718         >20.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 140420A: Swift/UVOT Detection

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

The Swift/UVOT began settled observations of the field of GRB 140420A
37636 s after the GBM trigger (***Author*** et al., GCN Circ. ????).
A source consistent with the optical position
*** POSITION REFERENCE is GCN_Circ-16425 ***
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  18:47:29.00 = 281.87082 (deg.)
    Dec (J2000) = +49:43:51.8  =  49.73105 (deg.)
with an estimated uncertainty of 0.53 arc sec. (radius, 90% confidence).

Preliminary detections 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

u                37636        38921         1264         20.22 +/- 0.10

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).