NOTE: uvot_fluxes_wget.pl vrs. 2024-08-27 fem at 250101d18h42m56s877051usUT
NOTE: Source region spec. is: 37.06873 19.19442 3"
NOTE: Used archived uvot source position of  37.06873  19.19442  3.00
NOTE: position reference is GCN_Circ_38752
NOTE: A UVOT position was reported in GCN_Circ_38752
NOTE: Possible detection in bb at T+546.3
NOTE: Possible detection in wh at T+132.8
NOTE: Possible detection in vv at T+620.4
NOTE: Possible detection in uu at T+290.7

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

GRB 250101A: Swift/UVOT Upper Limits

M. H. Siegel (PSU) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250101A
133 s after the BAT trigger (Page et al., GCN Circ. 38752).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-38761 ***
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           133          283          147         >17.9
u_FC               291          540          246         >17.7
white              133          943          258         >18.2
v                  620         4609          235         >18.5
b                  546          738           39         >18.1
u                  291         5116          337         >18.0
w1                 670         5019          235         >19.8
m2                4614         4814          197         >19.1
w2                 596         4404          216         >18.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.164 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 250101A: Swift/UVOT Detection

M. H. Siegel (PSU) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250101A
133 s after the BAT trigger (Page et al., GCN Circ. 38752).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-38761 ***
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  02:28:16.47 =  37.06864 (deg.)
    Dec (J2000) = +19:11:39.6  =  19.19433 (deg.)
with an estimated uncertainty of 0.43 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              133          283          147         18.03 +/- 0.05
v                  620          813           39         18.10 +/- 0.28
b                  546          738           39         18.66 +/- 0.21
u                  291          540          246         17.93 +/- 0.08
w1                 670         5019          235        >19.8
m2                4614         4814          197        >19.1
w2                 596         4404          216        >18.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.164 in the direction of the burst
(Schlegel et al. 1998).