image overlap message for exposure 2 of trigger 1426088
uvot_overlap.pl vrs. 2010-12-20b fem started at 251221d20h39m32s864057usUT
The observation of trigger 1426088 started 2025-12-21T05:30:09.6
Examining file ./1426088_g337_uvot_sky_image.fits
The exposure ID is 787987809
The exposure time is 249.935 (seconds)
The filter is U.
The uvot region is centered at (101.4129,0.7234) with a roll angle of 154.0
It is square with sides of 2.68 arc min. for an area of 7.17 sq arc min
The BAT error circle is centered at (101.4080,0.7290) with a radius of 3.000 arc min
This is 0.445 arc min from the center of the uvot region
The area of the BAT error circle is 28.27 sq. arc min
The UVOT/BAT overlap is 7.17 sq. arc min or 0.25 of the BAT error circle
The XRT error circle is centered at (101.4277,0.7322) with a radius of 0.035 arc min
This is 1.032 arc min from the center of the uvot region
The area of the XRT error circle is 0.004 sq. arc min
The UVOT/XRT overlap is 0.004 sq. arc min or 1.00 of the XRT error circle
image afterglow message for exposure 2 of trigger 1426088
find_uvot_ag.pl vrs. 2023-04-25a fem started at 251221d20h39m49s856368usUT
Observation start time is 2025-12-21T05:30:09.6
Examining file ./1426088_g337_uvot_catalog_image.fits
The exposure ID is 787987809
The exposure is 249.935 sec.
The bin size is 2 pixels
The filter is U
There are 22 detected source(s) for 1426088_g337
Aspect correction adds -0.00000 degrees (-0.000 sec of time = -0.00 arc sec) to RA
Aspect correction adds -0.00163 degrees (-5.88 arcsec) to Dec
Total aspect correction is 5.88 arcsec
Star catalogs centered at 101.4120 , 0.7232 with radius 2.58 arc min.
n_usno: 179 n_gsc: 224
Bright star catalog has no entries brighter than 12 mag
Mean distance difference (CAT_DELTA) for 22 matched entries is 0.556" for 1426088_g337
Mean and std. dev of mag. difference (MAG_DELTA) are 1.274 and 0.779 for 1426088_g337
Found 1 entries without IDs and 1 entries that are acceptable afterglow candidates for 1426088_g337.
Acceptable entries have no ID, XRT distances < 5.25", and are > 0.8*(80 - 10*(mag-6))" from any bright star
from any bright star and >21.6" from other rejected sources.
Magnitude criteria will be applied later.
BAT distances are from RA=101.4080 (06:45:37.92) DEC= 0.7290 (+00:43:44.4)
XRT distances are from RA=101.4277 (06:45:42.65) DEC= 0.7322 (+00:43:55.8)
-----------------
Entry 10 in the list of sources is a candidate afterglow for 1426088_g337 with genie
ra=101.39111 (06:45:33.87) dec=0.73796 (+00:44:16.7) +/- 0.7" mag=18.57+/-0.17
dist=133.4 REFID=22 major=0.9 minor=0.3 flag=16 (aperture_incomplete)
*** The position of this source is inconsistent with the XRT position.
The position is 68.8 arc sec from the BAT position.
This source is near the edge of image (1.018)
Found 7 entries in star catalog(s) within 20.0" of the candidate.
printing all entries
(Entries within 2 arc sec of a source list entry are considered a match)
RA Dec Sep. Match USNO/ USNO-B USNO-R USNO-V
GSC GSC-F GSC-J GSC-V
101.3914 0.7334 16.5 -1 USNO-B1 19.61 17.35 18.35
101.3928 0.7366 7.9 -1 USNO-B1 19.77 17.95 18.76
101.3911 0.7338 14.9 -1 USNO-B1 18.70 17.66 18.12
101.3904 0.7382 2.7 -1 USNO-B1 15.46 14.39 14.86 *
101.3928 0.7366 8.0 -1 GSC2.3 18.31 19.60 99.99
101.3911 0.7338 14.9 -1 GSC2.3 17.42 18.75 99.99
101.3904 0.7382 2.8 -1 GSC2.3 13.74 15.13 99.99 *
Due to star catalog entries marked with *, this is probably NOT the afterglow
These entries are within 5.25" or brighter than 12 mag
Found 3 entries in star catalog(s) within 10" of the XRT position.
RA Dec Sep. Match USNO/ USNO-B USNO-R USNO-V
GSC GSC-F GSC-J GSC-V
101.4305 0.7322 10.0 -1 USNO-B1 20.62 19.41 19.95
101.4263 0.7321 5.0 -1 GSC2.3 20.33 99.99 99.99
101.4303 0.7323 9.4 -1 GSC2.3 19.23 21.11 99.99
The closest star is 4.97" away.
List UVOT sources within 10" of the XRT position:
There are 21766.391 counts in the bkg source region of 5875.0000 pixels.
Rate in bkg region from 0 to 45 arcsec is 3.705 counts/pixel (5-sig UL in 4" is 19.75 mag) for 1426088_g337
There are 669.60034 counts in the xrt source region of 200.00000 pixels.
Rate in xrt region with 8 arcsec radius is 3.348 counts/pixel for 1426088_g337
XRT source is too far (61.9591311257631") from center -- do not compute local background.
There are no candidates inside BAT error circle, but outside XRT error circle.
Good candidates have no ID, acceptable profiles,
mag between 9.01 and 20.31, XRT distances < 5.25",
are > ~(80 - 10*(mag-6))" from any bright star, and have had duplicates removed.
SUMMARY: 0 good candidate(s) found.
Region file: 1426088_787987809_251221d20h39m49s856368usUT_bkg.region
# Region file format: DS9 version 3.0
global color=red font="helvetica 10 normal" select=1 edit=1 move=1 delete=1 include=1 fixed=0 source
fk5;circle(101.4129,0.7234,45")
fk5;-circle(101.40734020064,0.727872818771538,6")
fk5;-circle(101.407955390393,0.730483918551426,6")
fk5;-circle(101.413660152647,0.725969697492875,6")
fk5;-circle(101.40993790035,0.7164593630977,6")
Region file: 1426088_787987809_251221d20h39m49s856368usUT_xrt.region
# Region file format: DS9 version 3.0
global color=red font="helvetica 10 normal" select=1 edit=1 move=1 delete=1 include=1 fixed=0 source
fk5;circle(101.42771,0.73217,8")
image paragraph message for exposure 2 of trigger 1426088
SRCLIST PROBLEM: srclist filled telemetry buffer
WARNING -- because of the LARGE EXTINCTION, results should be used cautiously.
------ Start for Possible Stand-alone Circular ----
In response to GRB251221 (Swift/BAT trigger 1426088) at 05:24:31 UT,
---- UVOT paragraph for Joint or Stand-alone Circular ----
UVOT took a finding chart exposure of 250 seconds with the U filter starting
300 seconds after the BAT trigger. No credible afterglow candidate has been
found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the
XRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The
8'x8' region for the list of sources generated on-board covers 100% of the XRT
error circle. The list of sources is typically complete to about 18.0 mag. No
correction has been made for the large, but uncertain, extinction expected.
------- notes for trigger 1426088 ------
uvot_gcn_auto.pl vrs. 2023-03-28 fem at 251221d20h39m54s501819usUT
Command line: /Home/eud/uvot_tdrss/perl/uvot_gcn_auto.pl -trig=1426088
-expid=787987809 -meonly -msg_image
Results from standard processing of UVOT TDRSS data for this trigger should be
available at
http://heasarc.gsfc.nasa.gov/docs/swift/uvot_tdrss/1426088/
Links to data for all triggers can be found at
http://heasarc.gsfc.nasa.gov/docs/swift/uvot_tdrss/
Unreliable extinction found for xrt position. XRT position found for srclist.
XRT position found for Genie image. BAT position found.
UVOT exposure began at MET 787987809.56206 or about 2025:356:05:30:04 UT
Found 2869 stars in largest star catalog for srclist region. The stars will
eliminate afterglows from about 24% of the srclist region. Found 190 sources in
srclist catalog. WARNING -- srclist catalog buffer filled. Found 13 srclist
source(s) without IDs. There are 0 good candidate(s) in the srclist catalog.
Good candidates must be brighter than 18.12 mag.
Found 22 source(s) in Genie image catalog. Found 1 Genie image source(s)
without IDs. There are 0 good candidate(s) in the Genie image catalog. Good
candidates must be brighter than 20.31 mag. Found 217 stars in largest star
catalog for Genie image region. The stars will eliminate afterglows from about
22% of the Genie image region.
Genie image analysis:
Found 21766.4 counts in the large background region of 5875.0 pixels or a rate
of 3.705 counts/pixel in a radius of 45.0 arcsec. Based on this background, the
typical 5-sigma UL at a random point in the Genie image is 19.54 mag. for a
4-arcsec aperture.
Found 669.6 counts in the XRT position region of 200.0 pixels or a rate of
3.348 counts/pixel in a radius of 8.0 arcsec. The net count rate (using large
background region) at the XRT position is -0.286 +/- 0.105 (1-sigma) cps. The
3-sigma UL at the XRT position is 0.316 cps or 19.38 mag. The number of srclist
sources filled the available telemetry. The weakest source detected was 18.30
mag. The closest srclist source has ra= 101.4308 dec= 0.7204 mag=17.70
sep=43.78". The closest Genie source has ra= 101.4309 dec= 0.7203 mag=17.17
sep=44.27".
All AG candidates sorted by magnitude for the current finding chart.
(U/V/White SRCLIST mags < 17.5/17.5/18.5 are reliable. Mag > 18.5/18.5/19.5 are
not. Others are uncertain.)
(U/V/White Genie image mags < 18.0/18.0/19.0 are reliable. Mag > 19.0/19.0/20.0
are not. Others are uncertain.)
(Magnitudes followed by * have been corrected for exposure.)
---MET--- -dt- filter ---RA-- ---DEC--- -MAG/Limit Dist(") Source Asp.Corr?
787987809 300 U srclist found no candidates.
787987809 300 U image found no candidates.
List afterglow candidates for other finding charts.
787987651 142 WHITE srclist found no candidates.
787987651 142 WHITE image found no candidates.
787988386 877 WHITE srclist found no candidates.
787988386 877 WHITE image found no candidates.
------- Tokens for Quick GCN -------
CATALOG_TYPE: IMAGE
FILTER: u
GRB_DEC: 0.73217
GRB_ERROR: 5.25
GRB_RA: 101.42771
IMAGE_START_TIME: 05:30:04
MAGNITUDE: 19.4
MAG_ERROR: 3.0
MESSAGE_TYPE: NACK
SOURCE: XRT