image overlap message for exposure 1 of trigger 1073821
uvot_overlap.pl vrs. 2010-12-20b fem started at 210918d08h07m59s016984usUT
The observation of trigger 1073821 started 2021-09-18T08:01:01.8
Examining file 1073821_g160_uvot_sky_image.fits
The exposure ID is 653644861
The exposure time is 249.935 (seconds)
The filter is U.
The uvot region is centered at (250.4565,-45.5425) with a roll angle of 282.4
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 (250.4550,-45.5400) with a radius of 3.000 arc min
This is 0.163 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 (250.4669,-45.5421) with a radius of 0.082 arc min
This is 0.436 arc min from the center of the uvot region
The area of the XRT error circle is 0.021 sq. arc min
The UVOT/XRT overlap is 0.021 sq. arc min or 1.00 of the XRT error circle
image afterglow message for exposure 1 of trigger 1073821
find_uvot_ag.pl vrs. 2020-10-30 fem started at 210918d08h08m01s814046usUT
Observation start time is 2021-09-18T08:01:01.8
Examining file 1073821_g160_uvot_catalog_image.fits
The exposure ID is 653644861
The exposure is 249.935 sec.
The bin size is 2 pixels
The filter is U
There are 10 detected source(s) for 1073821_g160
Aspect correction adds -0.00034 degrees (-0.081 sec of time = -0.85 arc sec) to RA
Aspect correction adds 0.00223 degrees ( 8.03 arcsec) to Dec
Total aspect correction is 8.07 arcsec
Star catalogs centered at 250.4597 , -45.5415 with radius 2.48 arc min.
n_usno: 244 n_gsc: 0
Bright star catalog has no entries brighter than 12 mag
Mean distance difference (CAT_DELTA) for 8 matched entries is 1.144" for 1073821_g160
Mean and std. dev of mag. difference (MAG_DELTA) are 1.479 and 0.695 for 1073821_g160
Found 2 entries without IDs and 2 entries that are acceptable afterglow candidates for 1073821_g160.
Acceptable entries have no ID, XRT distances < 12.25", 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=250.4550 (16:41:49.20) DEC=-45.5400 (-45:32:24.0)
XRT distances are from RA=250.4669 (16:41:52.06) DEC=-45.5421 (-45:32:31.6)
-----------------
Entry 3 in the list of sources is a candidate afterglow for 1073821_g160 with genie
ra=250.45993 (16:41:50.38) dec=-45.52881 (-45:31:43.7) +/- 0.8" mag=18.62+/-0.17
dist=51.0 REFID=5 major=1.0 minor=1.0 flag=0
*** The position of this source is inconsistent with the XRT position.
The position is 42.2 arc sec from the BAT position.
Found 6 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
250.4593 -45.5308 7.2 -1 USNO-B1 99.99 18.74 99.99
250.4602 -45.5285 1.4 -1 USNO-B1 18.21 15.02 16.44 *
250.4619 -45.5282 5.4 -1 USNO-B1 18.41 17.59 17.95
250.4609 -45.5275 5.5 -1 USNO-B1 19.35 17.46 18.30
250.4650 -45.5258 16.6 -1 USNO-B1 18.07 17.19 17.58
250.4593 -45.5235 19.3 -1 USNO-B1 18.31 15.43 16.71
Due to star catalog entries marked with *, this is probably NOT the afterglow
These entries are within 3.5" or brighter than 12 mag
-----------------
Entry 4 in the list of sources is a candidate afterglow for 1073821_g160 with genie
ra=250.44569 (16:41:46.96) dec=-45.53342 (-45:32:00.3) +/- 1.4" mag=20.45+/-0.40
dist=62.0 REFID=8 major=1.5 minor=1.4 flag=0
*** The position of this source is inconsistent with the XRT position.
The position is 33.4 arc sec from the BAT position.
Found 6 entries in star catalog(s) within 20.0" of the candidate.
RA Dec Sep. Match USNO/ USNO-B USNO-R USNO-V
GSC GSC-F GSC-J GSC-V
250.4513 -45.5361 17.0 -1 USNO-B1 99.99 18.32 99.99
250.4461 -45.5376 15.2 -1 USNO-B1 20.27 17.50 18.73
250.4421 -45.5382 19.5 -1 USNO-B1 19.43 18.63 18.99
250.4458 -45.5329 1.9 -1 USNO-B1 17.78 13.84 15.59 *
250.4475 -45.5310 9.9 -1 USNO-B1 19.68 16.54 17.93
250.4408 -45.5336 12.4 -1 USNO-B1 18.62 17.77 18.15
Due to star catalog entries marked with *, this is probably NOT the afterglow
These entries are within 3.5" or brighter than 12 mag
Found 4 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
250.4652 -45.5412 5.5 -1 USNO-B1 19.68 18.30 18.91
250.4660 -45.5445 9.1 -1 USNO-B1 19.74 18.16 18.86
250.4681 -45.5398 9.0 -1 USNO-B1 19.63 18.66 19.09
250.4688 -45.5409 6.5 -1 USNO-B1 99.99 18.83 99.99
The closest star is 5.49" away.
List UVOT sources within 10" of the XRT position:
There are 28503.699 counts in the bkg source region of 6115.0000 pixels.
Rate in bkg region from 0 to 45 arcsec is 4.661 counts/pixel (5-sig UL in 4" is 19.63 mag) for 1073821_g160
There are 930.75146 counts in the xrt source region of 198.00000 pixels.
Rate in xrt region with 8 arcsec radius is 4.701 counts/pixel for 1073821_g160
There are 5363.6865 counts in the xrt_bkg source region of 1154.0000 pixels.
Rate in xrt_bkg region from 15 to 25 arcsec is 4.648 counts/pixel (5-sig UL in 4" is 19.63 mag) for 1073821_g160
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 20.18, XRT distances < 12.25",
are > ~(80 - 10*(mag-6))" from any bright star, and have had duplicates removed.
SUMMARY: 0 good candidate(s) found.
Region file: 1073821_653644861_210918d08h08m01s814046usUT_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(250.4565,-45.5425,45")
fk5;-circle(250.464966868901,-45.5374522687804,6")
fk5;-circle(250.459925051082,-45.528805455665,6")
fk5;-circle(250.445686602485,-45.533419666251,6")
Region file: 1073821_653644861_210918d08h08m01s814046usUT_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(250.4669,-45.5421,8")
Region file: 1073821_653644861_210918d08h08m01s814046usUT_xrt_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(250.4669,-45.5421,25")
fk5;-circle(250.4669,-45.5421,15")
fk5;-circle(250.464966868901,-45.5374522687804,6")
image paragraph message for exposure 1 of trigger 1073821
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 GRB210918 (Swift/BAT trigger 1073821) at 07:58:20 UT,
---- UVOT paragraph for Joint or Stand-alone Circular ----
UVOT took a finding chart exposure of 250 seconds with the U filter starting
133 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
coverage of the XRT error circle by the 8'x8' region for the list of sources
generated on-board is uncertain because the large number of sources filled the
available telemetry. 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 1073821 ------
uvot_gcn_auto.pl vrs. 2020-10-27 fem at 210918d08h08m07s474213usUT
Command line: /Home/eud/uvot_tdrss/perl/uvot_gcn_auto.pl -trig=1073821
-expid=653644861 -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/1073821/
Links to data for all triggers can be found at
http://heasarc.gsfc.nasa.gov/docs/swift/uvot_tdrss/
Unreliable extinction found for bat position. 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 653644861.8374 or about 2021:261:08:00:56 UT
Found 3384 stars in largest star catalog for srclist region. The stars will
eliminate afterglows from about 32% of the srclist region. Found 189 sources in
srclist catalog. WARNING -- srclist catalog buffer filled. Found 90 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 10 source(s) in Genie image catalog. Found 2 Genie image source(s)
without IDs. There are 0 good candidate(s) in the Genie image catalog. Good
candidates must be brighter than 20.18 mag. Found 240 stars in largest star
catalog for Genie image region. The stars will eliminate afterglows from about
27% of the Genie image region.
Genie image analysis:
Found 28503.7 counts in the large background region of 6115.0 pixels or a rate
of 4.661 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 19.47 mag. for a
4-arcsec aperture.
Found 930.8 counts in the XRT position region of 198.0 pixels or a rate of
4.701 counts/pixel in a radius of 8.0 arcsec. The net count rate (using local
background region) at the XRT position is 0.042 +/- 0.132 (1-sigma) cps or
21.62 mag and a range from 20.08 to 99.99 mag. The 3-sigma UL at the XRT
position is 0.438 cps or 19.08 mag. The number of srclist sources filled the
available telemetry. The weakest source detected was 18.79 mag. The closest
srclist source has ra= 250.4650 dec= -45.5374 mag=18.05 sep=17.42". The closest
Genie source has ra= 250.4650 dec= -45.5374 mag=17.17 sep=17.43".
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?
653644861 133 U srclist found no candidates.
653644861 133 U image found no candidates.
List afterglow candidates for other finding charts.
------- Tokens for Quick GCN -------
CATALOG_TYPE: IMAGE
FILTER: u
GRB_DEC: -45.54210
GRB_ERROR: 12.25
GRB_RA: 250.46690
IMAGE_START_TIME: 08:00:56
MAGNITUDE: 19.1
MAG_ERROR: 3.0
MESSAGE_TYPE: NACK
SOURCE: XRT