srclist overlap message for exposure 2 of trigger 1164980
uvot_overlap.pl vrs. 2010-12-20b fem started at 230420d19h40m44s587041usUT
The observation of trigger 1164980 started 2023-04-20T10:23:50.2
Examining file ./1164980_g288_uvot_sky_srclist.fits
The exposure ID is 703679030
The exposure time is undefined.
The filter is U.
The uvot region is centered at (161.0444,32.1085) with a roll angle of 306.2
It is square with sides of 8.03 arc min. for an area of 64.51 sq arc min
The BAT error circle is centered at (161.0130,32.0870) with a radius of 3.000 arc min
This is 2.054 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 25.30 sq. arc min or 0.89 of the BAT error circle
The XRT error circle is centered at (161.0482,32.1077) with a radius of 0.037 arc min
This is 0.197 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
srclist afterglow message for exposure 2 of trigger 1164980
find_uvot_ag.pl vrs. 2023-03-28 fem started at 230420d19h40m55s260535usUT
Observation start time is 2023-04-20T10:23:50.2
Examining file ./1164980_g288_uvot_catalog_srclist.fits
The exposure ID is 703679030
The exposure is 249.935 sec.
The bin size is 2 pixels
The filter is U
There are 16 detected source(s) for 1164980_g288
Aspect correction adds -0.00128 degrees (-0.307 sec of time = -3.90 arc sec) to RA
Aspect correction adds 0.00073 degrees ( 2.61 arcsec) to Dec
Total aspect correction is 4.69 arcsec
*** WARNING -- access to usno-b1 catalog failed.
Star catalogs centered at 161.0607 , 32.1196 with radius 5.68 arc min.
n_usno: -1 n_gsc: 0
*** WARNING -- no star catalog entries found.
-- this strongly suggests a problem with the catalogs.
-- cannot check for bright stars or nearby sources.
-- there is a high risk of false positives.
Bright star catalog has no entries brighter than 12 mag
Mean distance difference (CAT_DELTA) for 10 matched entries is 0.778" for 1164980_g288
Mean and std. dev of mag. difference (MAG_DELTA) are 2.014 and 0.609 for 1164980_g288
Found 7 entries without IDs and 2 entries that are acceptable afterglow candidates for 1164980_g288.
Acceptable entries have no ID, XRT distances < 5.5", 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=161.0130 (10:44:03.12) DEC=32.0870 (+32:05:13.2)
XRT distances are from RA=161.0482 (10:44:11.56) DEC=32.1077 (+32:06:27.7)
*** WARNING 43 per cent of entries have no IDs.
-----------------
Entry 1 in the list of sources is a candidate afterglow for 1164980_g288 with 5x5 stamp
ra=161.06967 (10:44:16.72) dec=32.09290 (+32:05:34.4) +/- 1.1" mag=19.30+/-0.35
dist=84.5 REFID=13
*** The position of this source is inconsistent with the XRT position.
The position is 174.1 arc sec from the BAT position.
src: 1 distr. of nearby unmatched sources: 1 0 0 0 0
Found 0 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)
*** If XRT position is correct, then this is NOT the afterglow
-----------------
Entry 4 in the list of sources is a candidate afterglow for 1164980_g288 with 5x5 stamp
ra=161.00435 (10:44:01.04) dec=32.13236 (+32:07:56.5) +/- 1.1" mag=19.95+/-0.35
dist=160.4 REFID=14
*** The position of this source is inconsistent with the XRT position.
The position is 165.4 arc sec from the BAT position.
src: 4 distr. of nearby unmatched sources: 1 1 0 0 0
Found 0 entries in star catalog(s) within 20.0" of the candidate.
*** If XRT position is correct, then this is NOT the afterglow
Found 0 entries in star catalog(s) within 10" of the XRT position.
List UVOT sources within 10" of the XRT position:
Good candidates have no ID, acceptable profiles,
mag between 9.01 and 18.12, XRT distances < 5.5",
are > ~(80 - 10*(mag-6))" from any bright star, and have had duplicates removed.
SUMMARY: 0 good candidate(s) found.
srclist paragraph message for exposure 2 of trigger 1164980
------ Start for Possible Stand-alone Circular ----
In response to GRB230420 (Swift/BAT trigger 1164980) at 10:19:01 UT,
---- UVOT paragraph for Joint or Stand-alone Circular ----
UVOT took a finding chart exposure of 250 seconds with the U filter starting
257 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 expected extinction corresponding to E(B-V) of
0.017.
------- notes for trigger 1164980 ------
uvot_gcn_auto.pl vrs. 2023-03-28 fem at 230420d19h40m57s344715usUT
Command line: /Home/eud/uvot_tdrss/perl/uvot_gcn_auto.pl -trig=1164980
-expid=703679030 -meonly -msg_srclist
Results from standard processing of UVOT TDRSS data for this trigger should be
available at
http://heasarc.gsfc.nasa.gov/docs/swift/uvot_tdrss/1164980/
Links to data for all triggers can be found at
http://heasarc.gsfc.nasa.gov/docs/swift/uvot_tdrss/
XRT position found for srclist. XRT position found for Genie image. BAT
position found.
UVOT exposure began at MET 703679030.209 or about 2023:110:10:23:45 UT
Access to USNO star catalog FAILED. This increases the odds of a FALSE
afterglow detection. There was likely a PROBLEM with the srclist star catalog
because no stars found. Found 16 sources in srclist catalog. Found 7 srclist
source(s) without IDs. There are 0 good candidate(s) in the srclist catalog.
Good candidates must be brighter than 18.12 mag.
Access to USNO star catalog FAILED. This increases the odds of a FALSE
afterglow detection. Found 2 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 20.62 mag. Found 0 stars in
largest star catalog for Genie image region. The stars will eliminate
afterglows from about 0% of the Genie image region.
Genie image analysis:
Found 13078.1 counts in the large background region of 6308.0 pixels or a rate
of 2.073 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 19.89 mag. for a
4-arcsec aperture.
Found 409.6 counts in the XRT position region of 196.0 pixels or a rate of
2.090 counts/pixel in a radius of 8.0 arcsec. The net count rate (using local
background region) at the XRT position is -0.001 +/- 0.087 (1-sigma) cps. The
3-sigma UL at the XRT position is 0.261 cps or 19.62 mag. The closest srclist
source has ra= 161.0683 dec= 32.0922 mag=15.47 sep=82.81". The closest Genie
source has ra= 161.0675 dec= 32.0937 mag=18.18 sep=77.39".
This paragraph is only useful if the XRT position is grossly wrong. There are 1
candidate(s) in the image data with mag < 20.06 inside the BAT error region,
but outside the XRT error region. The brightest such source is at RA=161.06746
(10:44:16.19), DEC=32.09373 (+32:05:37.4) (J2000). It has a mag of 18.18. It is
167.9" from the BAT position.
****THIS SOURCE IS OUTSIDE XRT ERROR CIRCLE--USE WITH CAUTION***
UVOT took a finding chart exposure of 250 seconds with the U filter starting
257 seconds after the BAT trigger. There is a candidate afterglow in the
rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 10:44:16.19 = 161.06746
DEC(J2000) = +32:05:37.4 = 32.09373
with a 90%-confidence error radius of about 0.77 arc sec. The estimated
magnitude is 18.18 with a 1-sigma error of about 0.16. No correction has been
made for the expected extinction corresponding to E(B-V) of 0.017.
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?
703679030 257 U srclist found no candidates.
703679030 257 U image found no candidates.
List afterglow candidates for other finding charts.
703678871 98 WHITE srclist found no candidates.
703678871 98 WHITE image found no candidates.
703679635 862 WHITE srclist found no candidates.
703679635 862 WHITE image found no candidates.
------- Tokens for Quick GCN -------
CATALOG_TYPE: IMAGE
FILTER: u
GRB_DEC: 32.10769
GRB_ERROR: 5.5
GRB_RA: 161.04817
IMAGE_START_TIME: 10:23:45
MAGNITUDE: 19.6
MAG_ERROR: 3.0
MESSAGE_TYPE: NACK
SOURCE: XRT