image overlap message for exposure 2 of trigger 853824
uvot_overlap.pl vrs. 2010-12-20b fem started at 180818d05h33m06s048308usUT
The observation of trigger 853824 started 2018-08-18T03:16:26.1
Examining file ./853824_g261_uvot_sky_image.fits
The exposure ID is 556254986
The exposure time is 249.946 (seconds)
The filter is U.
The uvot region is centered at (169.6324,-48.3432) with a roll angle of 336.0
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 (169.6110,-48.3440) with a radius of 3.000 arc min
This is 0.854 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 (169.6368,-48.3444) with a radius of 0.032 arc min
This is 0.191 arc min from the center of the uvot region
The area of the XRT error circle is 0.003 sq. arc min
The UVOT/XRT overlap is 0.003 sq. arc min or 1.00 of the XRT error circle
image afterglow message for exposure 2 of trigger 853824
find_uvot_ag.pl vrs. 2017-02-17 fem started at 180818d05h33m19s096593usUT
Observation start time is 2018-08-18T03:16:26.1
Examining file ./853824_g261_uvot_catalog_image.fits
The exposure ID is 556254986
The exposure is 249.946 sec.
The bin size is 2 pixels
The filter is U
There are 25 detected source(s) for 853824_g261
Aspect correction adds 0.00085 degrees (0.204 sec of time = 2.03 arc sec) to RA
Aspect correction adds 0.00113 degrees ( 4.08 arcsec) to Dec
Total aspect correction is 4.56 arcsec
Star catalogs centered at 169.6330 , -48.3433 with radius 2.63 arc min.
n_usno: 326 n_gsc: 0
Bright star catalog has no entries brighter than 12 mag
Mean distance difference (CAT_DELTA) for 26 matched entries is 0.776" for 853824_g261
Mean and std. dev of mag. difference (MAG_DELTA) are 1.043 and 0.858 for 853824_g261
Found 2 entries without IDs and 2 entries that are acceptable afterglow candidates for 853824_g261.
Acceptable entries have no ID, XRT distances < 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=169.6110 (11:18:26.64) DEC=-48.3440 (-48:20:38.4)
XRT distances are from RA=169.6368 (11:18:32.83) DEC=-48.3444 (-48:20:39.9)
-----------------
Entry 9 in the list of sources is a candidate afterglow for 853824_g261 with genie
ra=169.65328 (11:18:36.79) dec=-48.35546 (-48:21:19.7) +/- 0.9" mag=19.71+/-0.27
dist=56.0 REFID=21 major=1.0 minor=0.5 flag=0
*** The position of this source is inconsistent with the XRT position.
The position is 109.3 arc sec from the BAT position.
Found 5 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
169.6469 -48.3544 15.8 -1 USNO-B1 19.37 17.94 18.57
169.6470 -48.3550 15.1 -1 USNO-B1 21.63 19.06 20.20
169.6503 -48.3556 7.3 -1 USNO-B1 17.64 15.47 16.44
169.6517 -48.3594 14.6 -1 USNO-B1 19.05 17.70 18.30
169.6597 -48.3550 15.4 -1 USNO-B1 18.96 17.66 18.24
*** If XRT position is correct, then this is NOT the afterglow
-----------------
Entry 26 in the list of sources is a candidate afterglow for 853824_g261 with genie
ra=169.65955 (11:18:38.29) dec=-48.32428 (-48:19:27.4) +/- 0.7" mag=18.53+/-0.17
dist=90.7 REFID=4 major=1.0 minor=0.9 flag=0
*** The position of this source is inconsistent with the XRT position.
The position is 136.2 arc sec from the BAT position.
This source is near the edge of image (0.907)
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
169.6531 -48.3269 18.0 -1 USNO-B1 19.37 18.93 19.13
169.6530 -48.3257 16.6 -1 USNO-B1 16.25 14.62 15.35
169.6597 -48.3252 3.2 -1 USNO-B1 99.99 17.29 99.99 *
169.6597 -48.3248 2.1 -1 USNO-B1 17.86 16.48 17.09 *
169.6633 -48.3252 9.6 -1 USNO-B1 21.81 20.54 21.10
169.6658 -48.3225 16.3 -1 USNO-B1 18.16 17.00 17.52
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 0 entries in star catalog(s) within 10" of the XRT position.
List UVOT sources within 10" of the XRT position:
There are 41075.555 counts in the bkg source region of 5974.0000 pixels.
Rate in bkg region from 0 to 45 arcsec is 6.876 counts/pixel (5-sig UL in 4" is 19.42 mag) for 853824_g261
There are 1351.6075 counts in the xrt source region of 198.00000 pixels.
Rate in xrt region with 8 arcsec radius is 6.826 counts/pixel for 853824_g261
There are 8593.7832 counts in the xrt_bkg source region of 1237.0000 pixels.
Rate in xrt_bkg region from 15 to 25 arcsec is 6.947 counts/pixel (5-sig UL in 4" is 19.41 mag) for 853824_g261
Good candidates have no ID, acceptable profiles,
mag between 9.01 and 19.97, XRT distances < 5",
are > ~(80 - 10*(mag-6))" from any bright star, and have had duplicates removed.
SUMMARY: 0 good candidate(s) found.
Region file: 853824_556254986_180818d05h33m19s096593usUT_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(169.6324,-48.3432,45")
fk5;-circle(169.639633123829,-48.3465548651172,6")
fk5;-circle(169.644863860904,-48.3360015470399,6")
fk5;-circle(169.634870307682,-48.332669504865,6")
Region file: 853824_556254986_180818d05h33m19s096593usUT_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(169.63679,-48.34442,8")
Region file: 853824_556254986_180818d05h33m19s096593usUT_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(169.63679,-48.34442,25")
fk5;-circle(169.63679,-48.34442,15")
fk5;-circle(169.639633123829,-48.3465548651172,6")
image paragraph message for exposure 2 of trigger 853824
SRCLIST PROBLEM: srclist filled telemetry buffer
------ Start for Possible Stand-alone Circular ----
In response to GRB180818 (Swift/BAT trigger 853824) at 03:12:04 UT,
---- UVOT paragraph for Joint or Stand-alone Circular ----
UVOT took a finding chart exposure of 250 seconds with the U filter starting
240 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
0.11.
------- notes for trigger 853824 ------
uvot_gcn_auto.pl vrs. 2016-09-07 fem at 180818d05h33m21s545647usUT
Command line: /Home/eud/uvot_tdrss/perl/uvot_gcn_auto.pl -trig=853824
-expid=556254986 -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/853824/
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 556254986.1206 or about 2018:230:03:16:21 UT
Found 3208 stars in largest star catalog for srclist region. The stars will
eliminate afterglows from about 29% of the srclist region. Found 190 sources in
srclist catalog. WARNING -- srclist catalog buffer filled. Found 23 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 25 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 19.97 mag. Found 322 stars in largest star
catalog for Genie image region. The stars will eliminate afterglows from about
32% of the Genie image region.
Genie image analysis:
Found 41075.6 counts in the large background region of 5974.0 pixels or a rate
of 6.876 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 19.46 mag. for a
4-arcsec aperture.
Found 1351.6 counts in the XRT position region of 198.0 pixels or a rate of
6.826 counts/pixel in a radius of 8.0 arcsec. The net count rate (using local
background region) at the XRT position is -0.096 +/- 0.159 (1-sigma) cps. The
3-sigma UL at the XRT position is 0.476 cps or 19.19 mag. The number of srclist
sources filled the available telemetry. The weakest source detected was 18.21
mag. The closest srclist source has ra= 169.6353 dec= -48.3328 mag=17.65
sep=41.97". The closest Genie source has ra= 169.6396 dec= -48.3466 mag=18.19
sep=10.26".
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?
556254986 240 U srclist found no candidates.
556254986 240 U image found no candidates.
List afterglow candidates for other finding charts.
556254828 82 WHITE srclist found no candidates.
556254828 82 WHITE image found no candidates.
556255613 867 WHITE srclist found no candidates.
556255613 867 WHITE image found no candidates.
------- Tokens for Quick GCN -------
CATALOG_TYPE: IMAGE
FILTER: u
GRB_DEC: -48.34442
GRB_ERROR: 5
GRB_RA: 169.63679
IMAGE_START_TIME: 03:16:21
MAGNITUDE: 19.2
MAG_ERROR: 3.0
MESSAGE_TYPE: NACK
SOURCE: XRT