image overlap message for exposure 2 of trigger 867987
uvot_overlap.pl vrs. 2010-12-20b fem started at 181021d03h38m21s577146usUT
The observation of trigger 867987 started 2018-10-20T19:15:32.7
Examining file ./867987_g898_uvot_sky_image.fits
The exposure ID is 561755732
The exposure time is 149.868 (seconds)
The filter is U.
The uvot region is centered at (13.9840,-47.3849) with a roll angle of 193.1
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 (13.9670,-47.3800) with a radius of 3.000 arc min
This is 0.751 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 (13.9825,-47.3803) with a radius of 0.028 arc min
This is 0.280 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 867987
find_uvot_ag.pl vrs. 2017-02-17 fem started at 181021d03h38m34s100058usUT
Observation start time is 2018-10-20T19:15:32.7
Examining file ./867987_g898_uvot_catalog_image.fits
The exposure ID is 561755732
The exposure is 149.868 sec.
The bin size is 2 pixels
The filter is U
There are 9 detected source(s) for 867987_g898
Aspect correction adds -0.00014 degrees (-0.034 sec of time = -0.34 arc sec) to RA
Aspect correction adds -0.00163 degrees (-5.86 arcsec) to Dec
Total aspect correction is 5.87 arcsec
Star catalogs centered at 13.9883 , -47.3883 with radius 2.51 arc min.
n_usno: 64 n_gsc: 0
Bright star catalog has no entries brighter than 12 mag
Mean distance difference (CAT_DELTA) for 3 matched entries is 0.650" for 867987_g898
Mean and std. dev of mag. difference (MAG_DELTA) are 0.944 and 1.018 for 867987_g898
Found 6 entries without IDs and 6 entries that are acceptable afterglow candidates for 867987_g898.
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=13.9670 (00:55:52.08) DEC=-47.3800 (-47:22:48.0)
XRT distances are from RA=13.9825 (00:55:55.80) DEC=-47.3803 (-47:22:49.2)
*** WARNING 66 per cent of entries have no IDs.
-----------------
Entry 0 in the list of sources is a candidate afterglow for 867987_g898 with genie
ra=13.98236 (00:55:55.77) dec=-47.38117 (-47:22:52.2) +/- 0.8" mag=18.75+/-0.18
dist=3.1 REFID=3 major=1.1 minor=1.0 flag=0
Found 3 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
13.9860 -47.3831 11.3 -1 USNO-B1 17.95 99.99 99.99
13.9852 -47.3829 9.4 -1 USNO-B1 18.04 16.28 17.06
13.9871 -47.3801 12.2 -1 USNO-B1 20.10 19.54 19.79
uvot_check_outside found 13 of 13 good pixels
##### This source remains a candidate #####
It has no entries within 3.5" or brighter than 12 mag
-----------------
Entry 3 in the list of sources is a candidate afterglow for 867987_g898 with genie
ra=13.98732 (00:55:56.96) dec=-47.40056 (-47:24:02.0) +/- 0.8" mag=18.56+/-0.18
dist=73.8 REFID=6 major=4.4 minor=3.4 flag=2 (blended)
*** The position of this source is inconsistent with the XRT position.
The position is 89.1 arc sec from the BAT position.
Found 0 entries in star catalog(s) within 20.0" of the candidate.
*** If XRT position is correct, then this is NOT the afterglow
*** unacceptable major profile of 4.4
-----------------
Entry 4 in the list of sources is a candidate afterglow for 867987_g898 with genie
ra=13.98726 (00:55:56.94) dec=-47.40253 (-47:24:09.1) +/- 0.8" mag=18.72+/-0.18
dist=80.8 REFID=7 major=5.0 minor=3.8 flag=2 (blended)
*** The position of this source is inconsistent with the XRT position.
The position is 95.0 arc sec from the BAT position.
Found 0 entries in star catalog(s) within 20.0" of the candidate.
*** If XRT position is correct, then this is NOT the afterglow
*** unacceptable major profile of 5.0
-----------------
Entry 6 in the list of sources is a candidate afterglow for 867987_g898 with genie
ra=13.98786 (00:55:57.09) dec=-47.40952 (-47:24:34.3) +/- 0.8" mag=18.99+/-0.19
dist=105.9 REFID=8 major=4.4 minor=4.2 flag=0
*** The position of this source is inconsistent with the XRT position.
The position is 117.8 arc sec from the BAT position.
Found 0 entries in star catalog(s) within 20.0" of the candidate.
*** If XRT position is correct, then this is NOT the afterglow
*** unacceptable major profile of 4.4
-----------------
Entry 7 in the list of sources is a candidate afterglow for 867987_g898 with genie
ra=13.99336 (00:55:58.41) dec=-47.41083 (-47:24:39.0) +/- 1.2" mag=20.33+/-0.34
dist=113.0 REFID=9 major=0.8 minor=0.6 flag=0
*** The position of this source is inconsistent with the XRT position.
The position is 128.3 arc sec from the BAT position.
This source is near the edge of image (0.985)
Found 2 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
13.9970 -47.4079 13.6 -1 USNO-B1 99.99 19.79 99.99
13.9967 -47.4081 12.9 -1 USNO-B1 18.49 19.95 19.30
*** If XRT position is correct, then this is NOT the afterglow
-----------------
Entry 8 in the list of sources is a candidate afterglow for 867987_g898 with genie
ra=13.98701 (00:55:56.88) dec=-47.41239 (-47:24:44.6) +/- 1.4" mag=20.68+/-0.42
dist=116.0 REFID=1 major=1.0 minor=0.8 flag=0
*** The position of this source is inconsistent with the XRT position.
The position is 126.4 arc sec from the BAT position.
This source is near the edge of image (0.887)
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:
Unmatched source ra=13.98236 (00:55:55.77) dec=-47.38117 (-47:22:52.2) +/- 0.8" mag=18.75+/-0.18 dist=3.1 REFID=3 flag=0
There are 6343.0942 counts in the bkg source region of 6108.0000 pixels.
Rate in bkg region from 0 to 45 arcsec is 1.038 counts/pixel (5-sig UL in 4" is 19.89 mag) for 867987_g898
There are 131.52692 counts in the src source region of 50.000000 pixels.
Rate in src region with 4 arcsec radius is 2.631 counts/pixel for 867987_g898
There are 1312.0773 counts in the cand_src_bkg source region of 1247.0000 pixels.
Rate in cand_src_bkg region from 15 to 25 arcsec is 1.052 counts/pixel (5-sig UL in 4" is 19.88 mag) for 867987_g898
Good candidates have no ID, acceptable profiles,
mag between 9.01 and 20.44, XRT distances < 5",
are > ~(80 - 10*(mag-6))" from any bright star, and have had duplicates removed.
SUMMARY: 1 good candidate(s) found.
Region file: 867987_561755732_181021d03h38m34s100058usUT_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(13.9840,-47.3849,45")
fk5;-circle(13.9823646275711,-47.3811741893416,6")
fk5;-circle(13.9852027118064,-47.3828232121488,6")
Region file: 867987_561755732_181021d03h38m34s100058usUT_cand_src.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(13.9823646275711,-47.3811741893416,4")
Region file: 867987_561755732_181021d03h38m34s100058usUT_cand_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(13.9823646275711,-47.3811741893416,25")
fk5;-circle(13.9823646275711,-47.3811741893416,15")
fk5;-circle(13.9852027118064,-47.3828232121488,6")
image paragraph message for exposure 2 of trigger 867987
------ Start for Possible Stand-alone Circular ----
In response to GRB181020 (Swift/BAT trigger 867987) at 19:00:33 UT,
---- UVOT paragraph for Joint or Stand-alone Circular ----
UVOT took a finding chart exposure of 150 seconds with the U filter starting
877 seconds after the BAT trigger. There is a candidate afterglow in the
rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 00:55:55.77 = 13.98236
DEC(J2000) = -47:22:52.2 = -47.38117
with a 90%-confidence error radius of about 0.82 arc sec. This position is 3.1
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.75 with a 1-sigma error of about 0.18. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.01.
------- notes for trigger 867987 ------
uvot_gcn_auto.pl vrs. 2016-09-07 fem at 181021d03h38m36s915073usUT
Command line: /Home/eud/uvot_tdrss/perl/uvot_gcn_auto.pl -trig=867987
-expid=561755732 -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/867987/
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 561755732.67106 or about 2018:293:19:15:27 UT
Found 666 stars in largest star catalog for srclist region. The stars will
eliminate afterglows from about 6% of the srclist region. Found 190 sources in
srclist catalog. WARNING -- srclist catalog buffer filled. Found 168 srclist
source(s) without IDs. There are 0 good candidate(s) in the srclist catalog.
Good candidates must be brighter than 17.84 mag.
Found 9 source(s) in Genie image catalog. 1 source(s) are within 10.0" of the
xrt position. Found 6 Genie image source(s) without IDs. There are 1 good
candidate(s) in the Genie image catalog. Good candidates must be brighter than
20.44 mag. Found 60 stars in largest star catalog for Genie image region. The
stars will eliminate afterglows from about 6% of the Genie image region. The
closest srclist source has ra= 13.9408 dec= -47.4098 mag=16.11 sep=146.98".
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?
561755732 876 U srclist found no candidates.
561755732 876 U 13.98236 -47.38117 18.75/20.4 3.1 image Yes
List afterglow candidates for other finding charts.
561754976 120 U 13.98259 -47.38105 18.31/18.1 2.6 srclist Yes
561754976 120 U 13.98240 -47.38105 17.51/20.7 2.6 image Yes
------- Tokens for Quick GCN -------
CATALOG_TYPE: IMAGE
FILTER: u
GRB_DEC: -47.38117
GRB_ERROR: 0.82
GRB_RA: 13.98236
IMAGE_START_TIME: 19:15:27
MAGNITUDE: 18.75
MAG_ERROR: 0.18
MESSAGE_TYPE: ACK
SOURCE: XRT