image overlap message for exposure 2 of trigger 821881
uvot_overlap.pl vrs. 2010-12-20b fem started at 180404d04h58m29s811799usUT
The observation of trigger 821881 started 2018-04-04T00:50:58.4
Examining file ./821881_g322_uvot_sky_image.fits
The exposure ID is 544495858
The exposure time is 249.935 (seconds)
The filter is U.
The uvot region is centered at (83.5589,-37.1708) with a roll angle of 286.5
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 (83.5640,-37.1700) with a radius of 3.000 arc min
This is 0.251 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 (83.5490,-37.1681) with a radius of 0.033 arc min
This is 0.498 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 821881
find_uvot_ag.pl vrs. 2017-02-17 fem started at 180404d04h58m38s279339usUT
Observation start time is 2018-04-04T00:50:58.4
Examining file ./821881_g322_uvot_catalog_image.fits
The exposure ID is 544495858
The exposure is 249.935 sec.
The bin size is 2 pixels
The filter is U
There are 7 detected source(s) for 821881_g322
Aspect correction adds -0.00057 degrees (-0.136 sec of time = -1.63 arc sec) to RA
Aspect correction adds 0.00009 degrees ( 0.32 arcsec) to Dec
Total aspect correction is 1.66 arcsec
Star catalogs centered at 83.5611 , -37.1672 with radius 2.42 arc min.
n_usno: 73 n_gsc: 65
Bright star catalog has no entries brighter than 12 mag
Mean distance difference (CAT_DELTA) for 6 matched entries is 0.375" for 821881_g322
Mean and std. dev of mag. difference (MAG_DELTA) are 0.964 and 1.005 for 821881_g322
Found 1 entries without IDs and 1 entries that are acceptable afterglow candidates for 821881_g322.
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=83.5640 (05:34:15.36) DEC=-37.1700 (-37:10:12.0)
XRT distances are from RA=83.5490 (05:34:11.77) DEC=-37.1681 (-37:10:05.1)
-----------------
Entry 1 in the list of sources is a candidate afterglow for 821881_g322 with genie
ra=83.54876 (05:34:11.70) dec=-37.16790 (-37:10:04.5) +/- 0.7" mag=18.80+/-0.17
dist=1.0 REFID=5 major=1.1 minor=0.9 flag=0
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
83.5534 -37.1713 18.0 -1 USNO-B1 20.44 20.01 20.20
83.5475 -37.1694 6.3 -1 USNO-B1 20.55 19.62 20.03
83.5448 -37.1650 15.4 -1 USNO-B1 20.59 20.64 20.62
83.5447 -37.1653 15.0 -1 USNO-B1 21.11 20.71 20.89
83.5534 -37.1712 17.8 -1 GSC2.3 20.00 21.97 99.99
83.5475 -37.1694 6.3 -1 GSC2.3 19.52 21.76 99.99
83.5448 -37.1651 15.2 -1 GSC2.3 20.16 99.99 99.99
uvot_check_outside found 11 of 11 good pixels
##### This source remains a candidate #####
It has no entries within 3.5" or brighter than 12 mag
Found 2 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
83.5475 -37.1694 6.3 -1 USNO-B1 20.55 19.62 20.03
83.5475 -37.1694 6.3 -1 GSC2.3 19.52 21.76 99.99
The closest star is 6.35" away.
List UVOT sources within 10" of the XRT position:
Unmatched source ra=83.54876 (05:34:11.70) dec=-37.16790 (-37:10:04.5) +/- 0.7" mag=18.80+/-0.17 dist=1.0 REFID=5 flag=0
There are 9950.1973 counts in the bkg source region of 6080.0000 pixels.
Rate in bkg region from 0 to 45 arcsec is 1.637 counts/pixel (5-sig UL in 4" is 20.20 mag) for 821881_g322
There are 201.95921 counts in the src source region of 46.000000 pixels.
Rate in src region with 4 arcsec radius is 4.390 counts/pixel for 821881_g322
There are 2045.9688 counts in the cand_src_bkg source region of 1245.0000 pixels.
Rate in cand_src_bkg region from 15 to 25 arcsec is 1.643 counts/pixel (5-sig UL in 4" is 20.20 mag) for 821881_g322
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 20.75, 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: 821881_544495858_180404d04h58m38s279339usUT_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(83.5589,-37.1708,45")
fk5;-circle(83.5600663656143,-37.1777678086444,6")
fk5;-circle(83.548758848765,-37.1679033855127,6")
Region file: 821881_544495858_180404d04h58m38s279339usUT_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(83.548758848765,-37.1679033855127,4")
Region file: 821881_544495858_180404d04h58m38s279339usUT_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(83.548758848765,-37.1679033855127,25")
fk5;-circle(83.548758848765,-37.1679033855127,15")
image paragraph message for exposure 2 of trigger 821881
------ Start for Possible Stand-alone Circular ----
In response to GRB180404 (Swift/BAT trigger 821881) at 00:45:35 UT,
---- UVOT paragraph for Joint or Stand-alone Circular ----
UVOT took a finding chart exposure of 250 seconds with the U filter starting
302 seconds after the BAT trigger. There is a candidate afterglow in the
rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 05:34:11.70 = 83.54876
DEC(J2000) = -37:10:04.4 = -37.16790
with a 90%-confidence error radius of about 0.67 arc sec. This position is 1.0
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.80 with a 1-sigma error of about 0.17. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.04.
------- notes for trigger 821881 ------
uvot_gcn_auto.pl vrs. 2016-09-07 fem at 180404d04h58m40s953183usUT
Command line: /Home/eud/uvot_tdrss/perl/uvot_gcn_auto.pl -trig=821881
-expid=544495858 -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/821881/
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 544495858.41534 or about 2018:094:00:50:53 UT
Found 822 stars in largest star catalog for srclist region. The stars will
eliminate afterglows from about 7% of the srclist region. Found 86 sources in
srclist catalog. Found 29 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 7 source(s) in Genie image catalog. 1 source(s) are within 10.0" of the
xrt position. Found 1 Genie image source(s) without IDs. There are 1 good
candidate(s) in the Genie image catalog. Good candidates must be brighter than
20.75 mag. Found 69 stars in largest star catalog for Genie image region. The
stars will eliminate afterglows from about 8% of the Genie image region.
Found 1 srclist source(s) within 10.0" of the XRT position.
The brightest such source has ra= 83.5488 dec= -37.1678 mag=19.29 sep=1.36".
The closest srclist source has ra= 83.5488 dec= -37.1678 mag=19.29 sep=1.36".
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?
544495858 301 U 83.54880 -37.16776 19.29/18.1 1.4 srclist Yes
544495858 301 U 83.54876 -37.16790 18.80/20.8 1.0 image Yes
List afterglow candidates for other finding charts.
544495646 89 WHITE 83.54865 -37.16782 19.78/19.2 1.5 srclist Yes
544495646 89 WHITE 83.54846 -37.16774 19.40/20.9 2.1 image Yes
------- Tokens for Quick GCN -------
CATALOG_TYPE: IMAGE
FILTER: u
GRB_DEC: -37.16790
GRB_ERROR: 0.67
GRB_RA: 83.54876
IMAGE_START_TIME: 00:50:53
MAGNITUDE: 18.80
MAG_ERROR: 0.17
MESSAGE_TYPE: ACK
SOURCE: XRT