- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 31 May 02 00:29:17 UT
NOTICE_TYPE: HETE S/C_Alert
TRIGGER_NUM: 2042, Seq_Num: 1
GRB_DATE: 12425 TJD; 151 DOY; 02/05/31
GRB_TIME: 1578.72 SOD {00:26:18.72} UT
TRIGGER_SOURCE: Trigger on the 25-400 keV band.
GAMMA_RATE: 250 [cnts/s] on a 0.020 [sec] timescale
SC_LONG: 348 [deg East]
SUN_POSTN: 67.73d {+04h 30m 56s} +21.86d {+21d 51' 40"}
MOON_POSTN: 309.23d {+20h 36m 55s} -22.64d {-22d 38' 35"}
MOON_ILLUM: 78 [%]
COMMENTS: No s/c ACS pointing info available yet.
COMMENTS: Probable GRB.
COMMENTS: WXM S/N is less than a reasonable value.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 31 May 02 01:54:22 UT
NOTICE_TYPE: HETE Ground Analysis
TRIGGER_NUM: 2042, Seq_Num: 3
GRB_DATE: 12425 TJD; 151 DOY; 02/05/31
GRB_TIME: 1578.71 SOD {00:26:18.71} UT
TRIGGER_SOURCE: Trigger on the 25-400 keV band.
GAMMA_RATE: 250 [cnts/s] on a 0.020 [sec] timescale
SC_-Z_RA: 247 [deg]
SC_-Z_DEC: -22 [deg]
SC_LONG: 0 [deg East]
WXM_CNTR_RA: 229.002d {+15h 16m 00s} (J2000),
229.036d {+15h 16m 09s} (current),
228.288d {+15h 13m 09s} (1950)
WXM_CNTR_DEC: -19.397d {-19d 23' 48"} (J2000),
-19.406d {-19d 24' 20"} (current),
-19.213d {-19d 12' 46"} (1950)
WXM_MAX_SIZE: 120.00 [arcmin] diameter
WXM_LOC_SN: 4 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 0.0 Y= 0.0 [sig/noise]
WXM_LC_SN: X= 0.0 Y= 0.0 [sig/noise]
SUN_POSTN: 67.73d {+04h 30m 56s} +21.86d {+21d 51' 40"}
SUN_DIST: 162.34 [deg]
MOON_POSTN: 309.23d {+20h 36m 55s} -22.64d {-22d 38' 35"}
MOON_DIST: 73.97 [deg]
MOON_ILLUM: 78 [%]
GAL_COORDS: 343.80,31.77 [deg] galactic lon,lat of the burst
ECL_COORDS: 231.76,-1.23 [deg] ecliptic lon,lat of the burst
COMMENTS: Definite GRB.
COMMENTS: WXM error box is circular; not rectangular.
COMMENTS: Burst_Validity flag is true.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 31 May 02 03:57:14 UT
NOTICE_TYPE: HETE Ground Analysis
TRIGGER_NUM: 2042, Seq_Num: 4
GRB_DATE: 12425 TJD; 151 DOY; 02/05/31
GRB_TIME: 1578.71 SOD {00:26:18.71} UT
TRIGGER_SOURCE: Trigger on the 25-400 keV band.
GAMMA_RATE: 250 [cnts/s] on a 0.020 [sec] timescale
SC_-Z_RA: 247 [deg]
SC_-Z_DEC: -22 [deg]
SC_LONG: 0 [deg East]
WXM_CNTR_RA: 228.688d {+15h 14m 45s} (J2000),
228.722d {+15h 14m 53s} (current),
227.974d {+15h 11m 54s} (1950)
WXM_CNTR_DEC: -19.360d {-19d 21' 35"} (J2000),
-19.369d {-19d 22' 07"} (current),
-19.175d {-19d 10' 29"} (1950)
WXM_CORNER1: 229.2500 -19.7200 [deg]
WXM_CORNER2: 229.2500 -19.0000 [deg]
WXM_CORNER3: 228.1250 -19.0000 [deg]
WXM_CORNER4: 228.1250 -19.7200 [deg]
WXM_MAX_SIZE: 76.67 [arcmin] diameter
WXM_LOC_SN: 7 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 0.0 Y= 0.0 [sig/noise]
WXM_LC_SN: X= 0.0 Y= 0.0 [sig/noise]
SUN_POSTN: 67.73d {+04h 30m 56s} +21.86d {+21d 51' 40"}
SUN_DIST: 162.04 [deg]
MOON_POSTN: 309.23d {+20h 36m 55s} -22.64d {-22d 38' 35"}
MOON_DIST: 74.26 [deg]
MOON_ILLUM: 78 [%]
GAL_COORDS: 343.55,31.98 [deg] galactic lon,lat of the burst
ECL_COORDS: 231.47,-1.28 [deg] ecliptic lon,lat of the burst
COMMENTS: Definite GRB.
COMMENTS: Burst_Validity flag is true.
- GCN notice #1399
G. Ricker, J-L Atteia, N. Kawai, D. Lamb, and S. Woosley on behalf of
the HETE Science Team;
J. Doty, R. Vanderspek, J. Villasenor, G. Crew,G. Monnelly, N. Butler,
T. Cline, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin,
J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE
Operations and HETE Optical-SXC Teams;
Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, K. Torii,
T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner, and
T. Donaghy, on behalf of the HETE WXM Team;
M. Boer, J-F Olive, J-P Dezalay, and K. Hurley on behalf of the HETE
FREGATE Team;
write:
At 00:26:18.73 UTC (1578.73 s UT) on 31 May 2002, the HETE FREGATE and
WXM instruments detected event H2042, a short (~200 msec), hard GRB.
The WXM flight localization software produced a valid location in
spacecraft (relative) coordinates. However, since no real-time star
camera aspect was available, an absolute localization could not be
disseminated.
A preliminary localization was reported as a GCN Position Notice at
01:54:22 UT, ~88 min after the burst. The ground analysis has produced
a refined location which can be expressed as a 90% confidence rectangle
that is 43 arcminutes by 67 arcminutes. The corners of the rectangle
lie at the following J2000 coordinates:
RA = 15h 17m 00s, -19o 43' 00"
RA = 15h 17m 00s, -19o 00' 00"
RA = 15h 12m 30s, -19o 00' 00"
RA = 15h 12m 30s, -19o 43' 00".
In the FREGATE 30-400 keV band, H2042 had a duration of ~260
milliseconds. In the FREGATE 8-40 keV band, the burst had a duration
of ~1000 milliseconds. A total of 705 net counts were detected in the
8-40 keV band during this interval, corresponding to a fluence of ~1 x
10-7 ergs cm-2. The peak flux averaged over 0.20 s was >3 x 10-7 ergs
cm-2 s-1 (i.e., >10 x Crab flux). In the WXM 2-25 keV band, the
localization SNR was >7.
Further information (including a light curve) for GRB020531 is provided
at the following URL:
http://space.mit.edu/HETE/Bursts/
This message is citable.
Fregate light curve, trigger time scale is 0.02 sec.
The error region of GRB020531. The circle and smaller rectangle
are the error regions as calculated by two independent analysis
methods on the same data. The error region distributed by GCN
Notice and Circular is the rectangle that encloses both error
regions (in red). The parallelogram is the localization provided
by the IPN.
- GCN notice #1400
D.W. Fox and J.S. Bloom (Caltech) report on behalf of a larger
collaboration:
"We have observed the full error box of GRB020531 (Ricker et al., GCN
#1399) with the Palomar Oschin Telescope + NEAT with three 120s
exposures beginning on 04:50 UT 31 May 2002, less then 4.5 hours after
the burst. The summed exposure reaches to the POSS plate limit,
R~18. Visual comparison of the image against the Digitized Sky Survey
(DSS/SES) has not yet allowed us to identify any bright new stationary
objects. We identify two asteroids which are present at J2000
coordinates
Ast 1: 15:13:08.12 -19:22:13.1
Ast 2: 15:13:49.81 -19:29:13.1
at the epoch of our first image. Further analysis of these data are
in progress."
- GCN notice #1401
S. Snedden, D. Q. Lamb, B. C. Lee, D. L. Tucker, D. E. Vanden Berk, M.
Harvanek, A. N. Kleinman, S. Kleinman, J. Krzesinski, D. Long, and P.
R. Newman, on behalf of the SDSS GRB team, report:
"We have observed the field of GRB020531 (=H2042) (GCN 1399) using the
SDSS 0.5-m "Photometric Telescope" (PT) at APO under clear skies, a
bright moon, and poor seeing on UTC 2002 May 31 from 04:54 to 09:32
UTC, beginning less than 4.5 hours after the burst. We took a series
of ten 600 second r'-band exposures and fifteen 600 second i'-band
exposures (41.5' x 41.5' field of view) that cover the entire improved
HETE error rectangle for GRB020531 (GCN 1399). The summed images in r'
reach deeper than the POSS plate limit, R~18. Visual comparison of the
images and the DSS has not yet allowed us to identify any bright new
object."
This message is citable.
- GCN notice #1402
K. Hurley and T. Cline, on behalf of the Ulysses, Mars Odyssey,
and HETE GRB teams,
I. Mitrofanov, D. Anfimov, A.Kozyrev, M. Litvak and A.Sanin on behalf of the
HEND/Odyssey GRB team,
W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R.Starr, on behalf of
the GRS/Odyssey GRB team,
G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R.
Vanderspek, J. Villasenor, G. Crew,G. Monnelly, N. Butler, J.G.
Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, J. Braga, R.
Manchanda, G. Pizzichini, Y. Shirasaki, C. Graziani, M. Matsuoka, T.
Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi,
T. Tavenner, T. Donaghy, M. Boer, J-F Olive, and J-P Dezalay, on
behalf of the HETE GRB team, report:
Ulysses and Mars Odyssey (HEND) observed the short-duration, hard
spectrum GRB020531 (=H2042; GCN 1399). While the HEND response was
quite intense, the Ulysses signal was particularly weak and could only
be identified by restricting the search to the crossing window defined
by the HETE position. We have triangulated this burst to an ~46 square
arcminute (3 sigma) error box whose coordinates are:
15 h 15 m 04.10 s -19 o 24 ' 48.53 " (CENTER)
15 h 14 m 20.83 s -19 o 28 ' 36.33 " (CORNER)
15 h 15 m 14.46 s -19 o 21 ' 38.39 " (CORNER)
15 h 14 m 53.75 s -19 o 27 ' 58.57 " (CORNER)
15 h 15 m 47.53 s -19 o 20 ' 59.17 " (CORNER)
This error box may be improved.
- GCN notice #1403
D. Q. Lamb, S. Snedden, D. E. Vanden Berk, S. Allam, D. L. Tucker, B.
C. Lee, M. Harvanek, A. N. Kleinman, S. Kleinman, J. Krzesinski, D.
Long, and P. R. Newman, on behalf of the SDSS GRB team, report:
"Visual comparison of one 600 second r'-band image (41.5' x 41.5' field
of view) covering more than 90% of the IPN error box (GCN 1402) for
GRB020531 (=H2042) (GCN 1399), which was taken using the SDSS 0.5-m
"Photometric Telescope" (PT) at APO less than 4.5 hours after the burst
(GCN 1401), and the UK Schmidt second epoch Southern Survey (emulsion
IIaf) plate for this region (taken at 1993.389) shows no new object
brighter than the limiting magnitude of the UK Schmidt plate, which is
R ~ 20.5."
This message is citeable
- GCN notice #1404
H. S. Park, G. G. Williams, K. Lindsay on behalf of the Super-LOTIS
collaboration:
Super-LOTIS observed 95% of the IPN error box for GRB020531(GCNC#1402).
The observation began at UTC 2002 May 31 04:04 (3.6 hrs after the burst).
We find no optical transient in a sum of 20 images (60 s integration
each). The limiting magnitude is R~17.5.
This message is citable.
- GCN notice #1405
W. D. Li, A. V. Filippenko, and R. Chornock (UC Berkeley) report on
behalf of the Lick Observatory and Tenagra Observatory Supernova
Search (LOTOSS):
"We have observed a rectangle region of about 21' x 7' around the
position of GRB020531 (Richer et al., GCN #1399) with the 0.8-m Katzman
Automatic Imaging Telescope (KAIT) with 4x120s and 4x300s unfiltered
exposures beginning on May 31 04:56 UT, 2002, less than 4.5 hours after
the burst. The individual exposure reaches or exceeds the POSS II
plate limit, R~20.5. The same region was imaged again beginning on
Jun 1 06:05 UT, 2002. We used image subtraction to compare the
observations from these two nights, but have not yet found any bright
new stationary objects. We identified two asteroids whose J2000
coordinates are reported below:
Asteroid 1: mag about 19.5
R. A. = 15h14m35s.85, Decl. = -19 23'49".0 at May 31 4:57 UT
R. A. = 15h14m35s.70, Decl. = -19 23'48".7 at May 31 5:02 UT
Asteroid 2: mag about 20.0
R. A. = 15h14m54s.51, Decl. = -19 24'35".8 at May 31 5:06 UT
R. A. = 15h14m54s.36, Decl. = -19 24'36".4 at May 31 5:10 UT."
This message is citable.
- GCN notice #1406
D. West (Mulvane, KS), on behalf of the AAVSO International
GRB Network, reports:
The IPN error box for GRB020531 (Ricker et al, GCN 1399
and Hurley et al., GCN 1402) has been observed, using a
20cm telescope and SBIG ST-9E CCD under clear conditions.
Unfiltered exposures covering a 29x29arcmin field were
made; these frames cover 99percent of the IPN
error box, perhaps missing the extreme eastern point.
A series of 60sec exposures began at 0250UT on 020531
(2.4hrs after the burst), with the best 7 combined to
form a composite image. No new source down to a V magnitude
of 17.7 (GSC1.1) was seen.
- GCN notice #1407
K. Hurley and T. Cline, on behalf of the Ulysses, Mars Odyssey,
and HETE GRB teams,
I. Mitrofanov, D. Anfimov, A.Kozyrev, M. Litvak and A.Sanin on behalf of the
HEND/Odyssey GRB team,
W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R.Starr, on behalf of
the GRS/Odyssey GRB team,
G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R.
Vanderspek, J. Villasenor, G. Crew,G. Monnelly, N. Butler, J.G.
Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, J. Braga, R.
Manchanda, G. Pizzichini, Y. Shirasaki, C. Graziani, M. Matsuoka, T.
Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi,
T. Tavenner, T. Donaghy, M. Boer, J-F Olive, and J-P Dezalay, on
behalf of the HETE GRB team, report:
We have refined the IPN error box of the short duration, hard spectrum
GRB020531 (GCN 1402) to the following preliminary 3 sigma polygon with
approximately 22 square arcminute area. Its maximum dimension is about
10 arcminutes, which may facilitate deeper searches.
15 h 15 m 03.57 s -19 o 24 ' 51.00 " (CENTER)
15 h 14 m 53.98 s -19 o 24 ' 18.15 " (CORNER)
15 h 15 m 14.46 s -19 o 21 ' 38.39 " (CORNER)
15 h 15 m 17.07 s -19 o 21 ' 35.32 " (CORNER)
15 h 15 m 12.51 s -19 o 25 ' 32.46 " (CORNER)
15 h 14 m 53.75 s -19 o 27 ' 58.57 " (CORNER)
15 h 14 m 49.67 s -19 o 28 ' 03.27 " (CORNER)
This error box may be refined further.
- GCN notice #1408
M. Boer, A. Klotz (CESR/CNRS) J.L. Atteia (LAT/OMP),
C. Pollas (OCA) and H. Pinna (CEMES/CNRS) communicate:
"We have observed the entire IPN error box for GRB020531 (Ricker et al,
GCN 1399 and Hurley et al., GCN 1402) with the 25cm robotic TAROT
telescope starting on May 31 01:55:12 UT (89 minutes after the burst and
50 seconds after the GCN notice) under clear sky conditions.
11 unfiltered 30s exposures were acquired between 01:55:12 and 02:06:30 UT
and were coadded. Limit of magnitude is about R=18.0.
The coadded image can be seen at URL:
http://alain.klotz.free.fr/tarot/GRB020531
Two very faint sources were found that do not appear on the POSS I :
source A :
Ra(J2000.0) = 15h14min51s (+/- 1s)
Dec(J2000.0) = -19d25'06" (+/- 2")
R = 17.4 (+/- 0.4)
This could be asteroid 2 of GCN #1405.
source B:
Ra(J2000.0) = 15h14min57s (+/- 1s)
Dec(J2000.0) = -19d28'12" (+/- 2")
R = 17.1 (+/- 0.4)
Since we have no images taken at later times for comparison,
it is difficult to conclude on the nature of sources A and B.
We consider however that A is a likely asteroid.
Source B, if real, is a possible candidate for the GRB counterpart.
This message is citeable
- GCN notice #1411
GRB020531: Upper Limit for Detection of Two TAROT Sources
A. Dullighan, G. Monnelly, N. Butler, R. Vanderspek, P. Ford, and G.
Ricker (MIT)
write:
We obtained early epoch observations of the HETE error region of the
short gamma-ray burst GRB020531 (H2042; Ricker et al., GCN #1399)
with the Baade 6.5m telescope at the Magellan Observatory on 2002
June 1.17 UT using the LDSS-2 instrument. The observations took place
1.19 days after the burst. A mosaic of seven 300s R-band exposures
covered the entire IPN error region (Hurley et al., GCN #1402).
We detect neither source A nor source B that were reported by Boer et
al. (GCN #1408) from TAROT observations taken 1.5 hours after the
burst. For each of these two source locations, our 3 sigma upper
limit is R=23.3. If source B were the afterglow of GRB020531, our
result implies that the decay power law index was steeper than 1.93
between the epoch of the earlier TAROT observations and that of our
later Magellan observations.
This message may be cited.
- GCN notice #1415
GRB020531: Observations with the Chandra X-ray Observatory
N. Butler, A. Dullighan, P. Ford, G. Monnelly, G. Ricker, R. Vanderspek
(MIT); K. Hurley (U.C.- Berkeley); and D. Lamb (U.Chicago)
on behalf of the Chandra GRB ToO Team and the HETE Science Team
write:
On 5 June, the Chandra Observatory targeted the field of the short
duration gamma-ray burst GRB020531 that was initially localized by
the HETE satellite (Ricker et al., GCN1399). The observations, lasting
20 ksec, spanned the interval 04:00-10:04 UT, 5.15 - 5.40 days after
the burst. The refined IPN error region from Hurley et al. (GCN1407)
was completely contained within the field-of-view of the Chandra
ACIS-I array. The ACIS-I data set for the 20 ksec observation was
received at 22:23 UT, 18.4 hours after the observation began.
Within the refined IPN error region, we detect 10 sources in the
0.5-8 keV band:
# Chandra Name RA DEC dR(s) dD(") Cts
28 CXOU J151459.7-192532 15 14 59.74 -19 25 31.91 0.019 1.36 12
36 CXOU J151459.2-192609 15 14 59.18 -19 26 8.50 0.021 1.36 8
41 CXOU J151503.6-192423 15 15 3.59 -19 24 23.49 0.022 1.36 7
47 CXOU J151514.7-192221 15 15 14.69 -19 22 21.42 0.020 1.37 6
48 CXOU J151455.8-192454 15 14 55.76 -19 24 54.02 0.023 1.36 6
51 CXOU J151513.3-192450 15 15 13.30 -19 24 49.94 0.019 1.36 5
52 CXOU J151501.9-192358 15 15 1.86 -19 23 58.48 0.022 1.36 5
55 CXOU J151457.0-192439 15 14 56.96 -19 24 39.26 0.022 1.36 4
56 CXOU J151514.1-192428 15 15 14.14 -19 24 27.58 0.022 1.37 4
58 CXOU J151508.0-192338 15 15 7.96 -19 23 37.69 0.021 1.36 3
The # column refers to the source's relative ranking (in terms of total
counts) among all the sources detected in the entire ACIS-I field-of-view.
In addition, we detect 3 bright sources just outside of the refined IPN
error region:
0 CXOU J151515.3-192511 15 15 15.31 -19 25 10.71 0.019 1.35 67
5 CXOU J151517.8-192102 15 15 17.80 -19 21 2.20 0.020 1.36 44
15 CXOU J151458.3-192322 15 14 58.34 -19 23 22.32 0.020 1.35 19
For these three bright sources, we note that there are conspicuous
optical counterparts visible in an observation carried out with the
Baade 6.5 meter telescope at the Magellan Observatory on 1 June, 1.19
days after the GRB (see Dulligan et al., GCN1411, for observation
details). The three counterparts for #0, #5, and #15 have approximate
R magnitudes of 20.4, 23.6, and 20.8, respectively.
For both the TAROT A and B source locations (Boer et al., GCN1408), no
X-ray counts are detected in excess of the background rate.
The astrometry was calibrated using three USNO A2 catalog stars with
detectable X-ray emission and lying within the ACIS-I field-of-view.
In the above 2 tables, dR, the uncertainty in RA, and dD, the uncertainty
in DEC, were established by summing the following in quadrature for each
coordinate: the error reported by celldetect, the correlation error
between the X-ray and optical positions, and the error estimate from the
star reference catalog.
We gratefully acknowledge the timely assistance of the personnel at the
Chandra Science Center in the acquisition and preliminary processing of
these data.
This message may be cited.
- GCN notice #1416
A. Miceli, D. Q. Lamb, D. Zucker, K. Covey, J. Dembicky, and N. C.
Hastings report:
We have observed the field of GRB020531 (=H2042) (Ricker et al., GCN
1399) using the SPIcam (4.78' x 4.78' field of view) on the ARC
3.5-meter telescope at APO under clear skies and a bright moon on UTC
2002 June 1 from 07:27:53 to 07:43:05 UTC (beginning 1.3 days after the
burst), and under mostly clear skies but poor seeing on UTC 2002 June 6
from 04:38:33 to 04:54:22 UTC (beginning 7.2 days after the burst).
On both nights we took three 400-second r'-band exposures that cover
the entire refined hexagonal IPN error region for GRB020531 (Hurley et
al., GCN 1407). We have examined these images in the vicinity of the
ten X-ray sources seen in the first Chandra follow-up observation that
lie inside the refined IPN error region and the three bright X-ray
sources that lie just outside the refined IPN error region (Ricker et
al., GCN 1415). The table below lists the approximate r* magnitude or
the approximate limiting r* magnitude of any object that lies at the
location of these thirteen X-ray sources, based on a preliminary
analysis of a single r'-band image taken on each night. SPIcam RMS
astrometric errors are 0.2 arcsec or less.
---------------------------------------------------------------------------
Nearest
X-ray Optical RA Dec r* mag r* mag Comment
Source Source (deg) (deg) (June 1) (June 6)
---------------------------------------------------------------------------
cxo00 arc00 228.8139 -19.4194 --- 20.6 Outside June 1 FOV
cxo05 mag05 ----- ----- > 22.5 > 22.0 Magellan R ~ 23.6
cxo15 arc15 228.7431 -19.3892 20.7 20.7
cxo28 --- ----- ----- > 22.5 > 22.0
cxo36 --- ----- ----- > 22.5 > 22.0
cxo41 --- ----- ----- > 22.5 > 22.0
cxo47 --- ----- ----- > 22.5 > 22.0
cxo48 --- ----- ----- > 22.5 > 22.0
cxo51 --- ----- ----- > 22.5 > 22.0
cxo52 --- ----- ----- > 22.5 > 22.0
cxo55 arc55 228.7374 -19.4107 22.3 --- Outside June 6 FOV
cxo56 arc56 228.8091 -19.4073 20.5 20.5
cxo58 --- ----- ----- > 22.5 > 22.0
---------------------------------------------------------------------------
This message is citable.
- GCN notice #1418
D. A. Frail (Caltech/NRAO) and E. Berger (Caltech) report on behalf of a
larger collaboration:
"On 2002 June 1.16, 3.15 and 4.17 UT the VLA was used to image the
original IPN error box of GRB 020531 (GCN 1402) at a frequency of 4.86
GHz. Observations were also conducted at a frequency of 8.46 GHz on 2002
June 4.23 UT. No sources were detected within the entire IPN error box at
4.86 GHz above a 5-sigma level of 255 microJy at any epoch.
Further, an image was made by combining all three 4.86 GHz epochs and a
search was conducted for radio emission at the positions of the 10 Chandra
X-ray sources (GCN 1415). No radio sources brighter than 100 microJy
(~3-sigma) at 4.86 GHz and 180 microJy (~3-sigma) at 8.46 GHz, were found
coincident with the Chandra sources.
These limits are two to three times deeper than previous searches for
short durations bursts with the VLA (Hurley et al. ApJ, 567, 447, 2002)."
This message may be cited.
- GCN notice #1420 = #1421
A. Klotz, M. Boer (CESR/OMP/CNRS), and J.L. Atteia (LAT/OMP/CNRS), on
behalf of the TAROT collaboration communicate:
Following our first analysis (Boer et al., GCN #1408), we performed a
refined analysis of the images acquired by TAROT after the alert sent by
HETE for GRB 020531 (Ricker et al., GCN #1399). Within the IPN error
box we find a 3 sigma excess, elongated in the direction of the
telescope aberration, at the following position: RA = 15h15m12s, DEC =
-19.2433 with an error box of 7 arcsec, and a magnitude of 17.5.
Though this possible source is close to CXOU J151514.1-192428 (source #
56 in Butler et al., GCN #1415) both sources seem different.
In addition, the exposures taken by TAROT started at 01h54m28s UT, 6s
after the alert was sent by the GCN (and not 50s as mentioned in the
earlier circular).
This message is citeable
- GCN notice #1422
A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:
We have acquired BVRcIc all-sky photometry for
an 11x11 arcmin field centered at the IPN coordinates
for the HETE burst GRB020531 (Ricker et al, GCN 1399
and Hurley et al., GCN 1402/1407) with the USNOFS
1.0-m telescope on two photometric nights. Stars
brighter than V=14.0 are saturated and should be used with care.
We have placed the photometric data on our anonymous ftp site:
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb020531.dat
The astrometry in this file is based on linear plate solutions
with respect to UCAC2. The external errors are less than 50mas.
- GCN notice #1426
GRB020531: Results of a Second Epoch Observation with the Chandra X-ray
Observatory
N. Butler, A. Dullighan, P. Ford, G. Monnelly, G. Ricker, R. Vanderspek
(MIT); and D. Lamb (U.Chicago)
on behalf of the Chandra GRB ToO Team and the HETE Science Team
write:
Between 10 June 20:59 UT to 11 June 00:13 UT, the Chandra Observatory
targeted the field of the short duration gamma-ray burst GRB020531 that
was initially localized by the HETE satellite (Ricker et al., GCN1399).
This observation began 10.86 days after the GRB. This was a 10 ksec
observation with ACIS-I, following up the 20 ksec observation
performed with ACIS-I on 5 June (Butler et al., GCN 1415).
Of the 10 sources reported in GCN1415 lying within the refined IPN
error region (Hurley et al. GCN1407), only one source declined in
brightness with a significance greater than 2 sigma:
# Chandra Name RA DEC E1 Cnts E2 Cnts
48 CXOU J151455.8-192454 15 14 55.76 -19 24 54.02 6 ~0
This source faded in a manner that is consistent with the power-law behavior
that is characteristic of (long duration) gamma-ray burst afterglows. (A
power law index of -1.3 implies a decline in brightness by a factor of 2.6
between our 1st and 2nd epoch observations.)
We note that source #0 declined in brightness with a significance of 2.0
sigma, but remained ~2x brighter than would be expected based on a t^-1.3
extrapolation.
0 CXOU J151515.3-192511 15 15 15.31 -19 25 10.71 67 21
Here "E1 Cnts" and "E2 Cnts" denote, respectively, the epoch 1 and epoch 2
net counts for the source.
This message may be cited.
- GCN notice #1427
D.W. Fox and S.R. Kulkarni (Caltech), with P. Weissman (JPL) report:
"We have observed the error region of the short/hard gamma-ray burst
GRB020531 (GCN 1407) with the Hale Telescope and Large Format Camera
on Mt. Palomar on two occasions, June 1.3 and June 2.3 UT, for a total
integration of 1200s at each epoch.
Within less than 1" of the position of Chandra Source 48 of Butler et
al. (GCN 1415, 1426), aka CXOU J151455.8-192454, we find an object
with r'~22.4 mag that appears slightly extended in our (FWHM ~ 1.4")
images, and varies less than 0.1 mag between our two epochs. We
tentatively identify this object as the host galaxy of GRB020531.
Images will be posted shortly at
http://www.astro.caltech.edu/~derekfox/grb020531/ "
GRB020531 Host Galaxy, Hale Telescope + LFC, 1200s r', June 2.3 UT:
I have performed a registration of the Chandra positions from Butler
et al. (GCN 1415) against the sources in this (full) image, excluding
the putative afterglow and host of GRB020531. The X-ray error circle
for the candidate X-ray afterglow, CXO48/XT, includes this adjustment
and its associated uncertainty. An X-ray error circle for CXO55 (GCN
1415), as adjusted, is also indicated. Stars "A" through "D" are
present in the Henden photometric database (GCN 1422) with R-band
magnitudes of 19.59, 17.98, 19.72, and 16.071, respectively.
- GCN notice #1428
S. R. Kulkarni, R. Goodrich, E. Berger, D. W. Fox, J. S. Bloom and
C. A. Blake report, on behalf of the Caltech-NRAO-CARA collaboration:
N. Butler et al. (GCN 1426) suggested that a fading X-ray source, CXOU
J151455.8-192454 is the afterglow of the short hard burst GRB 020531
(Hurley et al. GCN 1407). Fox, Kulkarni and Weissman (GCN 1427)
identified an object within 1 arcsecond of CXOU J151455.8-192454 and
suggested that the object is the host galaxy of GRB 020531.
On June 12, 2002 (UT) we undertook imaging and spectroscopic
observations with the Echelle Spectrograph & Imager (ESI) on Keck II.
With a seeing of 0.6 arcseconds in the R and I bands we confirm that
the candidate object is indeed extended, with a size of about 1
arcsecond. Next, we obtained four 1800-s spectroscopic exposures
(Echelle mode) and found two features: a broad feature (Gaussian full
width at half maximum of 11.6 A) centered on 7455 Angstrom (A) and a
fainter feature centered around 9725 A. We suggest that the broad
feature is the [O II] 3728.8/3726.0 doublet with an intrinsic velocity
dispersion of 330 km/s and the fainter feature is Hbeta. If these
identifications are correct then the redshift of the candidate host
galaxy is 1.00.
The fluence and peak flux of GRB 020531 over the energy range 50 to 300
keV are 8E-7 erg cm^-2 and 6.4E-7 erg cm^-2 s^-1, respectively (Lamb et
al. 2002; astro-ph/0206151). Assuming, H0=65 km/s/Mpc and flat universe
with Omega-m=0.3, the isotropic energy release (without any k
correction) is 2.4E51 erg and 3.9E51 erg/s.
Lamb et al. (ibid) argue that GRB 020531 is a burst which belongs to
the short duration group. The isotropic energy release of this short
burst is not different from that of the true energy release (i.e.
after accounting for the opening angles of the jets; see Frail et al.
2001, ApJ 562, L55) inferred for the long duration bursts.
- GCN notice #1430
A. J. Castro-Tirado (IAA-CSIC and LAEFF-INTA), J. M. Castro Cerón (ROA),
A. de Ugarte Postigo (UCM), R. Hudec, M. Jélinek (ASU),
M. Bernas, P. Páta (CVUT) and J. Á. Berná (Univ. de Alicante)
on behalf of the BOOTES team,
report:
"We have obtained about 120 unfiltred exposures (120-s each) under
poor metereological conditions covering the possible short/hard GRB
020531 error box (HETE trigger 7688 at To = 00:26:18 UT, GCN 1399)
during the period 20:15 UT 30 May 2002 - 02:15 UT 31 May 2002
(i.e. between 4.19-hours before the trigger and 1.82-hours after
the trigger) with the wide-field camera of BOOTES-1
(
http://www.laeff.esa.es/BOOTES).
After a visual inspection of the IPN error box (GCN 1407) in all frames,
we do not find evidence of optical emission, in particular simultaneously
to the burst itself. We derive the following upper limits :
Date of mid-exposure Limiting magnitude Sky conditions
----------------------------- ------------------ --------------
May 30, 22:18 UT (To - 2 hr) 10.5 thin cirrus
May 31, 00:26 UT (To) 8.0 thick cirrus
May 31, 00:56 UT (T0 + 0.5 hr) 8.0 thick cirrus
The fact that no optical afterglow has been found for this GRB
(cf. GCN 1403, 1404, 1405, 1406, 1408, 1416, 1421, 1427) supports
the idea that most short GRBs might occur in a low density medium.
This would be also implied by the BOOTES detection of an optical
transient (OT) following the short/hard GRB 000313, if both, the OT
and the GRB are related (Castro-Tirado et al. 2002, submitted to A&A,
astro-ph/0206201)."
- GCN notice #1433
Isabel Salamanca, Evert Rol (University of Amsterdam), Nial Tanvir
(University of Hertfordshire), Lex Kaper (UoA), on behalf of a larger
collaboration, report:
"We have observed the error box of GRB 020531 (GCN #1399, #1402) with
the Wide Field Camera on the 2.5m Isaac Newton Telescope, La Palma. The
observations were performed in Harris V filter*, under non-photometric
conditions. The field was calibrated with the calibration provided by
Henden (GCN #1422). The results are summarized below:
mid-exposure exposure time lim. magn. seeing
(UT days) (min) (3 sigma) (arcsec)
May 31.92 30 24.7 1.4
June 2.99 40 25.2 1.2
We do not measure any source fading by more than 0.3 magnitude between
the two epochs.
A refined analysis of the Chandra sources (GCN #1415, #1426) visible
in our images is being carried out and will be published in a
following GCN Circular.
An image including the IPN errorbox can be found at
http://www.astro.uva.nl/~evert/grb020531/.
We acknowledge the assistance of the ING staff."
This message can be cited.
*) The Harris V filter is close to the standard Landolt V filter. For
the calibration, color correction terms have been used and can be
found at http://www.ast.cam.ac.uk/~wfcsur/photom.html.
[GCN OPS NOTE (19Jun02): This Circular was delayed 1.5 hours
because of an obselete address in the vetted list.]
- GCN notice #1434
Fading Optical Source in the Field of GRB020531
A. Dullighan, G. Monnelly, N. Butler, R. Vanderspek, P. Ford, G.
Ricker (MIT); H. Ebeling, R. Wainscoat (U. Hawaii);
N. Kawai, A. Yoshida (RIKEN, Japan)
write:
We have observed the error box of the short-hard burst source
GRB020531 (GCN #1399, #1402) with the Baade 6.5m telescope
at the Magellan Observatory on June 1.16 and June 10.13 UT,
and with the Subaru 8.2m telescope at Mauna Kea Observatory
on June 5.43 UT. The R band images were calibrated using the
data provided by Henden et al.(GCN #1422). Our observations
were as follows:
2002 Date Instrument, Exposure Time Limiting R Mag.
UT Telescope (sec) (3 sigma)
June 1.16 LDSS2, Baade 180 23.6
June 5.43 SuprimeCam, Subaru 420 25.5
June 10.13 LDSS2, Baade 360 x 2 24.0
We detect a fading optical counterpart for Chandra Source #5
(GCN #1415) in all three epochs.
2002 Date R Mag Error
UT of #5
June 1.16 23.12 0.20
June 5.43 23.79 0.06
June 10.13 23.96 0.20
The decline in brightness of the counterpart between the measurements
is consistent with a power law decay with alpha = 0.35 +/- 0.05.
The relative X-ray brightness of Chandra Source #5 at the two
epochs of the Chandra observations is consistent with the optical
decay index. However, the independent significance of any X-ray
decline is low (1.4 sigma level-of-confidence).
Since Source #5 lies just outside the current error box for GRB020531
(GCN #1407), its possible association, if any, with GRB020531
is unclear.
This message may be cited.
- GCN notice #1443
Isabel Salamanca, Evert Rol (University of Amsterdam), Nial Tanvir
(University of Hertfordshire), Lex Kaper (UoA), on behalf of a larger
collaboration, report:
We have performed differential photometry of the sources detected by
Chandra (GCN #1399) in the field of view of GRB 020531
(GCN #1399, #1402). The observations were done with the WFC on the
INT at La Palma. For more details see GCN 1433.
Of the 13 sources detected by Chandra, we detect 5 in both epochs:
cx00, cx15, cx48, cx55, cx56. Four more sources are detected only in
the second epoch: cx05,cx47,cx58 and cx52. We remark that the source
cx00 is also visible in the DSS.
We have perfomed differential photometry of the first 4 sources by
comparing them with 12 stars in the field. The relative accuracy
attained is 0.01 mag. The absolute photometry was done via the
photometry performed by Henden etal. (GCN #1422). The estimated error
in the zero point is higher, 0.4 mag, due to the fact that the
observations were performed under non-photometric conditions.
Below is a summary of the magnitudes of each object:
Id V mag
31 May 2 June
=====================================
5 >24.7 24.5
15 21.73 21.80
--- ---------------------------------
28 >24.7 >25.2
36 >24.7 >25.2
41 >24.7 >25.2
47 >24.7 23.8
48 23.27 23.20
51 >24.7 >25.2
52 >24.7 24.0
55 23.15 23.19
56 21.71 21.60
58 >24.7 ~25.2
The proposed afterglow candidate, cx48 (GCN #1426, #1427 and #1428) is
0.07 +/- 0.01 mag brighter in the second epoch than in the first.
This message may be cited.
Dr. Isabel E. de Salamanca
Anton Pannekoek Institute, UvA
Amsterdam - The Netherlands.
- GCN notice #1461
K. Hurley and T. Cline, on behalf of the Ulysses, Mars Odyssey,
and HETE GRB teams,
I. Mitrofanov, D. Anfimov, A.Kozyrev, M. Litvak and A. Sanin, on behalf of the
HEND/Odyssey GRB team,
W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of
the GRS/Odyssey GRB team, and
G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R.
Vanderspek, J. Villasenor, G. Crew, G. Monnelly, N. Butler, J.G.
Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, J. Braga, R.
Manchanda, G. Pizzichini, Y. Shirasaki, C. Graziani, M. Matsuoka, T.
Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi,
T. Tavenner, T. Donaghy, M. Boer, J-F Olive, and J-P Dezalay, on
behalf of the HETE GRB team, report:
We have further refined the IPN error box of the short duration, hard
spectrum GRB020531 (GCN 1399, 1402, and 1407) using the final Ulysses
ephemeris and clock corrections. The error box now has an area of
approximately 9 square arcminutes:
15 h 15 m 11.18 s -19 o 24 ' 27.80 " (CENTER)
15 h 15 m 05.61 s -19 o 23 ' 54.43 " (CORNER)
15 h 15 m 20.22 s -19 o 22 ' 00.52 " (CORNER)
15 h 15 m 02.15 s -19 o 26 ' 54.98 " (CORNER)
15 h 15 m 16.75 s -19 o 25 ' 01.16 " (CORNER)
A map will be posted shortly at
ssl.berkeley.edu/ipn3/020531. In it,
"GCN 1407" indicates the previous IPN error box, "C" indicates the Chandra
sources reported in GCN 1415 and 1426, and "T" indicates the TAROT
sources reported in GCN 1408, 1420, and 1421.
We do not expect further improvements to this error box.
Previous IAU Circulars 