- GCN notice #1836
J.Borkowski, D.Gotz, S.Mereghetti on behalf of the IBAS Localization Team,
S.Deluit, R.Walter, the INTEGRAL Science Data Center and the INTEGRAL
Science Working team report the detection of GRB030131 at UTC 07:39 in
the field of view of the IBIS telescope.
The burst lasted about 100 seconds.
The preliminary position is RA 13h 27m 8s and DEC +30deg 46m with an
uncertainty of 10' radius, due to the fact that most of the GRB occurred
during a satellite slew.
- GCN notice #1837
R. Chornock, W. Li, A. V. Filippenko, and S. Jha (UC Berkeley) report:
We imaged a 6.8' x 6.8' field centered at the position of GRB 030131
(GCN 1836) with the Katzman Automatic Imaging Telescope (KAIT) starting
at 11:12:23 UT, 3.6 hours after the burst. Visual comparison of a single
300s unfiltered exposure to the Digitized Sky Survey shows no new object
down to a limiting magnitude of about 19.5.
This message may be cited.
- GCN notice #1838
D.Gotz, S.Mereghetti and J.Borkowski for the IBAS localization team
report:
The refined position of GRB030131 is RA 13h 27m 56s, DEC +30deg 46' 7''
with an uncertainty of 5 arcmin radius.
These coordinates differ by 10.4 arcmin from the preliminary position
reported in GCN 1836.
This message can be cited
- GCN notice #1839
T. Grav (University in Oslo & Harvard-Smithsonian Center for Astrophysics)
report:
A 10' x 10' field centered on the position of GRB 030131 (GCN 1836)
was imaged with the 48" reflector at the Fred Whipple Lawrence
Observatory starting at 11:26:12 UT, 3.8 hours after the burst.
600s exposures in both V and R was compared to the Digitized
Sky Survey, and no new objects down to a limiting magnitude
of about 20.5 was found.
This message may be cited.
- GCN notice #1840
P.A. Price (RSAA/ANU) and D.W. Fox (Caltech) report on behalf of a
larger collaboration:
"We have imaged the full localization region of GRB030131 (GCN 1838)
with the Palomar 48-inch Oschin Telescope + NEAT camera, in six 120s
exposures over 10:42 UT to 11:31 UT. The summed image from these
unfiltered exposures reaches a limiting magnitude of R~21 mag as
estimated from the magnitude of several USNO-A2.0 stars in the image.
We identify no new sources by reference to images from the Second
Digitized Sky Survey. We estimate the magnitude of any new source to
be R>20 mag at the mean epoch of our observations, 11:16 UT, which is
3.62 hours after the burst."
- GCN notice #1841
K. Hurley and T. Cline, on behalf of the Ulysses GRB team,
A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL
SPI-ACS GRB team, and
S. Mereghetti, J. Borkowski, and D. Gotz, on behalf of the INTEGRAL
IBIS GRB team, report:
Ulysses observed this burst (GCN 1836, 1838). As observed by Ulysses,
it had a duration of approximately 100 s, a 25-100 keV fluence of approximately
1.E-06 erg/cm2, and a peak flux over 0.25 s of approximately 6.E-07 erg/cm2 s.
We have triangulated it to a preliminary annulus centered at RA, Decl. (2000)=
176.751,+40.439 degrees, with radius 22.616 +/- 0.032 degrees (3 sigma).
This annulus intersects the error circle given in GCN 1838 at:
RA DEC
202.037 30.699
202.079 30.757
201.944 30.693
202.046 30.832
reducing its area by a factor of about 5, to 16 sq. arcmin.
This localization may be improved.
- GCN notice #1843
K. Hurley and T. Cline, on behalf of the Ulysses GRB team,
A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL
SPI-ACS GRB team, and
S. Mereghetti, J. Borkowski, and D. Gotz, on behalf of the INTEGRAL
IBIS GRB team, report:
Further analysis of this event indicates that the IPN annulus (GCN 1841)
is consistent with the error circle given in GCN 1838, but cannot in
fact be used to constrain it. The error box given in GCN 1841 should be
disregarded.
- GCN notice #1845
M. Ishiguro (ISAS),
T. Soyano, H. Mito and Y. Urata on behalf of the Kiso GRB team:
" We have observed the entire INTEGRAL error circle of GRB030131 (Gotz
et al., GCN1838) with Kiso observatory 1.05 m Schmidt telescope. We
obtained two R-band data sets (300 sec x 3 frames), starting at 15:36
UT and 18:45 UT.
Our data;
Date Time (UT) Exposure Limiting mag.(R, SN=3)
01-31 15:36:47 300s x 3 19.7
01-31 18:45:00 300s x 3 20.0
# Limiting magnitude was estimated by comparison with
# U1200_07092706 13:27:46.834 +30:44:13.42 16.4 mag.
Comparison with DSS II red images, no new object was detected down to
the limiting magnitude. We also could not identify any variable
objects in the region reported by Hurley et al (GCN1841) using a PSF
matched image subtraction method."
This message may be cited.
- GCN notice #1847
S.Mereghetti (IASF-Milano), N.Produit (ISDC), J.Borkowski (ISDC), D.Gotz
(IASF-Milano) and the INTEGRAL Science Working Team report:
Further analysis of GRB030131 resulted in a better localization which
differs from the ones previously reported (GCN1836, 1838). Previous
results were affected by the fact that the burst occurred during a
satellite slew.
The new coordinates are RA: 13h 28m 31s DEC: +30deg 40' 45'' with an error
of 5 arcmin radius.
The GRB had a duration of about 150 s and a peak flux over 1 s of about
2x10e-7 erg/cm2/s in the 25-100 keV energy range.
- GCN notice #1849
A. Oksanen (Jyvaskylan Sirius ry) reports on behalf of Nyrola
Observatory GRB-team and AAVSO International GRB Network:
A 24' x 16 arcmin field covering the corrected INTEGRAL error circle of GRB
030131 (GCN 1848) was imaged with the 0.4m SCT at the Nyrola Observatory
starting at February 1, 2003 03:49 UT, 20 hours after the burst. The 19
x 180s Rc-exposures were sigma reject combined and compared to the
Digitized Sky Survey (DSS2R) and one faint (R=20.5) new object was found
near the image limit.
The position of the suspect is:
13:28:28.46 +30:42:05.4 J2000
using the USNO-A2.0 reference catalog.
The combined image may contain some processing artifacts so the
confidence that the suspect is a GRB OT is not very high. The FITS
frame and a JPEG picture showing the corrected error circle plus the
suspect OT are available on:
http://nyrola.jklsirius.fi/grb/grb030131/
This message may be cited.
- GCN notice #1850
D.W. Fox (Caltech) and P.A. Price (RSAA/ANU) report on behalf of the
Caltech-NRAO GRB collaboration:
"We have imaged the full corrected localization region of GRB030131
(GCN 1847) with the Palomar 48-inch Oschin Telescope + NEAT camera, in
six 120s exposures over 10:42 UT to 11:31 UT on 31 Jan 2003. The
summed image from these unfiltered exposures reaches a limiting
magnitude of R~21 mag as estimated from the magnitude of several
USNO-A2.0 stars in the image. We identify no bright new sources by
reference to images from the Second Digitized Sky Survey. We estimate
the magnitude of any new source to be R>20 mag at the mean epoch of
our observations, 11:16 UT, which is 3.62 hours after the burst.
"In particular, the afterglow candidate of Oksanen (GCN 1849) is not
present in our image, and we estimate R>21 for the quoted position at
this epoch."
- GCN notice #1851
T. Soyano, H. Mito and Y. Urata on behalf of the Kiso GRB team,
M. Ishiguro (ISAS) :
"We have observed the entire corrected localization region of
GRB030131(Mereghetti et al., GCN 1847) with Kiso observatory 1.05 m
Schmidt telescope. We obtained two R-band data sets (300 sec x 3
frames), starting at 15:36 UT and 18:45 UT. Our limiting magnitude
estimated from USNO-A2.0 stars is R~20. Comparison with DSS II red
images, no new object was detected down to the limiting magnitude.
We also could not identify the candidate of Okasanen (GCN 1849)
at first and second epoch."
This message may be cited.
- GCN notice #1852
S. Klose and F. Ludwig, Thuringer Landessternwarte Tautenburg
report:
The field of GRB 030131 was imaged in the R band with the Tautenburg
Schmidt telescope equipped with the prime focus CCD camera on Feb 4,
1:35 - 5:22 UT. The field of view is about 40 x 40 arcmin. Altogether
45 frames were taken (2 min exposure time each). The limiting magnitude of
the combinded image is about R=22.5 +/- 0.5. The GRB field is very rich in
galaxies. Exactly at the position of the potential afterglow
candidate reported by Oksanen et al. (GCN 1849) we do not detect any
source (R>~22.5). Several sources with R>~21 are visible within ~5 arcsec
of the reported OT coordinates.
This message may be cited.
- GCN notice #1857
D.W. Fox (Caltech), P.A. Price (RSAA/ANU), T. Herter (Cornell),
P. Appleton (IPAC), and G. Cotter (Cambridge) report on behalf of a
larger collaboration:
"We have observed the full corrected localization region (GCN 1847)
for GRB030131 with the 60-inch telescope on Mt. Palomar (P60), for
roughly 15 min each in Gunn r and i on the night of 4 Feb 2003 UT. We
have also observed a portion of this region with the 200-inch Hale
telescope + COSMIC (P200), for 30 min in R band on the night of 1 Feb
2003 UT (mean epoch 10:27 UT, or 26.8 hours post-burst).
"Visual comparison of the P60 images with our summed 48-inch + NEAT
(P48) image from 31 Jan 2003 UT (mean epoch 11:16 UT, or 3.62 hours
post-burst; c.f. GCN 1850) reveals a point-like source in the P48
image that is not present in the P60 images. The unfiltered P48
magnitude of this source, R~21.2 by reference to four nearby USNO-A2.0
stars, is near the limit of the P60 r image. However, the source lies
within the field of view of the P200 R-band image, and is barely
detected with R>~23.5 at that time.
The coordinates of the source relative to the GSC-II are:
RA 13:28:22.29, Dec +30:40:23.7 (J2000)
with an uncertainty of less than 1" in each coordinate. Inspection of
the individual P48 images reveals that the source is present at the
same position in each image (mean epochs 10:43 to 11:32 UT, 31 Jan
2003). The brightness of the source in the various images is roughly
constant, to within about one magnitude, although we observe possible
variability of the source within this range.
"We tentatively suggest that this source is the afterglow of
GRB030131. We consider this identification provisional in the absence
of further supporting observations."
- GCN notice #1866
J. Gorosabel (IAA-CSIC/STScI), A. Levan (U. Leicester/STScI),
A. Fruchter, J. Rhoads, J.M. Castro Cer=F3n (STScI), T. Tripp (Princeton)
report for a larger collaboration:
We have imaged the optical candidate (GCN 1857) of the INTEGRAL burst GRB
030131 (GCN 1836, GCN 1838, GCN 1847) with the 4-m KPNO telescope (equipped
with Mosaic, FOV=3D36'x36'). The observations were carried out on Feb
1.526-1.542 UT 2003 (~29 hours after the GRB) with a total exposure time of
4x500s and a seeing of 0.85".
We find a marginal detection (~3.5 sigma above the detection threshold) at
RA(J2000)=3D13:28:22.27 DEC(J2000)=3D30:40:23.7. The astrometry is based on
the USNO catalog and shows an internal uncertainty of 0.5" for each
coordinate. We have compared the offset of the object in our image from the
nearest USNO star with that found by D. Fox (personal communication) in
their discovery image. These offsets agree within 0.2", further
strengthening the association.
Preliminary aperture photometry centered on the object yields B=3D25.4+/-0.=
3.
Our photometric calibration is based on 11 USNO stars in the field. Under
the zero point obtained the star located at RA(J200)=3D13:28:18.=
16
DEC(J2000)=3D30:38:20.79 has B=3D18.18.
A smoothed image of the field can be seen at:
http://www.stsci.edu/~fruchter/GRB/030131/kpno/grb030131.kpno.gif
We thank D. Fox for providing valuable astrometric information.
- GCN notice #1971
A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:
We have acquired BVRcIc all-sky photometry for
a 20x20 arcmin field centered at the candidate
afterglow coordinates (Fox et al., GCN 1857)
for the INTEGRAL burst GRB030131 (GCNs 1836, 1838, 1847)
with the USNOFS 1.0-m telescope on one
photometric night. Stars brighter than V=13.5 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/grb030131.dat
The astrometry in this file is based on linear plate solutions
with respect to UCAC2. The external errors are less than 100mas.
The estimated external photometric error is 0.03mag.
In particular, the star located at RA(J2000)=13:28:18.16
DEC(J2000)=30:38:20.79, used as a comparison star by
Gorosabel et al. (GCN 1866) has B=18.95 +/- 0.03, making
the OT fainter than what was given in that GCN.
We will not be performing U-band calibration unless requested.
As always, you should check the dates on the .dat file prior
to final publication to get the latest photometry.
- Full paper with afterglow variability confirmation
Goetz et al,
AA 409, 831
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