GRB 070223
GCN Circular 6125
Subject
GRB070223: Swift burst
Date
2007-02-23T01:43:51Z (18 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
L. Vetere (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
S. Campana (INAF-OAB), M. M. Chester (PSU), N. Gehrels (NASA/GSFC),
D. Grupe (PSU), J. A. Kennea (PSU), W. B. Landsman (NASA/GSFC),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
M. Stamatikos (NASA/ORAU) and E. Troja (INAF-IASFPA) report on behalf
of the Swift Team:
At 01:15:00 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 070223 (trigger=261664). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 153.452, +43.121 which is
RA(J2000) = 10h 13m 49s
Dec(J2000) = +43d 07' 16"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows several peaks
with a duration of about 50 sec. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 01:16:50 UT, 110 seconds after the
BAT trigger. XRT found a bright, fading, uncatalogued X-ray source
located at RA, Dec 153.4533, +43.1336 which is
RA(J2000) = 10h 13m 48.7s
Dec(J2000) = 43d 08' 00.9"
with an uncertainty of 4.7 arcseconds (radius, 90% containment).
This location is 45 arcseconds from the BAT on-board position,
within the BAT error circle. The initial flux in the 2.5s image
was 3.0e-09 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of nominal 100 seconds with the
White (160-650 nm) filter starting 120 seconds after the BAT trigger,
and a finding chart in V starting 226 seconds after the trigger. No
afterglow candidate has been found in the initial data products.
Image catalog data are not available at this time. The 2.7'x2.7'
immediately available image covers 100% of the XRT error circle. The
list of sources is typically complete to about 18 mag. No correction
has been made for the expected extinction corresponding to E(B-V) of
0.01.
GCN Circular 6126
Subject
GRB 070223: MDM Observations
Date
2007-02-23T02:57:25Z (18 years ago)
From
Nestor Mirabal at Columbia U <mirabal@astro.columbia.edu>
N. Mirabal and J. P. Halpern (Columbia U.) report
on behalf of the MDM Observatory GRB follow-up team:
"We have observed the Swift location of GRB 070223 (Vetere et al.,
GCN 6125) with the MDM 1.3m telescope at a mean epoch
Feb. 23, 02:18 UT (~1 hr post-burst). Inside the XRT error circle,
we find no new optical sources to preliminary limiting
magnitudes R > 20.3, I > 20.0. Observations are ongoing.
This message may be cited."
GCN Circular 6127
Subject
GRB 070223: Liverpool Telescope Possible Afterglow Candidate
Date
2007-02-23T03:07:13Z (18 years ago)
From
Andrea Melandri at Liverpool John Moores U <axm@astro.livjm.ac.uk>
A. Melandri (Liverpool JMU) on behalf of the Liverpool GRB group
report
The 2-m Liverpool Telescope robotically followed up GRB070223
(Vetere et al., GCN 6125, trigger=261664) beginning ~18 minutes
after the GRB trigger time (UT:01:15:00).
We detect a very faint object inside the XRT position (Vetere et al.,
GCN 6125) not present in the USNO B1 catalog at this position
RA = 10:13:48.73
Dec = +43:08:00.54
with an uncertainty of 0.5 arcsec. In a coadded frames (with a total
integration time of 780 sec) the object has a magnitude R~23 +/- 0.3
(with respect the USNO B1) between 18 and 51 minutes after the burst.
At the moment it is not possible to state if the object is fading.
Further analysis and observations are ongoing.
GCN Circular 6128
Subject
GRB070223 - SDSS Pre-Burst Observations
Date
2007-02-23T05:10:05Z (18 years ago)
From
Richard J. Cool at U.of AZ/Steward Obs <rcool@as.arizona.edu>
Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona), David W. Hogg
(NYU), Michael R. Blanton (NYU), David J. Schlegel (LBNL), J.
Brinkmann (APO),
Donald Q. Lamb (Chicago), Donald P. Schneider (PSU), and Daniel E.
Vanden Berk
(PSU) report:
The Sloan Digital Sky Survey (SDSS) imaged the field of burst GRB070223
prior to the burst. As these data should be useful as a pre-burst
comparison
and for calibrating photometry, we are supplying the images and
photometry
measurements for this GRB field to the community.
Data from the SDSS, including 5 FITS images, 3 JPGS, and
3 files of photometry and astrometry, are being placed at
http://mizar.as.arizona.edu/~grb/public/GRB070223
We supply FITS images in each of the 5 SDSS bands of a 8'x8' region
centered
on the GRB position (ra=153.452 (10:13:48.5), dec=43.1210
(43:07:15.6); GCN
6125), as well as 3 gri color-composite JPGs (with different
stretches). The
units in the FITS images are nanomaggies per pixel. A pixel is 0.396
arcsec
on a side. A nanomaggie is a flux-density unit equal to 10^-9 of a
magnitude
0 source or, to the extent that SDSS is an AB system, 3.631e-6 Jy.
The FITS
images have WCS astrometric information.
In the file GRB070223_sdss.calstar.dat, we report photometry and
astrometry
of 308 bright stars (r<20.5) within 15' of the burst location. The
magnitudes
presented in this file are asinh magnitudes as are standard in the
SDSS (Lupton
1999, AJ, 118, 1406). Beware that some of these stars are not well-
detected
in the u-band; use the errors and object flags to monitor data quality.
In the files GRB070223_sdss.objects_flux.dat and
GRB070223_sdss.objects_magnitudes.dat, we report photometry of 1529
objects detected within 6' of the GRB position. We have removed
saturated
objects and objects with model magnitudes fainter than 23.0 in the r-
band.
The fluxes listed in GRB070223_sdss.objects_flux.dat are in nanomaggies
while the magnitudes listed in GRB070223_sdss.objects_magnitudes.dat are
asinh magnitudes.
All quantities reported are standard SDSS photometry, meaning that
they are
very close to AB zeropoints and magnitudes are quoted in asinh
magnitudes.
Photometric zeropoints are known to about 2% rms. None of the
photometry
is corrected for dust extinction. The Schlegel, Finkbeiner, and Davis
(1998) predictions for this region are A_U=0.078 mag, A_g=0.057 mag,
A_r =
0.042 mag, A_i=0.032 mag, and A_z=0.022 mag.
The file GRB070223_sdss.spectro.dat contains a list of the 2 objects
with
SDSS spectroscopy within 6 arcminutes of the GRB position. In
addition to
the redshift and 1-sigma error for each object, this file also lists the
object spectroscopic classification.
SDSS astrometry is generally better than 0.1 arcsecond per coordinate.
Users requiring high precision astrometry should take note that the SDSS
astrometric system can differ from other systems such as those used
in other
notices; we have not checked the offsets in this region.
More detailed information pertaining to our SDSS GRB releases can be
found
in our initial data release paper (Cool et al. 2006, PASP 118, 733).
See the
SDSS DR4 documentation for more details: http://www.sdss.org/dr5.
These data have been reduced using a slightly different pipeline than
that
used for SDSS public data releases. We cannot guarantee that the
values here
will exactly match those in the data release in which these data are
included.
In particular, we expect the photometric calibrations to differ by of
order
0.01 mag.
This note may be cited, but please also cite the SDSS data release
paper,
Adelman-McCarthy et al. (2006, ApJS, 162, 38), when using the data or
referring to the technical documentation.
GCN Circular 6130
Subject
GRB 070223: Swift-XRT Refined Analysis
Date
2007-02-23T11:01:49Z (18 years ago)
From
Loredana Vetere at PSU <vetere@astro.psu.edu>
L. Vetere (PSU) reports on behalf of the Swift-XRT team:
We have analysed the first four orbits (up to 16.5 ks after the BAT trigger) of
Swift XRT data for GRB 070223 (Vetere et al., GCN 6126). Using ~2.8 ks of
Photon Counting (PC) mode data we find the following refined position:
RA (J2000) = 10h 13m 48.4s
Dec(J2000) = +43d 07' 58.2"
with an error radius of 4.5 arcseconds (90% confidence). This is 4.4 arcsec away
from XRT initial position and 4.1 arcsec from the possible optical candidate
reported by A. Melandri (GCN 6127).
The WT lightcurve shows a rapid decay with a slope of alpha~2.3 while the PC
light curve shows a possible flattening (~0.6) but we still need more data to
confirm it.
The WT mode spectrum can be fitted with a single power law of photon index of
1.7 +/- 0.1 and column density of (4.5 +/-0.1 )e21 cm**-2. We note the Galactic
column density in the direction of the source is 1.1e20 cm**-2.
The 0.3-10 keV observed flux was 6.5e-10 ergs cm**-2 s**-1, which corresponds to
an unabsorbed flux of 9.2e-10 ergs cm**-2 s**-1.
This circular is an official product of the Swift-XRT team.
GCN Circular 6131
Subject
GRB070223: MASTER-VWF-Kislovodsk observations
Date
2007-02-23T12:42:11Z (18 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@observ.inetcomm.ru>
V. Lipunov, V.Kornilov, N.Shatskiy, E.Gorbovskoy, A.Belinski, D.Kuvshinov,
N.Tyurina, P.Gritsyk
Sternberg Astronomical Institute, Moscow Union 'Optic'
A. Tlatov, I.Golubov
Kislovodsk Solar Station of the Pulkovo observatory
MASTER Very Wide Field Camera located at Kislovodsk Solar Station
(http://observ.pereplet.ru, D=70 mm, 420 square degrees, 11 Mpixel's CCD)
has moved to the Swift-BAT trigger 261664 and it has taken a series of 5s
exposures starting 1 s after notice arrivel time at 01:23:11.719 UT
under good weather condition and yang moon.
We note that the GBR position (L. Vetere et al. GCN Circ No. 6125) was
at 5 degrees outside of the our field of view.
We note that the VWF camera continuously takes frames during the night.
These unfiltered images are calibrated relative to USNO A2.0 (R).
There is no OT was found inside Swift error box.
T-Tgrb Mean Time Limit Coadd? Note
491s 493.5s 11.0 no slightly moving
496s 498.5s 11.5 no
496s 521 s 12.5 10
496s 586 s 13.0 36
The message can be cited.
mailto: lipunov@sai.msu.ru
GCN Circular 6132
Subject
GRB 070223, Swift-BAT refined analysis
Date
2007-02-23T14:30:37Z (18 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
G. Sato (GSFC/ISAS), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), L. Vetere (PSU)
on behalf of the Swift-BAT team:
Using the data set from T-240 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 070223 (trigger #261664)
(Vetere, et al., GCN Circ. 6125). The BAT ground-calculated position is
RA, Dec = 153.453, 43.132 deg which is
RA(J2000) = 10h 13m 48.6s
Dec(J2000) = 43d 07' 55.4"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 82%.
The mask-weighted lightcurve starts at ~T-20 sec and then rises
to two main peaks at T+15 and T+35 sec with a long decaying profile
out to T+150 sec. T90 (15-350 keV) is 89 +- 2 sec (estimated error
including systematics).
The time-averaged spectrum from T-3.4 to T+98.5 is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.87 +- 0.12. The fluence in the 15-150 keV band is 1.7 +- 0.1 x 10^-6
erg/cm2. The 1-sec peak photon flux measured from T+34.35 sec
in the 15-150 keV band is 0.7 +- 0.1 ph/cm2/sec. All the quoted errors
are at the 90% confidence level.
The initial series of GCN Notices were delayed by ~460 sec because
the trigger occurred during a Malindi telemetry downlink pass
when the TDRSS messages are buffered on-board until the transmitter
becomes available.
GCN Circular 6133
Subject
GRB 070223: Optical-IR observation with KANATA
Date
2007-02-23T15:07:38Z (18 years ago)
From
Makoto Uemura at Hiroshima U <uemuram@hiroshima-u.ac.jp>
M. Uemura, A. Arai, and T. Uehara (Hiroshima Univ.),
report on behalf of the KANATA GRB team:
We took optical and IR images of the field of GRB070223 (GCN 6125) at
12:31-12:52 UT 23 Feb. using TRISPEC attached to the KANATA
1.5-m telescope at Higashi-Hiroshima Observatory, Japan.
We obtained 10 sets of V, J, and Ks-band images with a 123, 120, and 96-s
exposure time, respectively.
The images were calibrated with neighbor stars in the USNO A2.0 and 2MASS
catalog.
We cannot significantly detect the optical and IR afterglows.
at the position of the X-ray afterglow reported in GCN 6130.
The limit magnitudes are below:
UT Limit mag Exp. Time
Feb. 23.52863 V > 21.3 123 * 10
Feb. 23.52858 J > 18.7 120 * 10
Feb. 23.52843 Ks > 16.3 96 * 10
GCN Circular 6134
Subject
GRB070223: Swift/UVOT refined analysis
Date
2007-02-23T15:55:51Z (18 years ago)
From
Wayne Landsman at GSFC/SSAI <landsman@milkyway.gsfc.nasa.gov>
W. Landsman(NASA/GSFC), L. Angelini(GSFC/JHU) and J. Greiner(MPE) report
on behalf of the Swift UVOT team:
The Swift/UVOT observed the field of GRB 070223 starting 102s after the
BAT trigger (Vertere et al. 2007, GCN Circ. 6125) with the settling
exposure.
We do not find any source, in any of the UVOT observations, inside of
the refined XRT error circle (Vertere et al. 2007, GCN Circ. 6130).
We have the following 3-sigma upper limits for a source inside the XRT
error circle in the first exposure with the White filter, and in the
coadded frames with all filters:
Filter T_Start T_End Exp (s) 3sigma U.L. mag
White 120 219 98 20.2
V 102 295 79 18.9
B 5893 6084 189 20.6
U 5688 16398 351 20.5
UVW1 3863 16234 1069 21.2
UVM2 3658 3858 197 20.1
White 120 11872 1002 21.4
No correction has been made for the small extinction corresponding to
E(B-V) = 0.015
(Schlegel et al. 1998).
GCN Circular 6136
Subject
GRB 070223: Optical observations
Date
2007-02-23T23:53:25Z (18 years ago)
From
Alok Chandra Gupta at Nat. Astro. Obs./Yunnan Obs <alok@ynao.ac.cn>
A. C. Gupta
National Astronomical Observatories/Yunnan Observatory
CAS, P.O. Box 110, Kunming, Yunnan 650011, China
We observed the field of GRB 070223 (GCN 6125) with CCD detector
at our 1.02 meter telescope of the Yunnan observatory, Kunming,
China. We started our observation on Feb. 23, 2006 at UT 13:21:20.
We took 5 image frames of 200 seconds exposure time of each in
the optical R passband. There is no detection of optical afterglow
candidate in our combined 5 images. The 5-sigma limiting magnitude
of our observations is R ~ 20.0 mag.
GCN Circular 6150
Subject
VLA observation of GRB 070223
Date
2007-02-26T18:05:34Z (18 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on behalf of
the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the Very Large Array to observe the field of view toward GRB
070223 (GCN 6125) at a frequency of 8.46 GHz on 2007 February 25 at
4.93 UT. The GRB is undetected and the peak radio brightness at the
Liverpool Telescope Possible Afterglow Candidate position (GCN 6127)
is 41+/-56 uJy and at SWIFT-XRT position (GCN 6130) is 77+/-57 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 6162
Subject
GRB 070223: Optical Observations
Date
2007-03-01T01:21:30Z (18 years ago)
From
Nestor Mirabal at Columbia U <mirabal@astro.columbia.edu>
N. Mirabal (Columbia U.), A. Melandri (Liverpool JMU), and
J. P. Halpern (Columbia U.) report
"We have further analyzed deep R-band images of Swift
GRB 070223 (Vetere et al., GCN 6125) obtained with the
2-m Liverpool Telescope (Melandri, GCN 6127) and the
MDM 1.3m telescope (Mirabal & Halpern, GCN 6126) on
Feb. 23.025 and Feb. 23.272, respectively. The
afterglow candidate reported by Melandri (GCN 6127)
is not detected in our coadded frames. We therefore consider
it unlikely that this is the OT of GRB 070223.
In both sets of images, we find a faint object located at:
RA(J2000) = 10h 13m 48.19s
Dec(J2000) = +43d 07' 54.65 ''
with a preliminary magnitude of R~23.7, which is consistent with
the XRT position (Vetere, GCN 6130). We have not established
any optical variability at this time."
GCN Circular 6168
Subject
GRB 070223: NIR observations at WHT
Date
2007-03-06T16:49:26Z (18 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
A.J. Castro-Tirado, A. de Ugarte Postigo, M. Jelinek,
J. Gorosabel (IAA-CSIC), J. Licandro and D. Bramich
(ING La Palma), report:
"We have observed the XRT position of GRB 070223 (Vetere et al. GCN
6130) with the 4.2m WHT (+LIRIS) telescope at the Spanish Observatorio
del Roque de los Muchachos in La Palma. The observations were carried
out in the JHK-bands starting on Feb 23.165-23.195 UT. We detect a faint
object in all bands consistent with the one reported by Mirabal et al.
(GCNC 6162) and also with the XRT position given by Vetere et al.
Further imaging is required to confirm if this is the NIR afterglow
to GRB 070223."
This message can be quoted.
GCN Circular 6221
Subject
GRB070223: confirmation of nIR and optical afterglow
Date
2007-03-23T17:18:46Z (18 years ago)
From
Evert Rol at U.Leicester <er45@star.le.ac.uk>
E. Rol, N. Tanvir (Leicester), N. Mirabal (Columbia), K. Wiersema
(Amsterdam), J.P. Halpern (Columbia), A. Levan (Warwick), R.
Chapman (Hertfordshire), A. Melandri (Liverpool JMU) and D. Pinfield
(Hertfordshire), report on behalf of a larger collaboration:
We re-observed the position of the X-ray afterglow of GRB070223
(Vetere et al, GCN report 35.1) with the LIRIS instrument on the
William Herschel Telescope, between 7.99 and 8.08 days after the
burst. Our J and K images do not show any source inside the XRT 90%
error circle. As our observations are considerably deeper than the
first epoch LIRIS observations reported by Castro-Tirado et al (GCNC
6168; private communication), we conclude the source reported is the
nIR afterglow of GRB070223.
We also re-examined the optical images taken with the MDM telescope
(Mirabal et al., GCNC 6162), and find a faint optical source at the
position of the nIR afterglow. We point out that this is a different
source than the one located at RA (J2000) = 10 13 48.19, Dec (J2000) =
43 07 54.7 (S1, GCNC 6162), which now also falls outside the revised
XRT position (Vetere et al.).
We derive a position for the optical afterglow of (J2000):
RA = 10 13 48.39
Dec = +43 08 00.7
which fully agrees with the X-ray position (GCN report
35.1). Astrometry was done relative to the SDSS (Cool et al, GCNC
6128), and errors are about 0.3 arcsecond in each coordinate.
The latest MDM image is posted at
http://www.astro.columbia.edu/~mirabal/grb070223mdm.jpg