- GCN notice #959 == BeppoSAX MAIL n. 01/06
On Feb. 22, 07:23:30 U.T. a very bright GRB, possibly the brightest ever
observed by BeppoSAX has been detected simultaneously by the GRBM and WFC1
aboard BeppoSAX.
Preliminary coordinates from WFC are:
R.A.(2000)= 223.069
DEC.(2000)= 43.035
The error radius at this stage of analysis is 5'.
We are planning a BeppoSAX-NFI observation.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SAX_WFC BURST POSITION NOTICE
NOTICE_DATE: Thu 22 Feb 01 10:54:22 UT
NOTICE_TYPE: SAX-WFC Initial
GRB_DATE: 11962 TJD; 53 DOY; 01/02/22
GRB_TIME: 26610.00 SOD {07:23:30.00} UT
GRB_SAX_RA: 223.069d {+14h 52m 17s} (J2000),
223.079d {+14h 52m 19s} (current),
222.606d {+14h 50m 25s} (1950)
GRB_SAX_DEC: +43.035d {+43d 02' 06"} (J2000),
+43.030d {+43d 01' 49"} (current),
+43.239d {+43d 14' 21"} (1950)
GRB_SAX_ERROR: 0.083 [deg radius (stat+sys), 1-sigma]
GRB_SAX_INTEN: unknown
SUN_POSTN: 335.65d {+22h 22m 36s} -10.14d {-10d 08' 05"}
SUN_DIST: 113.34 [deg]
MOON_POSTN: 325.76d {+21h 43m 02s} -16.99d {-16d 59' 20"}
MOON_DIST: 110.66 [deg]
COMMENTS: SAX-WFC GRB Coordinates.
COMMENTS: We are planning a BeppoSAX-NFI observation
- red DSS finding chart
ps-file
- GCN notice #960 == BeppoSAX MAIL n. 01/07
GRB010222: BeppoSAX refined position
Refined coordinates of GRB010222 from BeppoSAX WFC are:
R.A.(2000)= 223.051
DEC.(2000)= 43.012
The error radius at this stage of analysis is 2.5'.
Please note that in GCN 959 the burst has been named GRB020223 instead of
GRB010222 due to a trivial typo.
G. Gandolfi
on behalf of BeppoSAX Mission Scientist
- GCN notice #961
A. Henden, on behalf of the USNO GRB team, reports:
A possible optical transient has been detected in the SAX
error box (GCN 960). It is about 18th magnitude in V. The
coordinates are:
223.05238 43.01844
15:45:04.4 +43:04:01 +/- 1arcsec
Observations continue.
- GCN notice #962
Sorry, early hours here. Sexagesimal coordinates:
14:52:12.0 +43:01:06 J2000
- GCN notice #963
J. McDowell, R. Kilgard (Harvard-Smithsonian CfA), P. M. Garnavich
(Notre Dame), K. Z. Stanek and S. Jha (Harvard-Smithsonian CfA)
report:
We have an independent detection of a new source in the revised SAX
error box (GCN 960). Its position, based on the GSC, agrees with that
of Henden (GCN 962): 14:52:12.55 43:01:06.26 (J2000).
Comparing to star "A" (R=17.0) from the USNO catalog (located at
14:52:07.55 42:58:48.66), we estimate the R-band magnitude of the
possible GRB010221 afterglow to be R=18.4+-0.1.
This message can be cited.
- GCN notice #965
P. M. Garnavich (Notre Dame), M. A. Pahre, S. Jha, M. Calkins,
K. Z. Stanek, J. McDowell and R. Kilgard (Harvard-Smithsonian Center
for Astrophysics) report:
A spectrum of the optical transient (GCN 961, 962, and 963) associated
with GRB010222 (GCN 959, 960) was obtained with the F. L. Whipple
Observatory 1.5m Tillinghast telescope (+ FAST spectrograph) on 2001
February 22 beginning at UT 12:18, 4.92 hours after the burst. Two
1200s spectra were obtained with a 3 arcsec wide slit and 300 l/mm
grating, yielding 6 Angstrom resolution over the range from 3620 to
7560 A. The OT was approximately R=18.4 mag around the time of the
spectroscopy (GCN 963).
This spectrum shows a blue continuum and many narrow absorption lines
with the following preliminary identifications:
Observed Line Rest Redshift
Wavelength ID Wavelength
(angstrom) (angstrom)
6405.9 FeII 2585.4 1.477
6438.7 FeII(UV1) 2598.4,2599.4 1.477
6924.2 MgII 2796 1.476
6941.6 MgII 2803 1.476
The FeII (2585,2599) and MgII (2796,2803) doublet absorption features
are strong, absorbing approximately 50 and 80% of the continuum at
those wavelengths. These absorption lines constrain the redshift of
the optical transient associated with GRB010222 to be at >= 1.476. If
the lines come from a host galaxy associated with the GRB, then the
redshift is 1.476.
Additional unidentified absorption lines appear in the spectrum, data
analysis is continuing.
This message can be cited.
- GCN notice #966 == BeppoSAX MAIL n. 01/08
GRB010222: BeppoSAX/NFI Observations
A BeppoSAX TOO observation of GB010214 has started about 9
hours after the GRB.
A preliminary analysis of MECS(1.6-10 keV) image of the first orbit shows
a bright unknown source in the WFC error circle.
The position is:
RA(2000) = 223.052
Delta(2000) = 43.012
The error radius is 1 arcminute.
This source is consistent with the detected optical transient (GCN 962
and 963).
G. Gandolfi
on behalf of BeppoSAX Mission Scientist
- GCN notice #967
A. Henden (USRA/USNO) and F. Vrba (USNO), on behalf of the
USNO GRB team and a larger European GRB collaboration, report:
We observed the BeppoSAX error box for GRB010222 (GCN 959, 960, 966)
with the USNOFS 1.0-m telescope under cloudy conditions.
The discovery of the optical transient for this burst
was given in Henden (GCN 961, 962). The final astrometry for
the OT, relative to USNO-A2.0, is
223.05229 43.01840
14:52:12.55 +43:01:06.2 (J2000)
with internal errors of 0.2arcsec. This is in agreement
with the values given in McDowell et al. (GCN 963).
A finding chart (R-band, 4.5x4.5arcmin, NE=upperleft) is given at
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb010222r.jpg
BVRcIc frames were taken shortly after the localization
posting. However, only the preliminary R-band measures
are reported here. The quality of the photometry suffered
due to the thick clouds, but is good enough to show definite
fading of the transient:
UT exp Rc err
010222.486 1x300 18.36 0.059
010222.510 2x300 18.52 0.054
010222.518 2x600 18.68 0.059
010222.533 2x600 18.67 0.057
Where the R-band magnitudes are relative to the bright USNO-A2.0
star (identified as "A" on the finding chart) at J2000 coordinates
14:52:14.80 +43:01:40.9 and that has an assumed magnitude R=14.70.
More careful all-sky calibration of this field will be performed
on the next few nights. The intent is to only calibrate in
BVRcIc; please contact Henden if you need U-band calibration as well.
- GCN notice #968
E. Berger (Caltech) and D. A. Frail (NRAO) report on behalf of a
larger collaboration:
"On 2001 February 22.62 UT we used the VLA to observe a field centered
at the position of the optical transient reported by Henden
(GCN#961,GCN#962) in the error circle of GRB010222 (GCN#959,
GCN#960). At 22 GHz we detect a radio source coincident with the
optical source. A preliminary reduction gives a flux of 0.70+/-0.15
mJy. Further observations are planned."
This message may be cited.
- GCN notice #969
The American Association of Variable Star Observers (AAVSO) reports on
behalf of Gary Billings, a member of the AAVSO International GRB Network,
imaging of the optical transient of GRB010222 (GCN 959,960)
at the location given by Henden et al. (GCN 961, 962) and confirmed by
McDowell et al. (GCN 963).
Astrometry on the suspected GRB (using Astrometrica + USNO A2.0) gives RA
14 52 12.6 and Dec 43 01 06, with errors of about 0.5" on each axis,
consistent with the measures given in McDowell et al. (GCN 963) and
Henden et al. (GCN 967).
Images of the possible detection can be downloaded from the following
URLs:
ftp://ftp.aavso.org/grb/grb010222-billings-a.fit -- shot between 1136 UT
and 1229 UT (22 Feb 2001), sum of 28 V-band exposures of 90 seconds.
ftp://ftp.aavso.org/grb/grb010222-billings-b.fit -- shot between 1241 and
1333 UT (22 Feb 2001), sum of 31 V-band exposures of 90 seconds.
This message can be cited.
- GCN notice #970
K. Z. Stanek, S. Jha, J. McDowell, R. Kilgard, J. Roll
(Harvard-Smithsonian CfA), P. M. Garnavich (Notre Dame) and J. Kaluzny
(Copernicus Astronomical Center) report:
R-band observations of the optical afterglow of the GRB010222 carried
out with the F. L. Whipple Observatory 1.2m telescope, starting at UT
11:10 (3.8 hours after the burst), indicate a fading behavior of the
source at 14:52:12.55 +43:01:06.2 (J2000):
HJD-2450000 UT R_c exp
1962.9610 010222 11:10 18.18+-0.02 600 sec
1962.9695 010222 11:23 18.21+-0.02 600 sec
1963.0106 010222 12:22 18.36+-0.02 600 sec
Errors in the magnitudes are statistical only. The R-band magnitudes
are relative to star "A" as marked in the finding chart at
http://cfa-www.harvard.edu/cfa/oir/Research/GRB/, assuming its
magnitude R=17.0 (see GCN 963). Our comparison star is different from
the star "A" of Henden & Vrba (GCN 967), which is saturated in our
images. These data should not be combined with that of Henden & Vrba
unless using common comparison stars.
We have also obtained UBVI observations of the afterglow, reductions
of which are under way.
This message can be cited.
- GCN notice #971
Michel Fich (U. Waterloo), Robin R. Phillips, Gerald Moriarty-Schieven,
Remo P.J. Tilanus (JAC), Dale A. Frail (NRAO), and Ian Smith (Rice U.)
report on behalf of the Dutch and Canadian GRB collaborations:
"We used the SCUBA sub-millimeter continuum bolometer array on the
JCMT to observe the optical (GCN #962, 963, 965) and radio counterpart
(GCN #968) to GRB 010222 between 13:03 and 18:16 on 2001 February 22 UT.
We detect a source at this location with a preliminary averaged 850
micron flux density of 4.2 +/- 1.2 mJy."
Further observations are planned.
- GCN notice #973
P.A. Price (Caltech), A. Gal-Yam, E. Ofek (Wise Observatory), S. Yost,
J.S. Bloom, T.J. Galama F. Harrison and S.R. Kulkarni (Caltech) report on
behalf of a larger collaboration:
"A. Gal-Yam and E. Ofek have observed the optical afterglow of GRB 010222
(GCN #961, #962) with the Wise 1-metre telescope in R-band at Feb 22.95 UT.
Preliminary photometry on the unflattened images against comparison star
`A' of Henden (GCN #967) yields a magnitude of R = 19.623 +/- 0.12 mag.
When combined with the data from Henden (GCN #967), we derive a temporal
decay slope of alpha = 0.89 +/- 0.09.
The results of the proper reduction will follow later. We report this
now in order to assist those preparing observations."
This message may be cited.
- GCN notice #974
S. Jha, T. Matheson, M. Calkins, M. A. Pahre, K. Z. Stanek,
J. McDowell, R. Kilgard (Harvard-Smithsonian CfA), and
P. M. Garnavich (Notre Dame) report:
Further reduction and analysis of the FLWO 1.5m spectrum of the GRB
010222 optical afterglow (GCN 965) reveals the presence of two
absorption systems along the line of sight to the gamma-ray burst, one
at z = 1.477 as reported, and another with weaker lines at z = 1.157.
The interstellar absorption lines observed from each system are as
follows, with identifications based on the ultraviolet spectral atlas
of Blades et al. (1988, ApJ, 334, 308):
Observed Line Rest Redshift
Wavelength Identification Wavelength
(A) (A)
7065.4 Mg I 2852.1 1.477
6941.7 Mg II 2802.7 1.477
6924.0 Mg II 2795.5 1.477
6438.5 Fe II 2599.4 1.477
6422.4 Mn II 2593.7 1.476
6405.4 Fe II 2585.9 1.477
6381.2 Mn II 2576.1 1.477
5900.1 Fe II 2382.0 1.477
5879.6 Fe II 2373.7 1.477
5805.4 Fe II 2343.5 1.477
5108.5 Zn II/Cr II blend 2061.9 1.478
5018.5 Zn II/Mg I blend 2025.6 1.478
4478.9 Si II 1808.0 1.477
4137.8 Al II 1670.8 1.477
3838.0 C IV blend 1549.0 1.478
3781.8 Si II 1526.7 1.477
6045.0 Mg II 2802.7 1.157
6028.2 Mg II 2795.5 1.156
5606.7 Fe II 2599.4 1.157
5574.1 Fe II 2585.9 1.156
5137.2 Fe II 2382.0 1.157
This message can be cited.
- GCN notice #975
J. P. U. Fynbo (ESO, Garching), J. Gorosabel (DSRI, Copenhagen),
B. L. Jensen, H. Pedersen, J. Hjorth (U. of Copenhagen),
M. I. Andersen (University of Oulu),
A. A. Kaas, T. Abbott, T. H. Dall and R. Oestensen (NOT), report
"Using the ALFOSC on the 2.5m Nordic Optical Telescope, we have
obtained R-band imaging of the optical counterpart of GRB 010222
(GCN #961, GCN #963). We have derived the following preliminary
magnitudes;
Date, Feb 2001(UT) R Texp(s)
=========================================
23.008--23.012 19.56+-0.03 300
23.015--23.019 19.53+-0.03 300
23.020--23.023 19.56+-0.03 300
23.083--23.086 19.65+-0.03 300
23.087--23.091 19.68+-0.03 300
23.145--23.148 19.76+-0.03 300
23.165--23.167 19.79+-0.05 100
Our zero-point is based on the the reference star 'A' of McDowell
et al. (GCN #963). We have fitted a power-law light curve to the
magnitudes reported by Stanek et al. (GCN #970) and to the ones
displayed above. We obtain a value for the slope of 0.86+-0.01
(chi^2/dof= 12.7/8=1.6), which is consistent with the one reported
by Price et al. (GCN #973)"
- GCN notice #976
Jerome A. Orosz, Utrecht University, The Netherlands, reports:
I have observed the field of GRB010222 (GCN 959,960) with the 1 meter
Jacobus Kapteyn Telescope on La Palma. The conditions were nearly
photometric (very thin cirrus moved in at the last minute) and the seeing
was 1.2 arcseconds. The preliminary magnitudes given are with respect to
star 'A' in Stanek et al.'s finding chart (GCN 970):
UT start Filter exptime airmass delta_mag
on Feb 23
06:16:28.0 R 600.0 1.037762 2.95 +/- 0.06
06:27:43.0 V 600.0 1.043099 2.83 +/- 0.07
06:38:45.0 I 600.0 1.050021 2.66 +/- 0.13
06:49:46.0 R 600.0 1.058645 2.82 +/- 0.15
Thus assuming star A has R=17, then the OT had R = 19.95 +/- 0.06
on UT 23.2614.
I have observed several Landolt fields that can be used to approximately
calibrate the field after the fact. These images and the GRB images are
available upon request.
This message can be cited.
- GCN notice #977
A. Di Paola, L.A. Antonelli, G. Li Causi, Osservatorio Astronomico
di Roma, Italy, G. Valentini, Osservatorio Astronomico di Teramo,
Italy, on behalf of a larger collaboration report:
"We observed the Optical Transient candidate of GRB 010222 reported
by Handen, GCN #961 and McDowell et al., GCN #963 in J and K band
with the AZT-24 1.1-meter telescope at Campo Imperatore (AQ).
The J-band observation started at February 23.0078 UT and the field
was imaged for a total exposure time of 2200 sec. A point-like source
was observed in a position consistent with the OT position (GCN #961,
#963). The source was detected with a S/N=10 and had a magnitude of
J=18.7+/-0.1. Another J-band observation started at February 23.1674
and the field was imaged for a total exposure time of 2200 sec. The
source was still detected at a S/N=5 and had a magnitude of J=19.3+/-0.2
The K-band observation started at Feb. 23.0681 UT and the field was
imaged for a total exposure time of 2700 sec. The source was detected
with a S/N=8 and had a magnitude of K=17.4+/-0.3.
The J-band images are posted at
http://argos.mporzio.astro.it/angelo/grb010222/
This message is citable."
- GCN notice #980
F. Massi, M. Dolci, E. Di Carlo, Osservatorio Astronomico di
Teramo, Italy, report:
We carried out R-band observations of the GRB010222 field at the 0.72 m
telescope of the Osservatorio Astronomico di Teramo, starting on Feb
23.083 UT and ending on Feb 23.156 UT, with a total integration time of
75 min. Preliminary data reduction shows a faint object at the location
indicated by Stanek et al. (GCN 970). Using their star "A" as a
comparison star, we found R=19.20 p/m 0.06 on our coadded unflattened
image. Further reduction is under way.
This message can be cited.
[GCN OPS NOTE(23Feb01): This Circular was receive 23 Feb 01 05:50 UT
but was delayed due to an improper account name.]
- GCN notice #982
C. Bartolini, A. Guarnieri, A. Piccioni (Dip. Astronomia, Univ. of Bologna),
S. Bernabei (Astron. Obs., Bologna) and G. Pupillo (ISAO, CNR, Bologna)
report:
"We have imaged the proposed optical counterpart (GCN #961) of GRB010222
(GCN #959, 960) on February 23 in the B and V bands with the 152 cm
Loiano telescope (plus EEV CCD) of the Observatory of Bologna.
The seeing was 4 arcseconds. The preliminary magnitudes are given with respect
to the comparison star "A" (GCN 963) = USNO 1275-08542334.
mean UT Filter exptime delta_mag
(s)
23.174 B 2400 2.04 +/- 0.07
23.199 V 1800 2.69 +/- 0.09
Thus assuming for the star "A" B=17.60, then the OT had B = 19.64 +/- 0.07".
- GCN notice #983
K. Z. Stanek, P. Challis, S. Jha, R. Kilgard, J. McDowell
(Harvard-Smithsonian CfA) and P. M. Garnavich (Notre Dame) report:
We have obtained additional R-band data for the optical afterglow of
the GRB010222 using the F. L. Whipple Observatory 1.2m telescope:
HJD-2450000 UT R_c exp
1963.9457 010223 10:48 20.16+-0.07 600 sec
Combined with our earlier R-band data (GCN 970), this indicates a
power-law decay with a slope of 0.89, consistent with previous
determinations (GCNs 973, 975).
In the B-band, between 4.3 hours and 24.2 hours after the burst the
afterglow dimmed by about 1.8 magnitudes:
HJD-2450000 UT B exp
1962.9855 010222 11:46 18.46+-0.02 600 sec
1963.8173 010223 07:43 20.25+-0.10 600 sec
This is consistent with no color evolution between B and R.
Errors in the magnitudes are statistical only. The B-band magnitudes
are relative to star "A" as marked in the finding chart at
http://cfa-www.harvard.edu/cfa/oir/Research/GRB/, assuming its
magnitude B=17.6.
Reductions of additional data are under way.
This message can be cited.
- GCN notice #984
GRB 010222 Kyoto optical observation
M. Uemura, R. Ishioka, H. Iwamatsu, T. Kato, Kyoto Univ., and
H. Yamaoka, Kyushu Univ., on behalf of VSNET-GRB collaboration report:
We observed the field of GRB 010222 starting at Feb. 22, 12:16 UT,
with 0.30-m Schmidt-Cassegren telescope (+ unfiltered CCD) at Kyoto
University. The GRB was detected on the images. The following photometry
has been obtained:
mid UT total exp. delta mag detection level
Feb. 22.534 (22.511-22.554) 2160s 3.09 (1.7 sigma)
22.852 (22.842-22.861) 1350s 4.61 (6.2 sigma)
The magnitudes are relative to PG 1450+432 (V=14.50). By assuming
Rc = 14.70 for this star (Henden et al.), the observed magnitudes are
17.8 and 19.3 respectively. The low detection level of the first run
was a result of low-alititude haze.
This message may be cited.
- GCN notice #985
N. Masetti, E. Palazzi (ITeSRE, CNR, Bologna), E. Pian (Oss. Astron. Trieste),
A. Zacchei, A. Magazzu, M. Pedani, F. Ghinassi (TNG) and M. Mignoli
(Oss. Astron. Bologna), on behalf of a larger collaboration, report:
"We observed the optical transient (Henden, GCNs #961, #962) associated
with GRB010222 (Piro, GCNs #959, #960) in the R band with TNG+Dolores
on 2001 Feb. 24.236 UT (i.e. ~2 days after the GRB). The total exposure
time was 4 minutes; seeing was 0.9 arcsec.
Using star `A' by Stanek et al. (GCN #970) as reference, we note that our
measurement, R = 20.88 +- 0.03, is ~0.4 mag fainter than the extrapolation
of the t^{-0.9} decay measured by Price et al. (GCN #973), Fynbo et al.
(GCN #975) and Stanek et al. (GCN #983).
The power-law decay between our TNG measurement and that made in the R
filter by Stanek et al. (GCN #983) on Feb. 23.45 has an index ~1.3. Thus,
our data seem to suggest that a break occurred at ~1 day after the GRB in
the R-band light curve of the afterglow.
Further observations are strongly encouraged to confirm (or reject) this
result.".
This message can be cited.
- GCN notice #986
G. Valentini, F. Massi, M. Dolci and E. Di Carlo,
Osservatorio Astronomico di Teramo (Italy), report:
New R-band observations of the GRB010222 field have been
carried out with the 512 x 512 CCD camera (4' x 4' FOV) at the focus
of the 0.72-m telescope of the Osservatorio Astronomico di Teramo.
A more accurate photometric calibration has been performed
both on these new data and on the ones previously reported
by us (GCN 980). The photometric stability during both nights
was roughly 0.06 mag.
Final results for the observations reported on Feb 23 (GCN 980) indicate
R=19.63 p/m 0.05 with respect to the R=17 star "A" from Stanek et al.
(GCN 970). However, a calibration made using SA106-1024 from the
Landolt catalogue yields R=16.7 for star "A" and R=19.33 for the
GRB counterpart candidate (seeing 3.6 arcsec). No colour correction
was applied.
The latest set of images was acquired starting on Feb 24.085 UT
and ending on Feb 24.174 UT, for a total exposure time of 2 hours.
The source was no longer detected above a 3-sigma limiting magnitude
R=21 (seeing about 5 arcsec).
This message can be cited.
- GCN notice #987
A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:
We have acquired preliminary UBVRcIc all-sky photometry for
the field of GRB010222 with the USNOFS 1.0-m telescope on one
photometric night with poor seeing. This 11x11arcmin field includes
the proposed counterpart and extends to approximately V=20.
All stars brighter than V=14 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/grb010222.dat
The current photometry has a potential external zero-point
error of about two percent that needs to be added in
quadrature to the Poisson errors given in the datafile and
also below. The astrometry in this file is based on linear
plate solutions with respect to USNO-A2.0. The internal errors
are less than 100mas.
In particular, the values for the two comparison stars noted
in the literature are:
ID U B V Rc Ic
Henden A GCN967 13.311 14.318 14.570 14.688 14.829
0.002 0.002 0.002 0.002 0.004
Stanek A GCN970 18.680 18.349 17.613 17.175 16.761
0.045 0.014 0.010 0.015 0.017
Note that Henden star A has nearly identical R-magnitude to
the value listed in USNO-A2.0, whereas observations made with
respect to Stanek star A will have to be adjusted fainter.
At least two additional nights of photometry will be added to the data
file when weather conditions permit.
- GCN notice #989
GRB 010222: Keck Spectroscopy
J. S. Bloom, S. G. Djorgovski (Caltech), J. P. Halpern (Columbia), S. R.
Kulkarni, T. J. Galama, P. A. Price, S. M. Castro (Caltech) report on
behalf of the larger Caltech-NRAO-CARA GRB Collaboration:
"We obtained two epochs of optical spectroscopy of the transient of GRB
010222 (GCN #959; #961) using the dual-CCD Low-Resolution Imaging
Spectrometer (LRIS; Oke et al. 1995) on the Keck I 10-m telescope on Mauna
Kea, Hawaii. We confirm the redshifts of the two absorption systems
previously reported by Garnavich et al. (GCN #965) and Jha et al. (GCN
#974). We find an additional absorption system at z=0.928 as well other
as yet unidentified absorption lines.
The first set of spectra were taken by R. -P. Kudritzki and F. Bresolin on
22.66 Feb 2001 UT using the 300/5000 grism (blue side) and 400/8500
grating (red side) with a total integration time of 1800s on-source in
both CCDs. The second set of spectra were taken by H. Spinrad, D. Stern,
A. Dey, A. Bunker, and S. Dawson on 23.66 Feb 2001 UT with the identical
setup and integration time as the first epoch.
A preliminary comparison of absorption-line strengths reveals no
significant variation of the equivalent widths between the two epochs."
We thank A. A. Henden for providing an image of the GRB field which
facilitated the first epoch of spectroscopy.
This message may be cited.
- GCN notice #990
A. Oksanen, M. Moilanen, H. Hyvonen, R. Pasanen, and
P. Tikkanen of the Nyrola Observatory GRB team and
the AAVSO International GRB network, report:
We observed the optical transient for GRB010222 (GCN 961) with
the 0.4m telescope and ST7E CCD camera of the Nyrola
Observatory on the night of 010222/010223 UT. Observing conditions
were quite good: sky was clear, but strong wind enlarged the star
images. Our preliminary untransformed BVR measures of the OT (GCN 961)
from that night, using Henden star A (GCN 967) as calibrated by
Henden (GCN 987) for the comparison star, are as follows:
UT (mid) mag merr filter exposure(s)
----------------------------------------------
20010222.8227 19.84 0.31 B 12x300
20010222.8744 19.57 0.13 Rc 12x300
20010222.9187 19.70 0.13 V 12x300
20010222.9661 19.69 0.15 Rc 12x300
20010223.0134 19.92 0.14 V 12x300
20010223.0628 19.92 0.17 Rc 12x300
20010223.1439 20.29 0.21 V 6x300
20010223.1665 20.11 0.31 Rc 6x300
The images are available on
http://nyrola.jklsirius.fi/grb/grb010222/.
We want to thank A. Henden (USRA/USNO) about preparing this circular.
This message can be cited.
- GCN notice #991
K. Z. Stanek and E. Falco (Harvard-Smithsonian CfA) report:
We have obtained additional R-band data for the optical afterglow of
the GRB010222 using the F. L. Whipple Observatory 1.2m telescope:
UT R_c exp
25.4385 21.48+-0.08 2x600 sec
Fitting a simple power-law decay to our data taken about one day after
the burst (GCN 983) and the current data yields a slope of about
1.3. This confirms the steepening decay of the optical afterglow, as
indicated by Masetti et al. (GCN 985). Fitting broken power-law to
all the data produces a food fit, but the parameters of the fit are at
present underconstrained, except that the break seems to be gradual,
beta<<1. Continuing imaging is needed, also in the BVI-bands if
possible.
The R-band magnitude is relative to star "A" as marked in the finding
chart at
http://cfa-www.harvard.edu/cfa/oir/Research/GRB/, assuming
its magnitude R=17.0. Because of the discrepancy between the values
assigned to "A" by Valentini et al. (GCN 986: R=16.7) and Henden (GCN
987: R=17.175), we decided for now to continue using R=17.0 as our
fiducial point.
This message can be cited.
- GCN notice #992
Remark: Correction to the magnitude of star "A" and GRB counterpart
candidate in GCN 986
G. Valentini, F. Massi, M. Dolci and E. Di Carlo,
Osservatorio Astronomico di Teramo (Italy), report:
New R-band observations of the GRB010222 field have been
carried out with the 512 x 512 CCD camera (4' x 4' FOV) at the focus
of the 0.72-m telescope of the Osservatorio Astronomico di Teramo.
A more accurate photometric calibration has been performed
both on these new data and on the ones previously reported
by us (GCN 980). The photometric stability during both nights
was roughly 0.06 mag.
Final results for the observations reported on Feb 23 (GCN 980) indicate
R=19.63 p/m 0.05 with respect to the R=17 star "A" from Stanek et al.
(GCN 970). However, a calibration made using SA106-1024 from the
Landolt catalogue yields R=17.42 p/m 0.01 for star "A" and R=20.05 p/m
0.05 for the GRB counterpart candidate (seeing 3.6 arcsec). No colour
correction was applied.
The latest set of images was acquired starting on Feb 24.085 UT
and ending on Feb 24.174 UT, for a total exposure time of 2 hours.
The source was no longer detected above a 3-sigma limiting magnitude
R=21 (seeing about 5 arcsec).
This message can be cited.
- GCN notice #993
During our Edgeworth-Kuiper belt object survey using Subaru telescope
at Mauna Kea, we observed optical counterpart of the GRB 010222
detected by BeppoSAX using accurate coordinate reported by the Naval
Observatory. Roughly estimated R-band magnitude was 18.9 +/- 0.1 at
22.642 (UT) using following stars PG1528+062A, SA104 338, and SA104
339. Due to the lack of standard star around 22.508 (UT), we conducted
relative photometry and obtained 18.4 +/- 0.1 at 22.508 (UT). This
preliminary result suggests the shallow slope for the lightcurve of
GRB 010222. We would like to express our hearty thanks to URATA Yuji
at the Science University of Tokyo for helping us to estimate
appropriate exposure time.
WATANABE, Jun-ichi National Astronomical Observatory of Japan
KINOSHITA, Daisuke Graduate University for Advanced Studies
FUSE, Tetsuharu National Astronomical Observatory of Japan
KOMIYAMA, Yutaka National Astronomical Observatory of Japan
FUJIHARA, Gary National Astronomical Observatory of Japan
POTTER, Bob National Astronomical Observatory of Japan
HARASAWA, Sumiko National Astronomical Observatory of Japan
This message can be cited.
- GCN notice #994
Dear Colleagues:
This note is to inform you that, under the aegis of our HST AO-9 program,
we have requested observations of GRB 010222 (GCN 959) with the Hubble
Space Telescope and the Chandra X-ray Observatory. This burst with a
bright optical (GCN 962, 963) and radio (GCN 968) afterglow appears to
be particularly well suited for detailed studies of the afterglow and
the circumburst medium.
The Hubble observations involves six visits: STIS/NUV-MAMA (Feb 26),
WFPC2 (Feb 28, March 9, March 15-19, TBD, TBD). In addition, a 30-ksec
ACIS Chandra observation is expected to be conducted on March 6.
We encourage parallel ground based observations of this burst so that
it will become a very well studied afterglow. We will be supplementing the
HST and Chandra observations with detailed multiwavelength observations
at facilities to which our group has access (e.g. Keck, Palomar, MDM,
HET). In the radio, we are undertaking observations with the VLA, JCMT,
IRAM, Ryle, OVRO and Nobeyama.
Shri Kulkarni, Titus Galama and Fiona Harrison on behalf of a large
international GRB collaboration.
- GCN notice #995
Interferometric Millimeter Observations of GRB 010222
M. Bremer (1), A. Castro-Tirado (2,3) and R. Moreno(1) report:
(1) IRAM (Grenoble, France)
(2) IAA-CSIC (Granada, Spain)
(3) LAEFF-INTA (Madrid, Spain)
We have observed the GRB 010222 radio counterpart with the Plateau
de Bure Interferometer (PdBI) in a compact five antenna configuration
on February 24.94 - 25.11 UT, using the position from Henden et al.
(GCN 967). Weather conditions were good for wavelengths of 3mm but
marginal for 1mm. The flux calibration was relative to CRL 618
(1.55 Jy at 3mm and 2 Jy at 1mm) and is accurate to about 10%.
The source was not detected. UV fits on the phase center give the
following upper limits (fit errors are one sigma) :
93.109 GHz : -0.49 +- 0.32 mJy/beam
232.032 GHz : -0.09 +- 1.6 mJy/beam
The results have been corrected for atmospheric decorrelation.
Synthesized beams were 9.3" x 5.2" at PA -57 degrees and 3.6" by 2.3"
at PA -46 degrees, respectively. No bright sources were detected
within the primary beam.
- GCN notice #996
S. R. Kulkarni (Caltech), D. A. Frail (NRAO), G. Moriarty-Schieven
(JAC), F. Bertoldi (MPIfR), F. Walter (OVRO), D. Shepherd (NRAO), R.
Sari (Caltech), D. E. Reichart (Caltech) and S. G. Djorgovski (Caltech)
report:
Observations of the afterglow of GRB 010222 have continued with the
SCUBA sub-millimeter continuum bolometer array on the James Clark
Millimetre Telescope (JCMT). The first observation, reported in GCN#971
by Fich et al. was begun 5.6 hrs after the burst on Feb 22 at 13:03 UT.
Two additional observations were made beginning on Feb 23.46 UT and
Feb. 24.68 UT, or 27.7 hrs and 56.8 hrs after the burst. The source
had a 350 GHz flux density of 4.2+/-1.2 mJy, 3.6+/-0.9 mJy and
4.2+/-1.3 mJy on these three days, respectively.
In contrast to the bright sub-millimeter emission, the source is weak
or undetectable at millimeter wavelengths. F. Bertoldi has conducted
observations with the Max-Planck Millimeter Bolometer (MAMBO) array
(220 GHz) on the IRAM 30-m telescope on the nights of February 23 and
the 24. The data reduction is in progress. However, the preliminary
results are 1.4+/-0.5 mJy and 1.2+/-0.3 mJy, respectively. F. Walter
and D. Shepherd have conducted observations at the OVRO Interferometer
(98 GHz). The observations of Feb 23.81 yield an upper limit of -0.3
+/-0.8 mJy. [At the time of the submission we recieved GCN 995
which reports similar upper limits from PdBI but for the epoch
Feb 24.94-25.11 UT].
The relative constancy of the 350 GHz flux density and the steep
spectrum between 220 GHz and 350 GHz (spectral slope>+2.4) cannot be
reconciled with standard afterglow models. Free-free or synchrotron
self-absorption in the millimeter band is unlikely because the source
is detectable at centimeter wavelengths (GCN#968). Thus we conclude
that the sub-millimeter flux originates as a distinct emission
component, separate from the main afterglow emission (which dominates
the centimeter fluxes).
The simplest hypothesis is that the the sub-millimeter flux arises from
the host galaxy. Indeed, the sub-millimeter flux of the host (assumed
to be at redshift of 1.467; GCN 965, GCN 989) is typical of
star-forming galaxies selected in SCUBA surveys. The star formation
rate estimated in the usual manner (Carilli & Yun, ApJ, L13, 1999) is
500 Msun/yr -- typical of the sample of dusty, high redshift starburst
galaxies (Smail et al. 2000; astro-ph/000823). This inference is
entirely consistent with models in which GRBs are related to massive
stars.
There is considerable diversity in the morphology and star-formation
rates of star-forming galaxies and this also appears to be the case for
GRB selected host galaxies. If the relation between GRBs and
starformation holds strictly then GRBs, thanks to the immense dust
penetrating power of gamma-rays, could be used to select a sample
of star-formation galaxies with no bias towards dust. The additional
advantage of this sample is that the afterglow offers the opportunity
to measure the redshift of the host galaxy (as is the case here).
There are other possible explanations for the sub-millimetric excess
such as reprocessing of the burst (flash) by the ambient dust or a very
strong reverse shock. We are investigating these possibilities but they
appear to be less likely or contrived.
In the host hypothesis, we expect the sub-millimeter emission to be
constant and we also expect a contribution (about 100 microJy) at 1.4
GHz (from synchrotron emission). Continued observations at radio
wavelengths are urgently required both to test the constancy of the
sub-millimeter flux and also to monitor the afterglow emission.
- GCN notice #998
The optical counterpart of GRB010222 has been observed using the
CFHT Multi Object Spectrograph in imaging mode at the Cassegrain
focus of the 3.6-m CFH Telescope on the night of Feb. 27 to 28.
One image was obtained in relatively poor conditions (seeing ~ 1.5").
A preliminary reduction using stars (223.008250,43.006507) and
(223.098277,42.994077) from Henden's list (GCN #987) gives:
Feb. 28.653 UTC R = 22.60 +/- 0.15
The relative photometry of the two stars used is consistent
with our image within 0.02 magnitudes. Using all the measurements
of the R magnitude of the OT published in the GCN's (corrected if
needed to put them back in the photometric system of Henden's list),
the R magnitude is following a nice power law decay with an index of
1.20 +/- 0.07 since 0.6 days after the burst.
An image of the OT and a graph of the decay are available at
http://www.cfht.hawaii.edu/~veillet/grb.html
S. Lilly and J. McDonald are acknowledged for their help in
this observation.
- GCN notice #999
GRB 010222: High-Resolution Keck Spectroscopy
S. Castro, S. G. Djorgovski, S. R. Kulkarni, J. S. Bloom, T. J. Galama,
D. E. Reichart, P. A. Price (Caltech), H. Ebeling (IfA Hawaii), and D. A.
Frail (NRAO), report on behalf of the Caltech-NRAO-CARA GRB collaboration:
Spectra of the optical transient associated with GRB 010222 (GCN # 959, 961)
have been obtained on 23.61 February UT by H. Ebeling, using the Echelle
Spectrograph and Imager (ESI) on the Keck-II 10-m telescope. Preliminary
analysis shows the following:
We confirm the existence of 3 absorption systems reported earlier (GCN # 965,
974, 989), with improved heliocentric redshifts as follows:
(1) z_abs = 1.4768 +- 0.0002 (based on 22 metallic lines)
This system, presumably associated with the host galaxy, appears to
have some kinematic substructure, possibly with two distinct systems at
z_1 = 1.47667 +- 0.00005 and z_2 = 1.47755 +- 0.00005, i.e., with a
restframe velocity separation of 106 km/s, typical for internal motions
in galaxies. The equivalent widths of the lines are unusually strong
in comparison to metallic line absorbers seen in the spectra of quasars,
indicating a high column density of gas, probably consistent with a
star-forming region environment.
(2) z_abs = 1.1561 +- 0.0001 (based on 9 metallic lines)
(3) z_abs = 0.9274 +- 0.0001 (based on 5 metallic lines)
Systems (2) and (3) are typical for the metallic line absorbers at
comparable redshifts. Detection of two such foreground systems is not
unusual. Further analysis of the data is in progress.
This note can be cited.
- GCN notice #1000
The optical counterpart of GRB010222 has been observed using the
CFHT Multi Object Spectrograph in imaging mode at the Cassegrain
focus of the 3.6-m CFH Telescope on the night of Feb. 28 to March 1.
Two 10 mn images were obtained in much better conditions than
the night before (GCN #998) with a seeing of about 0.8". There are
only a few point like sources in the vicinity of the OT. A star like
object ~11" S of the OT has been carefully measured with respect
to the two stars used in GCN #998 and has a very consistent R
magnitude on the MOS exposures (R = 20.13 +/- 0.02). A fainter
object 8" from the OT is used for internal consistency checks at
R = 22.35.
Precise reduction of the images from Feb. 28 and March 1 gives the
following results:
Feb. 28.653 UTC R = 22.73 +/- 0.10
Mar. 01.628 UTC R = 22.96 +/- 0.10
The index of the power law decay given in GCN #998 is not
significantly modified and found as 1.25 +/- 0.06.
There is not structure found on the OT, which is still seen as a
point source on the March 1 combined image.
More information (with the new images of the OT) can be found at
http://www.cfht.hawaii.edu/~veillet/grb.html
M. Pakull, L. Mirioni, and J. McDonald are acknowledged for their
help in this observation.
This message may be cited.
- GCN notice #1002
An Early Break in the Optical Light Curve of GRB 010222
Stephen Holland (Notre Dame)
Johan Fynbo (ESO)
Javier Gorosabel (DSRI)
Arne Henden (USNO)
Jens Hjorth (Copenhagen)
Brian Jensen (Copenhagen)
Holger Pedersen (Copenhagen)
We have obtained deep Cousins R-band images of the optical
afterglow associated with GRB 010222 using the 2.5m Nordic Optical
Telescope (NOT) at La Palma and the USNO 1.0m telescope at Flagstaff
Station. Preliminary magnitudes, using Rc = 17.175 for Stanek's
(2001a, GCN 970) Star "A", as calibrated by Henden (2001, GCN 987),
are:
UT(middle) Rc err Telescope
-----------------------------------------------
2001:02:23.0102 19.733 0.014 NOT
2001:02:23.0171 19.707 0.013 NOT
2001:02:23.0216 19.739 0.012 NOT
2001:02:23.0844 19.829 0.011 NOT
2001:02:23.0889 19.852 0.010 NOT
2001:02:23.1463 19.933 0.009 NOT
2001:02:23.1661 19.960 0.014 NOT
2001:02:23.2116 20.031 0.009 NOT
2001:02:23.2858 20.126 0.018 NOT
2001:02:24.0701 20.950 0.024 NOT
2001:02:24.1313 20.975 0.024 NOT
2001:02:24.1358 21.012 0.025 NOT
2001:02:24.1410 21.052 0.025 NOT
2001:02:24.1579 21.006 0.023 NOT
2001:02:24.1750 21.043 0.025 NOT
2001:02:24.1863 21.000 0.023 NOT
2001:02:24.2469 21.035 0.022 NOT
2001:02:25.0534 21.536 0.057 NOT
2001:02:25.0579 21.426 0.058 NOT
2001:02:25.2535 21.638 0.044 NOT
2001:02:25.2583 21.667 0.041 NOT
2001:02:22.4874 18.39 0.05 USNO
2001:02:22.5241 18.51 0.05 USNO
2001:02:22.5236 18.67 0.06 USNO
2001:02:22.5385 18.66 0.06 USNO
2001:02:24.4632 21.23 0.06 USNO
-----------------------------------------------
In order to maintain as much uniformity as possible in the
photometry we first restrict ourselves to data taken with the NOT.
This data extends from 0.70 to 2.95 days after the burst and is
consistent with a single power law with a slope of -1.24 +/- 0.02 (Q <
99.954%).
We supplemented this data with R-band photometry of GRB 010222
from Stanek et al. (2001a, GCN 970), Price et al. (2001, GCN 973),
Orosz (2001, GCN 976), Stanek et al. (2001b, GCN 983), Masetti et
al. (2001, GCN 985), Oksanen et al. (2001, GCN 990), Stanek & Falco
(2001, GCN 991), Velentini et al. (2001, GCN 992), Watanabe et
al. (2001, GCN 993), and Veillet (2001, GCN 1000). All the photometry
was adjusted to the photometric zero points of Henden (2001a, GCN
987), except for that of Veillet (2001, GCN 1000), which was used "as
is". The photometry was corrected for Galactic extinction assuming a
reddening of E(B-V) = 0.023 and an R-band extinction of A_R = 0.061.
The complete data set is not consistent with a single power law
(Q < 0.001%). Photometry earlier than 0.33 days after the burst is
weakly consistent with a single power law with a slope of -0.71 +/-
0.13 (Q = 77.969%), and the photometry later than 0.57 days after the
burst is consistent with a single power law with a slope of -1.24 +/-
0.02 (Q = 99.990%). Fitting a broken power law (see Holland et al.,
2000, A&A, 364, 467 for the method) to the light curve yields a break
at 0.48 +/- 0.11 days (11.5 +/- 2.6 hours) after the burst, and slopes
of -0.72 +/- 0.13 before the break and -1.24 +/- 0.02 after the break
(Q = 99.991%). The smooth function of Beuermann et al. (1999, A&A,
352, L26) with slopes of -0.67 +/- 0.34 before the break, -1.29 +/-
0.06 after the break, and an exponent of 1.8 +/- 4.4 provides a
slightly better fit (Q = 99.998%) to the data than the broken power
law does. Our fits suggest that the break occurred rapidly between
0.33 and 0.57 days (8 and 14 hours) after the burst. A plot of the
light curve and the two fits, along with a deep composite image of the
field containing the GRB, is available at
http://www.nd.edu/~sholland/grb/grb010222/index.html.
This message may be cited.
- GCN notice #1003
The optical counterpart of GRB010222 has been observed using the
CFHT Multi Object Spectrograph in imaging mode at the Cassegrain
focus of the 3.6-m CFH Telescope on the night of March 1 to 2.
Two 10 mn images were obtained with a seeing of about 0.8".
Photometric reduction made as outlined on GCN #1000 leads to:
Mar. 2.641 R = 23.10 +/- 0.10
The index of the power law decay fitting the R light curve data
since 0.6 days after the burst (including the revised and new
measurements by Holland et al. in GCN #1002) is 1.25 +/- 0.03,
the same as our previous determination (Veillet, GCN #1000) and
not significantly different from the GCN #1002 value.
While a few objects are now seen in a radius of 4", the OT is
still a point like object.
More information (with the new images of the OT) can be found at
http://www.cfht.hawaii.edu/~veillet/grb.html
M. Pakull, L. Mirioni, and J. McDonald are acknowledged for their
help in this observation.
This message may be cited.
- GCN notice #1004
R.J. Ivison, C.E. Jenner (University College London), W.E. Lundin,
R.P.J. Tilanus (JAC), and I.A. Smith (Rice University) report:
Further observations of GRB 010222 made using the SCUBA sub-millimeter
continuum bolometer array on the James Clerk Maxwell Telescope now fail
to significantly detect the counterpart described in GCN #971 and #996.
The observations, made between 14:54 and 18:05 on 2001 March 2 UT, give
a preliminary 850 micron flux density of 0.7 +/- 1.1 mJy. A 1-hour
observation on the previous night is consistent with this result.
It thus appears as if the source detected earlier is not the quiescent
host galaxy. Indeed, of the 17 bursts studied with SCUBA to date, that
have measured redshifts between 0.707 and 3.4, no conclusive detections
of quiescent sub-millimeter hosts have so far been found (Smith et al.
1999, A&A, 347, 92; Smith et al. 2001, A&A, in press).
At least at 850 microns, GRB 010222 may be similar to GRB 980329,
which also had an apparent excess in the SCUBA observations and whose
sub-millimeter flux decayed rapidly with time (unfortunately, the first
SCUBA observations were not made until 7 days after that burst).
A final SCUBA observation of GRB 010222 is planned during the coming week.
- GCN notice #1005
GRB 010222: Chandra Observation of the afterglow
G. P. Garmire, A. B. Garmire (Penn State), L. Piro(IAS/CNR Frascati),
E. Schlegel(Harvard-Smithsonian CfA)
A Chandra observation of GRB010222 (GCN 959, 960) with ACIS-S
started on Feb. 22 22:28 UT, i.e. 15 hours after the burst,
and lasted for 30 ksec.
The X-ray afterglow of the burst was detected at a position
RA(2000)= 14h52m12.51s, Decl(2000)=+43 01'06.2" (with an error of 1"),
consistent with the position of the OT (GCN963).
The source was very bright, and a more detailed analysis is under way
to take into account pile-up effects.
Gordon Garmire
ACIS IPI
[GCN OPS NOTE(04Mar01): This message was received on 01Mar01 21:00 UT,
but was delayed due it not being sent directly to the Circular processing
demon and because the GCN operator was on travel until 04 Mar.]
- GCN notice #1007
GeV/TeV Observations of GRB 010222
N. Goetting (1) and D. Horns (2) on behalf of the HEGRA Collaboration report:
(1) University of Hamburg (Germany)
(2) Max-Planck-Institut f. Kernphysik, Heidelberg (Germany)
On February 23rd beginning at UT 02:37 the BeppoSAX position of GRB 010222
(GCN 960) was observed by the stereoscopic HEGRA Cherenkov telescope system
on La Palma (approx. 19 hours after the outburst). The object was observed
for 4 hours at altitudes > 45 degrees under good weather conditions.
The source was not detected above a threshold photon energy of 760 GeV.
A preliminary data analysis gives an upper limit on the photon flux at
the 90% confidence level:
J(E > 760 GeV) < 9.4 * 10^(-12) erg cm^(-2) s^(-1)
Contemporaneous observations of the Crab nebula were used to derive
this upper limit.
- GCN notice #1009
P. Garnavich, J. Quinn (Notre Dame) and K. Z. Stanek (CfA)
The field of GRB 010222 was imaged with the 1.8m Vatican Advanced
Technology Telescope (VATT) on 2001 March 18 and 19 (UT). The
total exposure time in R band was 3 hours in average seeing of 1.2".
A faint source is detected within 0.2" of the position of the optical
afterglow (GCN 961, 962). Using PSF fitting photometry we
find R=24.53+/-0.25 mag assuming the Henden calibration
of the nearby stars (GCN 987). The estimated magnitude is consistent
with the extrapolated light curve assuming a power-law with
index -1.33 (after the break at 0.7 days).
A number of galaxies are visible within 10" of the afterglow. The
brightest is a compact galaxy with R=22 mag, 4.2" (PA=10 deg) from the
GRB. Three faint galaxies, all 4" from the afterglow have PA=280, 230,
and 200 deg with respect to the afterglow.
The VATT image is available at
http://cfa-www.harvard.edu/cfa/oir/Research/GRB/.
- GCN notice #1023
F. A. Harrison, S. A. Yost, S. R. Kulkarni report on behalf of a
larger collaboration:
We observed the field containing GRB010222 with Chandra ACIS for
17 ksec, beginning on March 3.44 UT. We detect an X-ray source
within 1" of the position of the optical transient (GCN 961, 962)
14:52:12.55 43:01:06.26 (J2000) and consistent with the X-ray
transient detected by the BeppoSAX NFI (GCN 966). Preliminary
analysis shows a 2-10 keV X-ray flux of 7.2e-14 erg/cm2/s for
this source.
This message may be cited.
- GCN notice #1051
R Cowsik and SG Bhargavi (IIA Bangalore, India) report:
Results of observations of afterglow of GRB 010222
obtained from 2.34-m VBT are as follows:
Feb 24.977 600s I 20.8 +- 0.2 **
Feb 24.9924 600s R 21.405 +/- 0.17
Feb 25.9816 900s I 21.42 +/-0.18
Feb 25.9955 900s R 21.99 +/-0.13
Feb 28.9014 1200s R >22.1
Feb 28.9257 2400s R >22.1
Mar 1.9319 1800s R >21.9
** It may be noted that some of these are the final numbers and
those quoted in Table.1 in astroph/0104363 (Cowsik et al.)
were priliminary.
Further details on measurements on these data may be obtained from Bhargavi
(2001; Ph D thesis).
We acknowledge S Ambika and K Jayakumar for observations.
This messge may be cited.
- GCN notice #1082
Isabel Salamanca, Paul Vreeswijk, Evert Rol, Lex Kaper (Anton
Pannekoek Institute, University of Amsterdam), Nial Tanvir (University
of Hertfordshire), Andy Fruchter (STScI), Ralph Wijers (SUNY, Stony
Brook), Chryssa Kouveliotou (NASA/MSFC), Thomas Augusteijn and
Almudena Zurita (La Palma) report:
On May 22, 2001, we have obtained B,V,R,I images of the field of GRB
010222
(Piro et al. GCN 959) with the Prime Focus Camera
at the 4.2-m William Herschel Telescope (La Palma, Spain). The aim of
these observations was to detect the host galaxy. The observations
were done in photometric conditions, with seeing 1.1 arcsec.
The details of the observation are as follows:
Filter Exposure Star 'A' Limiting mag
(sec) (Stanek, GCN 970) (3 sigma, aperture=1xFWHM)
---------------------------------------------------------------------
B 900 18.38 25.4
V 675 17.62 25.8
R 675 17.13 24.4
I 675 16.76 24.3
Photometry was done by using 7 standard stars in the field SA110 of
the Landolt Catalog (AJ, 1992, vol 104, pag 340). The resulting
magnitudes of star 'A' are in excellent agreement (between
0.01 and 0.04 mag) with the values reported by Henden et al. (GCN
987).
No host galaxy (or any other object) is detected at the position of
the optical afterglow of GRB010222
(RA = 14:52:12.55, DEC =+43:01:06.2, J2000).
Very close to the position of the GRB010222, we detect two objects,
most probably galaxies. The very faint galaxies reported by Garnavich
et al (GCN 1009) are not visible in our images, although there is a
hint of one of them.
The photometry and positions of these two galaxies are as follows:
Galaxy 1 RA = 14:52:12.4, DEC = +43:00:58.7, J2000
1.6 arcsec W, 7.6 arcsec S
----------------------------------------------------
B = 23.51 +/- 0.10
V = 23.16 +/- 0.11
R = 22.47 +/- 0.08
I = 20.77 +/- 0.12
Galaxy 2: RA = 14:52:12.7, DEC = +43:01:09.9, J2000
1.6 arcsec E, 3.6 arcsec N
------------------------------------------------------
B = 24.45 +/- 0.24
V = 23.79 +/- 0.18
R = 23.05 +/- 0.15
I > 24.3 (affected by fringing)
The error in the coordinates is about 0.24 arcsec. The error in the
magnitudes is the formal error obtained with the task 'phot' of Iraf.
A figure can be seen at
http://zon.wins.uva.nl/~evert/grb010222/
This message can be cited.
- GCN notice #1087
A. Fruchter, I. Burud, J. Rhoads and A. Levan (STScI) report:
We have reduced the now public archival HST images of GRB 010222, taken
on 28 February, 17 and 18 March, 5 and 6 April, and 4 and 5 May of
this year using the F606W (V/R) and F814W (I) filters on WFPC2. Using
the most recent data, we find that OT of GRB 010222 is clearly superposed
on a host galaxy.
In order to accurately determine the decay of the OT and the magnitude
of the host, we have drizzled the images onto an output grid that
allows interlacing of these 2-point dithered images. We have then fit
for the decay of the OT and the host galaxy flux using a small (~0."2)
aperture, which provides the best estimate of the OT as a function of
time, as well as using a larger aperture (~0."5), which is more
appropriate for determining the host galaxy magnitude.
We find that the late-time decay of the OT is significantly steeper
than previously reported. We find a power-law decay between 28 February
(day 6) and 5 May (day 71) of -1.7 +/- 0.05. Formally, we find
a slightly steeper decay (-1.73 +/- 0.02) in F606W than in F814W
(-1.64 +/- 0.04), but this discrepancy may indicate the level of
systematic error in the slope measurement rather than true color
evolution of the OT.
We find that the host galaxy is dominated by a compact core (FWHM ~ 0."15)
located directly under the OT. The magnitude of the host is
F606W(AB) = 26.0 +/- 0.1, F814W(AB) = 25.8 +/- 0.15.
Images of the host, as well as a plot of the coninuing decline of the OT,
are available at
http://www.stsci.edu/~fruchter/GRB/010222
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