- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 28 Mar 03 11:21:03 UT
NOTICE_TYPE: HETE S/C_Alert
TRIGGER_NUM: 2650, Seq_Num: 1
GRB_DATE: 12726 TJD; 87 DOY; 03/03/28
GRB_TIME: 40858.35 SOD {11:20:58.35} UT
TRIGGER_SOURCE: Trigger on the 6-120 keV band.
GAMMA_RATE: 441 [cnts/s] on a 1.300 [sec] timescale
SC_LONG: 204 [deg East]
SUN_POSTN: 6.77d {+00h 27m 05s} +2.93d {+02d 55' 32"}
MOON_POSTN: 322.33d {+21h 29m 20s} -20.11d {-20d 06' 30"}
MOON_ILLUM: 17 [%]
COMMENTS: No s/c ACS pointing info available yet.
COMMENTS: Probable GRB.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 28 Mar 03 12:14:13 UT
NOTICE_TYPE: HETE Ground Analysis
TRIGGER_NUM: 2650, Seq_Num: 3
GRB_DATE: 12726 TJD; 87 DOY; 03/03/28
GRB_TIME: 40858.34 SOD {11:20:58.34} UT
TRIGGER_SOURCE: Trigger on the 6-120 keV band.
GAMMA_RATE: 0 [cnts/s] on a 0.000 [sec] timescale
SC_-Z_RA: 0 [deg]
SC_-Z_DEC: 0 [deg]
SC_LONG: 204 [deg East]
SXC_CNTR_RA: 182.692d {+12h 10m 46s} (J2000),
182.734d {+12h 10m 56s} (current),
182.050d {+12h 08m 12s} (1950)
SXC_CNTR_DEC: -9.375d {-09d 22' 29"} (J2000),
-9.393d {-09d 23' 34"} (current),
-9.097d {-09d 05' 48"} (1950)
SXC_MAX_SIZE: 4.00 [arcmin] diameter
SXC_LOC_SN: 6 sig/noise (pt src in image)
SUN_POSTN: 6.77d {+00h 27m 05s} +2.93d {+02d 55' 32"}
SUN_DIST: 172.39 [deg]
MOON_POSTN: 322.33d {+21h 29m 20s} -20.11d {-20d 06' 30"}
MOON_DIST: 130.50 [deg]
MOON_ILLUM: 17 [%]
GAL_COORDS: 286.43,52.19 [deg] galactic lon,lat of the burst
ECL_COORDS: 186.21,-7.53 [deg] ecliptic lon,lat of the burst
COMMENTS: Definite GRB.
COMMENTS: SXC error box is circular; not rectangular.
COMMENTS: Burst_Validity flag is true.
COMMENTS: SXC data refined since S/C_Last Notice.
- red DSS finding chart
ps-file
According to USNO-A2.0, these are the two bright stars:
ID ra dec r_mag b_mag d' pa
U0750_07764513 12 10 41.29 -09 24 06.9 7.2 9.2 2.002 215.452
U0750_07764525 12 10 41.39 -09 24 08.1 7.5 9.4 2.005 214.568
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/HETE BURST POSITION NOTICE
NOTICE_DATE: Fri 28 Mar 03 13:21:46 UT
NOTICE_TYPE: HETE Ground Analysis
TRIGGER_NUM: 2650, Seq_Num: 4
GRB_DATE: 12726 TJD; 87 DOY; 03/03/28
GRB_TIME: 40858.34 SOD {11:20:58.34} UT
TRIGGER_SOURCE: Trigger on the 6-120 keV band.
GAMMA_RATE: 0 [cnts/s] on a 0.000 [sec] timescale
SC_-Z_RA: 0 [deg]
SC_-Z_DEC: 0 [deg]
SC_LONG: 204 [deg East]
WXM_CNTR_RA: 182.719d {+12h 10m 53s} (J2000),
182.761d {+12h 11m 03s} (current),
182.077d {+12h 08m 18s} (1950)
WXM_CNTR_DEC: -9.392d {-09d 23' 30"} (J2000),
-9.410d {-09d 24' 35"} (current),
-9.114d {-09d 06' 49"} (1950)
WXM_MAX_SIZE: 9.18 [arcmin] diameter
WXM_LOC_SN: 20 sig/noise (pt src in image)
WXM_IMAGE_SN: X= 20.3 Y= 13.8 [sig/noise]
WXM_LC_SN: X= 25.5 Y= 25.5 [sig/noise]
SXC_CNTR_RA: 182.711d {+12h 10m 51s} (J2000),
182.752d {+12h 11m 01s} (current),
182.068d {+12h 08m 16s} (1950)
SXC_CNTR_DEC: -9.352d {-09d 21' 05"} (J2000),
-9.370d {-09d 22' 10"} (current),
-9.073d {-09d 04' 23"} (1950)
SXC_MAX_SIZE: 1.73 [arcmin] diameter
SXC_LOC_SN: 6 sig/noise (pt src in image)
SUN_POSTN: 6.77d {+00h 27m 05s} +2.93d {+02d 55' 32"}
SUN_DIST: 172.42 [deg]
MOON_POSTN: 322.33d {+21h 29m 20s} -20.11d {-20d 06' 30"}
MOON_DIST: 130.50 [deg]
MOON_ILLUM: 17 [%]
GAL_COORDS: 286.45,52.22 [deg] galactic lon,lat of the burst
ECL_COORDS: 186.22,-7.50 [deg] ecliptic lon,lat of the burst
COMMENTS: Definite GRB.
COMMENTS: WXM error box is circular; not rectangular.
COMMENTS: SXC error box is circular; not rectangular.
COMMENTS: The WXM & SXC positions are consistant; overlapping error boxes.
COMMENTS: Burst_Validity flag is true.
COMMENTS: WXM data refined since S/C_Last Notice.
COMMENTS: SXC data refined since S/C_Last Notice.
- red DSS finding chart of improved position
ps-file
- GCN notice #1974
B.A. Peterson and P.A. Price (RSAA, ANU) report:
We have observed the error box of GRB 030328 (HETE #2650) with the SSO
40-inch telescope + WFI in B and R filters at Mar 28 12:37 UT. We
identify a source not present on the DSS 2 red plate. The coordinates of
this source are:
RA: 12:10:48.4 Dec: -9:20:51.3 (J2000)
with an error of 0.4 arcsec in each coordinate. At this stage, we
estimate that the afterglow candidate is roughly 18th magnitude.
Further observations are planned, and a finding chart will follow.
This message may be cited.
- GCN notice #1975
P.A. Price and B.A. Peterson (RSAA, ANU) report:
A finding chart for the optical afterglow candidate (GCN #1974) is
available from:
http://www.mso.anu.edu.au/~pap/grb030328finder.ps
The following offsets may be useful for spectroscopy:
Star RA (2000) Dec (2000)
A 12:10:53.8 -9:19:22.9
B 12:10:50.7 -9:20:59.8
A -> OT: 79.92" W, 88.40" S (PA -137.883 degrees)
B -> OT: 34.04" W, 8.50" S (PA -75.981 degrees)
This message may be cited.
- GCN notice #1976
P.A. Price (RSAA, ANU) reports:
The offset from Star B is 34.04" W, 8.50" N (*not* S).
My apologies for this typo.
- GCN notice #1977
P.A. Price and B.A. Peterson (RSAA, ANU) report:
We have observed the afterglow of GRB 030328 with the 40-inch telescope at
Siding Spring Observatory + Wide-Field Imager in R-band. From two
un-flattened frames taken at Mar 28.54 and 28.63, we derive a power-law
decay:
R/mag ~ 21.5 + 2.6 log(t/days)
based on assuming that the star at J2000 coordinates 12:10:50.7 -9:21:00
(Star B in GCN #1975) is R ~ 16.1 (as in USNO A2.0).
The corresponding decay index is alpha = 1.0 +/- 0.1.
This message may be cited.
- GCN notice #1978
J. Villasenor, G. Crew, R. Vanderspek, J. Doty, G. Monnelly, N. Butler,
T. Cline, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin,
G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of
the HETE Operations and HETE Optical-SXC Teams;
G. Ricker, J-L Atteia, N. Kawai, D. Lamb, and S. Woosley on behalf of
the HETE Science Team;
T. Donaghy, M. Suzuki, Y. Shirasaki, C. Graziani, M. Matsuoka, T.
Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi,
T. Tavenner, Y. Nakagawa, D. Takahashi, R. Satoh, and Y. Urata, on
behalf of the HETE WXM Team;
M. Boer, J-F Olive, J-P Dezalay, C. Barraud and K. Hurley on behalf
of the HETE FREGATE Team;
write:
At 11:20:58.34 UTC (40858.34 s UT) on 28 Mar 2003, the HETE FREGATE,
WXM, and SXC instruments detected event H2650, a long, bright GRB.
The burst triggered FREGATE in the 8-80 keV energy band; the flight
software incorrectly attributed the burst to particles, and therefore
the WXM and SXC flight localizations were not sent out. The operations
team quickly validated the SXC flight localization and disseminated it
in a GCN Notice at 12:14:13 UT, 53 minutes after the burst. The SXC
flight localization SNR was 6. The SXC flight localization can be
expressed as a 90% confidence circle that is 2 arcminutes in radius and
is centered at
SXC-Flight: RA = +12h 10m 46s, Dec = -09d 22' 29" (J2000).
Ground analysis of the WXM data and the SXC data for the burst produced
refined WXM and SXC localizations, which were reported in a GCN Notice
at 13:21:46 UT, 121 minutes after the burst. The WXM ground
localization SNR was 25. The WXM location can be expressed as a 90%
confidence circle that is 4.6 arcminutes in radius and is centered at
WXM-Ground: RA = +12h 10m 53s, Dec = -09d 23' 30" (J2000).
The SXC ground localization SNR was 10. The SXC ground localization
can be expressed as a 90% confidence circle that is 52 arcseconds in
radius and is centered at
SXC-Ground: RA = +12h 10m 51s, Dec = -09d 21' 05" (J2000).
The burst duration t_90 in the 30-400 keV band was ~ 100 s. The fluence
of the burst was 3.0 x 10-5 ergs cm-2 and the peak flux over 5.2 s was
7.3 x 10-7 ergs cm-2 s-1 in the same energy band.
A light curve and skymap for GRB030328 is provided at the following URL:
http://space.mit.edu/HETE/Bursts/GRB030328
- GCN notice #1979
P. Martini (OCIW), P. Garnavich (Notre Dame) and K.Z. Stanek (CfA)
We imaged the optical afterglow of GRB 030328 (Peterson & Price,
GCN 1974) with the Magellan 6.5-m Clay telescope and LDSS2
imaging/spectrograph on March 29.181 (0.708 days after the
burst). The R-band magnitude is estimated to be 20.8
assuming star "B" (GCN 1977) is R=16.1. This is slightly
brighter than the extrapolation of a powerlaw with alpha=1.0
found by Price & Peterson (GCN 1977).
This message may be cited.
- GCN notice #1980
P. Martini (OCIW), P. Garnavich (Notre Dame) and K.Z. Stanek (CfA)
Spectra of the optical afterglow of GRB 030328 (Peterson & Price,
GCN 1974) were obtained with the Magellan 6.5-m Clay telescope and
LDSS2 imaging/spectrograph starting at March 29.19 (UT). The
five spectra cover the wavelength range of 4000 to 9000 Ang.
with a resolution of 13 Ang. FWHM. Preliminary reduction of
the images reveals narrow absorption features which we identify
with a single absorption system at z=1.52:
observed (Ang) ID z
7069.6 MgII 2802.7 1.522
7049.2 MgII 2795.5 1.522
6554.6 FeII 2599.4 1.522
6005.7 FeII 2382.0 1.521
5987.6 FeII 2373.7 1.522
4207.9 AlII 1670.8 1.518
This suggests that the redshift of the GRB is at least z=1.52.
This message may be cited.
- GCN notice #1981
Evert Rol (U. of Amsterdam), Paul Vreeswijk & Andreas Jaunsen (ESO)
report for the GRACE collaboration:
The optical afterglow, discovered by Peterson & Price (GCN 1974), of
GRB 030328 (HETE trigger 2650, see GCN 1978), was observed around
March 29.08 UT with FORS1 at telescope unit 1 of the VLT. A total of
one hour of spectra were taken with the grism 300V and a slit width of
1 arcsecond, at a position angle of 104 degrees to also include object
B of Price & Peterson (GCN 1975) in the slit.
A preliminary reduction shows significant absorption lines, most of
which we identify with typical metal lines at a redshift of z=1.520.
We also find some hints for another system at z=1.29, but an improved
analysis is needed to confirm this.
We are thankful for the assistance of the ESO staff at Paranal; in
particular that of Andreas Kaufer.
- GCN notice #1982
D. Fugazza (TNG), L.A. Antonelli, F. Fiore,(INAF-OAR), S. Covino,
G. Ghisellini (INAF-OAB), E. Pian (INAF-OAT), N. Masetti (CNR-IASF),
A. Buzzoni, Tessicini (TNG) on behalf of a larger collaboration, report:
"On March 29 2003 we have obtained R band photometry of the optical
afterglow of GRB030328 (Peterson & Price GCN #1974) using DOLORES at
TNG. Observations were performed under moderate seeing conditions
(between 1" and 1.5").
A preliminary analysis of the images allowed us to derive the following
photometry for the OT calibrated by means of a Landolt standard field:
20.59 +/- 0.07 at UT 00:10:14, 12.82 hours after the burst
20.79 +/- 0.08 at UT 02:34:41, 15.23 hours after the burst
The photometry for the star "B" reported in GCN #1977 (Price and Peterson)
turns out to be:
16.31 +/- 0.06
We are particularly grateful to the TNG staff for their remarkable support to
these observations."
This message is citeable.
- GCN notice #1983
D. Fugazza (TNG), F. Fiore, M. Cocchia, L.A. Antonelli (INAF-OAR),
S. Covino (INAF-OAB), E. Pian (INAF-OATs), N. Masetti (CNR-IASF),
A. Buzzoni, G. Tessicini (TNG), on behalf of a larger collaboration,
report:
"Starting on March 29 2002 00:28 UT we have obtained low resolution
(R~1000) spectra of the optical afterglow of GRB030328 (Peterson &
Price GCN #1974) using DOLORES at TNG. Observations consisted of four
exposures, for a total of 2 hours, and cover the full spectral range
3800-8000 Angstrom, in good seeing conditions (between 1" and 1.5").
At the time of the observations the afterglow magnitude was R~20.7
(Fugazza et al. GCN #1982).
A preliminary analysis of the spectra reveals several absorption lines
associated with the z=1.52 system reported by Martini et al. (GCN
#1980), in particular MgII2803, MgII2796, FeII2600 and FeII2382.
Other narrow absorption lines are present in the spectra, but
a more detailed analysis is needed to their identification.
We are particularly grateful to the TNG staff for their remarkable
support to these observations."
This message is citeable.
- GCN notice #1984
A. Gal-Yam, E. O. Ofek and D. Polishook (Wise observatory, TAU) report:
We have observed the OT (Peterson & Price 2003, GCN 1974)
of GRB 030328 (Villasenor et al. 2003, GCN 1978) using the Wise observatory 1m
telescope + SITe CCD camera, starting March 28, 21:48 UT (10 hours after
the burst). B, V and R-band frames (300 s each) were obtained under fair
to moderate conditions, but incoming clouds prevented further observations.
We detect the OT on the R-band image, at magnitude about 20.5, roughly
consistent with the predictions of Price (GCN 1977) and the observations
of Fugazza et al. (GCN 1982). Further analysis is underway, and B and
V-band upper limits will be derived once the field is calibrated.
- GCN notice #1990
R. Burenin, D. Denissenko, M. Pavlinsky, R. Sunyaev, O. Terekhov, A.
Tkachenko (IKI); Z. Aslan, I. Khamitov, K. Uluc (TUG); U. Kiziloglu, A.
Alpar, A. Baykal (METU); I. Bikmaev, N. Sakhibullin, V. Suleymanov (KSU)
report:
Error box of GRB030328 (HETE Trigger #2650, GCN 1978) was observed with
1.5-m Russian-Turkish Telescope RTT150 at Bakyrlytepe (TUBITAK National
Observatory, Turkey) between Mar. 28.80 and 29.02 UT, starting appr.
9-10 hours after the burst. A set of 300-second exposures in BVRI Bessel
filters was obtained under poor photometric conditions.
We confirm the presence of the optical transient (OT) reported by
Peterson and Price (GCN 1974). R magnitude of the OT on Mar. 28.952
(0.480 day after the burst) is estimated to be 20.35, assuming that Star
B in GCN 1975 is R=16.1. This is brighter than the extrapolation of the
power law from Price and Peterson (GCN 1977).
OT is clearly visible in other filters in every 300-s exposure. The
magnitudes in BVI will be obtained after we calibrate the field.
The R image can be found at:
http://hea.iki.rssi.ru/~br/r.gif
Preliminary lightcurve in R:
http://hea.iki.rssi.ru/~br/lc_r.ps
This message may be cited.
- GCN notice #1991
V.Rumyantsev (CrAO), V.Biryukov(SAI) and A.Pozanenko (IKI) report:
We have obtained 44 unfiltered exposures (120-s each) of the GRB 030228
error box (HETE Trigger #2650). The images were taken with the AT-64
telescope of Crimean Astrophysical observatory and cover the period
(UT) 18:46 - 23:07 March 28, 2003. We used CCD SBIG ST-8 with
maximum of sensitivity in the red spectral band.
In a co-added image the OT is visible at the position of reported by B.A.
Peterson and P.A. Price (GCN 1974). The brightness was estimated in
respect to the star B (GCN 1982) as R = 20.9 +/- 0.2.
Start time exposure OT
March 28 18:46 44x120 s 20.9 +- 0.2
Detailed calibration is underway.
The image is available at
http://grb.rssi.ru/GRB030228
This message can be cited.
- GCN notice #1993
M. I. Andersen (Astrophysikalisches Institut Potsdam),
G. Masi (University of Rome "Tor Vergata" and ESO, Chile),
B. L. Jensen and J. Hjorth (University of Copenhagen) report:
We have obtained R-band observations of the optical afterglow of
GRB 030328 (Peterson & Price, GCN 1974), using the Danish 1.54m
telescope (La Silla) + DFOSC. Using the zero point reported by
Fugazza et al. (GCN 1982) (R = 16.31 for star B) a preliminary
analysis gives
Mar. 29, 02:59 UT 20.91 +/- 0.09
Mar. 29, 03:12 UT 20.73 +/- 0.07
Mar. 29, 03:34 UT 21.00 +/- 0.09
Mar. 29, 03:54 UT 20.85 +/- 0.06
Mar. 29, 04:15 UT 21.00 +/- 0.07
Mar. 29, 04:42 UT 20.95 +/- 0.07
Mar. 29, 05:21 UT 21.10 +/- 0.07
Mar. 29, 05:53 UT 21.03 +/- 0.07
Mar. 29, 07:17 UT 21.23 +/- 0.10
Mar. 29, 07:46 UT 21.36 +/- 0.11
A fit to this data set gives a decay index of alpha = 1.6 +/- 0.3. If
the two last data points are ignored and the two data points of Fugazza
et al. are included, a decay index of alpha = 1.2 +/- 0.2 is derived,
consistent with the early decay index of alpha = 1.0 +/- 0.1 reported
by Price & Peterson (GCN 1977). This may indicate that the light curve
steepened around t = 0.8 days.
- GCN notice #2007
GRB030328: X-ray Afterglow Observed with Chandra
N. R. Butler, H. L. Marshall, P. G. Ford, R. K. Vanderspek, G. R.
Ricker (MIT), J. G. Jernigan (U.C. Berkeley), and D. Q. Lamb (U. Chicago)
report:
Beginning at March 29.112 (t[burst] + 15.33 hr) Chandra Low Energy
Transmission Grating Spectrometer (LETGS) observations commenced of
a field centered on the HETE WXM+SXC localizations (Villasenor et al,
GCN 1978) of GRB030328. We report here on the first 2.6 ksec of data
downlinked from Chandra. An X-ray source is detected at a location
consistent with that of the optical transient found by Peterson & Price
(GCN1974), and a total of 13 counts are observed in the 0.2-10 keV band in
the 0th order image. Assuming a spectrum with photon index gamma=2 and
attenuated by a Galactic absorption column (nH=4.3 x 10^(20) cm^(-2)),
this corresponds to an average flux of ~3 x 10^(-13) ergs cm^(-2) s^(-1).
Our analyses are continuing, and more detailed results will be posted at:
http://space.mit.edu/HETE/
We thank Harvey Tananbaum for his generous allocation of Director's
Discretion Time to this observation, and the Chandra X-ray
Observatory Operations personnel for the impressive promptness with
which this observation was planned and carried out.
The preliminary results reported here may be cited.
- GCN notice #2008
C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University), R. Gualandi
(Bologna Astronomical Observatory), G. Pizzichini (IASF-CNR, Bologna) report:
On 2003, March 28, 22h 32m UT we observed the optical afterglow of GRB 030328
(Peterson and Price, GCN 1974) with the 152 cm telescope in Loiano. Using
the calibration reported by Fugazza et al. (GCN 1982) we obtained R = 20.45
(1800s exposure, preliminary estimate).
This message may be cited.
- GCN notice #2027
GRB030328: X-ray Fading and Spectrum Measured with Chandra
P. G. Ford, N. R. Butler, H. L. Marshall, R. K. Vanderspek, G. R.
Ricker (MIT), J. G. Jernigan (U.C. Berkeley), and D. Q. Lamb (U. Chicago)
report:
As reported in Butler et al. (GCN 2007), Chandra LETGS observations
commenced on March 29.112 (t[burst] + 15.33 hr) of a field centered
on the HETE WXM+SXC error region (Villasenor et al, GCN 1978) for
GRB030328. We report here on the first 39.7 ksec of data, which was
taken until March 29.744 (t[burst] + 30.51 hr). The relatively faint
X-ray afterglow reported in GCN 2007 is observed to fade in
brightness according to a power-law with a decay slope of -1.5 +/-
0.3. (This value is consistent with the decay slope value of -1.6
found by Andersen et al. (GCN 1993) in the optical.) The mean
counting rate was 0.023 counts/s (summed over the dispersed signal
from the LETGS, and including the 0th order flux). The source
spectrum, which we derive from our preliminary analysis of the
dispersed LETGS counts, is characterized as follows:
nH = 4.32 x 10^20 cm^(-2), fixed at the Galactic value in the source direction;
dN/dE = A * E^ (-gamma) ph cm^(-2) s^(-1) keV^(-1) ,
over the 0.8-2.7 keV range, with A = 0.0001, and gamma = 1.80
Thus, the mean flux for the 0.8 to 2.7 keV band over the duration of
the Chandra observation was ~1.7 x 10^(-13) ergs cm^(-2) s^(-1).
Our analyses are continuing, and more detailed results will be posted at:
http://space.mit.edu/HETE/
We thank Harvey Tananbaum for his generous allocation of Director's
Discretion Time to this observation, and the Chandra X-ray
Observatory Operations personnel for the impressive promptness with
which this observation was planned and carried out.
The preliminary results reported here may be cited.
- GCN notice #2036
P. Garnavich (Notre Dame), P. Martini (OCIW), and K.Z. Stanek (CfA)
We imaged the optical afterglow of GRB 030328 (Peterson & Price,
GCN 1974) with the Magellan 6.5-m Clay telescope and LDSS2
imaging/spectrograph on March 30.04 (1.57 days after the
burst). The 2x180 sec R-band images provide a magnitude
estimate of 21.93 +\- 0.06 assuming star "B" (GCN 1977)
is R=16.10. Using the Magellan photometry from March 29
(Martini et al. GCN 1979), we find a powerlaw decay index of
-1.3 +/- 0.1.
Our R-band magnitude estimate 1.57 days after the burst is close
to that predicted by Price & Peterson (GCN 1977) based
on early photometry and a decay index of -1.0.
This message may be cited.
- GCN notice #2076
GRB030328: Full Observation, X-ray Fading and Spectrum Measured with Chandra
N. R. Butler, H. L. Marshall, P. G. Ford, R. K. Vanderspek, G. R.
Ricker (MIT), J. G. Jernigan (U.C. Berkeley), and D. Q. Lamb (U. Chicago)
report:
We have analyzed the full 94.0 ksec (livetime) Chandra LETGS
observation of GRB030328 (Villasenor et al, GCN1978), lasting from
March 29.112 (t[burst] + 15.33 hr) until March 30.278 (t[burst] +
43.32 hr). The mean counting rate for the X-ray afterglow (Butler et
al. GCN2007) is 0.012 counts/s (summed over the dispersed signal from
the LETGS, and including the 0th order flux). We observe that the
brightness over the full observation decays with a slope -1.5 +/-
0.1, consistent with the value reported by Ford et al. (GCN2027).
(The chi^2 is 34.27 for 30 degrees of freedom, and the fit is
rejectable at only 73% confidence.) We see no evidence for a
temporal break. We fit the dispersed LETGS counts (+/-1 orders
summed) and the counts in 0th order jointly by minimizing chi^2,
requiring 12 or more counts per spectral bin. In the 0.5 to 3.0 keV
band, the data are well fit (chi^2/nu=48.45/48, rejectable at 54%
confidence) by an absorbed power-law:
dN/dE = A * E^ (-gamma) * exp(-NH * sigma[E]) ,
where NH = ( 5 +/- 3 ) x 10^20 cm^(-2) is the line of sight column
density, which is consistent with the anticipated galactic absorption
in the source direction; A = ( 6.8 +/- 0.9 ) x 10^(-5) ph cm^(-2)
s^(-1) keV^(-1); and gamma = 1.7 +/- 0.2 . These are 1 parameter
1-sigma confidence intervals.
Integrating the above model over the 0.5 to 3.0 keV band, the mean
flux for the duration of the Chandra observation is ~1.9 x 10^(-13)
ergs cm^(-2) s^(-1).
Our analyses are continuing, and more detailed results will be posted at:
http://space.mit.edu/HETE/
We thank Harvey Tananbaum for his generous allocation of Director's
Discretion Time to this observation, and the Chandra X-ray
Observatory Operations personnel for the impressive promptness with
which this observation was planned and carried out.
The preliminary results reported here may be cited.
- GCN notice #2103
V. Lipunov, A. Krylov, V. Kornilov, G. Borisov, A. Belinski,
I. Chilingarian, D. Kuvshinov, M. Kuznetsov, S. Potanin, V. Vitrischak
Sternberg Astronomical Institute, Alexsandr Krylov Observatory, Moscow
report:
We had been observing the OT of GRB030328 (HETE #2650, Peterson and Price,
GCN 1974) from 17:16UT 28/03/2003 (~5h after GRB) to 00:35UT 29/03/2003
(~13h after GRB). Sky conditions were quite poor, because of low position
of the object (25 degrees above the horizont at culmination). We obtained
about 70 one- to 3-minute exposures in R filter. There is no OT on the sum
of exposures for the 1-st hour of observations up to 17.7 R magnitude (3
sigma). There is no OT on the sum of all images up to 18.3 R magnitude (3
sigma).
It agrees with the powerlaw index alpha=-1 (GCN 1977, Peterson and Price).
Summarized images avaliable at:
http://observ.pereplet.ru/images/grb030328_1.gif - 1-st hour sum,
http://observ.pereplet.ru/images/grb030328_f.gif - whole sum
This message may be cited.
- GCN notice #2114
A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:
We have acquired UBVRcIc all-sky photometry for
a 11x11 arcmin field centered at the coordinates
of the optical transient (Peterson and Price, GCN 1974)
for the HETE burst GRB030328 (GCN 1978)
with the USNOFS 1.0-m telescope on one photometric
night. Stars brighter than V=13.0 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/grb030328.dat
The astrometry in this file is based on linear plate solutions
with respect to UCAC2. The external errors are less than 100mas.
The external photometric errors are approximately 0.03mag
at this stage.
Because of scattering from the two bright stars to the south of the
optical transient, this file has many false stars. You should carefully
match the RA,DEC of any object against USNO-B to ensure that the
object is real.
There is now a README file in that directory that gives
generic observational information and file formats.
We will most likely obtain an additional night of photometry
in a week or two when the moon is no longer a concern.
As always, you should check the dates on the .dat file prior to
final publication to get the latest photometry.
- GCN notice #2192
M.A. Ibrahimov, I.M. Asfandiyarov, B.B. Kahharov (UBAI), A.Pozanenko (IKI),
V.Rumyantsev (CrAO), G.Beskin (SAO) on behalf of large collaboration
report:
We have observed the OT of GRB030328 (Peterson and Price, GCN 1974) on
Mar.29 with 1.5m telescope of Mt.Maidanak High-altitude Observatory (UBAI).
Using star "A" as a reference (GCN 1975) and photometry by A.Henden (GCN
2114) we estimate the OT magnitudes:
Mid time (UT)
Mar.29 exposure filter mag err
18:00 5x300 B 22.77 0.43
18:48 5x300 R 22.10 0.28
Obtained R-magnitude is consistent with the measurement by P. Garnavich et
al. (GCN 2036).
This message may be cited.
- astro-ph/0601293 from 13 Jan 2006
Maiorano: The broadband afterglow of GRB 030328
We here report on the photometric, spectroscopic and polarimetric monitoring
of the optical afterglow of the Gamma-Ray Burst (GRB) 030328 detected by
HETE-2. We found that a smoothly broken power-law decay provides the best fit
of the optical light curves, with indices alpha_1 = 0.76 +/- 0.03, alpha_2 =
1.50 +/- 0.07, and a break at t_b = 0.48 +/- 0.03 d after the GRB. Polarization
is detected in the optical V-band, with P = (2.4 +/- 0.6)% and theta = (170 +/-
7) deg. Optical spectroscopy shows the presence of two absorption systems at z
= 1.5216 +/- 0.0006 and at z = 1.295 +/- 0.001, the former likely associated
with the GRB host galaxy. The X-ray-to-optical spectral flux distribution
obtained 0.78 days after the GRB was best fitted using a broken power-law, with
spectral slopes beta_opt = 0.47 +/- 0.15 and beta_X = 1.0 +/- 0.2. The
discussion of these results in the context of the "fireball model" shows that
the preferred scenario is a fixed opening angle collimated expansion in a
homogeneous medium.
- astro-ph/0604093 from 5 Apr 2006
Maiorano: Physics of the GRB 030328 afterglow and its environment
We report on the photometric, spectroscopic and polarimetric, monitoring of
the optical afterglow of Gamma-Ray Burst (GRB) 030328 detected by HETE-2.
Photometry, collected at 7 different telescopes, shows that a smoothly broken
powerlaw decay, with indices alpha_1 = 0.76 +/- 0.03, alpha_2 = 1.50 +/- 0.07
and a break at t_b = 0.48 +/- 0.03 days after the GRB, provides the best fit of
the optical afterglow decline. This shape is interpreted as due to collimated
emission, for which we determine a jet opening angle theta_{jet} of about 3.2
degrees. An achromatic bump starting around 0.2 d after the GRB is possibly
marginally detected in the optical light curves. Optical spectroscopy shows the
presence of two rest-frame ultraviolet metal absorption systems at z = 1.5216
+/- 0.0006 and at z = 1.295 +/- 0.001, the former likely associated with the
GRB host galaxy. Analysis of the absorption lines at z = 1.5216 suggests that
the host of this GRB may be a Damped Lyman-alpha Absorber. The optical V-band
afterglow appears polarized, with P= (2.4 +/- 0.6) % and theta = (170 +/- 7)
degrees, suggesting an asymmetric blastwave expansion. An X-ray-to-optical
spectral flux distribution of the GRB 030328 afterglow was obtained at 0.78
days after the GRB and fitted using a broken powerlaw, with an optical spectral
slope beta_{opt} = 0.47 +/- 0.15, and an X-ray slope beta_{X} = 1.0 +/- 0.2.
The discussion of these results in the context of the "fireball model" shows
that the preferred scenario for this afterglow is collimated structured jet
with fixed opening angle in a homogeneous medium.