GRB 060223B
GCN Circular 4844
Subject
GRB060223b: optical limit
Date
2006-02-28T10:55:47Z (21 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
M. Andreev (Institute of Astronomy), A. Pozanenko (IKI) on behalf of
larger GRB follow up collaboration report:
We observed the field of GRB060223b (Cummings et al. GCN 4821) in V-band
with the 60 cm telescope of peak Terskol observatory on Feb. 24 between
(UT) 02:24-02:41. No new source is detected in comparison of combined
image (18x60 s) with DSS2(R) at the refined XRT position (Perri et al. GCN
4835) and in a larger refined BAT position (Fenimore et al. GCN 4825).
The limiting magnitude is determined in comparison with USNO A2.0 (R):
Mid time, exp., mag.(UL)
(UT) (s)
Feb. 24 02:33 18x60 19.0
GCN Circular 4839
Subject
GRB 060223b: Swift/UVOT Upper Limits
Date
2006-02-27T15:33:11Z (21 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P. Schady (PSU/MSSL-UCL), J.R. Cummings (NASA/ORAU), P.Brown (PSU), A.
Cucchiara (PSU) on behalf of the Swift/UVOT team
The Swift/UVOT began observing the field of GRB 060223b at 16:23:16 UT on 24th
February 2006, ~22hrs after the BAT trigger (Cummings et al. GCN 4821).
Due to the proximity of a Mira variable star (~5th mag) observations were
not made in the V or B filters. No source is detected at the refined XRT
position (Perri et al. GCN 4835) in any of the other filters. The 3 sigma
upper limits from a set of three coadded exposures in each filter are as
follows:
Filter T_mid(hrs) Exp(s) 3sigUL(mag)
U 22.6 2300 20.5
UVW1 22.0 2522 20.8
UVM2 21.8 2524 21.1
UVW2 21.1 2524 21.3
T_mid is the mid-time of the set of coadded images relative to the time since
the BAT trigger. We note that this is a very crowded field with a high level of
Galactic extinction (E(B-V) = 0.393). All reported magnitudes are uncorrected
for Galactic extinction.
GCN Circular 4835
Subject
GRB 060223B: Swift XRT possible afterglow
Date
2006-02-25T21:22:25Z (21 years ago)
From
Matteo Perri at ISAC/ASDC <perri@asdc.asi.it>
M. Perri, M. Capalbi, L. Vetere (ASDC) L.A. Antonelli (ASDC/INAF-OAR),
G. Tagliaferri (INAF-0AB), D.N. Burrows (PSU) and J.R. Cummings
(GSFC/ORAU) report on behalf of the Swift XRT team:
The Swift XRT began observing the field of GRB 060223B (trigger #192152,
Cummings et al., GCN 4821) at 2006-02-24 14:46:47 UT, approximately 19
hours after the BAT trigger. In a first XRT exposure of ~10 ks we find a
marginal detection (5 net photons, SNR=2) of a faint uncatalogued X-ray
source at the following coordinates:
RA(J2000) = 16h 56m 58.8s
Dec(J2000) = -30d 48' 46" is
with an estimated uncertainty of 10 arcseconds (90% containment).
This position lies 30 arcseconds from the BAT refined position reported
by Fenimore et al. (GCN 4825).
The PSF corrected count rate is (7.5 +/- 3.9)e-4 cts/s, corresponding to
an unabsorbed 0.3-10 keV flux of about 5e-14 erg/cm2/s assuming a
power law spectrum with a photon index of 2 and Galactic absorption
of 1.8e21 cm^-2.
In a second exposure of about 9 ks, starting ~29 hours after the
trigger, the source is not detected.
We note that due to the small number of counts this source could be
a statistical fluctuation of the background and should be regarded as
a possible X-ray afterglow candidate.
This circular is an official product of the Swift XRT Team.
GCN Circular 4826
Subject
GRB 060223B: ART optical limits
Date
2006-02-24T04:50:21Z (21 years ago)
From
Ken ichi Torii at RIKEN <torii@ess.sci.osaka-u.ac.jp>
K. Torii (Osaka U.) reports on behalf of the ART collaboration:
The error region of GRB 060223B (Cummings et al. GCN 4821) was
observed with the 0.35m ART-3b in Toyonaka, Osaka. Repeated 60 s
exposures in BVRcIc were started at 19:43:39 UT (155 s after the BAT
trigger).
Preliminary analysis does not reveal a new object within the revised
BAT error radius (Fenimore et al. GCN 4825) and the following 3 sigma
upper limits are derived with reference to USNO-B1.0 catalog.
--------------------------------
StartUT Limits
================================
19:43:39 >12.5I (trailed)
19:46:31 >13.7R
19:47:36 >13.3I
================================
GCN Circular 4825
Subject
GRB 060223B: Swift-BAT refined analysis
Date
2006-02-24T03:13:31Z (21 years ago)
From
Hans Krimm at NASA-GSFC <krimm@milkyway.gsfc.nasa.gov>
E. Fenimore (LANL), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/ORAU), N. Gehrels (GSFC), D. Hullinger (UMD),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (ISAS),
J. Tueller (GSFC) report on behalf of the Swift-BAT team:
Using the data set from T-302 to T+110 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 060223B (trigger #192152)
(Cummings, et al., GCN 4821). The BAT ground-calculated position is
(RA,Dec) = 254.240, -30.820 deg {16h 56m 57.7s, -30d 49' 10.8"} (J2000)
+- 0.7 arcmin, (radius, sys+stat, 90% containment). The partial coding
was 67%.
The mask-weighted light curve shows a single broad peak from T-8 to T+6
with several subpeaks on top. There is no obvious spectral evolution
visible. In the lowest energy band, low-level emission extends out to T+50
secs. T90 (15-350 keV) is 10.2 +- 1 sec (estimated error including
systematics). Due to a preplanned slew, the BAT FOV moved away from the
burst at about T+110 sec, and no information is available about any
possible extended emission after that time.
The time-averaged spectrum from T-7.0 to T+4.9 is best fit by a simple
power-law model. The power-law index of the time-averaged spectrum is
1.49 +- 0.07. The fluence in the 15-150 keV band is
1.6 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from
T+3.0 sec in the 15-150 keV band is 2.9 +- 0.2 ph/cm2/sec. All the
quoted errors are at the 90% confidence level.
GCN Circular 4821
Subject
GRB 060223B: Swift detection of a bright burst
Date
2006-02-23T20:01:52Z (21 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <jayc@milkyway.gsfc.nasa.gov>
J. R. Cummings (NASA/ORAU), S. D. Barthelmy (GSFC), D. N. Burrows
(PSU), M. M. Chester (PSU), A. Cucchiara (PSU), J. A. Kennea (PSU),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer
(LANL), M. Perri (ASDC), L. Vetere (ASDC) and H. Z. Ziaeepour
(UCL-MSSL) report on behalf of the Swift Team:
At 19:41:04 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060223B (trigger=192152). Swift did not slew due to a
moon constraint. The BAT on-board calculated location is
RA,Dec 254.241, -30.807 {16h 56m 58s, -30d 48' 24"} (J2000)
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 15 sec. The peak count rate
was ~6000 counts/sec (15-350 keV), at ~3 sec after the trigger.
We anticipate that the narrow-field instruments will be able to
observe the burst at about T+18 hours.
[GCN OPS NOTE(23feb06): Per author's request, "060223" was changed to "060223B".]