Gamma-ray Burst 060223B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 23 Feb 06 19:41:22 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     192152,   Seg_Num: 0
GRB_RA:          254.241d {+16h 56m 58s} (J2000),
                 254.340d {+16h 57m 21s} (current),
                 253.441d {+16h 53m 46s} (1950)
GRB_DEC:         -30.807d {-30d 48' 24"} (J2000),
                 -30.816d {-30d 48' 57"} (current),
                 -30.729d {-30d 43' 45"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       6779 [cnts]    Image_Peak=580 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 50-350 keV
BKG_INTEN:       31481 [cnts]
BKG_TIME:        70846.96 SOD {19:40:46.96} UT
BKG_DUR:         8 [sec]
GRB_DATE:        13789 TJD;    54 DOY;   06/02/23
GRB_TIME:        70864.88 SOD {19:41:04.88} UT
GRB_PHI:          27.06 [deg]
GRB_THETA:        27.11 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     40.70 [sigma]
IMAGE_SIGNIF:    16.42 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +3 +15  -1  +1 -19  +1 
SUN_POSTN:       336.89d {+22h 27m 33s}   -9.66d {-09d 39' 29"}
SUN_DIST:         78.71 [deg]   Sun_angle= 5.5 [hr] (West of Sun)
MOON_POSTN:      277.69d {+18h 30m 46s}  -28.45d {-28d 27' 09"}
MOON_DIST:        20.40 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      352.46,  7.62 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      256.37, -8.11 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 120.95,-5.59 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 23 Feb 06 19:44:49 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     192152,   Seg_Num: 0
GRB_RA:          254.241d {+16h 56m 58s} (J2000),
                 254.340d {+16h 57m 21s} (current),
                 253.441d {+16h 53m 46s} (1950)
GRB_DEC:         -30.807d {-30d 48' 24"} (J2000),
                 -30.816d {-30d 48' 57"} (current),
                 -30.729d {-30d 43' 45"} (1950)
GRB_DATE:        13789 TJD;    54 DOY;   06/02/23
GRB_TIME:        70864.88 SOD {19:41:04.88} UT
TRIGGER_INDEX:   146
GRB_PHI:          27.06 [deg]
GRB_THETA:        27.11 [deg]
DELTA_TIME:      -31.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     40.70 [sigma]
IMAGE_SIGNIF:    16.42 [sigma]
LC_URL:          sw00192152000msb.lc
SUN_POSTN:       336.89d {+22h 27m 33s}   -9.66d {-09d 39' 26"}
SUN_DIST:         78.71 [deg]   Sun_angle= 5.5 [hr] (West of Sun)
MOON_POSTN:      277.73d {+18h 30m 55s}  -28.45d {-28d 27' 02"}
MOON_DIST:        20.43 [deg]
MOON_ILLUM:      24 [%]
GAL_COORDS:      352.46,  7.62 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      256.37, -8.11 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 120.95,-5.59 [deg].

GCN Circular #4821
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 060223 (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 Circular #4825
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 #4826
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 #4835
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 #4839
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 #4844
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
```

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Jochen Greiner, last update: 28-Feb-2006 [Disclaimer]