This file contains both GRBs 060223A and 060223B. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4813 SUBJECT: GRB 060223: Swift detection of a burst DATE: 06/02/23 06:29:33 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (NASA/ORAU), S. D. Barthelmy (NASA/GSFC), P. T. Boyd (NASA/GSFC), D. N. Burrows (PSU), M. Capalbi (ASDC), M. M. Chester (PSU), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. Perri (ASDC) report on behalf of the Swift Team: At 06:04:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060223 (trigger=192059). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 55.216, -17.139 {03h 40m 52s, -17d 08' 19"} (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 ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began taking data at 06:05:49 UT, 86 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image and no prompt position is available. We are waiting for down-linked data to detect and determine a position for the source. In response to the Swift/BAT trigger 192059, UVOT took a finding chart exposure of nominally 200 seconds with the V filter starting 86.5 seconds after the BAT trigger. There is a candidate afterglow in the sub-imagae and the list of sources generated on-board at (RA,DEC) (J2000) of (55.2065, -17.1301) with a 1-sigma error radius of about 1 arcsec. This position is 45.9 arcsec from the center of the BAT error circle. The estimated V magnitude is 17.6 with a 1-sigma error of about 0.5 mag. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4814 SUBJECT: GRB 060223: Swift/UVOT Confirmation of Optical Afterglow DATE: 06/02/23 08:08:32 GMT FROM: Padi Boyd at GSFC F. Marshall (GSFC) P. Boyd (GSFC), M. Chester (PSU), J. Cummings (ORAU) on behalf of the Swift/UVOT team report: We have further analyzed the four individual finding chart sub-images sent via TDRSS from the Swift UVOT containing the afterglow of GRB 060223 (Cummings et al., GCN 4813). The source is detected in the first 3 finding charts with an upper limit in the fourth finding chart as follows: Filter T_start(s) Exp(s) (mag/UL (detection significance)) V 86 200 18.0 +/- 0.14 (10 sigma) B 293 200 21.0 0.5 (2.5 sigma) V 835 200 19.6 0.4 (3.5 sigma) B 1042 200 >21.3 (2 sigma) Reported times are in seconds since the BAT trigger. These magnitudes are uncorrected for the expected Galactic extinction corresponding to E(B-V) = 0.12. We note that the higher than expected B-V inferred from the first three images could be caused by a redshift of z=3.3 or greater. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4815 SUBJECT: GRB 060223: Keck redshift DATE: 06/02/23 08:19:49 GMT FROM: Edo Berger at Carnegie Obs E. Berger (Carnegie), S. R. Kulkarni, A. Rau (Caltech), and D. B. Fox (Penn State) report on behalf of a large collaboration: "Starting on 2006, Feb 23.2875 UT (39 min after the burst) we obtained spectroscopic observations of the optical afterglow of GRB 060223 (GCNs 4813,4814) using LRIS on the Keck-I 10-m telescope. In a single 720 sec exposure we detect a broad absorption profile which we identify as Lyman-alpha at a redshift z=4.41, as well as metal absorption features from OI, SiII, SiII*, etc at the same redshift." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4820 SUBJECT: GRB 060223: Swift-BAT refined analysis DATE: 06/02/23 19:34:30 GMT FROM: Scott Barthelmy at NASA/GSFC J. Cummings (GSFC/NRC), S. Barthelmy (GSFC), L. Barbier (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC) on behalf of the Swift-BAT team: Using the partial data set from T-300 to T+302 sec from telemetry downlinks, we report further analysis of BAT GRB 060223 (trigger #192059) (Cummings, et al., GCN 4813; Marshall et al, GCN 4814). The BAT ground-calculated position is RA,Dec = 55.188,-17.130 deg {3h 40m 45.1s, -17d 7' 46.6"} (J2000) +- 1.2 arcmin, (radius, sys+stat, 90% containment). The BAT error circle contains the afterglow detected by UVOT (GCN 4813). The partial coding was 69%. The mask-weighted light curve shows a single episode of emission from T-4 to T+10 sec. There is a possible broad, faint precursor at ~T-25 sec, but no significant emission after T+10 sec. T90 (15-350 keV) is 11 +- 2 sec (estimated error including systematics). The time-averaged spectrum from T-2.9 to T+10.0 is best fit by a simple power-law model. The power-law index of the time-averaged spectrum is 1.74 +- 0.12. The fluence in the 15-150 keV band is 6.8 +- 0.5 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+0.08 sec in the 15-150 keV band is 1.4 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. Given the redshift reported for this burst (Berger et al, GCN 4815), z = 4.41, we calculate Eiso = 2.82 10^52 ergs in the 81-812 keV band in the rest frame of the source. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4821 SUBJECT: GRB 060223B: Swift detection of a bright burst DATE: 06/02/23 20:01:52 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift 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".] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4823 SUBJECT: GRB 060223: Swift XRT Team preliminary analysis DATE: 06/02/23 21:25:26 GMT FROM: Milvia Capalbi at ISAC/ASDC M. Capalbi, M. Perri, L. Vetere (ASDC), K.L. Page (U. Leicester), J. Kennea and D. Burrows (PSU) report on behalf of the Swift XRT team: We have analysed the Swift XRT data from the first seven orbits observation of GRB 060223 (Cummings et al. GCN 4813). We find an uncatalogued fading source at the following location: RA(J2000) = 03h 40m 49.74s Dec(J2000) = -17d 07' 48.0" We estimate an uncertainty of 3.7 arcseconds radius (90% containment). This position is 44 arcsec from the BAT position and 2.6 arcsec from the UVOT position given in GCN 4813. The large flare in the first orbit makes determination of an afterglow slope and extrapolation of the flux unreliable, and we will have to wait for further data before an afterglow slope can be established. A preliminary spectral fit to the Photon Counting mode data with an absorbed power law gives a photon index of 1.9 ± 0.3 and NH consistent with the Galactic value (5.92E+20 cm^-2). This circular is an official product of the Swift XRT Team. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4824 SUBJECT: GRB 060223a: Swift/UVOT refined analysis DATE: 06/02/24 02:02:39 GMT FROM: Alexander Blustin at MSSL-UCL A. J. Blustin (UCL-MSSL), J. R. Cummings (NASA/ORAU) report on behalf of the Swift/UVOT team: The Swift/UVOT began observing the field of GRB 060223a 72 s after the BAT trigger, detecting a red afterglow (Cummings et al., GCN 4813; Marshall et al., GCN 4814). Analysis of a more complete dataset shows that V was the only band to yield a significant detection of the afterglow, as to be expected given the redshift of the burst (z=4.41; Berger et al., GCN 4815). The magnitudes and 3-sigma upper limits from all filters are listed below. Filter T_range (MET) Exp (s) Mag/3sigUL V 72-81 9 17.7 +/- 0.4 V 85-285 200 17.8 +/- 0.1 V 545-1034 239 19.4 +/- 0.3 V 1294-11097 512 >19.6 B 292-492 200 >20.2 B 641-7249 731 >20.9 U 616-7044 532 >20.4 UVW1 593-6839 355 >20.4 UVM2 569-6634 355 >20.9 UVW2 521-10892 580 >21.1 These are uncorrected for the estimated Galactic extinction corresponding to E(B-V) = 0.12 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4825 SUBJECT: GRB 060223B: Swift-BAT refined analysis DATE: 06/02/24 03:13:31 GMT FROM: Hans Krimm at NASA-GSFC 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4826 SUBJECT: GRB 060223B: ART optical limits DATE: 06/02/24 04:50:21 GMT FROM: Ken ichi Torii at RIKEN 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 ================================ //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4827 SUBJECT: GRB 060223A:Xinglong optical limits DATE: 06/02/24 06:43:24 GMT FROM: W.K. Zheng at NAOC M.Zhai, W.K. Zheng, Y.L. Qiu, J.Y. Wei,J.Y. Hu and J.S Deng, report on behalf of the Xinglong GRB follow-up team: We observed the field of the GRB 20060223A(Cummings et al.GCN 4813)with the 0.8m telescope at Xinglong Observatory, National Astronomical Observatories,Chinese Academy of Sciences. We began observations on Feb 23.4787 UT, 5.4158 hours after the trigger without any filter. Within 600s exposure image we do not see the optical counterpart(Cummings et al.GCN 4813) down to 19.5 with 3-sigma detection. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4835 SUBJECT: GRB 060223B: Swift XRT possible afterglow DATE: 06/02/25 21:22:25 GMT FROM: Matteo Perri at ISAC/ASDC 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4839 SUBJECT: GRB 060223b: Swift/UVOT Upper Limits DATE: 06/02/27 15:33:11 GMT FROM: Patricia Schady at MSSL/Swift 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4844 SUBJECT: GRB060223b: optical limit DATE: 06/02/28 10:55:47 GMT FROM: Alexei Pozanenko at IKI, Moscow 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