//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6232 SUBJECT: GRB 070330: Swift detection of a burst DATE: 07/03/30 23:22:06 GMT FROM: Scott Barthelmy at NASA/GSFC D. Grupe (PSU), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), M. M. Chester (PSU), C. Guidorzi (Univ Bicocca&INAF-OAB), S. T. Holland (CRESST/GSFC/USRA), J. A. Kennea (PSU), C. B. Markwardt (GSFC/UMD), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), B. Sbarufatti (INAF-IASFPA), M. Stamatikos (NASA/ORAU) and M. C. Stroh (PSU) report on behalf of the Swift Team: At 22:51:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070330 (trigger=273180). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 269.519, -63.779 which is RA(J2000) = 17h 58m 05s Dec(J2000) = -63d 46' 44" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 10 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began taking data at 22:52:39 UT, 68 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source, however analysis of TDRSS data reveals a bright, fading uncatalogued point source at RA, Dec 269.5407, -63.7933 which is: RA(J2000) = 17h 58m 09.8s Dec(J2000) = -63d 47' 35.7" with an estimated uncertainty of 3.8 arcseconds radius (90% confidence). This position lies 62 arcsec from the BAT position. UVOT took a finding chart exposure of 400 seconds with the V filter starting 65 seconds after the BAT trigger. Automated source detection did not find an afterglow candidate, but visual inspection suggests a marginal detection at RA, DEC = 269.5418, -63.7930 with an estimated magnitude of 18.6. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction of about 0.2 magnitudes. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6233 SUBJECT: GRB 070330 - Watcher Observations DATE: 07/03/31 01:06:48 GMT FROM: John French at UCD,Ireland J.French (UCD), P.Kubanek (U. Valencia) and M.Jelinek (IAA), report on behalf of the Watcher collaboration: The Watcher 40cm automated telescope at the Boyden Observatory, South Africa, began imaging the field of GRB 070330 (Grupe et al, GCN 6232) at 22:57:40 UTC, 6.15min after the BAT trigger. An initial series of 10s unfiltered exposures shows no new source down to a limiting magnitude of approx. 16 mag. Stacking multiple frames to create a combined 848s exposure with a mean time of 23:06:40 UTC (15.15min post-trigger) fails to reveal any new source down a 3-sigma limiting magnitude of 18.2 mag. Further observations are continuing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6234 SUBJECT: GRB 070330: Swift-XRT refined analysis DATE: 07/03/31 04:43:32 GMT FROM: Dirk Grupe at PSU/Swift-XRT GRB 070330: Swift-XRT refined analysis D. Grupe (PSU) reports on behalf of the Swift/XRT team We have analyzed the first two orbits of GRB 070330 (Grupe et al., GCN 6232) with total observing times of 2.7 ks in photon counting mode in the Swift XRT. The Photon Counting mode image provides a refined XRT position at Ra, Dec= 269.5407, -63.7934, which is RA(J2000) = 17h 58m 09.8s Dec(J2000) = -63d 47' 36.1" with an error of 3.6" (90% confidence). This position is 0.4" away from the preliminary XRT position reported in GCN 6232. The X-ray light curve displays a flare at the beginning of the XRT observation with a peak at about 230s after the burst. The decay slope after the flare is 1.10+/-0.12. The prediction 24h after the burst is a 0.3-10.0 keV flux of 6e-14 ergs/s/cm2 or about 1.3e-3 XRT counts/s. The photon counting mode data can be fitted by a single absorbed power law model with a photon index Gamma=1.72+/-0.11 and an absorption column density consistent with the Galactic value (7.14e20 cm^-2; Dickey & Lockman, 1990). More analysis of the data will be presented in the GCN report. This circular is an official product of the Swift XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6235 SUBJECT: GRB 070330: TAROT La Silla observatory optical observations DATE: 07/03/31 07:22:04 GMT FROM: Alain Klotz at CESR-CNRS Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 070330 detected by SWIFT (trigger 273180) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 2.5 hours after the GRB trigger (the field was not risen when the burst occured). The date of trigger : t0 = 2007-03-30T22:51:30.816 We co-added a series of 180s exposures: We do not detect any OT at the XRT position (Grupe et al. GCNC 6234) with a limiting magnitude of: t0+2.5h to t0+3.5h : R > 17.4 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=329.9005 lat=-18.5620 and the galactic extinction in R band is 2.0 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6236 SUBJECT: GRB 070330, SMARTS optical/IR observations DATE: 07/03/31 18:03:40 GMT FROM: Bethany Cobb at Yale U B. E. Cobb, part of the larger SMARTS consortium, reports: Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 070330 (Grupe et al. GCN 6232) with a mid-exposure time of ~7.6 hours post-burst (2007-03-31 06:25 UT). Total summed exposure times amounted to 36 minutes in I and 30 minutes in J. No source is detected at the position of the X-ray afterglow (Grupe et al. GCN 6234) to approximate limiting magnitudes of I > 20.5 and J > 18.6. Magnitudes are calibrated using USNO-B1.0 values for I, and 2MASS values for J. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6237 SUBJECT: GRB 070330, Swift-BAT refined analysis DATE: 07/03/31 20:25:03 GMT FROM: Craig Markwardt at NASA/GSFC/UMD E. Fenimore (LANL), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), N. Gehrels (GSFC), D. Grupe (PSU), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team: Using the data set from T-240 to T+963 sec from the full telemetry downlink, we report further analysis of BAT GRB 070330 (trigger #273180) (Grupe et al., GCN Circ. 6232). The BAT ground-calculated position is RA, Dec = 269.533, -63.799 deg which is RA(J2000) = 17h 58m 7.9s Dec(J2000) = -63d 47' 54.7" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 80%. The mask weighted light curve consists of a single FRED-like peak. T90 (15-350 keV) is 9.0 +- 1 sec (estimated error including systematics). The time-averaged spectrum from T-1.1 to T+8.9 is best fit by a power law with an exponential cutoff. This fit gives a photon index -0.33 +- 1.76, and Epeak of 36.3 +- 6.1 keV (chi squared 56.05 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.8 +- 0.3 x 10^-07 erg/cm2 and the 1-sec peak flux measured from T-0.06 sec in the 15-150 keV band is 0.9 +- 0.1 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.06 +- 0.22 (chi squared 66.7 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6238 SUBJECT: UVOT observations of GRB070330 DATE: 07/03/31 21:18:15 GMT FROM: Patricia Schady at MSSL/Swift N.P.M. Kuin (MSSL-UCL), D. Grupe (PSU), P. Brown (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began taking data in the field of GRB070330 54s after the BAT trigger (Grupe et al., GCN 6232). The afterglow is only detected in the first UVOT V exposure, with a magnitude of V=18.69+/-0.24, after which the afterglow had decayed below the UVOT detection threshold, suggesting a decay rate of alpha_V > 0.8. The refined UVOT afterglow position is RA (J2000) = 17:58:09.98 (269.5426) Dec (J2000) = -63:47:34.80 (-63.7930) We note that the refined position is 0.5" away from the preliminary UVOT position reported in GCN 6232. The photometry results are given below for the 5 UVOT filters in which observations were made. Due to the presence of a bright star no observations could be obtained in the UVW2 and white filters. Filter Mid_T(s) Exp(s) Mag V 266 393 18.69+/-0.24 V 33978 1632 > 21.45 (3-sigma upper limit) M2 25521 2814 > 18.35 (3-sigma upper limit) ` W1 20282 1998 > 18.36 (3-sigma upper limit) U 25521 2814 > 21.60 (3-sigma upper limit) B 30318 3305 > 18.15 (3-sigma upper limit) Mid_T is the weighted mid time of the exposure since the BAT trigger. These magnitudes are not corrected for the expected reddening of E(B-V)=0.063. For the time being it is not possible to provide a redshift given the low signal-to-noise ratio of the data. Further analysis is ongoing. A high (~4) redshift is possible and we encourage further ground follow-up. [GCN OPS NOte(25aug07): Per UVOT Team request, the Mid_T value for the first V exposure ws changed from 462 to 266. Acknowledgements to F. Marshall.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6307 SUBJECT: GRB070330: Correction to UVOT position DATE: 07/04/19 12:52:41 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL-UCL), D. Grupe (PSU) report on behalf of the Swift/UVOT team An error has been noted in the UVOT position for the optical afterglow of GRB 070330 (GCN 6238). There is a typo in the RA expressed as degrees. The correct refined UVOT afterglow position is RA (J2000) = 17:58:09.98 (269.5416) Dec (J2000) = -63:47:34.80,6 (-63.7930) to a certainty of 0.5".