//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6466 SUBJECT: GRB 070529: Swift detection of a burst with an optical aterglow DATE: 07/05/29 13:13:10 GMT FROM: David Palmer at LANL S. T. Holland (CRESST/GSFC/USRA), L. M. Barbier (NASA/GSFC), S. D. Barthelmy (GSFC), P. J. Brown (PSU), S. Campana (INAF-OAB), G. Cusumano (INAF-IASFPA), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), O. Godet (U Leicester), C. Gronwall (PSU), C. Guidorzi (Univ Bicocca&INAF-OAB), H. A. Krimm (GSFC/USRA), V. La Parola (INAF-IASFPA), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), J. P. Osborne (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (Univ. Bicocca & INAF-OAB), G. Sato (GSFC/ISAS), B. Sbarufatti (INAF-IASFPA), R. L. C. Starling (U Leicester), G. Tagliaferri (INAF-OAB), E. Troja (INAF-IASFPA), D. E. Vanden Berk (PSU), S. D. Vergani (DIAS-DCU), L. Vetere (PSU) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team: At 12:48:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070529 (trigger=280706). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 283.750, +20.639 which is RA(J2000) = 18h 55m 00s Dec(J2000) = +20d 38' 21" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure at least 40 seconds long. The peak count rate was ~1500 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 12:50:39 UT, 131 seconds after the BAT trigger. XRT found a moderately bright, uncatalogued X-ray source. From downlinked data, we determined the position RA, Dec 283.7427, +20.6586 which is RA(J2000) = 18h 54m 58.26s Dec(J2000) = +20d 39' 31.04" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 76 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 7.2e-10 erg/cm2/s (0.2-10 keV). UVOT took a finding chart exposure of 400 seconds with the V filter starting 134 seconds after the BAT trigger. There is an afterglow candidate with V=17.4 mag located at RA, Dec 283.7425, +20.6594 which is RA(J2000) = 18h 54m 58.19s Dec(J2000) = 20d 39' 34.0" with an uncertainty of 0.5 arcsec (radius, 90% containment). The 2.7'x2.7' sub-image covers 100% of the XRT error circle. No correction has been made for the expected extinction of about 1.0 magnitudes. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6467 SUBJECT: GRB 070529: Xinglong TNT Optical Upper Limit DATE: 07/05/29 16:40:25 GMT FROM: W.K. Zheng at NAOC Y.Q. Lou, X.F. Wang, L.P. Xin, M.Zhai, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng, Y. Urata, and W.K. Zheng on behalf of EAFON report: We have imaged the field of GRB 070529 (Holland et al., GCN 6466) with the Xinglong TNT 80cm telescope. Observation was performed with V and R band. We noticed this was a crowded field and we didn't detect the OT (Holland et al., GCN 6466) in our combined images, the R band 3 sigma upper limit is ~20.1 derived from USNO-B1.0 with mean time 2.03 hours after the burst. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6468 SUBJECT: GRB 070529, Swift-BAT refined analysis DATE: 07/05/29 18:10:23 GMT FROM: Scott Barthelmy at NASA/GSFC A. Parsons (GSFC), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), S. T. Holland (CRESST/GSFC/USRA), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) on behalf of the Swift-BAT team: Using the data set from T-119 to T+283 sec from the recent telemetry downlink, we report further analysis of BAT GRB 070529 (trigger #280706) (Holland, et al., GCN Circ. 6466). The BAT ground-calculated position is RA, Dec = 283.725, 20.648 deg which is RA(J2000) = 18h 54m 54.0s Dec(J2000) = 20d 38' 54" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 16%. The mask-weighted lightcurve shows multiple overlapping peaks starting at T_0 and lasting out T+120 sec. There is a possible (~4 sigma) 10-sec peak at ~T-55 sec. T90 (15-350 keV) is 109 +- 3 sec (estimated error including systematics). The time-averaged spectrum from T-1.2 to T+120.9 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.38 +- 0.16. The fluence in the 15-150 keV band is 2.6 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+2.02 sec in the 15-150 keV band is 1.4 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6469 SUBJECT: GRB 070529: Swift-XRT refined analysis DATE: 07/05/29 18:42:41 GMT FROM: Boris Sbarufatti at INAF-IASF-Pa V. Mangano, B. Sbarufatti, V. La Parola (INAF-IASFPA), S. T. Holland (CRESST/USRA/GSFC) report on behalf of the Swift XRT team: We have analysed the first two orbits of XRT data of GRB 070529 (Holland et al., GCN Circ. 6466) with total exposure time of 3.6 ks in Photon Counting mode. The XRT position calculated on the second orbit data only, in order to avoid pile-up effects is: RA(J2000) = 18h 54m 58.2s Dec(J2000) = 20d 39' 31.5" with an uncertainty of 3.8 arcsec (radius, 90% containment). This is 0.9 arcsec from the initial X-ray position, 69 arcsec from the BAT refined position (Parsons et al., GCN Circ. 6468), and 2.3 arcsec from the UVOT position (Holland et al., GCN Circ. 6466). The XRT light curve follows a power-law decay with index 0.91 ± 0.05 up to T+7 ks. We extracted a spectrum of the PC data which can be fitted with an absorbed power law with photon index of 2.2 ± 0.2 and column density of (3.5+/-0.8) E21 cm-2, slightly in excess with respect to the Galactic absorption column (1.9E21 cm-2; Dickey & Lockman, 1990). The absorbed (unabsorbed) 0.3-10.0 keV average flux in the T+150 s - T+7 ks time interval is 1.6E-11 (2.8E-11) ergs cm-2 s-1. Assuming that the source continues its decay at the present rate, we predict an XRT count rate of 8.6E-3 counts/s at T+24 h, which corresponds to an observed flux of 7E-13 ergs cm-2 s-1. This circular is an official product of the Swift XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6470 SUBJECT: GRB 070529: Gemini Redshift DATE: 07/05/29 20:55:06 GMT FROM: Edo Berger at Carnegie Obs E. Berger (Carnegie), D. B. Fox and A. Cucchiara (Penn State) report: "Starting on 2007 May 29.59 UT we used GMOS on the Gemini North telescope to obtain a 900 sec spectrum of the afterglow of GRB 050729 (GCN 6466). The spectrum covers the wavelength range 5000-7900A. We find several strong absorption features corresponding to CIV, SiII, FeII, AlII, AlIII, etc. at a redshift of z=2.4996, which we identify as the redshift of the burst. At this redshift the observed fluence of 2.6e-6 erg/cm^2 (GCN 6468) translates to an isotropic equivalent energy of 3.8e52 erg." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6471 SUBJECT: GRB 070529: Optical aterglow from MIRO DATE: 07/05/29 21:19:20 GMT FROM: Kiran S Baliyan at Physical Research Lab, Ahmedabad,India K.S. Baliyan, S. Ganesh and Priyanksha (MIRO-PRL, Ahmedabad, India) report: We observed the field around the location of GRB070529 (18h 54m 58.19s, 20d 39' 34.0"), BAT trigger no. 280706, at 14:48:28 UT as reported by S. T. Holland on behalf of the Swift Team (GCN 6466). We started observations at 18:10:08 UT with 1296*1152 CCD mounted on the 1.2 M telescope of the Mt. Abu IR Observatory, Gurushikhar, Mount Abu, Rajasthan, operated by Physical Research Laboratory, Ahmedabad- India, in VR bands. A total of 12 images of 180 seconds exposure in R and 5 images in V band were taken. The visual inspection shows a very faint source near the above location in a very crowded field. Details will be reported after proper analysis of all the images. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6472 SUBJECT: GRB 070529: MARGE Observations DATE: 07/05/30 02:38:59 GMT FROM: Heather Swan at U.of Michigan/ROTSE H. Swan (U Mich), I. Smith (Rice), C. Akerlof (U Mich), and M. Skinner (Boeing) report on behalf of the MARGE collaboration: The AEOS Burst Camera (ABC) on the AEOS telescope, located at the Maui Space Surveillance System on Haleakala, observed the fading counterpart to GRB070529 (Swift trigger 280706 (GCN 6466)). The images are unfiltered 10s exposures which started less than 30 minutes after the trigger and ended ~ 2 hours later. We detect the OT first identified by S. T. Holland et al (GCN 6466). A preliminary analysis gives a magnitude of approximately 19.41 +/-0.04 at 13:20:35 UT. We calibrated the OT to the USNO-B1.0 R2 band magnitude of the nearby 17.35 mag star located at (J2000) RA = 283.73991, DEC = 20.657206. We find that the ABC data fades as a power law decay with index ~-1.1. Further analysis is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6473 SUBJECT: Swift/UVOT refined analysis of GRB070529 DATE: 07/05/30 14:37:07 GMT FROM: Massimiliano de Pasquale at MSSL-UCL M. De Pasquale (MSSL/UCL) and S. T. Holland (CRESST/USRA/GSFC) report, on the behalf of Swift UVOT team: The Swift Ultraviolet/Optical telescope (UVOT) began its initial V-band finding chart exposure of GRB070529 (Holland et al., GCN circ. 6466) 134 seconds after the trigger and the optical afterglow is clearly detected inside the refined XRT error circle (Mangano et al., GCN circ. 6469). Successively, the optical source appears to fade with a decay slope, based on the V band datapoints, of about -1.8. In the following table, we report the magnitudes and 3 sigma upper limits for this source. Errors are at 1 sigma level. Filter Time (s) Exp(s) Mag V 134-534 393 17.1 +/- 0.1 V 652-1253 420 19.3 +/- 0.4 V 40339-47072 2039 > 20.4 B 613-758 20 > 18.8 U 588-6277 439 > 20.1 UW1 564-7038 459 > 20.5 UM2 540-7038 592 > 20.8 UW2 628-6687 432 > 21.0 No observation was performed in the white filter, due to the crowded field. No correction has been made for the considerable Galactic reddening toward the burst, E(B-V)=0.3 (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6474 SUBJECT: GRB 070529: SARA upper limit DATE: 07/05/30 22:04:44 GMT FROM: Adria C. Updike at Clemson U A. C. Updike and D. H. Hartmann (Clemson University) report on behalf of the Clemson GRB Follow-Up Team: We observed the field of GRB 070529 (GCN 6466, Holland et al.) with the 0.9m SARA telescope at KPNO. Under decent weather conditions, we imaged the field from 06:14:58 UT, 17 hours and 26 minutes after the burst, until 07:52:12 UT. We obtained a total of 50 min of R-band exposures. In the stacked image at the location of the afterglow identified in UVOT observations (GCN 6466), we detect no new object to a limiting magnitude of R = 19.0 +/- 0.2. The SARA Homepage can be found at: http://saraobservatory.org This message may be cited.