//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5212 SUBJECT: GRB 060604: Swift detection of a burst with possible optical counterpart DATE: 06/06/04 18:46:18 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT M. J. Page (UCL-MSSL), A. J. Blustin (UCL-MSSL), J. R. Cummings (NASA/ORAU), N. Gehrels (NASA/GSFC), O. Godet (U Leicester), J. A. Kennea (PSU), K. M. McLean (LANL/UTD), K. L. Page (U Leicester), G. Sato (GSFC/JSPS/USRA) and M. Stamatikos (NASA/ORAU) report on behalf of the Swift Team: At 18:19:00 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060604 (trigger=213486). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 337.242, -10.905 {22h 28m 58s, -10d 54' 17"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single FRED peak with a duration of about 8 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~3 sec after the trigger. The XRT began observing the field at 18:20:48 UT, 109 seconds after the BAT trigger. XRT found a variable, uncatalogued X-ray source located at RA(J2000) = 22h 28m 54.9s, Dec(J2000) = -10d 55' 03.0", with an estimated uncertainty of 4.7 arcseconds (90% confidence radius). During the first 100s of data, the source shows bright flaring activity. This location is 65 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 2.9e-09 erg/cm2/s (0.2-10 keV). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 117 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at (RA,DEC) (J2000) of (337.2292,-10.9155) or (22h28m55.01s,-10o54'55.8") with a 1-sigma error radius of about 0.6 arc sec. This position is 7.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.0 with a 1-sigma error of about 0.5 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5213 SUBJECT: GRB 060604A: ROTSE-III Optical Limits DATE: 06/06/04 19:06:43 GMT FROM: Brad Schaefer at LSU B. E. Schaefer (Louisiana State) reports on behalf of the ROTSE collaboration: ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to GRB 060604A (Swift trigger 213486), producing images beginning 5.0 s after the GCN notice time. An automated response took the first image at 18:19:59.1 UT, 59.0 s after the burst, under excellent conditions. We took 10 5-sec, 10 20-sec and 20 60-sec eposures, with more ongoing. These unfiltered images are calibrated relative to USNO A2.0 (R). Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma error circle, for both single images and coadding into sets of 10; the field is not crowded. The XRT position and the UVOT position (M. J. Page et al. 2006, GCN 5212) has two faint stars nearby which might mask the fast fading optical transient. Individual images have limiting magnitudes ranging from 15.2-16.9; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 18:19:59.1 18:20:19.1 20 15.8 59.0 N 18:29:37.6 18:41:55.8 738 17.9 637.5 Y //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5214 SUBJECT: GRB 060604: BAT refined analysis DATE: 06/06/05 01:50:02 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift A. Parsons (GSFC), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), M. Koss (GSFC/UMD), C. Markwardt (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/JSPS/USRA), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), on behalf of the Swift-BAT team: Using the data set from T-119.2 to T+182.9 sec from the recent telemetry downlink, we report further analysis of BAT GRB 060604 (trigger #213486) (Page, et al., GCN 5212). The BAT ground-calculated position is (RA,Dec) 337.233, -10.937 deg {22h 28m 55.8s, -10d 56' 14.8"} (J2000) +- 2.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 72%. The burst was very weak in BAT. There was some low-level soft emission over ~25 seconds starting at T-50, followed by the main peak at T+0. T90 (15-350 keV) is 10 +- 3 sec (estimated error including systematics). The time-averaged spectrum from T-1.4 to T+8.3 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.90 +- 0.41. The fluence in the 15-150 keV band is 1.3 +- 0.3 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+2.28 sec in the 15-150 keV band is 0.6 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5215 SUBJECT: GRB 060604: Swift-XRT Team refined analysis DATE: 06/06/05 07:35:45 GMT FROM: Kim Page at U.of Leicester K.L. Page, E. Rol (U. Leicester) and M.J. Page (UCL-MSSL) report on behalf of the Swift-XRT team: We have analysed the first 3 orbits of X-ray data obtained for GRB 060604 (BAT trigger 213486). Using 5.1 ks of Photon Counting (PC) mode data, we find a refined position of: RA(J2000) = 22 28 54.97 Dec(J2000) = -10 54 59.9 with an uncertainty of 3.7 arcsec (90% containment). This is 3.3 and 4.1 arcsec from the on-board XRT and UVOT positions respectively (GCN 5212; Page et al.) and 74.6 arcsec from the ground-calculated BAT position given in GCN 5214 by Parsons et al. The source was at a high enough count-rate to remain in Windowed Timing (WT) mode for the whole of the (short) first orbit (117-255 seconds after the trigger). During this time, the light-curve shows two strong flares, peaking at ~137 and ~172 seconds after the burst. Underlying these flares is a steep decay of alpha_1 = 3.07 +/- 0.20. Between the end of the WT data and the start of the second orbit of (PC) data, there is a break to a much shallower slope of alpha_2 = 0.48 +/- 0.20. The WT flares show clear spectral evolution. The later PC data are well fitted by a single power-law with Gamma = 1.89 +/- 0.14, with no evidence for excess NH above the Galactic value of 4.57e20 cm^-2. (The 90% upper limit for any excess is 7e20 cm^-2.) Assuming the shallow decay contines, at 24 hours the count rate is predicted to be 0.030 count s^-1, corresponding to an observed (unabsorbed) flux of 1.40e-12 (1.57e-12) erg cm^-2 s^-1. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5216 SUBJECT: GRB 060604 optical photometry DATE: 06/06/05 10:27:29 GMT FROM: Nial Tanvir at IofA U.Cambridge N. Tanvir (U. of Hertfordshire), E. Rol (U. of Leicester) and P. Hewett (IoA, Cambridge) report: We imaged the Swift detected burst GRB 060604 (Page et al. GCN 5212) with the AUX-port camera on the WHT at June 5.169 UT. A 300s R-band exposure shows a source at the position of the UVOT counterpart which has apparently faded, thus confirming the afterglow ID. By comparison with the two nearby USNO stars, we estimate a magnitude of R=21.4 with an uncertainty (given the rough calibration) of 0.3 mag. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5218 SUBJECT: GRB 060604: redshift DATE: 06/06/05 12:24:51 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. J. Castro-Tirado, P. Amado (IAA-CSIC Granada), I. Negueruela (U. de Alicante), J. Gorosabel, M. Jelínek and A. de Ugarte Postigo (IAA-CSIC), report: "We have observed the optical afterglow of GRB 060604 (Page et al. GCN Circ. 5212) with the 2.5m Nordic Optical telescope (+ALFOSC) at Observatorio del Roque de los Muchachos (La Palma). Observations consisted of a 150 s V-band exposure with showed a faint object at the location of the proposed Swift/UVOT candidate, in agreement with Tanvir et al. (GCN Circ. 5216), plus a 1200 s exposure spectrum covering the range 3200-9100 A with the grism#4. Based on the presence of a strong continuum break around 4475 A which we identify as due to Ly-alpha, we estimate a redshift of z = 2.68. Further analysis is in progress" This message is citeable. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5219 SUBJECT: GRB060604: Swift/UVOT detections DATE: 06/06/05 14:25:51 GMT FROM: Alexander Blustin at MSSL-UCL A. J. Blustin (UCL-MSSL) and M. J. Page (UCL-MSSL) report on behalf of the Swift/UVOT team: The Swift/UVOT began observing the field of GRB060604 at 18:20:39 on 2006-06-04, 100 s after the BAT trigger (Page et al., GCN 5212). The afterglow candidate at the position reported by Page et al. (GCN 5212) was detected at greater than 2 sigma significance in the V, B, U, UVW1 and White filters. Magnitudes and 3-sigma upper limits from co-added images in the colour filters, and from two single images in the White filter, are given below. The weak detection in the UVW1 band is consistent with the tentative redshift of 2.68 reported by Castro-Tirado et al. (GCN 5218). Filter T_range(s) Exposure(s) Mag/3sig_UL Significance (sigma) V 100-10165 1127 21.2 +/- 0.6 2.4 B 4086-23420 1956 21.2 +/- 0.2 5.8 U 3881-29206 2705 21.1 +/- 0.2 4.4 UVW1 3677-28601 2900 22.1 +/- 0.4 2.8 UVM2 3472-27694 2139 21.1 (3sig_UL) UVW2 4496-6061 321 19.8 (3sig_UL) White 117-217 98 18.3 +/- 0.1 13.4 White 4290-4490 190 20.5 +/- 0.3 3.9 These magnitudes are uncorrected for Galactic extinction (E(B-V) = 0.043). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5253 SUBJECT: GRB 060604, optical observations DATE: 06/06/14 18:24:55 GMT FROM: Peter Garnavich at U of Notre Dame Peter Garnavich and Agata Karska (Notre Dame) We observed the position of GRB 060604 (Page et al., GCN 5212) with the Vatican Advanced Technology Telescope and 2KCCD camera on 2006 June 5.45 UT (16.5 hours after the burst). Six R-band images, each with an exposure time of 120s, were combined and a source detected at the Swift/UVOT position. Using an average of five USNO-B1.0 stars (magR2) to set the zero-point we estimate the brightness of the afterglow at R=21.6 +/- 0.2 mag. This is only slightly fainter than the observation by Tanvir et al. (GCN 5216) six hours earlier and suggests a slow decay or contamination from the host galaxy. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5488 SUBJECT: GRB 060604: VLA Observation DATE: 06/08/29 16:59:36 GMT FROM: Poonam Chandra at U Virginia/NRAO P. Chandra (UVA/NRAO) and D. A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: "We observed the field centered on the BAT position of the Swift burst GRB 060604 (GCN#5215) using the VLA at a frequency of 8.46 GHz and starting at 9.27 UT on Aug 21, about 76 days after the burst. There is no detection of the GRB with 2-sigma upper limit of 130 microJy. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."