//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5409 SUBJECT: GRB 060807: Swift detection of a burst DATE: 06/08/07 15:04:49 GMT FROM: Scott Barthelmy at NASA/GSFC M. De Pasquale (UCL-MSSL), S. D. Barthelmy (GSFC), S. Campana (INAF-OAB), J. R. Cummings (NASA/UMD), O. Godet (U Leicester), C. Guidorzi (Univ Bicocca&INAF-OAB), J. E. Hill (GSFC/USRA), S. T. Holland (GSFC/USRA), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), F. E. Marshall (NASA/GSFC), K. M. McLean (LANL/UTD), K. L. Page (U Leicester), D. M. Palmer (LANL), S. B. Pandey (UCL-MSSL), A. M. Parsons (GSFC), T. Sakamoto (NASA/ORAU) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team: At 14:41:35 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060807 (trigger=223217). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 252.527, +31.590 {16h 50m 07s, +31d 35' 25"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows 1, possibly 2, peaks with a duration of about 15 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began taking data at 14:43:21 UT, 106 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image, however analysis of downlinked data finds an uncatalogued, variable point source at the following location: RA(J2000): 16h 50m 02.77s, Dec(J2000) 31d 35m 31.1s with an estimated uncertainty of 4.2 arcseconds radius (90% containment). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 110 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The 3-sigma upper limit is about 19.7 mag. 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 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. The Malindi telemetry downlink gap has just started, so we will not get the full data set until ~22:30 UT. [GCN OPS NOTE(07aug06): Per author's request, the affilation of S.B.Pandey was changed.] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5410 SUBJECT: GRB 060807: optical limit DATE: 06/08/07 15:55:09 GMT FROM: Ken ichi Torii at Osaka U K. Torii (Osaka U.) reports on behalf of the ART collaboration: The error region of GRB 060807 (De Pasquale et al. GCN 5409) was observed with the 0.35m ART-3b in Toyonaka, Osaka. Under the bright moon, 60 s exposures in Ic band were repeated. Preliminary analysis does not reveal a new object within the XRT error region and the following upper limit is derived relative to USNO-B1.0 I magnitude. -------------------------------- StartUT Limit Exposure ================================ 14:44:37 >17.7 60s x 10 ================================ //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5411 SUBJECT: GRB 060807: Kanazawa R-band observation DATE: 06/08/07 16:00:20 GMT FROM: Daisuke Yonetoku at Kanazawa U S.Okuno, S.Tanabe, T.Kidamura, D.Yonetoku, T.Murakami, H.Kodaira, S.Yoshinari, S.Yokota, R.Kozaka, Y.Kodama, N.Emura, T.Asai, T.Nashimoto report on behalf of the Kanazawa GRB team: We have imaged the field of GRB 060807 (M. De Pasquale et al. GCN 5409) in R band with 0.3m telescope at Kanazawa Japan. The automated system took the first image at 300 s after the trigger (under poor conditions). Compared with the USNO-A2.0 catalog, no new source was detected brighter than the limiting magnitude of R>15.6 mag in the XRT error circle. Further observations and analysis are in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5412 SUBJECT: GRB 060807, optical observation DATE: 06/08/07 17:01:11 GMT FROM: Eri Sonoda at U of Miyazaki/Japan E.Sonoda, S.Maeno, M.Yamauchi (University of Miyazaki) "We have observed the field covering the error circle of GRB060807 (GCN 5409) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 14:44:19 UT on Aug. 8. After co-adding a set of 44 images (14:44:19 - 15:52:33 UT, 164s after the trigger) of 30 sec exposures, we have compared with the USNO A2.0 catalog. Preliminary analysis shows there is no new source brighter than 17.6 mag. " //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5415 SUBJECT: GRB060807 - SDSS Pre-burst Observations DATE: 06/08/07 18:17:45 GMT FROM: Richard J. Cool at U.of AZ/Steward Obs Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona), David W. Hogg (NYU), Michael R. Blanton (NYU), David J. Schlegel (LBNL), J. Brinkmann (APO), Donald Q. Lamb (Chicago), Donald P. Schneider (PSU), and Daniel E. Vanden Berk (PSU) report: The Sloan Digital Sky Survey (SDSS) imaged the field of burst GRB060807 prior to the burst. As these data should be useful as a pre-burst comparison and for calibrating photometry, we are supplying the images and photometry measurements for this GRB field to the community. Data from the SDSS, including 5 FITS images, 3 JPGS, and 3 files of photometry and astrometry, are being placed at http://mizar.as.arizona.edu/~grb/public/GRB060807 We supply FITS images in each of the 5 SDSS bands of a 8'x8' region centered on the GRB position (ra=252.527 (16:50:06.5), dec=31.5900 (31:35:24.0); Swift-BAT TRIGGER 223217), as well as 3 gri color-composite JPGs (with different stretches). The units in the FITS images are nanomaggies per pixel. A pixel is 0.396 arcsec on a side. A nanomaggie is a flux-density unit equal to 10^-9 of a magnitude 0 source or, to the extent that SDSS is an AB system, 3.631e-6 Jy. The FITS images have WCS astrometric information. In the file GRB060807_sdss.calstar.dat, we report photometry and astrometry of 676 bright stars (r<20.5) within 15' of the burst location. The magnitudes presented in this file are asinh magnitudes as are standard in the SDSS (Lupton 1999, AJ, 118, 1406). Beware that some of these stars are not well-detected in the u-band; use the errors and object flags to monitor data quality. In the files GRB060807_sdss.objects_flux.dat and GRB060807_sdss.objects_magnitudes.dat, we report photometry of 825 objects detected within 6' of the GRB position. We have removed saturated objects and objects with model magnitudes fainter than 23.0 in the r-band. The fluxes listed in GRB060807_sdss.objects_flux.dat are in nanomaggies while the magnitudes listed in GRB060807_sdss.objects_magnitudes.dat are asinh magnitudes. All quantities reported are standard SDSS photometry, meaning that they are very close to AB zeropoints and magnitudes are quoted in asinh magnitudes. Photometric zeropoints are known to about 2% rms. None of the photometry is corrected for dust extinction. The Schlegel, Finkbeiner, and Davis (1998) predictions for this region are A_U=0.148 mag, A_g=0.109 mag, A_r = 0.079 mag, A_i=0.060 mag, and A_z=0.042 mag. The file GRB060807_sdss.spectro.dat contains a list of the 3 objects with SDSS spectroscopy within 6 arcminutes of the GRB position. In addition to the redshift and 1-sigma error for each object, this file also lists the object spectroscopic classification. SDSS astrometry is generally better than 0.1 arcsecond per coordinate. Users requiring high precision astrometry should take note that the SDSS astrometric system can differ from other systems such as those used in other notices; we have not checked the offsets in this region. More detailed information pertaining to our SDSS GRB releases can be found in our initial data release paper (Cool et al. 2006, astro-ph/0601218). See the SDSS DR4 documentation for more details: http://www.sdss.org/dr5. These data have been reduced using a slightly different pipeline than that used for SDSS public data releases. We cannot guarantee that the values here will exactly match those in the data release in which these data are included. In particular, we expect the photometric calibrations to differ by of order 0.01 mag. This note may be cited, but please also cite the SDSS data release paper, Adelman-McCarthy et al. (2006, ApJS, in press, astro-ph/0507711), when using the data or referring to the technical documentation. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5417 SUBJECT: GRB060807: optical upper limit in white light DATE: 06/08/07 20:29:05 GMT FROM: Sven Duscha at MPE S. Duscha M. Muehlegger A. Stefanescu G. Kanbach,N. Prymak, F. Schrey H. Steinle (MPE Garching) of the OPTIMA-Burst team report from the 1.3m Skinakas Observatory (University of Crete Heraklion Greece): We observed the position of the XRT errorcircle of GRB 060807 (trigger #223217 De Pasquale et al. GCN Circ. 5409) on 2006 Aug 07 19:25 UT (mid-exposure; about 5 hours post burst): In a 20 min white light exposure we do not detect a counterpart candidate brighter than mag 20. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5420 SUBJECT: GRB060807: optical afterglow candidate DATE: 06/08/07 22:00:19 GMT FROM: Johan U. Fynbo at U.Copenhagen Johan P. U. Fynbo (DARK/NBI), Amanda Djupvik (NOT), Evert Rol (Leicester), Andreas Jaunsen (Oslo) report on behalf of a larger collaboration: "We have observed the field of GRB 060807 (De Pasquale et al., GCN5409) around Aug 7.9 with the Nordic Optical Telescope on La Palma. In the XRT error circle we detect a faint source at the position: (RA, Dec) = 16:50:02.6, +31:35:30.7 (J2000.0) with an uncertainty of about 0.5". The source is detected in the V, R and i bands and is not detected in the SDSS (Cool et al., GCN5415)." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5421 SUBJECT: GRB 060807: Refined analysis of the Swift-BAT burst DATE: 06/08/07 23:08:18 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC), L. Barbier (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), A. Parsons (GSFC), M. De Pasquale (UCL-MSSL), 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-120 to T+302 sec from the recent telemetry downlink, we report further analysis of BAT GRB 060807 (trigger #223217) (De Pasquale, et al., GCN Circ. 5409). The BAT ground-calculated position is (RA,Dec) = 252.505, 31.597 deg {16h 50m 1.3s, 31d 35' 48.0"} (J2000) +- 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 69%. The mask-weighted lightcurve shows a roughly triangular shaped peak starting at T-50, peaking at T+0, and ending at T+30 sec. T90 (15-350 keV) is 34 +- 4 sec (estimated error including systematics). The time-averaged spectrum from T-16.5 to T+24.7 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.57 +- 0.20. The fluence in the 15-150 keV band is 7.3 +- 0.9 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.14 sec in the 15-150 keV band is 0.8 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5422 SUBJECT: GRB 060807: K- and R-band observations DATE: 06/08/08 01:46:21 GMT FROM: Daniele Malesani at SISSA-ISAS,Trieste,Italy D. Malesani (SISSA) & S. Piranomonte (INAF/Roma) report on behalf of the MISTICI collaboration: We observed the candidate optical counterpart (Fynbo et al., GCN 5420) of GRB 060807 (De Pasquale et al., GCN 5409; Barthelmy et al., GCN 5421). Observations were carried out in the K and R filters, with NTT+SofI and VLT+FORS1, respectively. The mean times were 8.46 and 8.72 hr after the burst. The candidate is well detected in both filters, and shows a very red color. Preliminary calibrations against 2MASS and USNO-B1 (R1 magnitudes) shows R-K ~ 5 (assuming negligible time variations between the two epochs). We warn that there is some scatter (by ~0.2 mag) in the calibration for both the R- and K bands, so this value should be still considered as preliminary. We acknowledge prompt support from the VLT and NTT observing staffs, in particular Claudio Melo and Valentin Ivanov. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5423 SUBJECT: GRB 060807: XRT Team refined analysis DATE: 06/08/08 09:36:25 GMT FROM: Kim Page at U.of Leicester K.L. Page, O. Godet (U. Leicester) & Max De Pasquale (UCL-MSSL) report on behalf of the Swift-XRT team: We have analysed the first 4 orbits of Swift-XRT data obtained for GRB 060807 (trigger number 223217). All useful data were collected in Photon Counting mode, starting 117 seconds after the BAT trigger. Using these first 8.6 ks of data, we obtain a refined position of: RA(J2000) = 16 50 02.97 Dec(J2000) = +31 35 30.5 with an estimated uncertainty radius of 3.5 arcsec (90% containment). Analysis of the light-curve implies that there was a steep decay at the start of the observation, followed by a period of almost constant emission until the end of the first orbit. The data obtained for orbits 2-4 show a decline with alpha = 1.18 +/- 0.10. A spectrum formed from all the PC data for the first 4 orbits (117 s - 18 ks after the trigger), can be modelled with a power-law of photon index Gamma = 2.15 +/- 0.12, with an excess absorbing column of NH = (1.3 +/- 0.3)e21 cm^-2 in addition to the Galactic value of 2.44e20 cm^-2. The mean 0.3-10 keV observed flux for this time period is 1.02e-11 erg cm^-2 s^-1; the unabsorbed flux is 1.50e-11 erg cm^-2 s^-1. Assuming the light-curve continues to decay with alpha ~ 1.18, the count rate at 24 hours is predicted to be 0.016 count s^-1. This corresponds to an observed (unabsorbed) flux of 6.81e-13 (1.00e-12) erg cm^-2 s^-1. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5424 SUBJECT: GRB 060807: afterglow confirmation DATE: 06/08/08 10:46:49 GMT FROM: Daniele Malesani at SISSA-ISAS,Trieste,Italy D. Malesani (SISSA), J. Fynbo (DARK/NBI), S. Piranomonte (INAF/OAR), & A. Djupvik (NOT), report: We have performed relative photometry between the NOT (Fynbo et al., GCN 5420) and VLT (Malesani et al., GCN 5422) R-band images of GRB 060807 (De Pasquale et al., GCN 5409). We find that the object indicated by Fynbo et al. (GCN 5420) dimmed by 0.61 +- 0.06 mag between 6.69 and 8.93 hr after the GRB. This confirms that the object was indeed the optical afterglow of GRB 060807. Assuming a power-law time dependence F(t) propto t^-alpha, the inferred decay index is quite steep: alpha = 1.9 +- 0.2. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5425 SUBJECT: GRB 060807: UVOT Upper limits DATE: 06/08/08 11:58:39 GMT FROM: Shashi Pandey at MSSL S. B. Pandey and M. De Pasquale (UCL-MSSL) report on behalf of the Swift/UVOT team: The Swift UVOT began observing GRB 060807 (trigger #223217, M. De Pasquale et al., GCN Circular 5409) 110 seconds after the BAT trigger. No optical afterglow is detected in the XRT refined error circle (Page et al, GCN Circular 5423) and at location of the afterglow reported by Fynbo et al. 2006 (GCN Circular 5420). The 3-sigma limiting magnitudes for the coadded images for the UVOT filters are listed below: Filter T_range(s) Exposure(s) 3sig_Upper limit WHITE 110-6965 599 20.5 V 215-12151 1796 20.7 B 693-18617 1079 21.4 U 669-17927 1317 21.2 W1 645-17012 1318 20.4 M2 621-12834 1099 20.7 W2 721-11238 1102 20.8 T_range is calculated from the time of the burst. No correction has been made for the Galactic reddening of to E(B-V) = 0.03 mag (Schlegel et al. 1998) along the line of sight to the burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5430 SUBJECT: GRB060807: Optical limiting magnitudes DATE: 06/08/09 18:03:12 GMT FROM: AAVSO GRB Network at AAVSO D. T. Durig (Cordell-Lorenz Observatory, University of the South) and S. Sposetti (Gnosca, Switzerland) report on behalf of the AAVSO International High Energy Network on optical observations of GRB060807 (GCN #5409, De Pasquale et al.): D. T. Durig reports the following unfiltered (CR) limiting magnitude: 2006 Aug 08, 03:41:45 UT, CR < 20.0 (15 hours, post-burst) S. Sposetti reports the following R-band limiting magnitude: 2006 Aug 08, 19:45:00 UT, R < 20 (29 hours, post-burst) Details of these observations follow at the end of this report. FITS images of these observations are available from the AAVSO at ftp://ftp.aavso.org/grb , and full details of these observations are available at the following URLs: Durig: http://www.aavso.org/pipermail/aavso-hen/2006-August/006238.html Sposetti: http://www.aavso.org/pipermail/aavso-hen/2006-August/006240.html The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network. -------------------------- Observer: D. T. Durig ( CLW01 ) Report: Started 2 hours of 30 second unguided exposures and got a few thicker clouds near the end. So I added the first 150 good frames, total exposure 75 minutes. No OT observed, but there is a dim background variation at S/N~2 near reported position. Two accumulated hot pixels nearby center at 1 oclock position and one near top center of frame are artifacts. Gif image at http://arthur.sewanee.edu/obsv/view.php Bright moonlight made background very bad and limited depth of coverage. Observer: Stefano Sposetti Report: Observations begun at 19:45UT, aug 8th, about 29h later the Swift-BAT trigger, under good sky conditions affected by moonlight. A 90min stacked R-filtered image centred at 20:45UT doesn't show any OT brighter than 20mag (USNO A2.0 catalog). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5435 SUBJECT: GRB060807: Possible Highly Significant X-ray Emission Lines DATE: 06/08/10 20:07:55 GMT FROM: Nat Butler at MIT/CSR N. Butler (UC Berkeley) reports: We have analyzed the XRT PC mode data for GRB060807 (De Pasquale et al. 2006; GCN5409), also analyzed carefully by Page et al. (2006; GCN5423). We find identical spectral parameters (within errors) for the absorbed powerlaw model. However, we note that the fit goodness for the data in the 0.3-10 keV band from 0.1-250 ksec after the BAT trigger is marginal (chi^2/nu=138.8/103), rejectable at 99% confidence. The spectrum exhibits rare (see, e.g., Butler 2006, astro-ph/0604083, for a few additional possible cases) and narrow modulations about the best fit model. We can fit these modulations with 3 unresolved emission lines (giving a delta_chi^2 fit improvement of 39.0, for 6 additional degrees of freedom). We estimate a significance for the 3 line set of 5.0 sigma, including a decrease in the estimated significance due to the search for lines at many possible centroid energies in the 0.3-5.0 keV band. Plots of the spectrum with and without the 3 most significant lines can be found at: http://astro.berkeley.edu/~nat/GRB060807/xrt_060807_nolines.jpg , and http://astro.berkeley.edu/~nat/GRB060807/xrt_060807_lines.jpg . The centroid energies of the lines are 0.73, 0.90, and 1.24 keV, with uncertainties ~0.05 keV. The brightest line at 0.73 keV has a flux ~5 x 10^-14 erg cm^-2 s^-1 for the time period 0.1-250 ksec after the BAT trigger, or 3% of the 0.3-10 keV afterglow flux. Allowing associations for the lines with K-alpha transitions in H- or He-like species of common light metals or any ionization state in the Fe group elements, the 3-line set allows several redshift solutions. The highest probability peaks have dz/z~0.2 and occur at z=0.4, 1.0, 1.6, and 4.5. The large X-ray absorbing column (e.g., GCN5423) suggests that the source is not at high-z. An optical spectrum of the host galaxy or optical transient could resolve the redshift degeneracy and would provide important insight into the nature of the X-ray emission. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 5672 SUBJECT: GRB 060807: Detection of a possible host galaxy DATE: 06/10/01 17:32:47 GMT FROM: Christina Thoene at Niels Bohr Institute,DARK Cosmo Ctr Christina C. Thoene (DARK Cosmology Centre), Christina Henriksen (DARK, NOT) and Klaas Wiersema (Univ. of Amsterdam) report: We observed the field of GRB060807 on Sep. 20 and 22 with ALFOSC at the NOT on La Palma in V, R and i. At the position of the afterglow (GCN 5420), we detect an extended source, clearly visible in stacked images from all three filters (8x600s in V and R, 9x600s in I). We therefore conclude that the source is very likely the host galaxy of GRB060807. Photometry of the source gives values of V=24.9 +-0.1, R=24.26 +-0.05 and i=22.1 +-0.2 using photometric zeropoints from the NOT/ALFOSC webpage. This is a very red color as it was found for the color of the OT (GCN 5422) and might indicate a high redshift for this GRB. More bands however are required for a final conclusion. An image of the host in the R-band can be found at www.astro.ku.dk/~cthoene/GRBs/