This file contains both GRB 060805A and GRB 060805B. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5398 SUBJECT: GRB 060805: Swift detection of a burst DATE: 06/08/05 05:13:03 GMT FROM: Scott Barthelmy at NASA/GSFC H. Z. Ziaeepour (UCL-MSSL), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMD), N. Gehrels (NASA/GSFC), C. Guidorzi (Univ Bicocca&INAF-OAB), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), F. E. Marshall (NASA/GSFC), K. M. McLean (LANL/UTD), K. L. Page (U Leicester), M. J. Page (UCL-MSSL), D. M. Palmer (LANL) and T. Sakamoto (NASA/ORAU) report on behalf of the Swift Team: At 04:47:49 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060805 (trigger=222683). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 220.919, +12.592 {14h 43m 41s, +12d 35' 32"} (J2000) 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 ~5 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began taking data at 04:49:22 UT, 93 seconds after the BAT trigger. Although the XRT on-board centroid algorithm did not find a source in the image, ground analysis reveals a faint source at RA, Dec 14h 43m 43.59s, +12 35 11.8 (J2000) with an uncertainty of 5.9 arcsec. UVOT took a finding chart exposure of 100 seconds with the white filter starting 97 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. Image catalog data are not available at this time. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT 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 0.1 magnitudes. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5399 SUBJECT: GRB 060805 - SDSS Pre-Burst Observations DATE: 06/08/05 05:33:43 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 GRB060805 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/GRB060805 We supply FITS images in each of the 5 SDSS bands of a 8'x8' region centered on the GRB position (ra=220.932 (14:43:43.6), dec=12.5866 (12:35:11.8); Swift-BAT TRIGGER 222683), 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 GRB060805_sdss.calstar.dat, we report photometry and astrometry of 379 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 GRB060805_sdss.objects_flux.dat and GRB060805_sdss.objects_magnitudes.dat, we report photometry of 1683 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 GRB060805_sdss.objects_flux.dat are in nanomaggies while the magnitudes listed in GRB060805_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=0.124 mag, A_g=0.092 mag, A_r = 0.066 mag, A_i=0.050 mag, and A_z=0.036 mag. The file GRB060805_sdss.spectro.dat contains a list of the 8 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: 5400 SUBJECT: GRB 060805: KAIT observations DATE: 06/08/05 06:29:21 GMT FROM: Weidong Li at UC Berkeley KAIT/LOSS W. Li, University of California, Berkeley, on behalf of the KAIT GRB team, reports: The robotic 0.76-m Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory observed GRB 060805 detected with Swift (Trigger 222683; Ziaeepour et al. GCN 5398). A combination of filters is used: V, I, and clear. The first 15 s unfiltered image started at 04:49:48 UT, 119 s after the BAT trigger. Our automatic image processing pipeline did not identify any new source relative to the DSS II red image. We set the following limiting magnitudes (calibrated to USNO B1.0 catalog): start UT Exposure Filter Limiting mag 04:49:48 15 s clear 17.7 04:50:48 15 s I 16.7 04:51:13 20 s clear 18.0 04:51:45 45 s V 16.8 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5401 SUBJECT: GRB 060805: P60 Observations DATE: 06/08/05 06:34:56 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (Caltech) reports on behalf of a larger collaboration: We have imaged the field of GRB 050805 (Ziaeepour et al.; GCN 5398) with the automated Palomar 60-inch telescope. We obtained 2 x 60 s images in Kron R and Sloan i' and z' beginning approximately 3 minutes after the burst, before closing due to high humidity. We find no sources inside the XRT error circle to a limiting magnitude of R > 19.0 (calculated with respect to the USNO-B catalog). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5402 SUBJECT: GRB 060805: Swift/UVOT Upper Limits DATE: 06/08/05 16:01:09 GMT FROM: Shashi Pandey at MSSL S. B. Pandey, M. J. Page, H.Z. Ziaeepour and S. R. Oates (UCL-MSSL) report on behalf of the Swift/UVOT team: The Swift/UVOT began observing the field of GRB 060805 at 04:49:25 UT, 79 s after the BAT trigger (Ziaeepour et al. GCN 5398). No optical afterglow candidate has been found in the coadded images within the XRT error circle (Ziaeepour et al. GCN 5398). The 3-sigma limiting magnitudes for the coadded images for the 7 filters are listed below: Filter T_range(s) Exposure(s) 3sig_Upper limit WHITE 96-6633 511 20.1 V 79-11779 1583 20.3 B 680-6428 412 20.6 U 656-6223 432 20.2 W1 632-6019 432 19.7 M2 4182-12507 1105 20.6 W2 708-10866 1165 20.7 T_range is calculated from the time of the burst. These upper limits have not been corrected for the estimated Galactic reddening of E(B-V) = 0.024 mag (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5403 SUBJECT: GRB 060805: Swift-BAT Refined Analysis DATE: 06/08/05 16:28:08 GMT FROM: Hans Krimm at NASA-GSFC L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), M. Koss (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), 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-240 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 060805 (trigger #222683) (Ziaeepour, et al., GCN Circ. 5398). The BAT ground-calculated position is (RA,Dec) = 220.925, 12.576 deg {14h 43m 41.9s, 12d 34' 35.0"} (J2000) +- 2.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 96%. The currently available event data record has several gaps, most significantly from T+14.3 to T+19.5 sec. Based on the available data, the mask weighted light curve shows a single peak with a roughly square profile and a duration of ~6 sec. Emission was only seen below 100 keV, which is consistent with the very soft spectrum found. T90 (15-350 keV) is 5.4 +- 0.5 sec (estimated error including systematics). The time-averaged spectrum from T-1.6 to T+4.7 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.23 +- 0.42. The fluence in the 15-150 keV band is 7.4 +- 2.0 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T+0.71 sec in the 15-150 keV band is 0.3 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5404 SUBJECT: GRB 060805: XRT Team Refined Analysis DATE: 06/08/05 16:59:13 GMT FROM: Kim Page at U.of Leicester K.L. Page, O. Godet (U Leicester) & H.Z. Ziaeepour (UCL-MSSL) report on behalf of the Swift-XRT team: We have analysed the first 4 orbits of the XRT data obtained for GRB 060805 (trigger 222683), comprising 8.4 ks of Photon Counting mode data between 101 s - 18.3 ks after the BAT trigger. Using these data, we obtain a refined position of: RA(J2000) = 14 43 43.59 Dec(J2000) = +12 35 13.2 with an uncertainty of 3.9 arcsec (90% containment). This is 47.9 and 1.4 arcsec from the initial BAT and XRT positions respectively (GCN Circ 5398; Ziaeepour et al). The X-ray afterglow is faint, with a count rate of ~0.1 count s^-1 at 100 seconds after the trigger. After the first orbit, during which the count rate was close to constant, the afterglow decays with a slope of alpha = 1.06 +/- 0.35. The spectrum (using the combined data from all 4 orbits) can be well fitted by a simple power-law, of Gamma = 2.39 +0.64/-0.51, with a total absorbing column of about 1e21 cm^-2 (compared to the Galactic column density of 1.57e20 cm^-2). During the first orbit (between 101 and 935 seconds after the trigger), the 0.3-10 keV unabsorbed flux was 4.72e-12 erg cm^-2 s^-1. If the afterglow continues to fade with alpha ~ 1.06, the count rate at 24 hours is predicted to be 1.6e-3 count s^-1, corresponding to an observed (unabsorbed) flux of 5.92e-14 (8.92e-14) erg cm^-2 s^-1. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5405 SUBJECT: GRB 060805: optical upper limit in R DATE: 06/08/05 21:39:23 GMT FROM: Alexander Stefanescu at MPE M. Muehlegger, S. Duscha, A. Stefanescu, G. Kanbach, N. Primak, 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 060805 (trigger #222683, Ziaeepour, et al., GCN Circ. 5398) on 2006 Aug 05, 18:43 UT (mid-exposure; about 14 hours post burst): in a 30 min R-filter exposure we do not detect a counterpart candidate brighter than R=21.5 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5406 SUBJECT: GRB060805 Liverpool Telescope observations DATE: 06/08/06 12:29:48 GMT FROM: Evert Rol at U.Leicester E. Rol (U of Leicester) reports on behalf of the RoboNet telescope network: We observed the field of GRB060805 (Ziaeepour et al, GCN Circular 5398) with the 2m Liverpool Telescope during the night of 2006-08-05/06, in Sloan r' and i' filters. At the position of the refined XRT position (Page et al, GCN Circular 5404), we do not detect any source. The observations and limiting magnitude are detailed below. Calibration has been performed using the available SDSS data (Cool et al, GCN Circular 5399). start time T-delta exposure time filter limiting magnitude UT (mid-obs; days) (seconds) (5 sigma) 21:59:40 0.725 5 x 300 r' 22.9 22:27:28 0.748 7 x 300 i' 22.6 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5407 SUBJECT: IPN triangulation of GRB060805B DATE: 06/08/06 23:54:48 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, Mars Odyssey, and Konus GRB teams, I. Mitrofanov, A. Kozyrev, M. Litvak, A. Sanin, V. Tret'yakov and A. Parshukov, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, S. Golenetskii, E. Mazets, V. Pal'shin, and D. Frederiks on behalf of the Konus-Wind teams, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, and A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL SPI-ACS GRB team, report: Ulysses, Mars Odyssey, Konus, RHESSI, and INTEGRAL (SPI-ACS) observed this very intense, 8 s long burst at 52035 s. Spectral information will be given in a forthcoming GCN Circular. We have triangulated it to an ~ 46 sq. arcmin. error box (3 sigma), whose coordinates are RA(2000) DEC(2000) 18 h 10 m 01.78 s 58 o 08 ' 47.67 " (CENTER) 18 h 09 m 36.85 s 58 o 00 ' 55.18 " (CORNER) 18 h 09 m 47.45 s 57 o 57 ' 22.44 " (CORNER) 18 h 10 m 16.89 s 58 o 20 ' 22.15 " (CORNER) 18 h 10 m 27.16 s 58 o 16 ' 42.85 " (CORNER) This error box may be improved. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5413 SUBJECT: GRB 060805B: Swift/UVOT Upper Limits DATE: 06/08/07 17:01:42 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (UCL-MSSL) reports on behalf of the Swift/UVOT team: The Swift/UVOT began observing the field of the GRB060805B on Aug. 7th at 01:34:52 UT. No optical afterglow candidate has been found in the coadded images of any of the UV/optical lenticular filters within the IPN error box reported by Hurley et al. (GCN 5407). The 3-sigma limiting magnitudes for the coadded images for the 6 filters are listed below: Filter Tstart (UT) Exposure(s) 3sig upper limits V 02:02:23 1397 20.56 B 01:45:13 1397 21.61 U 01:41:44 1397 21.26 UVW1 01:34:52 2802 20.77 UVM2 02:05:50 3619 21.27 UVW2 01:48:42 2402 21.27 These upper limits have not been corrected for the estimated Galactic reddening of E(B-V) = 0.037 mag (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5414 SUBJECT: GRB 060805B: X-ray Afterglow Detection, Spectral/Spatial/Temporal Properties DATE: 06/08/07 17:45:13 GMT FROM: Nat Butler at MIT/CSR N. Butler (UC Berkeley) reports: We report the results of a spectral/spatial/temporal analysis of the Swift target-of-opportunity observation of the X-ray afterglow to GRB060805B (GCN 5407). We detect a bright and fading X-ray source <~0.7 arcmin from the center of the IPN error region. Using 130 cts (0.3-10 keV) from a total exposure of 16.7 ksec for the time interval 126-164 ksec after the IPN trigger, the count rate fades as t^-alpha, with alpha=-2.4+/-1.1. The spectrum is fit by an absorbed powerlaw, with column density N_H = (1.3+/-1.1) 10^21 cm^-2, consistent with the Galactic value in the source direction. Also, we find photon index Gamma=2.1+/-0.4 and unabsorbed flux (4.4+/-1.1) 10^(-13) erg cm^-2 s^-1. We determine the following position for the transient, with respect to the DSS positions of 23 optical sources and the XRT positions of 7 X-ray sources and including an estimate of the systematic error: RA, Dec: 18 10 05.41 +58 09 18.1 ; +/- 2.6" (J2000, 90% Conf.) We note that the X-ray source is near but not spatially consistent with a R~18.5 mag source in the DSS at RA, Dec: 18 10 5.64, +58 09 19.4. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5418 SUBJECT: GRB 060805B: RHESSI Spectral Fit DATE: 06/08/07 21:23:12 GMT FROM: Eric Bellm at UCB/SSL E. Bellm, M. Bandstra, S. Boggs, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, A. Zehnder, and K. Hurley, report: The preliminary fit to the time-integrated RHESSI spectrum of GRB060805B (Hurley et al., GCN 5407; Butler, GCN 5414) between 30 keV and 10 MeV is a Band function with alpha = -0.66 +0.12/-0.10 beta = -2.52 +0.16/-0.22 E0 = 240. +45/-40. keV Epeak = 320. +/-20. keV The 30 keV-10 MeV fluence is 1.13 +/- 0.046 E-4 erg/cm^2. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5428 SUBJECT: GRB 060805B: XRT Team Analysis DATE: 06/08/09 13:50:00 GMT FROM: Olivier Godet at U.of Leicester O. Godet, K. L. Page, M. R. Goad, E. Rol, P.T. O'Brien (U Leicester), P. Schady (UCL-MSSL), and K. Hurley (UCB) report on behalf of the Swift-XRT team: GRB 060805B was detected by IPN (GNC Circ 5407). XRT started to observe 35.1 hours after the IPN trigger for a present 25ks of data. The full IPN error box was within the XRT field of view. Using the ftool xrtcentroid, the first 25ks of the XRT data revealed an X-ray source in the IPN error box at (J2000): RA = 18 10 05.56 Dec = +58 09 16.3 with an uncertainty of 3.9 arcseconds (90% containment). This position consistent with that given by Butler 2006 (GCN Circ. 5414) does not correspond to any catalogued X-ray sources. We note that the X-ray position is consistent with the position of two optical sources S1 and S2 in the USNO-B1.0 (Monet et al. 2003) and APM-North (McMahon et al. 2000) catalogues, repectively. The source S1 (RA(J2000) = 18 10 05.56 and Dec = +58 09 19.3) is 2.9 arcseconds away from the XRT position. The source S2 (RA(J2000) = 18 10 05.60 and Dec = +58 09 19.1) is 2.8 arcseconds away from the XRT position. The positions of the optical sources are consistent with those reported by Butler 2006 (GCN Circ. 5414). The spectrum from the first 19ks of the PC data can be well fitted by an absorbed power-law with Gamma = 1.78 +0.36/-0.33. No clear evidence of absorption in excess over the Galactic absorption (nH(Gal) = 3.7e20 cm^-2 from Dickey & Lockman 1990) is seen in the data. The unabsorbed flux in the 0.5-10 keV energy band is 3.9 +1.8/-1.1e-13 erg cm^-2 s^-1. These results are consistent with those given by Butler (2006; GCN Circ 5414). Using the initial 19ks of data did not allow us to determine if the X-source was really fading. Indeed, fitting the light-curve with a constant (C) gives a value of chi^2/dof=6.5/7 with C = 0.0087+/-0.0012, while using a power-law gives a value of chi^2/dof=4.0/6 with alpha = 1.62 +1.70/-1.56 (http://www.swift.ac.uk/grb060805b.shtml). Using a power-law allows an improvement of delta chi^2 = 2.5 for 1 dof i.e. less than 90% confidence. Adding 6 ks of data obtained at later time allows us to confirm that the X-ray source is actually fading with a decay slope of alpha = 1.20 +0.72/-0.53 (http://www.swift.ac.uk/grb060805b.shtml) and is likely to be the afterglow of GRB 060805B. We would like to encourage ground observations in order to determine the redshift of this burst. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5429 SUBJECT: GRB 060805B: optical observation at Sierra Nevada DATE: 06/08/09 16:00:58 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia D. Martínez and A. J. Castro-Tirado (IAA-CSIC Granada), on behalf of a larger collaboration, report: "Following the detection by the IPN of the bright GRB 060805B (Hurley et al. GCNC 5407), we have obtained I-band frames with the 1.5m OSN telescope in Spain starting on Aug 8.04 UT (i.e. 58.3 hr post-burst). Six exposures (300s each) in the I-band filter were taken under non optimum technical conditions. Within the Swift/XRT X-ray afterglow error box (Butler GCNC 5414, Godet et al. GCNC 5428), we only detect a single optical source which is also present in the DSS2 with about the same brightness. The limiting magnitude of our combined I-band image is I = 20.5". //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5437 SUBJECT: GRB 060805B: pseudo-z from spectral parameters of the prompt emission DATE: 06/08/11 08:36:17 GMT FROM: Alexandre Pelangeon at LATT,OMP,Toulouse A. Pelangeon & J-L. Atteia (LATT-OMP) report: We have used the spectral parameters of GRB 060805B provided by Bellm et al. (GCNC 5418) to compute the spectral pseudo-redshift** of this burst localized by IPN (Hurley et al., GCNC 5407). We find a pseudo-redshift pz= 1.3 +/- 0.2 (90% error). ** cf. http://www.ast.obs-mip.fr/grb/pz //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5454 SUBJECT: GRB060805B: optical observations DATE: 06/08/15 13:41:20 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 an error box of the GRB060805B (Hurley et al. GCN 5407) with the Z-600 telescope of peak Terskol Observatory on Aug. 7 between (UT) 22:37 - 22:52 in R-band. Within the Swift/XRT error box (Butler GCN 5414, Godet et al. GCN 5428) in a combined image (15x60 s) we clearly detect only the source (USNO-B1.0 1481-0304497) mentioned earlier (Butler GCN 5414, Godet et al. GCN 5428). The limiting magnitude of the combined image is R~19.0. The message may be cited. [GCN OPS NOTE(15aug06): This Circular was delayed by ~1 hr due to problems at the GCN end.]