This file contains both GRB 060912 'A' and 'B'. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5558 SUBJECT: GRB 060912: Swift detection of a burst with an optical afterglow DATE: 06/09/12 14:24:06 GMT FROM: Scott Barthelmy at NASA/GSFC C. P. Hurkett (U Leicester), S. D. Barthelmy (GSFC), P. J. Brown (PSU), D. N. Burrows (PSU), M. M. Chester (PSU), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), O. Godet (U Leicester), C. Guidorzi (Univ Bicocca&INAF-OAB), S. T. Holland (GSFC/USRA), S. Immler (GSFC/USRA), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), F. E. Marshall (NASA/GSFC), K. M. McLean (LANL/UTD), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), A. M. Parsons (GSFC), P. Romano (INAF-OAB), T. Sakamoto (NASA/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (NASA/ORAU) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team: At 13:55:54 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060912 (trigger=229185). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 5.286, +20.971 {00h 21m 09s, +20d 58' 17"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single FRED-like peak (FWHM ~3 sec) with a total duration of about 7 sec. The peak count rate was ~6000 counts/sec (15-350 keV), at ~1 sec after the trigger. We note that the spectrum is hard and the main emission is confined to ~3 sec. It is possible that the burst is short, although it appears with existing data to be long. A lag analysis will be done with the event data in ~3 hours. The XRT began taking data at 13:57:43 UT, 109 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image but ground analysis of flight data reveals a fading source at Ra, Dec 00h 21m 08.2 +20 58 18.6 (J2000), with an uncertainty of 3.9" (radius, 90% containment). This is 7 arcseconds from the BAT position and 1 arcsecond from the UVOT position. UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 113 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 00:21:08.16 (5.2840) DEC(J2000) = +20:58:17.8 (20.9716) with a 1-sigma error radius of about 0.5 arc sec. This position is 7.0 arc sec. from the center of the BAT error circle. The estimated magnitude is 16.1 with a 1-sigma error of about 0.5 mag. The afterglow fades to about 18th magnitude in the subsequent white finding chart. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05. We note that there is a 2MASS galaxy in the Hyperleda catalog at 00:21:08.6 20:58:08 (PGC # 1639821), 11.5 arc sec from the UVOT position. The diameter of the galaxy is 0.36 arcmin. //////////////////////////////////////////////////////////////////////// 5559 removed because it was of an incompatible format. It was resubmitted as 5560. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5560 SUBJECT: GRB 060912: Correction to GCN 5559 DATE: 06/09/12 16:50:25 GMT FROM: W.K. Zheng at NAOC M.Zhai, L.P. Xing, 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 060912 with the TNT 0.8m telescope at Xinglong Observatory.The first image was taken at 13:57:23 UT, 89s after the burst. The optical counterpart (Hurkett et al. GCN 5558) were well detected in our clear and R band images.Preliminary analysis shows the OT fade to ~19 about 35 minutes after the burst in our white images. We encourage deeper observation. Further analysis is under progress. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5561 SUBJECT: GRB 060912, Swift-BAT refined analysis DATE: 06/09/12 18:45:57 GMT FROM: Scott Barthelmy at NASA/GSFC A. Parsons (GSFC), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMD), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), C. P. Hurkett (U Leicester), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), J. Norris (GSFC), D. Palmer (LANL), 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+183 sec from recent telemetry downlinks, we report further analysis of BAT GRB 060912 (trigger #229185) (Hurkett, et al., GCN Circ. 5558). The BAT ground-calculated position is RA,Dec = 5.286,+20.971 deg {0h 21m 8.7s,+20d 58' 16.3"} (J2000) +- 0.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 33%. The mask-weighted lightcurve has a single peak with a faster rise than decay. T90 (15-350 keV) is 5.0 +- 0.5 sec (estimated error including systematics). The time-averaged spectrum from T-0.6 to T+6.1 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.74 +- 0.09. The fluence in the 15-150 keV band is 1.3 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.02 sec in the 15-150 keV band is 8.5 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The spectral lag calculation (Norris & Bonnell, ApJ, 2006) shows this burst to be clearly in the long-burst class. The lag is 190 +28 -40 ms between the 15-25 and 50-100 keV bands and 83 +43 -43 ms between the 25-50 and 100-350 bands. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5562 SUBJECT: GRB 060912: Swift XRT Team Refined Analysis DATE: 06/09/12 18:46:12 GMT FROM: Cheryl Pauline Hurkett at Leicester U C. P. Hurkett, K.L. Page and E. Rol (U Leicester) report on behalf of the Swift XRT team: We have analysed the Swift XRT data from the first orbit observation of GRB 060912 (Hurkett et al., GCN 5558), with a total exposure of 1.7 ks seconds. The refined XRT position is: RA(J2000) = 00 21 08.23 Dec(J2000) = +20 58 15.8 This position is 10.9 arcseconds from the BAT position given in GCN 5558 (Hurkett et al. 2006), 2.8 arcseconds from the XRT position and 2.0 arcseconds from the UVOT given in the same GCN. We estimate an uncertainty of 3.6 arcseconds radius (90% containment). The 0.3-10.0 keV Photon Counting (PC) mode starts 135 seconds after the BAT trigger (T0). The count rate is declining with a decay slope of 0.62 (+/-0.12). A preliminary spectral fit to the PC data gives a spectral power law photon index of 2.08 +/- 0.20 in the [0.3-10] keV band, with a free absorption of 0.17 (+/- 0.06)e22 cm^-2 (Galactic absorption at this location is 4.20e20 cm^-2). The average (in the time range 135-1860 seconds from trigger) estimated unabsorbed 0.3-10 keV flux is then about 2.9E-11 erg/cm2/s. The XRT count rate extrapolated to T0+24 hr is estimated to be about 0.025 cps, corresponding to an unabsorbed 0.3-10 keV flux of about 1.73E-12 erg/cm2/s. This Circular is an official product of the Swift XRT Team. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5563 SUBJECT: GRB 060912B: a long GRB detected with INTEGRAL DATE: 06/09/12 18:57:39 GMT FROM: Diego Gotz at IASF-CNR D.Gotz (CEA, Saclay), S.Mereghetti, A.Paizis (IASF-Milano), S.Soldi, N.Mowlavi, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A GRB lasting about 200 s has been detected by IBAS in IBIS/ISGRI data at 17:33:40 UT on September 12, 2006. The coordinates (J2000) are: R.A.: 271.2167 [degrees], DEC.: -19.8804 [degrees] with an uncertainty of 2.5 arcmin (90% c.l.). The peak flux in the 20-200 keV is 0.08 ph/cmsq/s. The fluence in the same band is 6E-7 erg/cmsq. A plot of the light curve will be posted at http://ibas.mi.iasf.cnr.it/IBAS_Results.html This message can be cited. We apologize for the mistake about the character format. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5564 SUBJECT: GRB060912: OPTIMA-Burst optical observations DATE: 06/09/12 22:03:59 GMT FROM: Alexander Stefanescu at MPE A. Stefanescu, F. Schrey, S. Duscha, M. Muehlegger, N. Primak, G. Kanbach, H. Steinle (MPE Garching) of the OPTIMA-Burst Team report the following: "OPTIMA-Burst at the 1.3m Skinakas Observatory, of the University of Crete, Greece observed the Swift XRT-errorcircle of GRB 060912 (GCN Circ. 5558, C.P. Hurkett et al.) starting at 19:21UT (~5.5h after the Burst). We detect a source consistent with the source reported by C.P. Hurkett et al. and M. Zhai et al. (GCN Circ. 5560). We estimate the magnitude of the source as R=21.6 +- 0.2 There is no known minor planet brighter than 23 mag within 5' of the source according to MPChecker" //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5565 SUBJECT: GRB060912: Swift/UVOT Observations DATE: 06/09/12 23:29:18 GMT FROM: Peter Brown at PSU P. J. Brown (PSU) & C. P. Hurkett (U Leicester) report on behalf of the Swift UVOT team: Swift/UVOT began settled observations of GRB060912 (BAT trigger 229185) at 13:57:47 UT, 113 seconds after the initial Swift BAT trigger (Hurkett et al., GCN Circ. 5558). The fading optical counterpart seen in the white finding charts was also detected by UVOT in V, B, U, UVW1 and marginally in UVM2. The relatively shallow upper limit in UVW2 prevents us from constraining the redshift well. The magnitudes from early observations and the upper limit in UVW2 are tabulated below. Filter T_range(s) Exp(s) Magnitude White 113-212 100 16.0 +/- 0.1 White 859-958 100 18.1 +/- 0.1 V 219-618 400 17.4 +/- 0.1 V 964-1363 400 18.4 +/- 0.2 B 697-1776 79 19.5 +/- 0.4 U 672-691 20 17.6 +/- 0.2 UVW1 649-668 20 18.51 +/- 0.4 UVM2 624-1861 119 19.3 +/- 0.4 UVW2 725-1814 78 > 19.5 (3.0-sigma) T_range is the span of the exposure in seconds from the BAT trigger. The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E(B-V)=0.05. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5566 SUBJECT: GRB 060912B: Watcher observations DATE: 06/09/13 00:07:52 GMT FROM: John French at UCD,Ireland J.French (UCD Dublin), P.Kubanek (AsU AV CR Ondrejov & ISDC Versoix), and Martin Jelinek (IAA Granada) report on behalf of the Watcher collaboration: The Watcher 0.4 m telescope, located at the Boyden Observatory, South Africa, began observing the location of GRB 060912B at 17:34:44 UT (60s after the burst). We detect a bright source (Rmag = 12.1+/-0.2) at RA 18:05:00.005, DEC -19:51:42.37 J2000, which is present in USNO-B1.0 (as U0675_24058876 with coordinate end figures 0.005 and 42.37), but significantly brighter than expected. Unfiltered images, calibrated relative to USNO, give an approximate Rmag = 12.1+/-0.2 for the source, as opposed to the value of 14.4 quoted in the catalog. The object is not present in Simbad as a known variable star. We do not, however, expect that this source is associated with GRB 060912B due to the absence of significant decay up to T0+4hrs. Finding charts can be found at: http://bermuda.ucd.ie/~jfrench/060912/charts.html //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5567 SUBJECT: GRB060912: optical observations DATE: 06/09/13 00:40:52 GMT FROM: Alexei Pozanenko at IKI, Moscow B. Hafizov, M. Ibrahimov (MAO), A. Pozanenko (IKI), on behalf of larger GRB follow up collaboration report: We observed the afterglow of GRB060912 (Hurkett et al. GCN 5558) with 1.5m telescope of Maidanak Astronomical Observatory (MAO) in BR-bands on September 12 between (UT) 17:25 and 19:30. The afterglow candidate (Hurkett et al. GCN 5558, Zhai et al. GCN 5560) is detected on a single 120 s images. Preliminary photometry of the optical transient in R-band at Sep. 12 17:30 (UT) is R~20.5m. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5568 SUBJECT: GRB 060912: Redshift of nearby 2MASS galaxy DATE: 06/09/13 06:56:08 GMT FROM: Edo Berger at Carnegie Obs E. Berger (Carnegie Observatories) reports on behalf of a larger collaboration: "Starting on 2006 Sep. 13.22 UT we used GMOS on Gemini-South to obtain an 1800 sec spectrum of the bright 2MASS galaxy located 11" away from the optical afterglow position of GRB 060912 (GCN 5558), at a position angle that also included the afterglow position. The spectrum of the 2MASS galaxy it typical of an early-type galaxy with CaII H&K, Mg b, and Na D absorption features at a redshift, z=0.0936. At the position of the afterglow we do not detect any clear continuum emission or emission lines (4000-7000 A). If the 2MASS galaxy is in fact the host galaxy of GRB 060912, then the isotropic-equivalent gamma-ray energy is only 2.6e49 erg. Moreover, the nature of the host galaxy would suggest that the GRB is most likely to be a short burst. Deep imaging observations to search for a faint galaxy at the position of the afterglow are planned." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5570 SUBJECT: Konus-Wind observation of GRB 060912 DATE: 06/09/13 14:56:16 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team report: The GRB 060912 (Swift-BAT trigger 229185, GCN 5558) triggered Konus-Wind at 50157.788 s UT (13:55:57.788). As observed by Konus-Wind, it had a duration of ~8 s. Its spectrum is well fitted by a power law model in the energy range 20 keV - 2 MeV, with alpha = -1.94 +/- 0.2 for time interval T0 - (T0 + 8s). The burst fluence is ~4x10-6 erg/cm2 and the 256-ms peak flux is 1.8x10-6 erg/cm2 s (both in the 20 keV - 2 MeV energy range). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5573 SUBJECT: GRB 060912A: Probable Host Galaxy DATE: 06/09/14 12:59:41 GMT FROM: Andrew Levan at U.of Leicester A.J. Levan, P. Jakobsson, R. Chapman (U. Hertfordshire), N. Tanvir, E.Rol (U. Leicester) report for a larger collaboration: We observed the location of GRB 050912A using the VLT and FORS1 in the VRI bands beginning at Sept 14. 03:51 UT. At the location of the optical afterglow given by Hurkett et al. (GCN Circ. 5558) we find an extended source which we suggest is the host galaxy of GRB 060912A. The location of the afterglow lies at the eastern end of this galaxy and the afterglow may still contribute significantly at this time. Images of the field can be found at http://star-www.herts.ac.uk/~levan/060912A/ We thank the staff of the VLT for their assistance with these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5574 SUBJECT: GRB 060912A: VLA Observation DATE: 06/09/14 14:45:18 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 060912A (GCN#5562) using the VLA at a frequency of 8.46 GHz and starting at 8.19 UT on September 14, 2006. There is no detection of the GRB with 2-sigma upper limit of 65 microJy. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5617 SUBJECT: GRB 060912A: Redshift of probable host galaxy DATE: 06/09/26 20:17:04 GMT FROM: Pall Jakobsson at U Hertfordshire P. Jakobsson, A. Levan, R. Chapman (U. Hertfordshire), E. Rol, N. Tanvir (U. Leicester), P. Vreeswijk (ESO), D. Watson (DARK, NBI) We obtained 6*1200 s spectra of the proposed host galaxy of GRB 060912A (Levan et al. GCN 5573), using FORS2 on the VLT. The combined spectrum shows a very strong emission line at 7218A which we identify with [OII] 3727A at a redshift of z = 0.937. At the same redshift we also identify H-gamma in emission and possibly NeIII 3869A. The properties of this host galaxy (in particular strong [OII] emission) are similar to those seen in long-duration GRB hosts. We conclude that the proximity of this burst to a low redshift elliptical galaxy was most likely coincidental. We thank the VLT staff for their assistance in these observations.