//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8435 SUBJECT: GRB 081029: Swift detection of a burst DATE: 08/10/29 01:52:55 GMT FROM: David Palmer at LANL T. Sakamoto (NASA/UMBC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), C. Guidorzi (INAF-OAB), S. T. Holland (CRESST/USRA/GSFC), H. A. Krimm (CRESST/GSFC/USRA), J. Mao (INAF-OAB), D. M. Palmer (LANL), M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team: At 01:43:56 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 081029 (trigger=332931). Swift could not immediately slew to the burst due to an Earth limb constraint. The BAT on-board calculated location is RA, Dec 346.704, -68.160 which is RA(J2000) = 23h 06m 49s Dec(J2000) = -68d 09' 34" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for an image trigger, the BAT light curve shows nothing remarkable. Due to an observing constraint, Swift will not slew until T0+41.3 minutes. There will be no XRT or UVOT data until that time. Burst Advocate for this burst is T. Sakamoto (Taka.Sakamoto AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8436 SUBJECT: GRB 081029: ROTSE-III Detection of Optical Counterpart DATE: 08/10/29 01:57:59 GMT FROM: Eli Rykoff at UCSB E.S. Rykoff (UCSB), report on behalf of the ROTSE collaboration: ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded to GRB 081029 (Swift trigger 332931, GCN 8435, Sakamoto et al.). The first image was at 01:45:22.8 UT, 86.0 s after the burst (8.8 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a 16.5 magnitude, fading source with coordinates: 23:07:05.36 -68:09:19.74 (J2000), with positional uncertainty of 1" or better start UT mag mlim(of image) ---------------------------------- 01:45:22.8 16.5 17.8 This source is not visible in DSS (second epoch), 2MASS or the MPChecker database. A jpeg image is available at http://www.rotse.net/images/gsb332931_3c011-020_key.jpg Note that the object marked 36 is the candidate in question. Continuing observations are in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8437 SUBJECT: GRB 081029: GROND Detection of the Optical/NIR Afterglow DATE: 08/10/29 02:49:45 GMT FROM: Jochen Greiner at MPI C. Clemens, S. Loew and J. Greiner (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 081029 (Swift trigger 332931; Sakamoto et al., GCN #8435) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla Observatory (Chile). Observations started at 01:52 UT on October 29th, 2008, 8.2 min after the GRB trigger, and are continuing. They were performed at an average seeing of 1.0" and at an average airmass of 1.3. We found a bright point source at the position reported by Rykoff et al. (GCN #8436), at magnitude r'=17.8 during the first 4 min integration, calibrated with the GROND zeropoint. The object is seen in g' band, implying a redshift smaller than 3.5. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8438 SUBJECT: GRB 081029: UVES/VLT Absorption Redshift DATE: 08/10/29 06:08:18 GMT FROM: Paolo D'Avanzo at INAF-OAB V. D'Elia, (INAF-OAR), S. Covino, P. D'Avanzo (INAF-OAB), report on behalf of the MISTICI collaboration Following the detection of GRB 081029 (Sakamoto et al. GCN 8435), we triggered observations with the UVES camera, mounted at ESO-VLT. The observations were performed using both dichroics. We took two spectra starting around Oct 29 at 02:06 UT (about 23 minutes after the burst) and covering the range 300-1000 nm. We detect several absorption features, both ground and fine structure, namely, the SiII 1253, SiII 1260, SiII* 1264, OI 1302, SiII 1304, SiII* 1309, CII 1334 and CII* 1335. These features are interpreted as produced by the gas in the GRB host galaxy, at the redshift z=3.8479+/-0.0002 Further analysis is in progress. We are very grateful for the excellent support of the VLT staff and in particular to Antonio De Ugarte Postigo. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8441 SUBJECT: GRB 081029: REM observations DATE: 08/10/29 08:12:57 GMT FROM: Stefano Covino at Brera Astronomical Observatory S. Covino, P. D'Avanzo, L.A. Antonelli, D. Malesani, D. Fugazza, L. Calzoletti, S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini, V. D'Elia, F. D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C. Guidorzi, G.L. Israel, E. Maiorano, N. Masetti, A. Melandri, E. Meurs, L. Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella, G. Stratta, G. Tagliaferri, G. Tosti, V.Testa, S.D. Vergani, F. Vitali report on behalf of the REM team: The robotic 60-cm REM telescope located at La Silla (Chile) observed automatically the field of the GRB 081029 (Sakamoto et al., GCN 8435) on Oct 29, starting about 2 min after the burst time. The afterglow reported by Rykoff et al. (GCN 8436) and Clemens et al. (GCN 8437) is clearly detected both in the optical and infrared bands at a magnitude level H~14.6 about 2.5 min after the burst. [GCN OPS NOTE(29oct08): Per author's request, the second (duplicate) author was replaced with "P. D'Avanzo".] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8443 SUBJECT: GRB 081029: Enhanced Swift-XRT position DATE: 08/10/29 09:11:14 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 2569 s of XRT Photon Counting mode data and 3 UVOT images for GRB 081029, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 346.7729, -68.1561 which is equivalent to: RA (J2000): 23h 07m 5.51s Dec (J2000): -68d 09' 21.9" with an uncertainty of 1.5 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401 http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an extension of this method. This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8446 SUBJECT: GRB081029: Swift XRT refined analysis DATE: 08/10/29 11:10:09 GMT FROM: Jirong Mao at INAF-OAB J. Mao, R. Margutti, C. Guidorzi (INAF-OAB) and T. Sakamoto (NASA/ UMBC) report on behalf of the Swift-XRT team: We have analysed the first 3 orbits of Swift-XRT data obtained for GRB 081029 (Sakamoto et al., GCN Circ. 8435). From T+2.7 to T+16.7 ks after the burst, data were collected in Photon Counting (PC) mode with a total net exposure of 7 ks. The UVOT-enhanced position was given by Goad et al. in GCN Circ. 8443. The light curve shows a decay that can be fit with a simple power law with an index of 0.57 +- 0.05. The PC spectrum accumulated between T+2.7 and T+16.7 ks can be fit with a absorbed power-law model with a photon index of 1.9 +- 0.1 and an absorbing equivalent hydrogen column density consistent with the Galactic one in the GRB direction (2.7e20 cm^-2; Kalberla et al. 2005). The observed (unabsorbed) 0.3-10 keV flux is 6.9(7.5)e-12 erg cm^-2 s^-1. If the light-curve continues to decay with alpha ~ 0.57, the count rate 24 hours after the burst is estimated to be 0.03 count s^-1, which corresponds to an observed flux of 2.1e-12 erg cm^-2 s^-1. This is an official product of the Swift-XRT team. [GCN OPS NOTE(29oct08): Per author's request, the GRB name in the subject was changed from 080229 to 081029.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8447 SUBJECT: GRB 081029: Swift-BAT refined analysis DATE: 08/10/29 12:48:10 GMT FROM: Scott Barthelmy at NASA/GSFC J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 081029 (trigger #332931) (Sakamoto, et al., GCN Circ. 8435). The BAT ground-calculated position is RA, Dec = 346.776, -68.179 deg, which is RA(J2000) = 23h 07m 06.3s Dec(J2000) = -68d 10' 43.4" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 58%. The mask-weighted light curve shows a single relatively smooth peak starting at ~T-50 sec, peaking at ~T+60 sec, and ending at ~T+300 sec. T90 (15-350 keV) is 270 +- 45 sec (estimated error including systematics). The time-averaged spectrum from T-35.6 to T+268.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.43 +- 0.18. The fluence in the 15-150 keV band is 2.1 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+52.37 sec in the 15-150 keV band is 0.5 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/332931/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8448 SUBJECT: GRB 081029: Redshift Confirmation from Gemini-South DATE: 08/10/29 14:43:19 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara, D. B. Fox (Penn State), S. B. Cenko (Berkeley) and E. Berger (Harvard) report on behalf of a larger collaboration: Starting at 07:04 UT on 2008 November 29 (T0+5h) we observed the optical counterpart of GRB 081029 (Sakamoto et al., GCN 8435, Rykoff et al., GCN 8436) using Gemini-South with the GMOS-South spectrograph (R~1600). We acquired 2x900s spectra covering the wavelength range 4000A-8000A. We detect a damped Lyman-alpha system (DLA) at redshift z=3.847. We also detect several metal absorption features which we interpret as SiIV(1393,1402), SiII1526 and 1260, SiII*1264, CI1560, CII1334, CII*1335, CIV(1548,1550), FeII1608, NV(1238,1242) at the same redshift. In combination with the strong metal absorption features, the detection of a DLA at z=3.847 confirms that this is the redshift of GRB 081029 and its host galaxy. Our results are consistent with those of D'Elia et al. (GCN 8438). We thank the Gemini staff, in particular Rodrigo Damele, for conducting these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8449 SUBJECT: GRB 081029: PROMPT Detections DATE: 08/10/29 15:35:18 GMT FROM: James Philip West at UNC/Chapel Hill J. P. West, J. Haislip, T. Brennan, D. Reichart, M. Nysewander, A. LaCluyze, K. Ivarsen, J. A. Crain, A. Foster, R. Holmes, M. Schubel, R. Rhine, J. Styblova, A. Trotter, and E. Weaver report: Skynet observed the localization of GRB 081029 (Sakamoto et al., GCN 8435) with three of the 16" PROMPT telescopes at CTIO beginning 92 seconds after the trigger (64 seconds after notification) in BVRI. We detect the afterglow (Rykoff et al., GCN 8436) in individual exposures in VRI. At 147 seconds after the burst we measure V ~ 16.8 mag (calibrated to 9 NOMAD stars), at 174 seconds we measure R ~ 15.7 mag (calibrated to 10 USNO stars), and at 296 seconds we measure I ~ 15.8 mag (calibrated to 10 USNO stars). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8450 SUBJECT: GRB 081029: UVOT Detection of the Optical Afterglow DATE: 08/10/29 16:41:01 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) & T. Sakamoto (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT observed the field of GRB 081029 starting 2708 s after the BAT trigger (Sakamoto et al., 2008, GCNC 8435). The late start to the follow-up observations is due to an Earth limb constraint at the time of the BAT trigger. We detect the optical afterglow (Rykoff et al., GCNC 8436) in the v, b, and white filters. This is consistent with a redshift of z = 3.8479 (D'Elia, et al., 2008, GCNC 8438). The refined UVOT source position is RA (J2000.0) = 23:07:05.35 = 346.77229 (deg) Dec (J2000.0) = -68:09:19.8 = -68.15549 (deg) with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence, statistical + systematic). Magnitudes and 3-sigma upper limits are reported below. TSTART and TSTOP are the start and stop times of the exposure, in seconds since the BAT trigger. Exposure is the total exposure time, in seconds, during that interval. Filter TSTART TSTOP Exposure Mag Err Comments v 2687 2887 197 19.02 0.20 8557 8757 197 18.66 0.21 b 3072 3272 197 >20.5 3-sigma upper limit 4507 4707 197 20.05 0.20 u 2867 21,932 1601 >21.9 3-sigma upper limit uvw1 4097 21,019 1968 >21.8 3-sigma upper limit uvm2 3892 16,685 1590 >21.7 3-sigma upper limit uvw2 3482 15,250 1279 >21.7 3-sigma upper limit white 2708 7856 147 20.50 0.30 4712 4912 197 19.41 0.10 The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E_{B-V} = 0.03 mag (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383,627). The power-law decay index in the v band between 8557 and 15,864 s is consistent with no decay. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8452 SUBJECT: GRB 081029, SMARTS optical/IR afterglow observations DATE: 08/10/29 23:19:48 GMT FROM: Bethany Cobb at UC Berkeley B. E. Cobb (UC Berkeley) reports: Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 081029 (GCN 8435, Sakamoto et al.) at three epochs with mid-exposure times of 2008-10-29 04:18 UT (2.57 hrs post-burst), 04:50 UT (3.10 hrs post-burst) and 05:21 UT (3.62 post-burst). At each epoch, several dithered images were obtained in each filter, with total summed exposure times of 180s in each of BRIJK and 120s in each of H and V. The GRB afterglow (e.g. GCN 8436, Rykoff et al. and GCN 8437, Clemens et al.) is detected in all our filters: filter 2.57 hrs 3.10 hrs 3.62 hrs B 19.69+/-0.04 19.85+/-0.04 20.00+/-0.05 V 18.26+/-0.03 18.38+/-0.03 18.57+/-0.04 R 17.32+/-0.02 17.50+/-0.02 17.66+/-0.02 I 16.79+/-0.03 16.94+/-0.03 17.15+/-0.03 J 15.83+/-0.08 16.02+/-0.08 16.03+/-0.08 H 15.00+/-0.08 15.13+/-0.08 15.32+/-0.08 K 14.25+/-0.08 14.35+/-0.08 14.60+/-0.08 These preliminary magnitudes are calibrated using Landolt standard stars in the optical and 2MASS stars in the IR. Between 2.57 hrs and 3.62 hours post-burst, the afterglow decays with an approximate optical decay rate of alpha~-0.9 (where afterglow flux is proportional to t^alpha). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8634 SUBJECT: Radio observation of GRB 081029 with ATCA DATE: 08/12/08 01:59:11 GMT FROM: Aquib Moin at CIRA/ATNF Aquib Moin (Curtin Institute of Radio Astronomy / Australia Telescope National Facility), Steven Tingay (Curtin Institute of Radio Astronomy), Chris Phillips (Australia Telescope National Facility), Gregory Taylor (University of New Mexico), Mark Wieringa (Australia Telescope National Facility) and Ralph Martin (Perth Observatory) report: We observed the SWIFT/UVOT refined position of the GRB 081029 optical afterglow (GCN 8450) at 4.800 and 4.928 GHz with the Australia Telescope Compact Array (ATCA) between 01:15:05 UT, November 24, 2008 and 20:35:30 UT November 25, 2008. We did not detect a radio source at the optical afterglow position of the GRB 081029 (GCN 8450). The data at 4.800 and 4.928 GHz were merged and the radio flux density at the afterglow position found out to be -0.168 +/- 0.219 mJy/beam (1-sigma). The Australia Telescope Compact Array (/ Parkes telescope / Mopra telescope / Long Baseline Array) is part of the Australia Telescope which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. See the 4.800 & 4.928 GHz combined image at: http://cira.ivec.org/dokuwiki/doku.php/grb/grb081029_field_image