//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7226 SUBJECT: GRB 080129 (?): Swift detection of a possible burst DATE: 08/01/29 06:31:10 GMT FROM: Stefan Immler at NASA/GSFC S. Immler (CRESST/GSFC/UMD), D. N. Burrows (PSU), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), D. Perez (U Leicester), M. Perri (ASDC), M. Stamatikos (NASA/ORAU) and G. Stratta (ASDC) report on behalf of the Swift Team: At 06:06:45 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible GRB 080129 (trigger=301981). The BAT on-board calculated location is RA, Dec 105.280, -7.827 which is RA(J2000) = 07h 01m 07s Dec(J2000) = -07d 49' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve for this event appears to show a duration of about 80 sec with a peak of ~600 counts/sec (15-350 keV), at ~30 sec after the trigger although, as is usual for image triggers, the TDRSS light curve is noisy. The location of the source, 1.4 degrees from the Galactic plane raises the possibility that this is a Galactic transient. Further analysis will require the downlinked data from Malindi. Because of an Earth limb constraint, the spacecraft did not slew promptly to the BAT position, and so there are no immediate XRT or UVOT data products to analyze. Swift will slew to this position at about T+3006 s, or about 06:56 UT. Burst Advocate for this burst is S. Immler (immler AT milkyway.gsfc.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: 7227 SUBJECT: GRB 080129 (?): UVOT Upper Limits DATE: 08/01/29 07:15:34 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) reports on behalf of the Swift Team: UVOT took a 100 s finding chart exposure of the field of the possible GRB 080129 (Immler et al., GCN Circ. 7226) with the white (160-650 nm) filter starting 3207 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The 3-sigma upper limit at the centre of the BAT position is white ~= 18.5 on the UVOT photometric system (Poole et al. 2008). The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle and contains no uncatalogued sources. This list of sources is typically complete to about 18 mag. This field is 1.42 degrees from the Galactic place, and no correction has been made for the expected Galactic extinction corresponding to a reddening of E(B-V) = 1.02. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7228 SUBJECT: GRB 080129: Swift XRT position DATE: 08/01/29 07:22:11 GMT FROM: Matteo Perri at ISAC/ASDC M. Perri (ASDC), G. Stratta (ASDC) and D.N. Burrows (PSU) report on behalf of the Swift XRT team: The Swift XRT began observing the possible GRB 080129 (trigger #301981, Immler et al., GCN Circ. 7226) at 07:00:08 UT, about 53 min after the BAT trigger. Analysis of prompt downlinked data finds an uncataloged X-ray source located at RA, Dec 105.2848, -7.8463 which is RA(J2000) = 07 01 8.35 Dec(J2000) = -07 50 46.8 with an uncertainty of 3.3 arcsec (radius, 90% containment). This location is 71 arcseconds from the BAT on-board position, within the BAT error circle (Immler et al., GCN Circ 7226). Further analysis will be reported in a subsequent circular. This circular is an official product of the Swift XRT Team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7229 SUBJECT: GRB 080129: Gemini-South Imaging Observations DATE: 08/01/29 08:23:04 GMT FROM: Josh Bloom at UC Berkeley J. S. Bloom (UC Berkeley) reports on behalf of the larger GRAASP collaboration: "Automatically triggering off of the original GCN/SWIFT_BAT_POSITION notice for GRB 080129 (GCN 7226), we observed the field with Gemini South + GMOS in the r-band starting at 06:50:21.4 2008-01-29 in a series of 5 dithered exposures of 5 minutes apiece. Consistent with the position of the X-ray source (GCN 7228) we find a point-like object at: 07:01:08.20 -07:50:46.3 (J2000) (preliminary uncertainty of 300 mas rms relative to 2MASS). We suggest that this is the optical afterglow of GRB 080129 but cannot confirm variability at this time. More observations are encouraged." We thank the Gemini Staff for conducting these observations. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7230 SUBJECT: GRB 080129: Enhanced Swift-XRT position DATE: 08/01/29 10:36:12 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 399 s of overlapping XRT Photon Counting mode and UVOT V-band data for GRB 080129, 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 = 105.28406, -7.84705 which is equivalent to: RA (J2000): 07h 01m 8.17s Dec (J2000): -07d 50' 49.4" with an uncertainty of 2.7 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, astro-ph/0708.0986 http://www.swift.ac.uk/xrt_positions/Goad.pdf). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7231 SUBJECT: GRB 080129: GROND detection of the optical/NIR afterglow, and fading DATE: 08/01/29 11:10:18 GMT FROM: Jochen Greiner at MPI T. Kruehler, S. Loew, J.Greiner, C.Clemens, A. Kuepcue Yoldas, A. Yoldas (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 080129 observed by Swift (Immler et al. 2008, GCN#7226) simultaneously in grizJHK with GROND mounted at the 2.2m MPI/ESO telescope at La Silla (Chile). Observations started at 06:11 UT, about 4 min after the GRB. We find a point source not present in the Digital Sky Survey images inside the Swift/XRT error circle of the X-ray afterglow (Perri et al. 2008, GCN#7228; Goad et al. 2008, GCN#7230). The coordinates are (+- 0.5 arcsec error): RA (2000.0) = 07h 01m 08.2s Decl. (2000.0) = -07d 50' 47' consistent with the optical source reported by J. S. Bloom (GCN#7229). We estimate magnitudes of 22.8 (r), 21.5 (i), 20.6 (z), 18.9 (J), 18.1 (H) and 17.0 (K) calibrated against USNO and 2MASS field stars. These magnitudes are not corrected for galactic extinction. The source is fading by about 0.5 mag during the first 90 min, suggesting it to be the optical/NIR afterglow of GRB 080129. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7232 SUBJECT: GRB 080129: GROND detection in all bands, and fading DATE: 08/01/29 11:19:56 GMT FROM: Jochen Greiner at MPI T. Kruehler, S. Loew, J.Greiner, C.Clemens, A. Kuepcue Yoldas, A. Yoldas (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 080129 observed by Swift (Immler et al. 2008, GCN#7226) simultaneously in grizJHK with GROND mounted at the 2.2m MPI/ESO telescope at La Silla (Chile). Observations started at 06:11 UT, about 4 min after the GRB. We find a point source not present in the Digital Sky Survey images inside the Swift/XRT error circle of the X-ray afterglow (Perri et al. 2008, GCN#7228; Goad et al. 2008, GCN#7230). The coordinates are (+- 0.5 arcsec error): RA (2000.0) = 07h 01m 08.2s Decl. (2000.0) = -07d 50' 47' consistent with the optical source reported by J. S. Bloom (GCN#7229). We estimate magnitudes of 22.8 (r), 21.5 (i), 20.6 (z), 18.9 (J), 18.1 (H) and 17.0 (K) calibrated against USNO and 2MASS field stars. These magnitudes are not corrected for galactic extinction. The source is fading by about 0.5 mag during the first 90 min, suggesting it to be the optical/NIR afterglow of GRB 080129. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7233 SUBJECT: GRB 080129: Gemini-South photometry DATE: 08/01/29 11:48:14 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley and J. S. Bloom (UC Berkeley) report on behalf of the GRAASP collaboration: Preliminary photometry of our first series of r-band observations of the candidate afterglow of GRB 080129 (Immler et al., GCN 7226; Bloom, 7229) yields the following magnitudes, calibrated using three DSS stars*: t=44 min: R = 22.93 +/- 0.06 t=50 min: R = 22.86 +/- 0.05 t=56 min: R = 22.78 +/- 0.04 t=62 min: R = 22.56 +/- 0.04 t=68 min: R = 22.87 +/- 0.05 As these magnitudes are approximately consistent with the value reported by Kruehler et al. (GCN 7231/7232) we do not confirm general fading behavior of this source over the interval of our observations. However, we note that the fourth exposure shows statistically significant evidence of a short-lived rebrightening. While an instrumental cause has not been ruled out, given the location in the Galactic plane of the source and the very slow fading reported by Kruehler et al. (0.5 mag from 4 to ~94 minutes, atypical of extragalactic GRBs), it is possible that the GRB may be an analog of GRB 070610 / SWIFT J195509.6+261406 (Pagani et al., GCN 6489; Kasliwal et al. 2007, arXiv:0708.0226), which showed extensive short-time scale early-time variability above a nearly-constant baseline. Further observations (including rapid-time-series optical observations), and further analysis of the X-ray afterglow, are encouraged to further investigate the nature of this source. --- *Calibration stars are: ra dec R2 07:01:10.5033 -07:50:24.020 17.130 07:01:07.7333 -07:51:24.620 17.040 07:01:04.7193 -07:50:46.690 17.310 [GCN OPS NOTE(29jan08): Per author's request, the "Greiner" citation was changed to "Kruehler".] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7234 SUBJECT: GRB 080129: TAROT La Silla observatory optical observations DATE: 08/01/29 12:29:15 GMT FROM: Alain Klotz at CESR-CNRS Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 080129 detected by SWIFT (trigger 301981) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 352.7s after the GRB trigger (270.9s after the notice). The elevation of the field decreased from from 42 degrees above horizon and weather conditions were good. The date of trigger : t0 = 2008-01-29T06:06:45.216 The fiirst image is 90.0s exposure in tracking mode. We do not detect any OT with a limiting magnitude of: t0+352.7s to t0+442.7s : R > 16.4 We co-added a series of exposures: t0+448.5s to t0+1039.0s : R > 18.3 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=220.9983 lat= -1.4244 and the galactic extinction in R band is about 9 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7235 SUBJECT: GRB 080129, Swift-BAT refined analysis DATE: 08/01/29 16:35:01 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), S. Immler (CRESST/GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080129 (trigger #301981) (Immler, et al., GCN Circ. 7226). The BAT ground-calculated position is RA, Dec = 105.297, -7.840 deg which is RA(J2000) = 07h 01m 11.2s Dec(J2000) = -7d 50' 24" with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 46%. The mask-weighted light curve shows a single broad peak starting at ~T-20 sec, peaking at ~T+20, and ending at ~T+50. T90 (15-350 keV) is 48 +- 10 sec (estimated error including systematics). The time-averaged spectrum from T-15.0 to T+49.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.34 +- 0.26. The fluence in the 15-150 keV band is 8.9 +- 1.4 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+24.50 sec in the 15-150 keV band is 0.2 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The majority of the indicators say this is a GRB, but at this time we can not rule out a galactic source explanation for this trigger. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/301981/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7236 SUBJECT: GRB 080129: optical limit by Pi of the Sky DATE: 08/01/29 21:04:53 GMT FROM: Grzegorz Wrochna at Soltan Inst.for Nuclear Studies M.Cwiok, W.Dominik, G.Kasprowicz, A.Majcher, A.Majczyna, K.Malek, L.Mankiewicz, M.Molak, K.Nawrocki, L.W.Piotrowski, D.Rybka, M.Sokolowski, J.Uzycki, G.Wrochna, A.F.Zarnecki on behalf of "Pi of the Sky" collaboration http://grb.fuw.edu.pl "Pi of the Sky" apparatus located at Las Campanas Observatory imaged the region of GRB 080129 from 6:09:21 UT, i.e. 155s after the GRB (74s after the trigger), with 10s exposures (IR-cut filter only). No new object has been detected within the XRT error box. Limiting magnitude for 10s exposures is >11.8 mag. The limit for 20 coadded images is >12.5 mag. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7238 SUBJECT: GRB 080129: KAIT optical limits DATE: 08/01/30 00:16:38 GMT FROM: Weidong Li at UC Berkeley KAIT/LOSS W. Li and A. V. Filippenko, University of California, Berkeley, on behalf of the KAIT GRB team, report: We imaged the field of GRB 080129 detected by Swift (trigger 301981; Immler et al. GCN 7226) with the robotic 0.76-m Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory. The automatic sequence was not executed due to poor weather, but a manual sequence was observed remotely. In total, 14 x 20 s unfiltered observations were observed. Our first 20 s image started at 6:11:31 UT, 286 s after the GRB trigger. We did not detect the optical/NIR afterglow candidate reported by Bloom (GCN 7229) and Kruehler et al. (GCN 7231) to a limiting magnitude of 17.9 (calibrated to USNO B1). A 200 s co-added image with the middle exposure time at 643 s after the GRB trigger did not detect the afterglow candidate to a limiting magnitude of 20.0. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7240 SUBJECT: GRB 080129: Swift-XRT refined analysis DATE: 08/01/30 16:42:11 GMT FROM: Giulia Stratta at ASDC G. Stratta (ASDC), M. Perri (ASDC) and D. N. Burrows (PSU) report on behalf of the Swift-XRT team: The Swift-XRT began observing GRB 080129 (trigger=301981) on 2008-01-29 at 07:00:17 UT, 53 minutes after the BAT trigger (Immler et al., GCN Circ. 7226). Using 2045 s of overlapping XRT Photon Counting mode and UVOT v-band data for GRB 080129, we find a refined astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 105.284125, -7.846722 which is equivalent to: RA (J2000): 07h 01m 8.19s Dec (J2000): -07d 50' 48.2" with an uncertainty of 2.0 arcsec (radius, 90% confidence). This is 1.2 arcsec away from the previous position derived from the XRT and UVOT data reported in Goad et al. (GCN Circ. 7230), 51 arcsec from the refined BAT position of Barthelmy et al. (GCN Circ. 7235) and 1.9 arcsec from the Gemini South position (GCN Circ. 7229). The X-ray light curve from T + 3.2 ks to T + 85.8 ks can be fitted by a broken power law model (chi2 of 39 for 28 degrees of freedom) with a temporal break at about T + 15.5 ks and decay indices alpha1 = 0.6 +/- 0.1 and alpha2 = 1.5 +/- 0.1 before and after the break, respectively. The 0.3-10 keV spectrum from T + 3.2 ks to T + 32.2 ks is well fit by an absorbed power law (reduced chi2 of 1.02, with 20 degrees of freedom). The best fit photon index is 2.0 +/- 0.1, with an hydrogen column density of (2 +/- 1)e21 cm^-2, in addition to the Galactic column along the line of sight of 6.3e21 cm^-2 (Kalberla et al. 2005). The observed (unabsorbed) flux in the 0.3-10 keV band is 4.2e-12 (8.5e-12) erg cm^-2 s^-1. The timing and spectral behaviors are completely consistent with those of a typical GRB X-ray afterglow, removing any uncertainty about the nature of this burst. The predicted XRT count rate 48 hours after the trigger is 1.6e-3 count s^-1, which corresponds to an observed 0.3-10.0 keV flux of 1.3e-12 ergs cm^-2 s^-1. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7241 SUBJECT: GRB 080129: Optical observations from OSN DATE: 08/01/30 20:18:53 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (ESO, Santiago), D. Diaz Fraile, F. Aceituno, E. Rodríguez, A.J. Castro-Tirado, J. Gorosabel, M. Jelinek (IAA-CSIC, Granada) and A. Pozanenko (IKI, Moscow) report on behalf of a larger collaboration: We have observed GRB 080129 (Immler et al. GCN 7226) with the 1.5m OSN telescope at Sierra Nevada Observatory (Granda, Spain). The observations consist of a series of 625x19s exposures in I-band, and range from 29.8614 Jan 2008 to 30.0166 Jan 2008 UT (0.607-0.762 days after the burst). We do not detect any source in the individual frames down to an average limiting magnitude I < 20.3. However, the combined frame does show the source identified by Bloom et al. (GCN 7229) at I ~ 22.1. A finding chart can be seen at: http://www.iaa.es/~deugarte/GRBs/080129/080129_OSN_fc.jpg This message may be cited. [GCN OPS NOTE(31jan08): Per author's request, M. Jelinek was added to the author list.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7246 SUBJECT: GRB 080129: Swift/UVOT Refined Upper Limits DATE: 08/01/31 13:12:48 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/GSFC/USRA) and S. Immler (CRESST/UMCP/GSFC) report on the behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 080129 starting 3188 s after the BAT trigger (Immler et al. 2007, GCN Circ. 7226). We do not find any source, in any of the UVOT observations, at the location of the Gemini-South source (Bloom, 2007 GCN Circ. 7229). The 3-sigma upper limits for detecting a source at this location in the co-added images are: Filter T_start T_stop Exp(s) Mag (3-sigma upper limit) ----------------------------------------------------------------- v 3188 21,457 2023 21.3 b 4134 28,152 2164 22.2 u 3929 27,239 1278 21.5 uvw1 3724 32,166 1182 21.3 uvm2 3519 22,362 1279 21.2 uvw2 4545 17,372 1920 21.7 white 3207 28,940 2856 23.1 ----------------------------------------------------------------- This burst occurred 1.43 degrees from the Galactic plane, so the Galactic reddening along the line of sight is highly uncertain. The values quoted above are not corrected for Galactic extinction. All photometry is on the UVOT flight system described in Poole et al. (2008).