//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14195 SUBJECT: GRB 130211A: Swift detection of a burst DATE: 13/02/11 03:58:20 GMT FROM: Scott Barthelmy at NASA/GSFC S. R. Oates (UCL-MSSL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), C. B. Markwardt (NASA/GSFC), K. L. Page (U Leicester) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 03:36:32 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130211A (trigger=548276). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 147.523, -42.339 which is RA(J2000) = 09h 50m 05s Dec(J2000) = -42d 20' 18" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several overlapping peaks with a duration of about 20 sec. The peak count rate was ~900 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 03:38:26.0 UT, 113.9 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 147.53605, -42.34244 which is equivalent to: RA(J2000) = 09h 50m 08.65s Dec(J2000) = -42d 20' 32.8" with an uncertainty of 4.0 arcseconds (radius, 90% containment). This location is 36 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 2.16 x 10^21 cm^-2 (Kalberla et al. 2005). The initial flux in the 2.5 s image was 7.98e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 125 seconds after the BAT trigger. No credible 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 typical 3-sigma upper limit has been about 19.6 mag. Results from the list of sources generated on-board are not available at this time. No correction has been made for the expected extinction corresponding to E(B-V) of 0.54. Burst Advocate for this burst is S. R. Oates (sro AT mssl.ucl.ac.uk). 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: 14196 SUBJECT: GRB 130211A: GROND detection of the afterglow DATE: 13/02/11 09:50:35 GMT FROM: Vladimir Sudilovsky at MPE F. Knust, J. Greiner, and V. Sudilovsky (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 130211A (Swift trigger 548276; Oates et al., GCN 14195) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile). Observations started at 03:45 UT on 11.02.2013, 9 min after the GRB trigger. They were performed at a seeing improving over time from 3" to 1.2", and at an average airmass of 1.0. We find one variable source inside the 4.0" error circle, at coordinates RA (2000.0) = 09:50:08.736 Decl (2000.0) = -42:20:32.64 with an error of 0.3". Based on 1500s exposure in g'r'i'z' and 1200s in JHK started at 06:09 UT, we estimate preliminary AB magnitudes of: g' > 25.3 mag, r' = 23.5 +- 0.1 mag, i' = 22.2 +- 0.1 mag, z' = 21.7 +- 0.1 mag, J = 20.6 +- 0.2 mag, H = 20.1 +- 0.2 mag, and K > 19.5 mag. Given magnitudes are calibrated against GROND zeropoints (g'r'i'z') as well as 2MASS field stars (JHK) and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.53 mag in the direction of the burst (Schlegel et al. 1998). After correcting for the expected foreground extinction, the spectral energy distribution of this source is well-fit by a power-law with slope b~1.4. The reduced flux in g' and r' imply a redshift of z~4.3. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14197 SUBJECT: GRB 130211A: Swift-BAT refined analysis DATE: 13/02/11 13:32:29 GMT FROM: Scott Barthelmy at NASA/GSFC T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), S. R. Oates (UCL-MSSL), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC) (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 130211A (trigger #548276) (Oates, et al., GCN Circ. 14195). The BAT ground-calculated position is RA, Dec = 147.524, -42.330 deg which is RA(J2000) = 09h 50m 05.7s Dec(J2000) = -42d 19' 47.1" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 40%. The mask-weighted light curve shows multiple, weak, overlapping peaks starting at ~T-10 sec, peaking at ~T-2 sec, and ending at ~T+30 sec. T90 (15-350 keV) is 25.1 +- 6.3 sec (estimated error including systematics). The time-averaged spectrum from T-1.56 to T+32.00 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.81 +- 0.24. The fluence in the 15-150 keV band is 6.4 +- 1.0 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-1.58 sec in the 15-150 keV band is 0.7 +- 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/548276/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14198 SUBJECT: GRB 130211A: Swift-XRT refined Analysis DATE: 13/02/11 18:58:03 GMT FROM: Phil Evans at U of Leicester D.N. Burrows (PSU), O.M. Littlejohns (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), G. Stratta (ASDC), J.A. Kennea (PSU), M.C. Stroh (PSU) and S.R. Oates report on behalf of the Swift-XRT team: We have analysed 9.2 ks of XRT data for GRB 130211A (Oates et al. GCN Circ. 14195), from 120 s to 29.1 ks after the BAT trigger. The data comprise 201 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The refined XRT position is RA, Dec = 147.53616, -42.34237 which is equivalent to: RA (J2000): 09 50 08.68 Dec(J2000): -42 20 32.5 with an uncertainty of 3.6 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=2.85 (+0.27, -0.23). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 3.55 (+/-0.14). The best-fitting absorption column is 5.9 (+/-0.4) x 10^21 cm^-2, in excess of the Galactic value of 2.2 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.5 x 10^-11 (2.3 x 10^-10) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Total column: 5.9 (+/-0.4) x 10^21 cm^-2 Galactic foreground: 2.2 x 10^21 cm^-2 Excess significance: 15.9 sigma Photon index: 3.55 (+/-0.14) If the light curve continues to decay with a power-law decay index of 2.85, the count rate at T+24 hours will be 1.3 x 10^-7 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.3 x 10^-18 (3.1 x 10^-17) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00548276. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14199 SUBJECT: GRB 130211A: Swift/UVOT Upper Limits DATE: 13/02/11 21:58:48 GMT FROM: Samantha Oates at MSSL S. R. Oates (MSSL-UCL) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 130211A 125 s after the BAT trigger (Oates et al., GCN Circ. 14195). No optical afterglow consistent with the optical position (Knust et al. GCN Circ. 14196) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 125 275 147 >21.8 white 125 17061 1076 >22.9 v 4470 22933 1646 >21.7 b 3854 16303 1278 >22.4 u 284 29091 650 >21.3 w1 4880 28760 1082 >21.8 m2 4674 27853 1175 >21.6 w2 4265 22020 1968 >22.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.53 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14358 SUBJECT: GRB 130211A: Retraction of afterglow candidate DATE: 13/04/02 14:04:00 GMT FROM: Vladimir Sudilovsky at MPE V. Sudilovsky and J. Greiner (both MPE Garching) report on behalf of the GROND team: Based on follow-up observations taken on 2013-03-29 (T+47 days after the initial Swift trigger 548276; Oates et al., GCN 14195) of the source reported in GCN 14196, we retract our classification of this object. Since there is no significant time variability associated with this source, we conclude that it cannot be the afterglow of GRB 130211A. The final magnitudes of this source (all AB) are: g' > 24.0 mag, r' = 23.5 +/- 0.1 mag, i' = 22.3 +/- 0.1 mag, z' = 21.7 +/- 0.1 mag, J = 20.9 +/- 0.2 mag, H = 20.5 +/- 0.2 mag, and K > 20.2 mag. We note that the large r'-i' color is consistent with the 4000 Angstrom break expected from a galaxy at z~0.8. However, we caution that at this time there are not enough data to make a definitive statement about this source. Given magnitudes are calibrated against GROND zeropoints (g'r'i'z') as well as 2MASS field stars (JHK) and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.53 mag in the direction of the burst (Schlegel et al. 1998).