GRB130427B

This page lists all entries on GRB130427B in GRBweb

Summary IPN Swift GCN 14460 GCN 14461 GCN 14467 GCN 14469 GCN 14477 GCN 14479 GCN 14493 GCN 14496 GCN 14499

Summary table
Variable Value Source
T0 13:20:41 UTC GCN_circulars,Swift Det
ra 314.8985° Swift
decl -22.5463° Swift
pos_error 1.42e-04° Swift
T90 27.0 s Swift
T90_start 13:20:41 UTC Swift
fluence 1.50e-06 erg/cm² Swift
redshift 2.7800 GCN_circulars,Other
T100 27.0 s
GBM_located False
mjd 56409.55603009259 GCN_circulars,Swift Det
IPN table
GRB_name GRB130427B
ra 314.8917°
decl -22.5333°
pos_error 5.00e-02°
redshift 2.7800
Swift table
GRB_name GRB130427B
t_trigger 13:20:41 UTC
ra 314.8985°
decl -22.5463°
pos_error 1.42e-04°
T90 27.0 s
fluence 1.50e-06 erg/cm²
redshift 2.7800
GCN 14460 table
GRB_name GRB130427B
GCN_number 14460
Detection_method Swift Det
t_trigger 13:20:41 UTC
ra 314.8910°
decl -22.5300°
Circular_text TITLE: GCN CIRCULAR NUMBER: 14460 SUBJECT: GRB 130427B: Swift detection of a burst with optical counterpart DATE: 13/04/27 13:31:58 GMT FROM: Scott Barthelmy at NASA/GSFC A. Maselli (INAF-IASFPA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (NASA/GSFC/ORAU), V. Mangano (INAF-IASFPA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), C. J. Mountford (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 13:20:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130427B (trigger=554635). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 314.891, -22.530 which is RA(J2000) = 20h 59m 34s Dec(J2000) = -22d 31' 49" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows 3 peaks with a total duration of about 40 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 13:21:59.1 UT, 77.4 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 314.89766, -22.54548 which is equivalent to: RA(J2000) = 20h 59m 35.44s Dec(J2000) = -22d 32' 43.7" with an uncertainty of 4.4 arcseconds (radius, 90% containment). This location is 59 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. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 4.41 x 10^20 cm^-2 (Kalberla et al. 2005). The initial flux in the 2.5 s image was 1.15e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 87 seconds after the BAT trigger. There is a candidate afterglow in the list of sources generated on-board at RA(J2000) = 20:59:35.64 = 314.89848 DEC(J2000) = -22:32:46.5 = -22.54626 with a 90%-confidence error radius of about 1.10 arc sec. This position is 7.6 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.19. No correction has been made for the expected extinction corresponding to E(B-V) of 0.07. Burst Advocate for this burst is A. Maselli (maselli AT ifc.inaf.it). 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.)
GCN 14461 table
GRB_name GRB130427B
GCN_number 14461
Detection_method Swift-BAT Det
ra 314.8984°
decl -22.5464°
Circular_text TITLE: GCN CIRCULAR NUMBER: 14461 SUBJECT: GRB 130427B: Faulkes Telescope North afterglow detection DATE: 13/04/27 13:39:57 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), J. Japeli, A. Gomboc (U. Ljubljana), A. Melandri (INAF-OAB) on behalf of a large collaboration report: The 2-m Faulkes Telescope North automatically began observing GRB 130427B (Maselli et al. GCN Circ. 14460) at 4.6 minutes from the Swift/BAT trigger time. The automatic LT-TRAP procedure identified a bright uncatalogued object at the following position consistent with that reported by Maselli et al.: RA= 20:59:35.62 Dec= -22:32:46.9 (J2000). Its magnitude is estimated to be 15.5 in the R band.
GCN 14467 table
GRB_name GRB130427B
GCN_number 14467
Detection_method Swift-XRT Det
ra 314.8985°
decl -22.5467°
Circular_text TITLE: GCN CIRCULAR NUMBER: 14467 SUBJECT: GRB 130427B: Enhanced Swift-XRT position DATE: 13/04/27 17:43:09 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 1221 s of XRT Photon Counting mode data and 2 UVOT images for GRB 130427B, 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 = 314.89849, -22.54670 which is equivalent to: RA (J2000): 20h 59m 35.64s Dec (J2000): -22d 32' 48.1" with an uncertainty of 1.8 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) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN 14469 table
GRB_name GRB130427B
GCN_number 14469
Detection_method Swift-BAT Det
ra 314.9000°
decl -22.5480°
Circular_text TITLE: GCN CIRCULAR NUMBER: 14469 SUBJECT: GRB 130427B: Swift-BAT refined analysis DATE: 13/04/27 18:55:42 GMT FROM: Scott Barthelmy at NASA/GSFC 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), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-60 to T+243 sec from recent telemetry downlinks, we report further analysis of BAT GRB 130427B (trigger #554635) (Maelli, et al., GCN Circ. 14460). The BAT ground-calculated position is RA, Dec = 314.900, -22.548 deg, which is RA(J2000) = 20h 59m 36.0s Dec(J2000) = -22d 32' 51.6" with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 22%. The mask-weighted light curve shows shows a very small peak at ~T-3 sec, the main peak starting at ~T-1 sec, peaking at ~T+2 sec, and ending at ~T+40 sec. T90 (15-350 keV) is 27.0 +- 7.3 sec (estimated error including systematics). The time-averaged spectrum from T-1.29 to T+32.71 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.64 +- 0.15. The fluence in the 15-150 keV band is 1.5 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+0.71 sec in the 15-150 keV band is 3.0 +- 0.4 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/554635/BA/
GCN 14477 table
GRB_name GRB130427B
GCN_number 14477
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 14477 SUBJECT: GRB 130427B: MITSuME Okayama upper limits DATE: 13/04/28 00:28:48 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 130427B (Maselli et al., GCNC 14460) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2013-04-27 18:47:30 UT (~5.4 h after the burst). We did not find any new point source within the enhanced XRT circle (Osborne et al., GCNC 14467) in all the three bands. Photometric results of the OT are listed below. We used GSC2.3 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.22892 18:50:19 2160.0 >18.0 >18.3 >17.9 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]
GCN 14479 table
GRB_name GRB130427B
GCN_number 14479
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 14479 SUBJECT: GRB 130427B: Swift-XRT refined Analysis DATE: 13/04/28 01:32:05 GMT FROM: Phil Evans at U of Leicester V. Mangano (INAF-IASFPA), D.N. Burrows (PSU), J.A. Kennea (PSU), M.C. Stroh (PSU), B.P. Gompertz (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU) and A. Maselli report on behalf of the Swift-XRT team: We have analysed 7.3 ks of XRT data for GRB 130427B (Maselli et al. GCN Circ. 14460), from 67 s to 24.2 ks after the BAT trigger. The data comprise 120 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 14467). The late-time light curve (from T0+11.6 ks) can be modelled with a power-law decay with a decay index of alpha=1.9 (+0.6, -0.5). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.93 (+0.14, -0.13). The best-fitting absorption column is 8.3 (+2.8, -2.6) x 10^20 cm^-2, in excess of the Galactic value of 4.4 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 1.79 (+0.23, -0.11) and a best-fitting absorption column consistent with the Galactic value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 0 (+4.7, -0) x 10^20 cm^-2 Galactic foreground: 4.4 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.79 (+0.23, -0.11) If the light curve continues to decay with a power-law decay index of 1.9, the count rate at T+24 hours will be 9.7 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.8 x 10^-14 (4.2 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00554635. This circular is an official product of the Swift-XRT team.
GCN 14493 table
GRB_name GRB130427B
GCN_number 14493
Detection_method Other
redshift 2.7800
Circular_text TITLE: GCN CIRCULAR NUMBER: 14493 SUBJECT: GRB 130427B: Tentative VLT/X-shooter redshift DATE: 13/04/28 18:13:02 GMT FROM: Dong Xu at DARK/NBI H. Flores (GEPI/Obs. de Paris), S. Covino (INAF), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), J. Fynbo, T. Kruehler, D. Xu (DARK/NBI) and N. Tanvir (U. Leicester) report on behalf of the X-Shooter GRB collaboration: We have observed the afterglow of the GRB 130427B (Maselli et al., GCN 14460) with the ESO VLT equipped with the X-shooter spectrograph. The observation started on 2013-04-28 at 9:45 UT. A total exposure of 2x600 s was obtained just before morning twilight, covering the spectral range from 300 to 2500 nm. In the spectrum we detect a feature consistent with a damped Lyman-alpha line in the UVB arm at redshift of z=2.78 +/- 0.02. Given the low S/N of the spectrum, this redshift measurement should be considered tentative. We thank the Paranal staff for enthusiastic support, in particular Andrea Mehner and Christophe Martayan.
GCN 14496 table
GRB_name GRB130427B
GCN_number 14496
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 14496 SUBJECT: GRB 130427B: RATIR Optical and NIR Observations DATE: 13/04/29 01:39:53 GMT FROM: Nat Butler at Az State U Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB) J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of GRB 130427B (Maselli, et al., GCN 14460) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on Sierra San Pedro Mrtir from 2013/04 28.44 to 2013/04 28.48 UTC (21.26 to 22.19 hours after the BAT trigger), obtaining a total of 0.71 hours exposure in the r' and i' bands and 0.29 hours exposure in the Z, Y, J, and H bands. For a source within the Swift-XRT error circle (Osborne, et al., GCN 14467), in comparison with USNO-B1 and 2MASS, we obtain the following upper limits (3-sigma): r' > 22.08 i' > 22.06 Z > 21.28 Y > 20.77 J > 20.57 H > 19.84 These limits, in the AB system and not corrected for Galactic extinction in the direction of the GRB, were derived from PSF-fitting photometry, because of the presence of a 16.5 magnitude star only 5 arcseconds to the south of the SWIFT-XRT source position. We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir.
GCN 14499 table
GRB_name GRB130427B
GCN_number 14499
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 14499 SUBJECT: GRB 130427B: MITSuME Ishigakijima upper limits DATE: 13/04/29 06:41:41 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 130427B (Maselli et al., GCNC 14460) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. The observation started on 2013-04-28 18:47:24 UT (~1.23 days after the burst). We did not find any new point source within the enhanced XRT circle (Osborne et al., GCNC 14467) in all the three bands. Three sigma upper limits of the OT are listed below. We used GSC2.3 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 1.25418 19:26:42 3540.0 >20.6 >20.7 >20.1 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]