GRB130420A

This page lists all entries on GRB130420A in GRBweb

Summary Fermi GBM IPN Swift GCN 14405 GCN 14406 GCN 14407 GCN 14408 GCN 14409 GCN 14410 GCN 14413 GCN 14415 GCN 14416 GCN 14418 GCN 14419 GCN 14422 GCN 14424 GCN 14427 GCN 14428 GCN 14429 GCN 14431 GCN 14436 GCN 14437 GCN 14439 GCN 14440 GCN 14441 GCN 14445

Summary table
Variable Value Source
GRB_name_Fermi GRB130420313
T0 7:28:29 UTC GCN_circulars,Swift Det
ra 196.1065° Swift
decl 59.4242° Swift
pos_error 6.47e-05° Swift
T90 104.962 s Fermi_GBM
T90_error 8.809 s Fermi_GBM
T90_start 7:29:20.276 UTC Fermi_GBM
fluence 1.16e-05 erg/cm² Fermi_GBM
fluence_error 2.43e-07 erg/cm² Fermi_GBM
redshift 1.2970 Swift
T100 156.238 s
GBM_located False
mjd 56402.31144675926 GCN_circulars,Swift Det
Fermi GBM table
GRB_name_Fermi GRB130420313
trigger_name bn130420313
ra 196.1100°
decl 59.4200°
pos_error 3.89e+00°
datum 2013-04-20
t_trigger 7:30:19.925 UTC
T90 104.962 s
T90_error 8.809 s
T90_start 7:29:20.276 UTC
fluence 1.16e-05 erg/cm²
fluence_error 2.43e-07 erg/cm²
flux_1024 5.41e+00 erg/cm²/s
flux_1024_error 4.58e-01 erg/cm²/s
flux_1024_time 7.04e-01 erg/cm²/s
flux_64 9.28e+00 erg/cm²/s
flux_64_error 2.11e+00 erg/cm²/s
IPN table
GRB_name GRB130420A
ra 196.1000°
decl 59.4167°
pos_error 5.00e-02°
redshift 1.2970
Swift table
GRB_name GRB130420A
t_trigger 7:28:29 UTC
ra 196.1065°
decl 59.4242°
pos_error 6.47e-05°
T90 123.5 s
fluence 7.10e-06 erg/cm²
redshift 1.2970
GCN 14405 table
GRB_name GRB130420A
GCN_number 14405
Detection_method Swift-BAT Det
ra 196.1065°
decl 59.4241°
Circular_text TITLE: GCN CIRCULAR NUMBER: 14405 SUBJECT: GRB 130420A: Faulkes Telescope North candidate DATE: 13/04/20 07:46:12 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), A. Melandri (INAF-OAB), D. Kopac, A. Gomboc (U. Ljubljana), on behalf of a large collaboration report: The 2-m Faulkes Telescope North automatically began observing GRB 130420A at 4.35 minutes from the Swift/BAT trigger time. The automatic LT-TRAP procedure identified a bright uncatalogued object at the following position: RA= 13:04:25.57 Dec= +59:25:26.7 (J2000). Its magnitude is estimated to be 15.9 in the R band.
GCN 14406 table
GRB_name GRB130420A
GCN_number 14406
Detection_method Swift Det
t_trigger 7:28:29 UTC
ra 196.1000°
decl 59.4240°
Circular_text TITLE: GCN CIRCULAR NUMBER: 14406 SUBJECT: GRB 130420A: Swift detection of a burst with an optical counterpart DATE: 13/04/20 07:50:15 GMT FROM: David Palmer at LANL M. J. Page (UCL-MSSL), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), S. R. Oates (UCL-MSSL) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 07:28:29 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130420A (trigger=553977). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 196.100, +59.424 which is RA(J2000) = 13h 04m 24s Dec(J2000) = +59d 25' 25" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a very gradual beginning and a large peak at T+100 seconds. The total duration was about 200 sec. Because of the gradual beginning, the trigger was an image rather than a rate trigger. The peak count rate was ~3985 counts/sec (15-350 keV), at ~110 sec after the trigger. The XRT began observing the field at 07:40:44.8 UT, 735.3 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 196.1061, 59.4241 which is equivalent to: RA(J2000) = 13h 04m 25.46s Dec(J2000) = +59d 25' 26.8" with an uncertainty of 2.6 arcseconds (radius, 90% containment). This location is 11 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 1.26 x 10^20 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 150 seconds with the White filter starting 738 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 13:04:25.57 = 196.10654 DEC(J2000) = +59:25:26.9 = 59.42415 with a 90%-confidence error radius of about 0.75 arc sec. This position is 5.1 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.22 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01. Burst Advocate for this burst is M. J. Page (m.page AT 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.)
GCN 14407 table
GRB_name GRB130420A
GCN_number 14407
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 14407 SUBJECT: GRB 130420A: ROTSE-III Detection of Optical Counterpart DATE: 13/04/20 08:08:48 GMT FROM: Tolga Guver at UA GRB 130420A: ROTSE-III Detection of Optical Counterpart T. Guver (Sabanci U), report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 130420A (Swift trigger 553977). The first image was at 07:29:51.5 UT, 82.0 s after the burst (7.5 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a 15.5 magnitude, fading source with coordinates: 13:04:25.5 +59:25:27.2 (J2000), with positional uncertainty of 1" or better start UT mag mlim(of image) ---------------------------------- 07:34:12.7 15.5 16.5 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/gsq553977_3b03_img.jpg Note that the object marked 91 is the candidate in question. Continuing observations are in progress.
GCN 14408 table
GRB_name GRB130420A
GCN_number 14408
Detection_method correction
Circular_text TITLE: GCN CIRCULAR NUMBER: 14408 SUBJECT: GRB 130420A: PAIRITEL NIR detections DATE: 13/04/20 08:16:50 GMT FROM: Adam Morgan at U.C. Berkeley A. N. Morgan (UC Berkeley) reports: We observed the field of GRB 130420A (Page et al., GCN 14406) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2013-Apr-20 07h37m23s UT, 8.9 minutes after the Swift Trigger. In mosaics (effective exposure time of ~10 minutes) taken simultaneously in the J, H, and Ks filters, we detect the optical afterglow (Guidorzi et al., GCN 14405; Page et al., GCN 14406; Guver et al., GCN 14407). The preliminary photometry yields: post burst t_mid (hr) exp.(m) filt mag m_err 0.28 9.75 J 15.59 0.05 0.28 9.75 H 14.99 0.07 0.28 9.75 Ks 14.13 0.12 Observations are ongoing. All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values.
GCN 14409 table
GRB_name GRB130420A
GCN_number 14409
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 14409 SUBJECT: GRB 130420A: RATIR Optical and NIR Observations DATE: 13/04/20 11:56:25 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Alan M. Watson (UNAM), Nat Butler (ASU), 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 130420A (Page, et al., GCN 14406) 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 20.41 to 2013/04 20.45 UTC (2.48 to 3.38 hours after the BAT trigger), obtaining a total of 0.36 hours exposure in the r' and i' bands and 0.14 hours exposure in the Z, Y, J, and H bands. For a source within the Swift-XRT error circle, in comparison with SDSS DR8 and 2MASS, we find: r' 19.81 +/- 0.02 i' 19.41 +/- 0.02 Z 19.37 +/- 0.06 Y 18.99 +/- 0.07 J 19.16 +/- 0.07 H 18.87 +/- 0.11 These magnitudes are in the AB system and not corrected for Galactic extinction in the direction of the GRB. Uncertainties are 1-sigma. Comparison to the earlier photometry of Morgan et al. (GCN 14408) shows that this source has faded by about 2.5 magnitudes in J and H. We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir. -- Dr. Alan M. Watson Instituto de Astronoma Universidad Nacional Autnoma de Mxico
GCN 14410 table
GRB_name GRB130420A
GCN_number 14410
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 14410 SUBJECT: GRB 130420A: T21 optical observations DATE: 13/04/20 13:06:20 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report: We have detected GRB 130420A optical afterglow at iTelescope Observatory T21 (Mayhill, New Mexico) 0.43-m/6.8 astrograph and FLI ProLine PL6303E CCD. Two unfiltered images with 600 sec exposure time were made. The afterglow was detected at following position RA 13:04:25.51 and DEC +59:25:27.2. The following magnitudes were obtained from the observations using NOMAD1 1494-0215473 (R=16.220) as the comparison: Tmid(sec)+T0 Filter Exp. time Mag Mag err. Limit 7258 unfiltered 600 19.49CR 0.20 20.60 7885 unfiltered 600 19.61CR 0.24 20.48
GCN 14413 table
GRB_name GRB130420A
GCN_number 14413
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 14413 SUBJECT: GRB 130420A: Weihai Optical Observations DATE: 13/04/20 13:57:41 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK/NBI), C. Cao, S.M. Hu (SDU) report: We observed the field of GRB 130420A (Page et al., GCN 14406) using the 1m telescope located in Weihai, Shandong Province, China. Observations started at 11:41:32 UT, 2013-04-20 (i.e., 4.218 hr after the BAT trigger) and 12x180s I-band frames were obtained. The optical afterglow (Page et al., GCN 14406) is clearly detected in our stacked image to be of I=19.4 mag, calibrated with nearby USNO B1 stars. It has decayed by about 0.5 mag, compared to the measurement in Watson et al. (GCN 14409). We thank Dayong Ren for carrying out these observations.
GCN 14415 table
GRB_name GRB130420A
GCN_number 14415
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 14415 SUBJECT: GRB130420A : Xinglong TNT optical upper limit DATE: 13/04/20 15:59:58 GMT FROM: L.P. Xin at NAOC L.P. Xin, M. Zhai, J. Y. Wei, Y. L. Qiu, J. Wang, J. S. Deng, C. Wu, X.H. Han report on behalf of EAFON team: We began to observe the field of GRB 130420A (Page et al., GCN 14406 ) using 80cm TNT telescope located at Xinglong observatory, China at 12:16:56 UT on 2013-04-20. We obtained 12x300s R-band images in a poor seeing and cloudy weather, with a median time of 5.3 hr after the BAT trigger. The afterglow reported (Page et a., GCN 14406 ) is not detected in the stacked image, down to a 3 sigma limit of R~18.0 mag, calibrated with USNO B2 stars. This message may be cited.
GCN 14416 table
GRB_name GRB130420A
GCN_number 14416
Detection_method Swift-XRT Det
ra 196.1063°
decl 59.4241°
Circular_text TITLE: GCN CIRCULAR NUMBER: 14416 SUBJECT: GRB 130420A: Enhanced Swift-XRT position DATE: 13/04/20 17:34:00 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 2151 s of XRT Photon Counting mode data and 2 UVOT images for GRB 130420A, 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 = 196.10626, +59.42406 which is equivalent to: RA (J2000): 13h 04m 25.50s Dec (J2000): +59d 25' 26.6" with an uncertainty of 1.7 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, 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 14418 table
GRB_name GRB130420A
GCN_number 14418
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 14418 SUBJECT: GRB 130420A: GMG optical observation DATE: 13/04/20 18:49:21 GMT FROM: Xiao-hong Zhao at Yunnan Obs X.-H. Zhao (YNAO and PSU), J. Mao (RIKEN and YNAO), J.-M. Bai (YNAO) report on behalf of a larger collaboration: We observed the field of GRB 130420A (Page et al., GCN 14406) with 2.4m Gao-Mei-Gu (GMG) telescope. Observations started at 13:36:00 UT on 2013-04-20 (i.e., 6.13 hrs after the burst, ~2 hrs later than the observation of Xu et al., GCN 14413) and 3x600s R-band and 1x600s I-band images were obtained. The optical counterpart of this burst was detected in both bands. The mag are R~19.4 and I~20.2 calibrated with USNO B1 stars. We thank the GMG staff, especially Yu-Xin Xin, Gui-Hua He and Jian-Duo He for performing these observations.
GCN 14419 table
GRB_name GRB130420A
GCN_number 14419
Detection_method Swift-BAT Det
ra 196.1180°
decl 59.4210°
Circular_text TITLE: GCN CIRCULAR NUMBER: 14419 SUBJECT: GRB 130420A, Swift-BAT refined analysis DATE: 13/04/20 19:33:42 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift GRB 130420A, Swift-BAT refined analysis A. Y. Lien (NASA/GSFC/ORAU), 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), C. B. Markwardt (GSFC), M. J. Page (UCL-MSSL), 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-239 to T+303 sec from the recent telemetry downlink, we report further analysis of BAT GRB 130420A (trigger #553977) (Page et al., GCN 14406). The BAT ground-calculated position is RA, Dec = 196.118, 59.421 deg which is RA(J2000) = 13h 04m 28.3s Dec(J2000) = +59d 25' 16.8" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 86%. The mask-weighted light curve shows a precursor beginning gradually at about T-20 seconds and increasing irregularly to about T+100 seconds. The main emission had a FRED shape peaking at about T+110 seconds that was detectable until about T+200 seconds. T90 (15-350 keV) is 123.5 +- 13.1 sec (estimated error including systematics). The time-averaged spectrum from T-19.7 to T+189.9 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.52 +- 0.25, and Epeak of 33.2 +- 6.8 keV (chi squared 42.40 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 7.1 +- 0.3 x 10^-06 erg/cm2 and the 1-sec peak flux measured from T+110.67 sec in the 15-150 keV band is 3.4 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.18 +- 0.05 (chi squared 66.06 for 57 d.o.f.). 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/553977/BA/
GCN 14422 table
GRB_name GRB130420A
GCN_number 14422
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 14422 SUBJECT: GRB 130420A: Swift-XRT refined Analysis DATE: 13/04/20 19:50:05 GMT FROM: Phil Evans at U of Leicester A. Maselli (INAF-IASFPA), V. Mangano (INAF-IASFPA), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), P.A. Evans (U. Leicester), B.P. Gompertz (U. Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB) and M.J. Page report on behalf of the Swift-XRT team: We have analysed 7.9 ks of XRT data for GRB 130420A (Page et al. GCN Circ. 14406), from 742 s to 19.7 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN. Circ 14416). The light curve can be modelled with a power-law decay with a decay index of alpha=0.81 (+/-0.05). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.29 (+0.14, -0.13). The best-fitting absorption column is 7.1 (+2.5, -2.4) x 10^20 cm^-2, in excess of the Galactic value of 1.3 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.1 x 10^-11 (4.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 7.1 (+2.5, -2.4) x 10^20 cm^-2 Galactic foreground: 1.3 x 10^20 cm^-2 Excess significance: 4.1 sigma Photon index: 2.29 (+0.14, -0.13) If the light curve continues to decay with a power-law decay index of 0.81, the count rate at T+24 hours will be 0.021 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.5 x 10^-13 (8.5 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00553977. This circular is an official product of the Swift-XRT team.
GCN 14424 table
GRB_name GRB130420A
GCN_number 14424
Detection_method Swift-UVOT Det
ra 196.1065°
decl 59.4242°
Circular_text TITLE: GCN CIRCULAR NUMBER: 14424 SUBJECT: GRB 130420A: Swift/UVOT Detection DATE: 13/04/20 21:06:26 GMT FROM: Samantha Oates at MSSL S. R. Oates, M. De Pasquale, and M. J. Page (UCL-MSSL) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 130420A 739 s after the BAT trigger (Page et al., GCN Circ. 14406). A source consistent with the XRT position (Goad et al. GCN Circ. 14416) is detected in the initial UVOT exposures. The GRB is detected in all filters and is therefore consistent with being at a redshift of ~<1.6. The preliminary UVOT position is: RA (J2000) = 13:04:25.55 = 196.10647 (deg.) Dec (J2000) = +59:25:27.1 = 59.42420 (deg.) with an estimated uncertainty of 0.50 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 739 888 147 17.14 +/- 0.03 v 1072 1092 20 17.66 +/- 0.31 b 1171 1191 19 18.13 +/- 0.21 u 1146 1166 20 17.19 +/- 0.17 w1 1122 1141 19 17.51 +/- 0.29 m2 1097 1465 58 18.30 +/- 0.31 w2 1049 1240 39 18.50 +/- 0.33 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).
GCN 14427 table
GRB_name GRB130420A
GCN_number 14427
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 14427 SUBJECT: Skynet/GORT observations of GRB130420A DATE: 13/04/20 22:28:05 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/NC AnTPROMPT/Skynet A. Trotter, N. Frank, A. LaCluyze, D. Reichart, K. McLin, L. Cominsky, T. Berger, J. A. Crain, H. T. Cromartie, R. Egger, A. Foster, J. Haislip, K. Ivarsen, M. Maples, J. Moore, M. Nysewander, and E. Speckhard report: Skynet observed the Swift/BAT localization of GRB 130420A (Page et al., GCN 14406, Swift trigger 553977) with the 14" GLAST Optical Robotic Telescope (GORT) at the Hume observatory in California, beginning ~100s after the trigger in RcIc, and continuing until the source set at t=4.9h. We detect the afterglow reported by Guidorzi et al. (GCN 14405) at RA 13:04:06.6, Dec +59:25:25.2 (J2000), within the error circle reported by the Swift XRT (GCN 14406). Photometry was calibrated to six SDSS stars in the field. The afterglow exhibits a rising light curve in both Rc and Ic bands at early times, peaking at t=330s (peak Rc~16, Ic~15.5), after which it fades with an approximate temporal index alpha~-1. There is some evidence for flattening of the Ic-band light curve at t>1h, at which time Ic~18.7. Follow-up observations at GORT have been scheduled. A preliminary light curve of the first night's data can be found at: http://skynet.unc.edu/grb/grb130420a.png
GCN 14428 table
GRB_name GRB130420A
GCN_number 14428
Detection_method Optical
ra 196.1065°
decl 59.4241°
Circular_text TITLE: GCN CIRCULAR NUMBER: 14428 SUBJECT: GRB 130420A: ISON-NM optical observations DATE: 13/04/21 03:58:45 GMT FROM: Alexei Pozanenko at IKI, Moscow L. Elenin (KIAM), A. Volnova ( IKI), V. Savanevych (KNURE), A. Bryukhovetskiy (NSFCTC), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the Swift GRB 130420A (Page et al., GCN 14406) with 0.45-m telescope of ISON-NM observatory on Apr. 20, between (UT) 07:30:54 - 10:51:49. The observation started automatically 144 s after burst trigger. We took several unfiltered images of 30, 60 and 300 s exposures. The optical counterpart of GRB 130418A (Guidorzi et al., GCN 14405; Page et al., GCN 14406; Guver et al., GCN 14407) is clearly visible in single images. Coordinates of the counterpart are (J2000) RA = 13:04:25.56 Dec = +59:25:26.8 with uncertainties of 0.2" coincide with the coordinates reported early (Guidorzi et al., GCN 14405, Guver et al., GCN 14407). A photometry of single and later combined image is based on the SDSS stars with assumed R-magnitude J130421.49+592547.6 R = 16.13 J130416.49+592509.2 R = 16.95 J130443.88+592659.3 R = 14.54 Preliminary light curve can be found at http://grb.rssi.ru/GRB130420A/GRB130420A_lightcurve_ISON-NM.png The light curve is clearly exhibit a fast rise and peaked with 16.1 mag at ~0.0207days after burst trigger following steep power law decay and later at 0.05 days swallowing to the typical afterglow power law.
GCN 14429 table
GRB_name GRB130420A
GCN_number 14429
Detection_method Fermi GBM Det
t_trigger 7:30:19.920 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 14429 SUBJECT: GRB 130420A: Fermi GBM observation DATE: 13/04/21 04:44:55 GMT FROM: Shaolin Xiong at UAH Shaolin Xiong (UAH) and Arne Rau (MPE) report on behalf of the Fermi GBM Team: "At 07:30:19.92 UT on 20 April 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 130420A (trigger 388135822 / 130420313), which was also detected by the Swift (Page et al. 2013, GCN 14406). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 134 degrees. The GBM light curve consists of precursors and a bright peak with a duration (T90) of about 102 s (50-300 keV). The time-averaged spectrum from T0-10 s to T0+27 s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is 1.00 +/- 0.13 and the cutoff energy, parameterized as Epeak, is 56 +/- 3 keV. The event fluence (10-1000 keV) in this time interval is (1.4 +/- 0.05)E-5 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.0 s in the 10-1000 keV band is 5.2 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN 14431 table
GRB_name GRB130420A
GCN_number 14431
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 14431 SUBJECT: GRB 130420A: Continued RATIR Optical and NIR Observations DATE: 13/04/21 16:54:47 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM 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 again observed the field of GRB 130420A (Page et al., GCN 14406) 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 21.30 to 2013/04 21.47UTC (23.66 to 27.79 hours after the BAT trigger), obtaining a total of 1.44 hours exposure in the r' and i' bands and 0.59 hours exposure in the Z, Y, J, and H bands. The afterglow is well-detected. In comparison with SDSS DR8 and 2MASS, we obtain: r' 22.11 +/- 0.08 i' 21.90 +/- 0.09 Z 21.52 +/- 0.18 Y 21.40 +/- 0.31 J 21.24 +/- 0.26 H 20.38 +/- 0.23 These magnitudes are in the AB system, quoted with 1-sigma uncertainty, and not corrected for Galactic extinction in the direction of the GRB. In comparison with our observations on the previous night (Watson et al., GCN 14409), the afterglow has faded by more than about 2 magnitudes in all bands. We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir.
GCN 14436 table
GRB_name GRB130420A
GCN_number 14436
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 14436 SUBJECT: GRB 130420A: Early RAPTOR Simultaneous Multi-Color Observations DATE: 13/04/22 17:34:49 GMT FROM: James Wren at LANL J. Wren, W.T. Vestrand, P. Wozniak, and H. Davis, of Los Alamos National Laboratory report: The RAPTOR network of robotic optical telescopes made follow-up observations of Swift trigger 553977 (Page, et al., GCN 14406). Our RAPTOR-S and RAPTOR-T robotic telescopes located in Los Alamos, NM, began imaging at 07:29:52.95 UTC, 83.4 s after the Swift BAT trigger and continued during the entire period the BAT was detecting the dominant gamma-ray pulse (Lien, et al., GCN 14419). We detect optical emission during the gamma-ray emitting interval at the location of the counterpart reported by the Faulkes team (Guidorzi, et al., GCN 14405). In subsequent images we see a rapid rise in brightness at the same location, peaking at about T+300s. These observations were made simultaneously using SDSS g', r', i', z' and clear filters. Our unfiltered observations are consistent with the lightcurve published by the ISON team (Elenin, et al., GCN 14428).
GCN 14437 table
GRB_name GRB130420A
GCN_number 14437
Detection_method Other
redshift 0.9405
Circular_text TITLE: GCN CIRCULAR NUMBER: 14437 SUBJECT: GRB 130420A: Redshift from 10.4m GTC DATE: 13/04/22 18:33:44 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), N. Tanvir (U. Leicester), R. Sanchez-Ramirez (IAA-CSIC), C.C. Thoene (IAA-CSIC), J. Gorosabel (UPV/EHU, IAA-CSIC), and J. P. U. Fynbo (DARK/NBI) report: We obtained spectroscopy of the afterglow of GRB 130420A (Page et al. GCN 14406) with the 10.4m GTC telescope on the 22nd April 2013, starting at 03:42 UT (1.84 days after the burst). The observation consisted of 4x900 s using the R500B grating, with a resolution of R~500 in the range 3600 - 8700 A. The spectrum shows an emission line that we identify as [OII] from the host and several absorption features that correspond to MgII, MgI, FeII and AlIII at a common redshift of 1.297, which we identify as the redshift of the GRB. We also note the presence of an unrelated nearby galaxy (at an angular separation of 2.5") which shows emission lines of [OII], H-beta and [OIII] at a redshift of 0.584. We acknowledge the excellent support of the GTC staff.
GCN 14439 table
GRB_name GRB130420A
GCN_number 14439
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 14439 SUBJECT: GRB 130420A: Continued RATIR Optical and NIR Observations DATE: 13/04/22 21:22:43 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Alan M. Watson (UNAM), Nat Butler (ASU), 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 again observed the field of GRB 130420A (Page et al., GCN Circular 14406) 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 22.35 to 2013/04 22.47 UTC (48.84 to 51.69 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. The afterglow is again detected in several bands. In comparison with SDSS DR8 and 2MASS, we obtain: r' 22.63 +/- 0.17 i' 22.46 +/- 0.17 Z 21.62 +/- 0.25 Y > 21.32 J > 21.39 H > 20.91 These magnitudes are in the AB system, quoted with 1-sigma uncertainty, and not corrected for Galactic extinction in the direction of the GRB. The upper limits are at the 3-sigma level. In comparison with our earlier observations (Watson et al., GCN Circular 14409; Butler et al., GCN Circular 14431), we see that the afterglow faded by about 2 magnitudes from about 3 to about 25 hours after the Swift trigger, but then by only about another 0.5 magnitudes from about 25 to about 50 hours after the Swift trigger. We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir.
GCN 14440 table
GRB_name GRB130420A
GCN_number 14440
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 14440 SUBJECT: GRB 130420A: ROTSE-III data analysis DATE: 13/04/24 21:13:55 GMT FROM: Farley V. Ferrante at Southern Methodist U/ROTSE F. V. Ferrante (SMU), G. Dhungana (SMU), T. Guver (Sabanci U), W. Zheng (UC Berkeley), H. Flewelling (IfA/Hawaii), F. Yuan (Australian National University), and R. Kehoe (SMU) report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 130420A (Swift trigger 553977; Guidorzi et al., GCN 14405; Page et al., GCN 14406; Guver et al., GCN 14407). The first image was at 07:29:51.5 UT, 82.0 s after the burst (7.5 s after the GCN notice time). We continued to monitor the source reported in GCN 14405, 14406, and 14407. The unfiltered images are calibrated relative to USNO A2.0. We took 220 20-sec exposures and observed a maximum magnitude of 15.5. Further analysis of ROTSE-IIIb data using RPHOT indicates that the afterglow of GRB 130420A displays a single power-law decay with index alpha = - 0.70 up to ~1500 s after the burst. After the power law fall-off, the afterglow continued to be detected in subsequent images for ~6 ks. The minimum observed magnitude was 17.5.
GCN 14441 table
GRB_name GRB130420A
GCN_number 14441
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 14441 SUBJECT: GRB 130420A: Continued RATIR Optical and NIR Observations DATE: 13/04/25 01:25:12 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM 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 again observed the field of GRB 130420A (Page et al., GCN Circular 14406) 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 24.26 to 2013/04 24.46 UTC (94.73 to 99.64 hours after the BAT trigger), obtaining a total of 2.84 hours exposure in the r' and i' bands and 1.19 hours exposure in the Z, Y, J, and H bands. For a source within the Swift-XRT error circle, in comparison with SDSS DR8 and 2MASS, we obtain the following upper limits (3-sigma) in the AB magnitude system: r' > 23.15 i' > 23.02 Z > 21.75 Y > 21.44 J > 21.72 H > 21.16 These magnitudes are not corrected for Galactic extinction in the direction of the GRB. In comparison with our earlier observations (Watson et al., GCN Circular 14409; Butler et al., GCN Circular 14431; Watson et al., GCN Circular 14439), the source has faded by about at least a magnitude in r' and i' between about 50 and about 97 hours. We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir.
GCN 14445 table
GRB_name GRB130420A
GCN_number 14445
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 14445 SUBJECT: GRB 130420A: Continued Skynet/GORT Observations/Detections DATE: 13/04/25 22:19:25 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet A. Trotter, N. Frank, A. LaCluyze, D. Reichart, K. McLin, L. Cominsky, T. Berger, H. T. Cromartie, R. Egger, A. Foster, J. Haislip, K. Ivarsen, M. Maples, J. Moore, M. Nysewander, E. Speckhard, and J. A. Crain report: Skynet continued observing the field of GRB 130420A (Page et al., GCN 14406, Swift trigger #553977) with the 14" GLAST Optical Robotic Telescope (GORT) at the Hume Observatory in California. It took 214 80-s exposures in Ic at times t=20.48-23.30h and t=26.25-28.56h after burst trigger, and 96 80-s exposures in Rc at t=23.33-26.15h. We performed photometry on the stacked exposures in each band, calibrated to six SDSS stars in the field. We detect the afterglow in both Ic and Rc bands at t~24h: band exp length mean time since trig mag(Vega) Ic 4.76h 24.37h 21.04 (+0.43,-0.31) Rc 2.47h 24.77h 21.00 (+0.25,-0.21) As we note in Trotter et al. (GCN 14427), and as Elenin et al. (GCN 14428) confirm, the afterglow exhibits a rising light curve at early times, peaking at t=330s (peak Rc~16, Ic~15.5). After the peak, the light curve fades with a power law index alpha~-0.9. A preliminary light curve of the first and second nights' data is at: http://skynet.unc.edu/grb/grb130420a_2.png