GRB110420B

This page lists all entries on GRB110420B in GRBweb

Summary Fermi GBM IPN Swift GCN 11944 GCN 11946 GCN 11947 GCN 11949 GCN 11950 GCN 11952 GCN 11953 GCN 11955

Summary table
Variable Value Source
GRB_name_Fermi GRB110420946
T0 22:42:11 UTC GCN_circulars,Swift Det
ra 320.0450° Swift
decl -41.2770° Swift
pos_error 1.71e-02° Swift
T90 0.128 s Fermi_GBM
T90_error 0.516 s Fermi_GBM
T90_start 22:42:11.670 UTC Fermi_GBM
fluence 2.44e-07 erg/cm² Fermi_GBM
fluence_error 2.73e-08 erg/cm² Fermi_GBM
T100 0.798 s
GBM_located False
mjd 55671.94596064815 GCN_circulars,Swift Det
Fermi GBM table
GRB_name_Fermi GRB110420946
trigger_name bn110420946
ra 320.0450°
decl -41.2769°
pos_error 1.51e+01°
datum 2011-04-20
t_trigger 22:42:11.734 UTC
T90 0.128 s
T90_error 0.516 s
T90_start 22:42:11.670 UTC
fluence 2.44e-07 erg/cm²
fluence_error 2.73e-08 erg/cm²
flux_1024 1.29e+00 erg/cm²/s
flux_1024_error 2.96e-01 erg/cm²/s
flux_1024_time -2.56e-01 erg/cm²/s
flux_64 1.20e+01 erg/cm²/s
flux_64_error 1.78e+00 erg/cm²/s
IPN table
GRB_name GRB110420B
ra 320.0500°
decl -41.2667°
pos_error 5.00e-02°
Swift table
GRB_name GRB110420B
t_trigger 22:42:11 UTC
ra 320.0450°
decl -41.2770°
pos_error 1.71e-02°
T90 0.084 s
fluence 5.30e-08 erg/cm²
GCN 11944 table
GRB_name GRB110420B
GCN_number 11944
Detection_method Swift Det
t_trigger 22:42:11 UTC
ra 320.0490°
decl -41.2640°
Circular_text TITLE: GCN CIRCULAR NUMBER: 11944 SUBJECT: GRB 110420B: Swift detection of a short hard burst DATE: 11/04/20 22:51:27 GMT FROM: Scott Barthelmy at NASA/GSFC B. Sbarufatti (INAF-OAB/IASFPA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), M. M. Chester (PSU), V. D'Elia (ASDC), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA), A. Melandri (INAF-OAB), D. M. Palmer (LANL), M. Stamatikos (OSU/NASA/GSFC) and E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team: At 22:42:11 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110420B (trigger=451794). Swift did not immediately slew because of an observing constraint. The BAT on-board calculated location is RA, Dec 320.049, -41.264, which is RA(J2000) = 21h 20m 12s Dec(J2000) = -41d 15' 51" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of about 64 milli-sec. The peak count rate was ~6000 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+40.4 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is B. Sbarufatti (boris.sbarufatti AT brera.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 11946 table
GRB_name GRB110420B
GCN_number 11946
Detection_method Swift-BAT Det
ra 320.0450°
decl -41.2770°
Circular_text TITLE: GCN CIRCULAR NUMBER: 11946 SUBJECT: GRB 110420B: Swift-BAT refined analysis DATE: 11/04/21 01:20:10 GMT FROM: Scott Barthelmy at NASA/GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), B. Sbarufatti (INAF-OAB/IASFPA), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT SHB GRB 110420B (trigger #451794) (Sbarufatti, et al., GCN Circ. 11944). The BAT ground-calculated position is RA, Dec = 320.045, -41.277 deg, which is RA(J2000) = 21h 20m 10.9s Dec(J2000) = -41d 16' 38.0" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%. The mask-weighted light curve shows a FRED-like pulse starting at ~T+0.00 and ending at ~T+0.08 sec. T90 (15-350 keV) is 0.084 +- 0.021 sec (estimated error including systematics). The time-averaged spectrum from T-0.004 to T+0.100 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -1.52 +- 2.56, and Epeak of 79.5 +- 30.0 keV (chi squared 67.2 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 5.3 +- 1.1 x 10^-8 erg/cm2 and the 1-sec peak flux measured from T-0.45 sec in the 15-150 keV band is 0.7 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.11 +- 0.27 (chi squared 73.8 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/451794/BA/
GCN 11947 table
GRB_name GRB110420B
GCN_number 11947
Detection_method Swift-XRT Other
ra 320.1047°
decl -41.2971°
Circular_text TITLE: GCN CIRCULAR NUMBER: 11947 SUBJECT: GRB 110420B: Swift-XRT afterglow candidate DATE: 11/04/21 07:06:31 GMT FROM: Boris Sbarufatti at INAF-OAB/IASFPA B. Sbarufatti (INAF-OAB/IASFPA), V. Mangano (INAF/IASFPA) report on behalf of the Swift-XRT team: We have analyzed 4.5 ks of XRT data for GRB 110420B (Sbarufatti et al. GCN Circ. 11944), from 2.6 ks to 14.4 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. We find an afterglow candidate with XRT position RA, Dec = 320.10472, -41.29713 which is equivalent to: RA (J2000): 21 20 25.13 Dec(J2000): -41 17 49.7 with an uncertainty of 4.0 arcsec (radius, 90% confidence). We cannot determine at the present time whether the source is fading. The source lies 3.2 arcmin from the BAT onboard position and 2.95 arcmin from the BAT refined position (Markwardt et al., GCN Circ. 11946). The observed rate is 4.5 x 10^-3 counts/s (1.4 x 10^-13 erg cm^-2 s^-1), corresponding to a 3.8 sigma level detection. More data are needed in order to confirm the nature of the source.
GCN 11949 table
GRB_name GRB110420B
GCN_number 11949
Detection_method GROND
ra 320.1058°
decl -41.2977°
Circular_text TITLE: GCN CIRCULAR NUMBER: 11949 SUBJECT: GRB 110420B, GROND observations DATE: 11/04/21 12:35:44 GMT FROM: Andrea Rossi at TLS Tautenburg P. Afonso (MPE Garching), A. Rossi, S. Klose (TLS Tautenburg), and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 110420B (Swift trigger 451794; Sbarufatti et al. GCN 11944) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope on La Silla. Observations started at 7:00 UT on April 21, 8.15 hours after the GRB trigger. They were obtained under challenging sky conditions, with a seeing > 1.5 arcsec, an average airmass of 1.7, bright moonlight, and passing cirrus. In a first epoch, centered on the refined BAT error circle (Markwardt et al., GCN 11946), we do not detect any new object down to the DSS2 limit. The XRT error circle (Sbarufatti et al., GCN 11947) was not covered by these observations in g'r'i'z'. A subsequent epoch started about 30 min later and was centered on the XRT afterglow candidate (Sbarufatti et al., GCN 11947). Here we note the presence of a relatively bright object at the border of the XRT error circle at coordinates RA, DEC (J2000) 21:20:25.389, -41:17:51.79 (+/- 0.5 arcsec), which could be a galaxy seen nearly face-on. This object is also visible in the DSS2-red image. Unfortunately, due to the bad seeing we cannot decide with certainty at the moment if this object is a galaxy or a star. Its r'-band magnitude is r'(AB) = 19.5 +/- 0.1. No other source is detected inside the XRT error circle down to r'(AB) = 23.2. Magnitudes are derived by calibrating the images against GROND zeropoints and 2MASS field stars. We note that the Galactic reddening along the line of sight is E(B-V) = 0.03 mag (Schlegel et al. 1998).
GCN 11950 table
GRB_name GRB110420B
GCN_number 11950
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 11950 SUBJECT: GRB 110420B: Spectral lag indicates short hard burst DATE: 11/04/21 13:39:01 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC) and J. Norris (BSU) report: For GRB 110420B (Trigger 451794, GCNs 11944 & 11946), the spectral lag analysis of the Swift-BAT data for 40 msec covering the spike, yields a lag of 0.6 +/-2.0 msec for the 25-50 to 100-300 keV bands and 2.4 +4/-2 msec for the 15-25 to 50-100 keV bands, both using a lightcurve binning of 2 msec.
GCN 11952 table
GRB_name GRB110420B
GCN_number 11952
Detection_method Fermi GBM Det
t_trigger 22:42:11.730 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 11952 SUBJECT: GRB 110420B: Fermi GBM observation DATE: 11/04/21 13:55:31 GMT FROM: Lin Lin at UAH/NAOC Lin Lin (UAH) reports on behalf of the Fermi GBM Team: "At 22:42:11.73 UT on 20 April 2011, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 110420B (trigger 325032133 / 110420946). This burst was also detected by the Swift/BAT (Sbarufatti et al. 2011, GCN 11944). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 123 degrees. The GBM light curve shows a fast rise slow decay peak, with a duration (T90) of about 0.048 s (50-300 keV). The time-averaged spectrum from T0-0.024 s to T0+0.040 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.12 +/- 0.31 and the cutoff energy, parameterized as Epeak, is 296.8 +/- 58.7 keV. The event fluence (10-1000 keV) in this time interval is (2.65 +/- 0.36)E-7 erg/cm^2. The 0.008-sec peak photon flux measured starting from T0-0.016 s in the 10-1000 keV band is 44.1 +/- 6.1 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN 11953 table
GRB_name GRB110420B
GCN_number 11953
Detection_method retraction
Circular_text TITLE: GCN CIRCULAR NUMBER: 11953 SUBJECT: GRB 110420B: Swift-XRT afterglow candidate retraction DATE: 11/04/21 14:09:18 GMT FROM: Boris Sbarufatti at INAF-OAB/IASFPA B. Sbarufatti (INAF-OAB/IASFPA) and V. Mangano (INAF/IASFPA) report on behalf of the Swift XRT team: Further observations of the field of GRB 110420B (Sbarufatti et al. GCN Circ. 11944) have shown that the X-ray source reported by Sbarufatti et al. (GCN Circ. 11947) has not faded. Moreover, the position is marginally consistent with the known X-ray source 1RXS J212024.5-411816. Therefore we conclude that the XRT source is not the burst afterglow. This circular is an official product of the Swift-XRT team.
GCN 11955 table
GRB_name GRB110420B
GCN_number 11955
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 11955 SUBJECT: GRB 110420B: Swift/UVOT Upper Limits DATE: 11/04/21 14:29:56 GMT FROM: Samantha Oates at MSSL S. R. Oates (MSSL-UCL) & B. Sbarufatti (INAF-OAB/IASFPA) report on behalf of the Swift-UVOT team The Swift/UVOT began settled observations of the field of GRB 110420B 2562 s after the BAT trigger (Sbarufatti et al., GCN Circ. 11944). No optical afterglow is found within the BAT error circle. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag ############################################################### white_FC 2562 2711 147 >20.6 white 2562 4765 540 >20.5 v 3541 16124 1322 >19.9 b 2926 22368 621 >20.4 u 2720 28151 1730 >20.0 w1 3950 28007 2844 >19.6 m2 3745 27103 2416 >19.5 w2 3336 15211 1279 >19.7 ############################################################### The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).