batgrbproduct Analysis for Trigger=311874
Analysis Summary
Notes:
- 1) No attempt has been made to eliminate the non-significant decimal places.
- 2) This batgrbproduct analysis is done of the amount of data for this trigger downloaded to date.
- 3) This page will be updated for up to 8 downlinks after the trigger.
======================================================================
BAT GRB EVENT DATA PROCESSING REPORT
Process Script Ver: batgrbproduct v2.41
Process Start Time (local time): Sun May 18 05:26:50 EDT 2008
Host Name: gcn5
Current Working Dir: /local/data/raid2/prebascript/trigger311874/GCN5_download_cron
======================================================================
Trigger: 00311874 Segment: 000
BAT Trigger Time: 232752174.784 [s; MET]
Trigger Stop: 232752182.976 [s; MET]
UTC: 2008-05-17T21:22:51.986120 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 102.254712634596 Dec: 50.7307421877239 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 9.81
Image Trigger?: NO
Rate S/N Ratio: 11.8321595661992 [ if not an image trigger ]
Image S/N Ratio: 9.81
Flight Position: [ source = BAT ]
RA: 102.254712634596 Dec: 50.7307421877239 [deg; J2000]
Ground Position: [ source = BAT pre-slew burst ]
RA: 102.274081603591 Dec: 50.7412401415749 [deg; J2000]
{ 06h 49m 05.8s , +50d 44' 28.5" }
+/- 2.35569378380565 [arcmin] (estimated 90% radius based on SNR)
+/- 1.33772029547423 [arcmin] (formal 1-sigma fit error)
SNR: 8.94375806958854
Angular difference between Flight and Ground position is 0.968360 arcmin
Partial Coding Fraction: 0.4960938 [ including projection effects ]
Duration
T90: 64.5760000050068 +/- 27.1590315834141
Measured from: 0.488000005483627
to: 65.0640000104904 [s; relative to TRIGTIME]
T50: 24.3159999847412 +/- 14.179803231133
Measured from: 4.47200000286102
to: 28.7879999876022 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 3.88400000333786
to: 4.88400000333786 [s; relative to TRIGTIME]
Total Fluence
Measured from: -0.892000019550323
to: 68.3079999983311 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 0.258475 0.327110 0.272965 0.063853
0.056561 0.057203 0.051582 0.046661 [error]
Peak 0.025733 0.030835 0.014804 0.003517
0.007126 0.007219 0.006464 0.005690 [error]
[ fluence units of on-axis counts / fully illuminated detector ]
======================================================================
=== Fluence/Peak Flux Summary ===
Model Band1 Band2 Band3 Band4 Band5 Total
15-25 25-50 50-100 100-350 15-150 15-350 keV
Fluence Power-law 7.93e-08 1.42e-07 1.96e-07 5.60e-07 5.64e-07 9.93e-07 erg/cm2
Error 2.41e-08 2.71e-08 5.02e-08 3.07e-07 1.21e-07 3.49e-07 erg/cm2
Peak flux Power-law 2.60e-01 2.11e-01 1.15e-01 9.28e-02 6.27e-01 6.79e-01 ph/cm2/s
Error 1.01e-01 5.92e-02 5.02e-02 7.76e-02 1.76e-01 1.95e-01 ph/cm2/s
Fluence Cutoff-PL 7.17e-08 1.53e-07 2.04e-07 2.34e-07 5.41e-07 6.66e-07 erg/cm2
Error 2.92e-08 3.51e-08 5.68e-08 4.31e-07 1.30e-07 4.40e-07 erg/cm2
Peak flux Cutoff-PL 2.27e-01 2.66e-01 9.65e-02 7.30e-03 5.95e-01 5.96e-01 ph/cm2/s
Error 1.14e-01 9.46e-02 8.40e-02 7.02e-02 1.77e-01 1.84e-01 ph/cm2/s
Fluence Band 7.09e-08 1.52e-07 2.03e-07 2.33e-07 5.40e-07 6.85e-07 erg/cm2
Error 2.89e-08 3.51e-08 5.67e-08 4.31e-07 1.30e-07 4.41e-07 erg/cm2
Peak flux Band 2.25e-01 2.66e-01 9.69e-02 7.41e-03 5.96e-01 5.95e-01 ph/cm2/s
Error 1.06e-01 7.59e-02 4.57e-02 7.49e-02 1.65e-01 1.63e-01 ph/cm2/s
=== Time-averaged spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.538 0.330 - - 8.65e-04 1.69e-04 39.550 57
CPL 0.894 1.539 84.9 5000.0 1.85e-03 7.31e-03 38.882 56
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.867 0.495 - - 4.43e-03 1.50e-03 60.880 57
CPL -0.013 2.605 41.4 5000.0 6.09e-02 1.54e+00 59.020 56
Model : spectral model: simple power-law (PL) and cutoff power-law (CPL)
Ph_index : photon index: E^-{Ph_index} (minus sign is not included in the index)
Ph_90err : 90% error of the photon index
Epeak : Epeak in keV
Epeak_90err: 90% error of Epeak
Norm : normalization at 50 keV in PL model and at 1 keV in CPL model
Nomr_90err : 90% error of the normalization
chi2 : Chi-Squared
dof : degree of freedom
=== T90/T50 calculation in the 50-300 keV band (BATSE band) using 64 ms lc ===
T90 in the 50-300 keV band: 6.976000 sec.
T50 in the 50-300 keV band: 3.904000 sec.
=== Table of the duration information ==
Value tstart tstop
T100 69.200 -0.892 68.308
T90 64.576 0.488 65.064
T50 24.316 4.472 28.788
Peak 1.000 3.884 4.884
Image
Pre-slew 15-350 keV image (Event data; bkg subtracted)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
102.2741 +50.7412 0.0214 29.2 -68.2 0.9276 8.9 TRIG_00311874
------------------------------------------
Foreground time interval of the image:
-0.892 52.117 (delta_t = 53.009 [sec])
Background time interval of the image:
-239.784 -0.892 (delta_t = 238.892 [sec])
Lightcurves
Notes:
- 1) All plots contain as much data as has been downloaded to date.
- 2) Multiple plots of different time binning/intervals are shown to cover all scenarios of short/long GRBs, rate/image triggers, and real/false positives.
- 3) For all the mask-weighted lightcurves, the y-axis units are counts/sec/det where a det is 0.4 x 0.4 = 0.16 sq cm.
- 4) The verticle lines correspond to following: green dotted lines are T50 interval, black dotted lines are T90 interval, blue solid line(s) is a spacecraft slew start time, and orange solid line(s) is a spacecraft slew end time.
- 5) Time of each bin is in the middle of the bin.
1 s binning
From T0-310 s to T0+310 s
From T100_start - 20 s to T100_end + 30 s
Full time interval
64 ms binning
Full time interval
From T100_start to T100_end
From T0-5 sec to T0+5 sec
16 ms binning
From T100_start-5 s to T100_start+5 s
8 ms binning
From T100_start-3 s to T100_start+3 s
2 ms binning
From T100_start-1 s to T100_start+1 s
SN=5 or 10 sec. binning (whichever binning is satisfied first)
SN=5 or 10 sec. binning (T < 200 sec)
Spectra
Notes:
- 1) The fitting includes the systematic errors.
- 2) For long bursts, a spectral fit of the pre-slew DRM will introduce some errors in both a spectral shape and a normalization if the PHA file contains a lot of the slew/post-slew time interval.
- 3) For fits to more complicated models (e.g. a power-law over a cutoff power-law), the BAT team has decided to require a chi-square improvement of more than 6 for each extra dof.
Time averaged spectrum fit using the pre-slew DRM
Power-law model
Time interval is from -0.892 sec. to 68.308 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.53836 ( -0.324501 0.334506 )
Norm@50keV : 8.649990E-04 ( -1.699945E-04 1.670367E-04) )
------------------------------------------------------------
Chi-Squared = 39.55013 using 59 PHA bins.
Reduced chi-squared = 0.6938620 for 57 degrees of freedom
Null hypothesis probability = 0.962
Photon flux (15-150 keV) in 69.20 sec: 0.109138 ( -0.0204404 0.020474 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.64481e-07 ( -1.19358e-07 1.21905e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.892 sec. to 68.308 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.894308 ( -1.81941 1.25837 )
Epeak [keV] : 84.9135 ( -84.9035 9915.09 )
Norm@50keV : 1.848267E-03 ( -1.848267E-03 1.277340E-02) )
------------------------------------------------------------
Chi-Squared = 38.88162 using 59 PHA bins.
Reduced chi-squared = 0.6943147 for 56 degrees of freedom
Null hypothesis probability = 0.960
Photon flux (15-150 keV) in 69.20 sec: 0.106521 ( -0.0214531 0.021216 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.40825e-07 ( -1.28877e-07 1.31571e-07 ) ergs/cm2
Band function
Time interval is from -0.892 sec. to 68.308 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.943572 ( -9.05643 1.85666 )
beta : -9.33013 ( -0.669871 11.2783 )
Epeak [keV] : 88.0063 ( -87.9063 9911.99 )
Norm@50keV : 1.743722E-03 ( -1.743722E-03 1.291866E-02) )
------------------------------------------------------------
Chi-Squared = 38.88495 using 59 PHA bins.
Reduced chi-squared = 0.7069991 for 55 degrees of freedom
Null hypothesis probability = 0.951
Photon flux (15-150 keV) in 69.20 sec: 0.106535 ( -0.0214698 0.021204 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.40307e-07 ( -1.28724e-07 1.31689e-07 ) ergs/cm2
Peak spectrum fit using the pre-slew DRM
Power-law model
Time interval is from 3.884 sec. to 4.884 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.86701 ( -0.467980 0.522009 )
Norm@50keV : 4.433281E-03 ( -1.531821E-03 1.476820E-03) )
------------------------------------------------------------
Chi-Squared = 60.87978 using 59 PHA bins.
Reduced chi-squared = 1.068066 for 57 degrees of freedom
Null hypothesis probability = 0.338
Photon flux (15-150 keV) in 1.000 sec: 0.627459 ( -0.176306 0.176333 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.07669e-08 ( -1.34106e-08 1.41807e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 3.884 sec. to 4.884 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.259696E-02 ( -2.98740 2.22357 )
Epeak [keV] : 41.3886 ( -41.3786 9958.61 )
Norm@50keV : 6.090252E-02 ( -6.090252E-02 3.01777 )
------------------------------------------------------------
Chi-Squared = 59.02025 using 59 PHA bins.
Reduced chi-squared = 1.053933 for 56 degrees of freedom
Null hypothesis probability = 0.366
Photon flux (15-150 keV) in 1.000 sec: 0.595391 ( -0.173919 0.180642 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.34267e-08 ( -1.22542e-08 8.3777e-09 ) ergs/cm2
Band function
Time interval is from 3.884 sec. to 4.884 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : 3.681742E-03 ( -10.0037 4.19446 )
beta : -9.33843 ( -0.661574 19.3384 )
Epeak [keV] : 42.3341 ( -42.2341 9957.67 )
Norm@50keV : 5.802919E-02 ( -1.93468 85.1490 )
------------------------------------------------------------
Chi-Squared = 59.03177 using 59 PHA bins.
Reduced chi-squared = 1.073305 for 55 degrees of freedom
Null hypothesis probability = 0.330
Photon flux (15-150 keV) in 1.000 sec: 0.595569 ( -0.163134 0.167535 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.7318e-08 ( -1.42252e-08 1.22705e-08 ) ergs/cm2
Plot creation:
Sun May 18 05:51:20 EDT 2008