batgrbproduct Analysis for Trigger=311762
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): Fri May 16 06:53:20 EDT 2008
Host Name: gcn5
Current Working Dir: /local/data/raid2/prebascript/trigger311762/GCN5_download_cron
======================================================================
Trigger: 00311762 Segment: 000
BAT Trigger Time: 232589829.824 [s; MET]
Trigger Stop: 232589830.336 [s; MET]
UTC: 2008-05-16T00:17:07.030760 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 120.629533847551 Dec: -26.1760175623149 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 8.61
Image Trigger?: NO
Rate S/N Ratio: 15.0665191733194 [ if not an image trigger ]
Image S/N Ratio: 8.61
Flight Position: [ source = BAT ]
RA: 120.629533847551 Dec: -26.1760175623149 [deg; J2000]
Ground Position: [ source = BAT pre-slew burst ]
RA: 120.66128530009 Dec: -26.1464170172796 [deg; J2000]
{ 08h 02m 38.7s , -26d 08' 47.1" }
+/- 2.13410956532288 [arcmin] (estimated 90% radius based on SNR)
+/- 1.16011231449219 [arcmin] (formal 1-sigma fit error)
SNR: 10.2993256679047
Angular difference between Flight and Ground position is 2.465387 arcmin
Partial Coding Fraction: 0.3867188 [ including projection effects ]
Duration
T90: 5.76000002026558 +/- 0.213016433189357
Measured from: 0.15599998831749
to: 5.91600000858307 [s; relative to TRIGTIME]
T50: 5.01199999451637 +/- 0.420019040395933
Measured from: 0.444000005722046
to: 5.45600000023842 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 0.0519999861717224
to: 1.05199998617172 [s; relative to TRIGTIME]
Total Fluence
Measured from: 0.0839999914169312
to: 6.05599999427795 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 0.130006 0.175426 0.100423 0.011477
0.021317 0.021860 0.019359 0.016704 [error]
Peak 0.039856 0.089325 0.054372 0.007052
0.009183 0.009773 0.008563 0.007151 [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 4.92e-08 7.45e-08 8.46e-08 1.83e-07 2.63e-07 3.93e-07 erg/cm2
Error 1.11e-08 1.09e-08 1.92e-08 8.55e-08 4.47e-08 1.04e-07 erg/cm2
Peak flux Power-law 5.94e-01 5.99e-01 4.25e-01 4.80e-01 1.81e+00 2.10e+00 ph/cm2/s
Error 1.44e-01 9.28e-02 7.40e-02 1.66e-01 2.66e-01 3.02e-01 ph/cm2/s
Fluence Cutoff-PL 4.81e-08 7.65e-08 8.51e-08 1.29e-07 2.59e-07 3.39e-07 erg/cm2
Error 1.24e-08 1.41e-08 1.99e-08 1.51e-07 4.92e-08 1.38e-07 erg/cm2
Peak flux Cutoff-PL 5.00e-01 6.78e-01 4.59e-01 1.57e-01 1.75e+00 1.79e+00 ph/cm2/s
Error 1.69e-01 1.28e-01 9.04e-02 1.40e-01 2.74e-01 3.32e-01 ph/cm2/s
Fluence Band 4.71e-08 7.76e-08 8.31e-08 1.57e-07 2.58e-07 3.53e-07 erg/cm2
Error 1.19e-08 1.51e-08 2.06e-08 1.38e-07 4.48e-08 1.25e-07 erg/cm2
Peak flux Band 4.52e-01 7.29e-01 4.22e-01 2.88e-01 1.73e+00 1.91e+00 ph/cm2/s
Error 1.66e-01 1.40e-01 8.33e-02 2.51e-01 2.62e-01 3.37e-01 ph/cm2/s
=== Time-averaged spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.817 0.271 - - 4.79e-03 8.00e-04 64.395 57
CPL 1.594 0.990 82.9 5000.0 6.34e-03 1.56e-02 64.283 0
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.496 0.233 - - 1.45e-02 2.10e-03 57.734 57
CPL 0.350 1.350 69.1 222.8 5.79e-02 1.99e-01 54.675 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: 0.576000 sec.
T50 in the 50-300 keV band: 0.320000 sec.
=== Table of the duration information ==
Value tstart tstop
T100 5.972 0.084 6.056
T90 5.760 0.156 5.916
T50 5.012 0.444 5.456
Peak 1.000 0.052 1.052
Image
Pre-slew 15-350 keV image (Event data; bkg subtracted)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
120.6613 -26.1464 0.0187 38.7 154.8 0.4030 10.3 TRIG_00311762
------------------------------------------
Foreground time interval of the image:
0.084 6.056 (delta_t = 5.972 [sec])
Background time interval of the image:
-239.824 0.084 (delta_t = 239.908 [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 0.084 sec. to 6.056 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.81686 ( -0.263421 0.277726 )
Norm@50keV : 4.786127E-03 ( -8.114451E-04 7.879026E-04) )
------------------------------------------------------------
Chi-Squared = 64.39496 using 59 PHA bins.
Reduced chi-squared = 1.129736 for 57 degrees of freedom
Null hypothesis probability = 0.234
Photon flux (15-150 keV) in 5.972 sec: 0.663881 ( -0.098689 0.098798 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.62996e-07 ( -4.43684e-08 4.51274e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.084 sec. to 6.056 sec.
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.59376 ( -1.26486 0.714553 )
Epeak [keV] : 82.8639 ( -82.8539 9917.14 )
Norm@50keV : 6.343338E-03 ( -6.343338E-03 2.476325E-02) )
------------------------------------------------------------
Chi-Squared = 64.28324 using 59 PHA bins.
but latest trial 2.10604 gives Chi-Squared = 0.659241
Reduced chi-squared = 1.147915 for 56 degrees of freedom
Null hypothesis probability = 0.209
Photon flux (15-150 keV) in 5.972 sec: 0.659262 ( -0.051084 0.09946 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.58765e-07 ( -5.00812e-08 4.82681e-08 ) ergs/cm2
Band function
Time interval is from 0.084 sec. to 6.056 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -1.28657 ( -8.71343 4.13504 )
beta : -1.96273 ( -8.03728 0.398126 )
Epeak [keV] : 50.8774 ( -50.7774 9949.12 )
Norm@50keV : 9.992107E-03 ( -9.992108E-03 4644.90 )
------------------------------------------------------------
Chi-Squared = 64.16788 using 59 PHA bins.
Reduced chi-squared = 1.166689 for 55 degrees of freedom
Null hypothesis probability = 0.186
Photon flux (15-150 keV) in 5.972 sec: 0.657476 ( -0.100865 0.101316 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.58316e-07 ( -4.3816e-08 4.5859e-08 ) ergs/cm2
Peak spectrum fit using the pre-slew DRM
Power-law model
Time interval is from 0.084 sec. to 1.020 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.49562 ( -0.232651 0.233234 )
Norm@50keV : 1.449156E-02 ( -2.103171E-03 2.095917E-03) )
------------------------------------------------------------
Chi-Squared = 57.73381 using 59 PHA bins.
Reduced chi-squared = 1.012874 for 57 degrees of freedom
Null hypothesis probability = 0.448
Photon flux (15-150 keV) in 0.9360 sec: 1.80697 ( -0.26604 0.26675 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.28721e-07 ( -1.99218e-08 2.0197e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.084 sec. to 1.020 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.349837 ( -1.58575 1.11419 )
Epeak [keV] : 69.1237 ( -18.1913 427.418 )
Norm@50keV : 5.789048E-02 ( -5.789048E-02 0.340380 )
------------------------------------------------------------
Chi-Squared = 54.67530 using 59 PHA bins.
Reduced chi-squared = 0.9763446 for 56 degrees of freedom
Null hypothesis probability = 0.525
Photon flux (15-150 keV) in 0.9360 sec: 1.75169 ( -0.27465 0.27384 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.18603e-07 ( -2.21972e-08 2.3649e-08 ) ergs/cm2
Band function
Time interval is from 0.084 sec. to 1.020 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : 0.352581 ( -2.24637 4.64742 )
beta : -2.03103 ( -1.83149 0.525560 )
Epeak [keV] : 52.7113 ( -27.6384 27.5707 )
Norm@50keV : 0.162695 ( -1.28962 78.5942 )
------------------------------------------------------------
Chi-Squared = 52.96493 using 59 PHA bins.
Reduced chi-squared = 0.9629987 for 55 degrees of freedom
Null hypothesis probability = 0.553
Photon flux (15-150 keV) in 0.9360 sec: 1.73353 ( -0.26749 0.25699 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.22377e-07 ( -2.06828e-08 2.06669e-08 ) ergs/cm2
Plot creation:
Fri May 16 07:21:27 EDT 2008