batgrbproduct Analysis for Trigger=311658
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): Thu May 15 17:31:42 EDT 2008
Host Name: gcn5
Current Working Dir: /local/data/raid2/prebascript/trigger311658/GCN5_download_cron
======================================================================
Trigger: 00311658 Segment: 000
BAT Trigger Time: 232524076.608 [s; MET]
Trigger Stop: 232524078.656 [s; MET]
UTC: 2008-05-15T06:01:13.816640 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 3.15011728837097 Dec: 32.5992622180551 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 7.05
Image Trigger?: NO
Rate S/N Ratio: 8.42614977317636 [ if not an image trigger ]
Image S/N Ratio: 7.05
Flight Position: [ source = BAT ]
RA: 3.15011728837097 Dec: 32.5992622180551 [deg; J2000]
Ground Position: [ source = BAT pre-slew burst ]
RA: 3.16597760415807 Dec: 32.5638498637488 [deg; J2000]
{ 00h 12m 39.8s , +32d 33' 49.9" }
+/- 1.63086639178312 [arcmin] (estimated 90% radius based on SNR)
+/- 0.798974549412723 [arcmin] (formal 1-sigma fit error)
SNR: 15.1238912913088
Angular difference between Flight and Ground position is 2.271014 arcmin
Partial Coding Fraction: 0.08496094 [ including projection effects ]
Duration
T90: 20.8159999549389 +/- 5.24815243201247
Measured from: -1.92800000309944
to: 18.8879999518394 [s; relative to TRIGTIME]
T50: 10.0479999780655 +/- 3.11224678103672
Measured from: 1.0639999806881
to: 11.1119999587536 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 1.37199997901917
to: 2.37199997901917 [s; relative to TRIGTIME]
Total Fluence
Measured from: -2.63199999928474
to: 24.0239999890327 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 1.684436 1.777751 0.515340 -0.037174
0.116878 0.119743 0.112384 0.109750 [error]
Peak 0.117686 0.201962 0.046466 -0.004332
0.026495 0.027040 0.023349 0.020936 [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 7.06e-07 7.39e-07 5.45e-07 6.51e-07 2.24e-06 2.64e-06 erg/cm2
Error 8.12e-08 6.80e-08 9.92e-08 2.25e-07 2.29e-07 3.58e-07 erg/cm2
Peak flux Power-law 1.77e+00 1.30e+00 6.36e-01 4.41e-01 3.91e+00 4.15e+00 ph/cm2/s
Error 4.50e-01 2.36e-01 1.80e-01 2.33e-01 7.15e-01 7.53e-01 ph/cm2/s
Fluence Cutoff-PL 6.55e-07 8.40e-07 4.08e-07 5.81e-08 1.95e-06 1.96e-06 erg/cm2
Error 9.21e-08 9.65e-08 1.53e-07 1.39e-07 2.60e-07 2.99e-07 erg/cm2
Peak flux Cutoff-PL 1.53e+00 1.56e+00 6.06e-01 7.38e-02 3.76e+00 3.77e+00 ph/cm2/s
Error 5.89e-01 4.34e-01 2.90e-01 2.95e-01 7.89e-01 8.33e-01 ph/cm2/s
Fluence Band 6.46e-07 8.34e-07 4.16e-07 2.49e-07 2.03e-06 2.13e-06 erg/cm2
Error 8.94e-08 9.45e-08 1.31e-07 2.59e-07 2.36e-07 4.09e-07 erg/cm2
Peak flux Band 1.50e+00 1.61e+00 5.80e-01 2.09e-01 3.78e+00 3.94e+00 ph/cm2/s
Error 5.56e-01 2.98e-01 1.91e-01 1.29e-01 7.25e-01 7.89e-01 ph/cm2/s
=== Time-averaged spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 2.437 0.185 - - 8.55e-03 1.13e-03 53.801 57
CPL 0.942 1.210 25.0 15.6 7.49e-02 2.96e-01 47.245 0
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 2.033 0.319 - - 2.57e-02 5.66e-03 62.090 57
CPL 0.458 2.568 40.1 5000.0 2.13e-01 7.70e+00 60.359 0
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: 0.000000 sec.
T50 in the 50-300 keV band: 0.000000 sec.
=== Table of the duration information ==
Value tstart tstop
T100 26.656 -2.632 24.024
T90 20.816 -1.928 18.888
T50 10.048 1.064 11.112
Peak 1.000 1.372 2.372
Image
Pre-slew 15-350 keV image (Event data; bkg subtracted)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
3.1660 +32.5638 0.0127 41.6 -69.8 4.1912 15.1 TRIG_00311658
------------------------------------------
Foreground time interval of the image:
-2.632 24.024 (delta_t = 26.656 [sec])
Background time interval of the image:
-239.608 -237.298 (delta_t = 2.310 [sec])
-235.608 -178.938 (delta_t = 56.670 [sec])
-177.608 -177.468 (delta_t = 0.140 [sec])
-60.608 -43.034 (delta_t = 17.574 [sec])
-41.608 -2.632 (delta_t = 38.976 [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 -2.632 sec. to 24.024 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 2.43651 ( -0.179491 0.190771 )
Norm@50keV : 8.547487E-03 ( -1.132327E-03 1.120068E-03) )
------------------------------------------------------------
Chi-Squared = 53.80142 using 59 PHA bins.
Reduced chi-squared = 0.9438846 for 57 degrees of freedom
Null hypothesis probability = 0.596
Photon flux (15-150 keV) in 26.66 sec: 1.61594 ( -0.13952 0.1396 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.24206e-06 ( -2.26589e-07 2.31502e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -2.632 sec. to 24.024 sec.
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.942456 ( -1.38082 1.03863 )
Epeak [keV] : 25.0030 ( -24.9930 6.19088 )
Norm@50keV : 7.490407E-02 ( -7.490407E-02 0.517380 )
------------------------------------------------------------
Chi-Squared = 47.24455 using 59 PHA bins.
but latest trial 1.99410 gives Chi-Squared = 3.70967
Reduced chi-squared = 0.8436527 for 56 degrees of freedom
Null hypothesis probability = 0.791
Photon flux (15-150 keV) in 26.66 sec: 1.53096 ( -0.14927 0.15006 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.95359e-06 ( -2.411e-07 2.79799e-07 ) ergs/cm2
Band function
Time interval is from -2.632 sec. to 24.024 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -1.44473 ( -1.07834 3.23757 )
beta : -3.33854 ( -6.66146 0.823173 )
Epeak [keV] : 20.1637 ( -12.2145 28.2983 )
Norm@50keV : 3.569987E-02 ( -0.183838 46.6813 )
------------------------------------------------------------
Chi-Squared = 47.52916 using 59 PHA bins.
Reduced chi-squared = 0.8641664 for 55 degrees of freedom
Null hypothesis probability = 0.753
Photon flux (15-150 keV) in 26.66 sec: 1.55215 ( -0.15104 0.14034 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.0251e-06 ( -2.40297e-07 2.30809e-07 ) ergs/cm2
Peak spectrum fit using the pre-slew DRM
Power-law model
Time interval is from 1.368 sec. to 2.376 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 2.03302 ( -0.300677 0.336665 )
Norm@50keV : 2.569016E-02 ( -5.772285E-03 5.548760E-03) )
------------------------------------------------------------
Chi-Squared = 62.08950 using 59 PHA bins.
Reduced chi-squared = 1.089289 for 57 degrees of freedom
Null hypothesis probability = 0.300
Photon flux (15-150 keV) in 1.008 sec: 3.91318 ( -0.71443 0.71501 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.39243e-07 ( -4.93769e-08 5.03153e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 1.368 sec. to 2.376 sec.
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.457872 ( -3.45787 1.67755 )
Epeak [keV] : 40.0591 ( -40.0491 9959.94 )
Norm@50keV : 0.213447 ( -0.213447 15.1943 )
------------------------------------------------------------
Chi-Squared = 60.35872 using 59 PHA bins.
but latest trial 2.13528 gives Chi-Squared = 1.96777
Reduced chi-squared = 1.077834 for 56 degrees of freedom
Null hypothesis probability = 0.321
Photon flux (15-150 keV) in 1.008 sec: 3.75693 ( -0.80972 0.76866 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.10786e-07 ( -5.47183e-08 6.62992e-08 ) ergs/cm2
Band function
Time interval is from 1.368 sec. to 2.376 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.530519 ( -9.46948 5.53052 )
beta : -2.67408 ( -7.32592 0.724887 )
Epeak [keV] : 38.2384 ( -38.1384 9961.76 )
Norm@50keV : 0.203384 ( -1.51349 434.545 )
------------------------------------------------------------
Chi-Squared = 59.47479 using 59 PHA bins.
Reduced chi-squared = 1.081360 for 55 degrees of freedom
Null hypothesis probability = 0.316
Photon flux (15-150 keV) in 1.008 sec: 3.77536 ( -0.77306 0.67734 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.26444e-07 ( -4.6742e-08 5.14755e-08 ) ergs/cm2
Plot creation:
Thu May 15 17:55:48 EDT 2008