batgrbproduct Analysis for Trigger=228581
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): Wed Jan 2 03:54:19 EST 2008
Host Name: gcn5
Current Working Dir: /local/data/raid2/prebascript/trigger228581/GCN5_download_cron
======================================================================
Trigger: 00228581 Segment: 000
BAT Trigger Time: 179398643.776 [s; MET]
Trigger Stop: 179398644.8 [s; MET]
UTC: 2006-09-08T08:57:22.344940 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 31.8346478600979 Dec: 0.370562530869732 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 8.73
Image Trigger?: NO
Rate S/N Ratio: 16.5227116418583 [ if not an image trigger ]
Image S/N Ratio: 8.73
Flight Position: [ source = BAT ]
RA: 31.8346478600979 Dec: 0.370562530869732 [deg; J2000]
Ground Position: [ source = BAT pre-slew burst ]
RA: 31.8250270053575 Dec: 0.332849347926447 [deg; J2000]
{ 02h 07m 18.0s , +00d 19' 58.3" }
+/- 1.12514064526261 [arcmin] (estimated 90% radius based on SNR)
+/- 0.310347084994889 [arcmin] (formal 1-sigma fit error)
SNR: 25.7019331109616
RA = 2h 7m 18.0s (31.825027 deg.)
Dec = 0d 19' 58" (0.332849 deg.)
Angular difference between Flight and Ground position is 2.335258 arcmin
Partial Coding Fraction: 0.4609375 [ including projection effects ]
Duration
T90: 19.2800000011921 +/- 1.33033529343473
Measured from: -8.04399999976158
to: 11.2360000014305 [s; relative to TRIGTIME]
T50: 7.41200000047684 +/- 0.67679242593042
Measured from: -4.81599998474121
to: 2.59600001573563 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 0.967999994754791
to: 1.96799999475479 [s; relative to TRIGTIME]
Total Fluence
Measured from: -12.9799999892712
to: 15.5119999945164 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 0.967546 1.591687 1.358001 0.341462
0.041852 0.044763 0.041455 0.034019 [error]
Peak 0.064623 0.142123 0.147463 0.035850
0.008623 0.010144 0.009702 0.007384 [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 3.25e-07 6.54e-07 1.03e-06 3.55e-06 2.86e-06 5.56e-06 erg/cm2
Error 2.24e-08 2.62e-08 4.10e-08 3.29e-07 1.02e-07 3.49e-07 erg/cm2
Peak flux Power-law 7.30e-01 9.53e-01 9.12e-01 1.55e+00 3.11e+00 4.14e+00 ph/cm2/s
Error 1.08e-01 8.77e-02 7.40e-02 2.62e-01 2.41e-01 3.31e-01 ph/cm2/s
Fluence Cutoff-PL 2.96e-07 6.70e-07 1.06e-06 2.20e-06 2.80e-06 3.99e-06 erg/cm2
Error 2.89e-08 2.90e-08 4.89e-08 6.99e-07 1.11e-07 0.00e+00 erg/cm2
Peak flux Cutoff-PL 5.77e-01 1.01e+00 1.02e+00 7.28e-01 3.03e+00 3.34e+00 ph/cm2/s
Error 1.35e-01 1.02e-01 1.01e-01 3.26e-01 2.46e-01 4.00e-01 ph/cm2/s
Fluence Band 2.92e-07 6.68e-07 1.06e-06 2.18e-06 2.80e-06 4.07e-06 erg/cm2
Error 2.86e-08 2.89e-08 4.89e-08 7.00e-07 1.11e-07 0.00e+00 erg/cm2
Peak flux Band 5.77e-01 1.01e+00 1.02e+00 7.29e-01 3.03e+00 3.34e+00 ph/cm2/s
Error 1.35e-01 1.02e-01 1.01e-01 3.26e-01 2.47e-01 4.00e-01 ph/cm2/s
=== Time-averaged spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.351 0.063 - - 1.03e-02 3.45e-04 50.695 57
CPL 0.967 0.269 150.7 112.4 1.53e-02 4.28e-03 44.180 56
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.063 0.124 - - 2.69e-02 2.03e-03 62.145 57
CPL 0.134 0.614 115.2 57.1 7.03e-02 4.76e-02 53.671 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: 17.728000 sec.
T50 in the 50-300 keV band: 6.528000 sec.
=== Table of the duration information ==
Value tstart tstop
T100 28.492 -12.980 15.512
T90 19.280 -8.044 11.236
T50 7.412 -4.816 2.596
Peak 1.000 0.968 1.968
Image
Pre-slew 15-350 keV image (Event data; bkg subtracted)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
31.8250 +0.3328 0.0075 26.4 89.2 4.0430 25.7 TRIG_00228581
------------------------------------------
Foreground time interval of the image:
-12.980 11.125 (delta_t = 24.105 [sec])
Background time interval of the image:
-19.575 -12.980 (delta_t = 6.595 [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 -12.980 sec. to 15.512 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.35084 ( -6.269789E-02 6.253505E-02) )
Norm@50keV : 1.026389E-02 ( -3.454331E-04 3.454071E-04) )
------------------------------------------------------------
Chi-Squared = 50.69486 using 59 PHA bins.
Reduced chi-squared = 0.8893835 for 57 degrees of freedom
Null hypothesis probability = 0.709
Photon flux (15-150 keV) in 28.49 sec: 1.23672 ( -0.04525 0.04537 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.85552e-06 ( -1.02108e-07 1.02308e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -12.980 sec. to 15.512 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.966914 ( -0.277978 0.259745 )
Epeak [keV] : 150.720 ( -40.7768 184.105 )
Norm@50keV : 1.532123E-02 ( -3.557487E-03 4.995271E-03) )
------------------------------------------------------------
Chi-Squared = 44.18022 using 59 PHA bins.
Reduced chi-squared = 0.7889325 for 56 degrees of freedom
Null hypothesis probability = 0.873
Photon flux (15-150 keV) in 28.49 sec: 1.20881 ( -0.04864 0.04869 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.79857e-06 ( -1.11877e-07 1.10373e-07 ) ergs/cm2
Band function
Time interval is from -12.980 sec. to 15.512 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.896498 ( -0.309680 0.442182 )
beta : -1.67553 ( -8.32447 0.267816 )
Epeak [keV] : 130.500 ( -61.6784 170.105 )
Norm@50keV : 1.669905E-02 ( -4.714993E-03 1.869747E-02) )
------------------------------------------------------------
Chi-Squared = 43.79589 using 59 PHA bins.
Reduced chi-squared = 0.7962889 for 55 degrees of freedom
Null hypothesis probability = 0.861
Photon flux (15-150 keV) in 28.49 sec: 1.20483 ( -0.04969 0.04953 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.7952e-06 ( -1.10293e-07 1.11752e-07 ) ergs/cm2
Peak spectrum fit using the pre-slew DRM
Power-law model
Time interval is from 0.968 sec. to 1.968 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.06330 ( -0.125100 0.123054 )
Norm@50keV : 2.689372E-02 ( -2.027854E-03 2.024967E-03) )
------------------------------------------------------------
Chi-Squared = 62.14478 using 59 PHA bins.
Reduced chi-squared = 1.090259 for 57 degrees of freedom
Null hypothesis probability = 0.298
Photon flux (15-150 keV) in 1.000 sec: 3.10937 ( -0.24044 0.24075 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.84631e-07 ( -2.2912e-08 2.2904e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.968 sec. to 1.968 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.134225 ( -0.659302 0.567713 )
Epeak [keV] : 115.152 ( -26.0948 88.0911 )
Norm@50keV : 7.028871E-02 ( -3.059989E-02 6.452785E-02) )
------------------------------------------------------------
Chi-Squared = 53.67133 using 59 PHA bins.
Reduced chi-squared = 0.9584165 for 56 degrees of freedom
Null hypothesis probability = 0.564
Photon flux (15-150 keV) in 1.000 sec: 3.03170 ( -0.24677 0.24599 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.76459e-07 ( -2.4355e-08 2.4427e-08 ) ergs/cm2
Band function
Time interval is from 0.968 sec. to 1.968 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.134908 ( -0.567018 0.660227 )
beta : -9.35186 ( -0.648139 11.2066 )
Epeak [keV] : 115.185 ( -26.1464 88.0100 )
Norm@50keV : 7.024035E-02 ( -3.055191E-02 6.462802E-02) )
------------------------------------------------------------
Chi-Squared = 53.67140 using 59 PHA bins.
Reduced chi-squared = 0.9758436 for 55 degrees of freedom
Null hypothesis probability = 0.525
Photon flux (15-150 keV) in 1.000 sec: 3.03176 ( -0.24681 0.2462 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.76497e-07 ( -2.4528e-08 2.42e-08 ) ergs/cm2
Plot creation:
Wed Jan 2 04:16:47 EST 2008