batgrbproduct Analysis for Trigger=331475
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 Oct 12 19:58:34 EDT 2008
Host Name: gcn5
Current Working Dir: /local/data/raid2/prebascript/trigger331475/GCN5_download_cron
======================================================================
Trigger: 00331475 Segment: 000
BAT Trigger Time: 245509827.072 [s; MET]
Trigger Stop: 245509829.12 [s; MET]
UTC: 2008-10-12T13:10:23.902940 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 30.2174055107331 Dec: -17.6414535051542 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 7.78
Image Trigger?: NO
Rate S/N Ratio: 17.606816861659 [ if not an image trigger ]
Image S/N Ratio: 7.78
Flight Position: [ source = BAT ]
RA: 30.2174055107331 Dec: -17.6414535051542 [deg; J2000]
Ground Position: [ source = BAT pre-slew burst ]
RA: 30.1847535450489 Dec: -17.626619759353 [deg; J2000]
{ 02h 00m 44.3s , -17d 37' 35.8" }
+/- 1.69093356314935 [arcmin] (estimated 90% radius based on SNR)
+/- 0.768311728077212 [arcmin] (formal 1-sigma fit error)
SNR: 14.3622775914992
Angular difference between Flight and Ground position is 2.068347 arcmin
Partial Coding Fraction: 0.2617188 [ including projection effects ]
Duration
T90: 30.3359999656677 +/- 7.01809318091378
Measured from: -21.1999998986721
to: 9.13600006699562 [s; relative to TRIGTIME]
T50: 10.0159999728203 +/- 6.76540850334611
Measured from: -6.51199990510941
to: 3.50400006771088 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 0.467999994754791
to: 1.46799999475479 [s; relative to TRIGTIME]
Total Fluence
Measured from: -23.3759999871254
to: 15.055999994278 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 0.213225 0.547711 0.587620 0.243790
0.055550 0.057606 0.053406 0.046545 [error]
Peak 0.029726 0.043016 0.068147 0.015481
0.009252 0.010091 0.010283 0.008134 [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 8.33e-08 2.16e-07 4.50e-07 2.39e-06 1.21e-06 3.15e-06 erg/cm2
Error 1.91e-08 2.96e-08 4.91e-08 6.11e-07 1.31e-07 6.29e-07 erg/cm2
Peak flux Power-law 2.57e-01 3.58e-01 3.69e-01 6.96e-01 1.21e+00 1.68e+00 ph/cm2/s
Error 1.01e-01 8.78e-02 7.54e-02 2.99e-01 2.41e-01 3.55e-01 ph/cm2/s
Fluence Cutoff-PL 7.38e-08 2.22e-07 4.75e-07 1.33e-06 1.19e-06 2.03e-06 erg/cm2
Error 2.40e-08 3.24e-08 6.22e-08 1.12e-06 1.39e-07 1.12e-06 erg/cm2
Peak flux Cutoff-PL 1.78e-01 3.71e-01 4.27e-01 2.88e-01 1.15e+00 1.26e+00 ph/cm2/s
Error 1.24e-01 1.03e-01 1.04e-01 4.17e-01 2.49e-01 4.50e-01 ph/cm2/s
Fluence Band 7.25e-08 2.21e-07 4.74e-07 1.32e-06 1.19e-06 2.07e-06 erg/cm2
Error 2.38e-08 3.23e-08 6.22e-08 1.12e-06 1.39e-07 1.12e-06 erg/cm2
Peak flux Band 1.27e-01 2.74e-01 3.35e-01 2.55e-01 8.87e-01 9.93e-01 ph/cm2/s
Error 1.20e-01 1.06e-01 1.01e-01 4.24e-01 2.46e-01 4.64e-01 ph/cm2/s
=== Time-averaged spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 0.944 0.185 - - 2.86e-03 3.10e-04 56.373 57
CPL 0.453 0.755 186.3 5000.0 4.65e-03 4.03e-03 55.109 56
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 0.956 0.323 - - 1.05e-02 2.07e-03 70.733 57
CPL -0.287 1.780 110.5 4963.1 3.50e-02 1.19e-01 68.561 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: 13.952000 sec.
T50 in the 50-300 keV band: 5.824000 sec.
=== Table of the duration information ==
Value tstart tstop
T100 38.432 -23.376 15.056
T90 30.336 -21.200 9.136
T50 10.016 -6.512 3.504
Peak 1.000 0.468 1.468
Image
Pre-slew 15-350 keV image (Event data; bkg subtracted)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
30.1848 -17.6266 0.0134 33.6 69.7 1.6956 14.4 TRIG_00331475
------------------------------------------
Foreground time interval of the image:
-23.376 15.056 (delta_t = 38.432 [sec])
Background time interval of the image:
-239.072 -101.252 (delta_t = 137.820 [sec])
-100.072 -71.232 (delta_t = 28.840 [sec])
-70.072 -23.376 (delta_t = 46.696 [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.
- 4) For short bursts (T90<1sec), the specrtum is also fit with Blackbody, OTTB, and Double Blackbody.
Time averaged spectrum fit using the pre-slew DRM
Power-law model
Time interval is from -23.376 sec. to 15.056 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.944200 ( -0.189061 0.180488 )
Norm@50keV : 2.859146E-03 ( -3.114678E-04 3.076529E-04) )
------------------------------------------------------------
Chi-Squared = 56.37311 using 59 PHA bins.
Reduced chi-squared = 0.9890019 for 57 degrees of freedom
Null hypothesis probability = 0.499
Photon flux (15-150 keV) in 38.43 sec: 0.328432 ( -0.036033 0.03621 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.21276e-06 ( -1.31231e-07 1.31281e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -23.376 sec. to 15.056 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.452549 ( -0.890652 0.620001 )
Epeak [keV] : 186.325 ( -186.315 9813.67 )
Norm@50keV : 4.652831E-03 ( -2.005144E-03 6.054350E-03) )
------------------------------------------------------------
Chi-Squared = 55.10905 using 59 PHA bins.
Reduced chi-squared = 0.9840901 for 56 degrees of freedom
Null hypothesis probability = 0.509
Photon flux (15-150 keV) in 38.43 sec: 0.321648 ( -0.037494 0.037367 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.18848e-06 ( -1.40185e-07 1.37161e-07 ) ergs/cm2
Band function
Time interval is from -23.376 sec. to 15.056 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.304745 ( -11.5194 2.08264 )
beta : -1.19012 ( -0.373123 0.235794 )
Epeak [keV] : 140.558 ( -46.6175 849.074 )
Norm@50keV : 5.682064E-03 ( -2.56729 8.34917 )
------------------------------------------------------------
Chi-Squared = 54.80825 using 59 PHA bins.
Reduced chi-squared = 0.9965137 for 55 degrees of freedom
Null hypothesis probability = 0.482
Photon flux (15-150 keV) in 38.43 sec: 0.321628 ( -0.037488 0.037615 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.18778e-06 ( -1.40012e-07 1.37756e-07 ) ergs/cm2
Peak spectrum fit using the pre-slew DRM
Power-law model
Time interval is from 0.464 sec. to 1.472 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.956353 ( -0.330421 0.316238 )
Norm@50keV : 1.049170E-02 ( -2.077649E-03 2.061176E-03) )
------------------------------------------------------------
Chi-Squared = 70.73346 using 59 PHA bins.
Reduced chi-squared = 1.240938 for 57 degrees of freedom
Null hypothesis probability = 0.104
Photon flux (15-150 keV) in 1.008 sec: 1.20568 ( -0.239941 0.24113 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.16193e-07 ( -2.3871e-08 2.40579e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.464 sec. to 1.472 sec.
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.286830 ( -2.18056 1.38045 )
Epeak [keV] : 110.541 ( -36.6984 9889.46 )
Norm@50keV : 3.501646E-02 ( -3.501645E-02 0.202271 )
------------------------------------------------------------
Chi-Squared = 68.56091 using 59 PHA bins.
but latest trial 41.1411 gives Chi-Squared = 26.0185
Reduced chi-squared = 1.224302 for 56 degrees of freedom
Null hypothesis probability = 0.121
Photon flux (15-150 keV) in 1.008 sec: 1.15239 ( -0.249201 0.24933 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.11926e-07 ( -2.54589e-08 2.5196e-08 ) ergs/cm2
Band function
Time interval is from 0.464 sec. to 1.472 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : 0.281787 ( -1.37507 1.73078 )
beta : -8.48736 ( )
Epeak [keV] : 110.759 ( )
Norm@50keV : 3.484452E-02 ( )
------------------------------------------------------------
Chi-Squared = 68.56095 using 59 PHA bins.
Reduced chi-squared = 1.246563 for 55 degrees of freedom
Null hypothesis probability = 0.103
Photon flux (15-150 keV) in 1.008 sec: 0.886950 ( -0.241197 0.25 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.88544e-08 ( -2.4852e-08 2.48147e-08 ) ergs/cm2
Plot creation:
Sun Oct 12 20:18:46 EDT 2008