batgrbproduct Analysis for Trigger=318166
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): Mon Jul 28 10:20:48 EDT 2008
Host Name: gcn5
Current Working Dir: /local/data/raid2/prebascript/trigger318166/GCN5_download_cron
======================================================================
Trigger: 00318166 Segment: 000
BAT Trigger Time: 238890682.816 [s; MET]
Trigger Stop: 238890684.864 [s; MET]
UTC: 2008-07-27T22:31:19.842180 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 255.47815111617 Dec: -40.8407209418678 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 7.59
Image Trigger?: NO
Rate S/N Ratio: 8.66025403784439 [ if not an image trigger ]
Image S/N Ratio: 7.59
Flight Position: [ source = BAT ]
RA: 255.47815111617 Dec: -40.8407209418678 [deg; J2000]
Ground Position: [ source = BAT pre-slew burst ]
RA: 255.4025573412 Dec: -40.8519395878804 [deg; J2000]
{ 17h 01m 36.6s , -40d 51' 07.0" }
+/- 2.42981986548399 [arcmin] (estimated 90% radius based on SNR)
+/- 1.15628261461973 [arcmin] (formal 1-sigma fit error)
SNR: 8.55654163643237
Angular difference between Flight and Ground position is 3.496453 arcmin
Partial Coding Fraction: 0.671875 [ including projection effects ]
Duration
T90: 8 +/- 2.23606797749979
Measured from: -2.81600001454353
to: 5.18399998545647 [s; relative to TRIGTIME]
T50: 3 +/- 2.23606797749979
Measured from: -0.816000014543533
to: 2.18399998545647 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: -0.816000014543533
to: 0.183999985456467 [s; relative to TRIGTIME]
Total Fluence
Measured from: -2.81600001454353
to: 6.18399998545647 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 0.278259 0.080816 0.022481 0.003538
0.026093 0.022910 0.020764 0.020852 [error]
Peak 0.036616 0.020461 -0.004511 0.006385
0.008926 0.007793 0.006860 0.007020 [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 9.38e-08 3.84e-08 9.24e-09 2.71e-09 1.43e-07 1.44e-07 erg/cm2
Error 1.64e-08 1.36e-08 7.44e-09 4.45e-09 2.89e-08 3.02e-08 erg/cm2
Peak flux Power-law 3.77e-01 1.52e-01 3.57e-02 1.02e-02 5.71e-01 5.74e-01 ph/cm2/s
Error 1.16e-01 7.52e-02 4.01e-02 2.13e-02 2.11e-01 2.13e-01 ph/cm2/s
Fluence Cutoff-PL 9.38e-08 3.84e-08 9.22e-09 2.68e-09 1.43e-07 1.44e-07 erg/cm2
Error 1.64e-08 1.36e-08 7.43e-09 4.41e-09 2.89e-08 3.02e-08 erg/cm2
Peak flux Cutoff-PL 3.75e-01 1.76e-01 1.35e-02 7.80e-05 5.64e-01 5.64e-01 ph/cm2/s
Error 1.68e-01 1.38e-01 3.45e-02 1.61e-02 2.04e-01 2.04e-01 ph/cm2/s
Fluence Band 9.38e-08 3.64e-08 7.79e-09 1.97e-09 1.41e-07 1.34e-07 erg/cm2
Error 1.15e-08 5.64e-09 3.20e-09 2.85e-08 2.25e-08 0.00e+00 erg/cm2
Peak flux Band 3.78e-01 1.55e-01 3.74e-02 1.18e-02 5.88e-01 5.77e-01 ph/cm2/s
Error 1.57e-01 7.19e-02 3.81e-02 1.16e-02 2.12e-01 2.14e-01 ph/cm2/s
=== Time-averaged spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 4.054 0.666 - - 6.94e-04 5.95e-04 54.702 57
CPL 1.812 0.000 2.0 8.4 3.98e-02 0.00e+00 54.699 0
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 3.086 0.980 - - 1.95e-03 1.81e-03 62.133 57
CPL 1.031 4.970 13.5 18.5 5.74e-02 0.00e+00 61.119 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 9.000 -2.816 6.184
T90 8.000 -2.816 5.184
T50 3.000 -0.816 2.184
Peak 1.000 -0.816 0.184
Image
Pre-slew 15-350 keV image (Event data; bkg subtracted)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
255.4026 -40.8519 0.0226 38.0 -167.3 0.3957 8.6 TRIG_00318166
------------------------------------------
Foreground time interval of the image:
-2.816 6.184 (delta_t = 9.000 [sec])
Background time interval of the image:
-202.615 -13.966 (delta_t = 188.649 [sec])
-12.816 -2.816 (delta_t = 10.000 [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 -2.816 sec. to 6.184 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 4.05430 ( -0.604042 0.728349 )
Norm@50keV : 6.935244E-04 ( -6.935244E-04 4.955012E-04) )
------------------------------------------------------------
Chi-Squared = 54.70162 using 59 PHA bins.
Reduced chi-squared = 0.9596775 for 57 degrees of freedom
Null hypothesis probability = 0.562
Photon flux (15-150 keV) in 9.000 sec: 0.448501 ( -0.075256 0.075334 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.43084e-07 ( -2.79702e-08 2.9898e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -2.816 sec. to 6.184 sec.
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.81162 ( )
Epeak [keV] : 1.96782 ( -1.93715 14.8348 )
Norm@50keV : 3.979266E-02 ( )
------------------------------------------------------------
Chi-Squared = 54.69889 using 59 PHA bins.
but latest trial 0.228200 gives Chi-Squared = 64.9810
Reduced chi-squared = 0.9767658 for 56 degrees of freedom
Null hypothesis probability = 0.524
Photon flux (15-150 keV) in 9.000 sec: 0.448211 ( -0.075216 0.075295 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.43045e-07 ( -2.79504e-08 2.99124e-08 ) ergs/cm2
Band function
Time interval is from -2.816 sec. to 6.184 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -1.45616 ( -0.688945 1.04666 )
beta : -5.15233 ( -0.729665 13.8212 )
Epeak [keV] : 15.1513 ( -15.0513 9984.85 )
Norm@50keV : 1.135930E-02 ( -4.872488E-02 6.735190E-02) )
------------------------------------------------------------
Chi-Squared = 75.39388 using 59 PHA bins.
Reduced chi-squared = 1.370798 for 55 degrees of freedom
Null hypothesis probability = 3.534E-02
Photon flux (15-150 keV) in 9.000 sec: 0.449030 ( -0.07474 0.074738 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.4086e-07 ( -2.5974e-08 3.09591e-08 ) ergs/cm2
Peak spectrum fit using the pre-slew DRM
Power-law model
Time interval is from -0.816 sec. to 0.184 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 3.08575 ( -0.809773 1.14998 )
Norm@50keV : 1.947430E-03 ( -1.947430E-03 1.681501E-03) )
------------------------------------------------------------
Chi-Squared = 62.13284 using 59 PHA bins.
Reduced chi-squared = 1.090050 for 57 degrees of freedom
Null hypothesis probability = 0.298
Photon flux (15-150 keV) in 1.000 sec: 0.570618 ( -0.210398 0.211357 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.43772e-08 ( -1.04495e-08 1.20433e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.816 sec. to 0.184 sec.
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.03087 ( -4.03087 5.90848 )
Epeak [keV] : 13.4945 ( -13.4845 23.5362 )
Norm@50keV : 5.741027E-02 ( )
------------------------------------------------------------
Chi-Squared = 61.11878 using 59 PHA bins.
but latest trial 45.7794 gives Chi-Squared = 5.98609
Reduced chi-squared = 1.091407 for 56 degrees of freedom
Null hypothesis probability = 0.297
Photon flux (15-150 keV) in 1.000 sec: 0.564474 ( -0.203355 0.2049 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.19258e-08 ( -8.5777e-09 1.15921e-08 ) ergs/cm2
Band function
Time interval is from -0.816 sec. to 0.184 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -1.33849 ( -8.66151 2.43963 )
beta : -9.36348 ( -0.636521 19.3633 )
Epeak [keV] : 13.0862 ( -12.9862 17.0585 )
Norm@50keV : 2.680190E-02 ( -0.256407 654.612 )
------------------------------------------------------------
Chi-Squared = 61.38631 using 59 PHA bins.
Reduced chi-squared = 1.116115 for 55 degrees of freedom
Null hypothesis probability = 0.258
Photon flux (15-150 keV) in 1.000 sec: 0.587933 ( -0.212189 0.212555 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.24329e-08 ( -8.6289e-09 1.19392e-08 ) ergs/cm2
Plot creation:
Mon Jul 28 11:02:02 EDT 2008