batgrbproduct Analysis for Trigger=176918
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 Dec 31 09:07:19 EST 2007
Host Name: gcn5
Current Working Dir: /local/data/raid2/prebascript/trigger176918/SDC
======================================================================
Trigger: 00176918 Segment: 000
BAT Trigger Time: 158703344.192 [s; MET]
Trigger Stop: 158703345.216 [s; MET]
UTC: 2006-01-11T20:15:43.242160 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 286.33719257667 Dec: 70.3598868857769 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 6.97
Image Trigger?: NO
Rate S/N Ratio: 18.5202591774521 [ if not an image trigger ]
Image S/N Ratio: 6.97
Flight Position: [ source = BAT ]
RA: 286.33719257667 Dec: 70.3598868857769 [deg; J2000]
Ground Position: [ source = BAT pre-slew burst ]
RA: 286.43266129838 Dec: 70.3771471289469 [deg; J2000]
{ 19h 05m 43.8s , +70d 22' 37.7" }
+/- 1.51977261687644 [arcmin] (estimated 90% radius based on SNR)
+/- 0.691876696802943 [arcmin] (formal 1-sigma fit error)
SNR: 16.7276388711324
RA = 19h 5m 43.8s (286.432661 deg.)
Dec = 70d 22' 38" (70.377147 deg.)
Angular difference between Flight and Ground position is 2.185427 arcmin
Partial Coding Fraction: 0.2851562 [ including projection effects ]
Duration
T90: 58.8320000171661 +/- 4.29058130905367
Measured from: -1.2039999961853
to: 57.6280000209808 [s; relative to TRIGTIME]
T50: 21.1440000236034 +/- 3.49172738252821
Measured from: 2.28799998760223
to: 23.4320000112057 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 0.363999992609024
to: 1.36399999260902 [s; relative to TRIGTIME]
Total Fluence
Measured from: -2.02799999713898
to: 61.6960000097752 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 0.509755 0.584681 0.837775 0.341266
0.062464 0.064524 0.057378 0.047598 [error]
Peak 0.047206 0.029804 0.095829 0.016735
0.009980 0.011211 0.010589 0.007989 [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 1.24e-07 3.04e-07 5.97e-07 2.89e-06 1.61e-06 3.92e-06 erg/cm2
Error 2.53e-08 3.60e-08 5.40e-08 6.56e-07 1.42e-07 6.68e-07 erg/cm2
Peak flux Power-law 2.90e-01 4.12e-01 4.34e-01 8.47e-01 1.40e+00 1.98e+00 ph/cm2/s
Error 1.17e-01 1.02e-01 7.88e-02 3.35e-01 2.67e-01 3.76e-01 ph/cm2/s
Fluence Cutoff-PL 1.24e-07 3.05e-07 5.97e-07 2.87e-06 1.61e-06 3.90e-06 erg/cm2
Error 2.53e-08 3.61e-08 5.41e-08 6.52e-07 1.42e-07 7.26e-07 erg/cm2
Peak flux Cutoff-PL 2.08e-01 4.08e-01 4.90e-01 4.69e-01 1.35e+00 1.58e+00 ph/cm2/s
Error 1.95e-01 1.31e-01 1.29e-01 4.79e-01 2.96e-01 5.98e-01 ph/cm2/s
Fluence Band 1.22e-07 3.03e-07 5.96e-07 2.87e-06 1.61e-06 2.94e-06 erg/cm2
Error 2.50e-08 3.59e-08 5.40e-08 7.31e-07 1.42e-07 0.00e+00 erg/cm2
Peak flux Band 2.08e-01 4.08e-01 4.90e-01 4.71e-01 1.35e+00 1.58e+00 ph/cm2/s
Error 1.95e-01 1.31e-01 1.29e-01 4.65e-01 2.95e-01 5.94e-01 ph/cm2/s
=== Time-averaged spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.029 0.167 - - 2.36e-03 2.13e-04 62.529 57
CPL 0.972 0.209 1000.0 0.0 2.51e-03 2.14e-04 62.874 56
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 0.923 0.319 - - 1.22e-02 2.31e-03 66.480 57
CPL 0.008 2.111 143.9 4958.1 2.72e-02 1.09e-01 65.560 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: 55.616000 sec.
T50 in the 50-300 keV band: 16.064000 sec.
=== Table of the duration information ==
Value tstart tstop
T100 63.724 -2.028 61.696
T90 58.832 -1.204 57.628
T50 21.144 2.288 23.432
Peak 1.000 0.364 1.364
Image
Pre-slew 15-350 keV image (Event data; bkg subtracted)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
286.4327 +70.3771 0.0115 33.2 113.5 1.5561 16.7 TRIG_00176918
------------------------------------------
Foreground time interval of the image:
-2.028 19.213 (delta_t = 21.241 [sec])
Background time interval of the image:
-299.192 -2.028 (delta_t = 297.164 [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 -2.028 sec. to 61.696 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.02908 ( -0.170319 0.164652 )
Norm@50keV : 2.364523E-03 ( -2.148235E-04 2.118559E-04) )
------------------------------------------------------------
Chi-Squared = 62.52948 using 59 PHA bins.
Reduced chi-squared = 1.097008 for 57 degrees of freedom
Null hypothesis probability = 0.286
Photon flux (15-150 keV) in 63.72 sec: 0.272694 ( -0.02569 0.025841 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.61276e-06 ( -1.42249e-07 1.42452e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -2.028 sec. to 61.696 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.971864 ( -0.190603 0.226574 )
Epeak [keV] : 1000.000 ( )
Norm@50keV : 2.514650E-03 ( -2.207868E-04 2.069976E-04) )
------------------------------------------------------------
Chi-Squared = 62.87373 using 59 PHA bins.
Reduced chi-squared = 1.122745 for 56 degrees of freedom
Null hypothesis probability = 0.246
Photon flux (15-150 keV) in 63.72 sec: 0.272582 ( -0.025677 0.025832 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.61341e-06 ( -1.42274e-07 1.42637e-07 ) ergs/cm2
Band function
Time interval is from -2.028 sec. to 61.696 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.897289 ( -9.10271 3.04228 )
beta : -1.02912 ( -0.164568 0.170328 )
Epeak [keV] : 34.1994 ( -34.0994 9965.80 )
Norm@50keV : 3.752803E-03 ( -1.594994E-03 603.776 )
------------------------------------------------------------
Chi-Squared = 62.52948 using 59 PHA bins.
Reduced chi-squared = 1.136900 for 55 degrees of freedom
Null hypothesis probability = 0.226
Photon flux (15-150 keV) in 63.72 sec: 3.14400 ( -3.144 3.39342 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.61223e-06 ( -1.42274e-07 1.42503e-07 ) ergs/cm2
Peak spectrum fit using the pre-slew DRM
Power-law model
Time interval is from 0.364 sec. to 1.364 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.922539 ( -0.329634 0.308534 )
Norm@50keV : 1.219937E-02 ( -2.338968E-03 2.282929E-03) )
------------------------------------------------------------
Chi-Squared = 66.47960 using 59 PHA bins.
Reduced chi-squared = 1.166309 for 57 degrees of freedom
Null hypothesis probability = 0.183
Photon flux (15-150 keV) in 1.000 sec: 1.40059 ( -0.26622 0.26837 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.35749e-07 ( -2.4919e-08 2.4938e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.364 sec. to 1.364 sec.
Parameters : value lower 90% higher 90%
Photon index: 7.960825E-03 ( -3.00796 1.21488 )
Epeak [keV] : 143.863 ( -60.0061 9856.14 )
Norm@50keV : 2.719386E-02 ( -1.682411E-02 0.200982 )
------------------------------------------------------------
Chi-Squared = 65.55958 using 59 PHA bins.
but latest trial 1.18215 gives Chi-Squared = 5.38290
but latest trial 0.231021 gives Chi-Squared = 3.84170
Reduced chi-squared = 1.170707 for 56 degrees of freedom
Null hypothesis probability = 0.179
Photon flux (15-150 keV) in 1.000 sec: 1.34832 ( -0.30648 0.28614 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.34949e-07 ( -2.5891e-08 2.5482e-08 ) ergs/cm2
Band function
Time interval is from 0.364 sec. to 1.364 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.844305 ( -9.15569 5.84430 )
beta : -0.922544 ( -0.308532 0.329641 )
Epeak [keV] : 16.2103 ( -7.812500E-02 9.765625E-04) )
Norm@50keV : 1.778798E-02 ( -2.347850E-03 2.290011E-03) )
------------------------------------------------------------
Chi-Squared = 66.47961 using 59 PHA bins.
Reduced chi-squared = 1.208720 for 55 degrees of freedom
Null hypothesis probability = 0.138
Photon flux (15-150 keV) in 1.000 sec: 1.34907 ( -0.30432 0.28577 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.34948e-07 ( -2.5848e-08 2.5396e-08 ) ergs/cm2
Plot creation:
Mon Dec 31 09:18:41 EST 2007