batgrbproduct Analysis for Trigger=157870
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 9 14:13:36 EST 2008
Host Name: gcn5
Current Working Dir: /local/data/raid2/prebascript/trigger157870/GCN5_download_cron
======================================================================
Trigger: 00157870 Segment: 000
BAT Trigger Time: 149857896 [s; MET]
Trigger Stop: 149857960 [s; MET]
UTC: 2005-10-01T11:11:36.241320 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 350.972781554212 Dec: -31.5278427417636 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 7.29
Image Trigger?: YES
Rate S/N Ratio: 0 [ if not an image trigger ]
Image S/N Ratio: 7.29
Flight Position: [ source = BAT ]
RA: 350.972781554212 Dec: -31.5278427417636 [deg; J2000]
Ground Position: [ source = BAT pre-slew burst ]
RA: 350.981908925252 Dec: -31.5189954110892 [deg; J2000]
{ 23h 23m 55.7s , -31d 31' 08.4" }
+/- 2.39000936715285 [arcmin] (estimated 90% radius based on SNR)
+/- 1.37732982991009 [arcmin] (formal 1-sigma fit error)
SNR: 8.76087569739097
RA = 23h 23m 55.7s (350.981909 deg.)
Dec = -31d 31' 8" (-31.518995 deg.)
Angular difference between Flight and Ground position is 0.706906 arcmin
Partial Coding Fraction: 0.7421875 [ including projection effects ]
Duration
T90: 189.071999996901 +/- 22.9591763707417
Measured from: -11.7319999933243
to: 177.340000003576 [s; relative to TRIGTIME]
T50: 61.9760000109673 +/- 39.0443344547218
Measured from: 90.4519999921322
to: 152.428000003099 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 130.419999986887
to: 131.419999986887 [s; relative to TRIGTIME]
Total Fluence
Measured from: -25.5679999887943
to: 196.719999998808 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 1.361215 1.257552 0.683410 0.027238
0.075850 0.077354 0.067866 0.060406 [error]
Peak 0.020489 0.022241 0.016146 0.002955
0.004544 0.004724 0.004151 0.003542 [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 4.33e-07 5.55e-07 5.19e-07 8.56e-07 1.79e-06 2.36e-06 erg/cm2
Error 4.80e-08 3.98e-08 6.64e-08 2.22e-07 1.49e-07 2.88e-07 erg/cm2
Peak flux Power-law 1.90e-01 1.76e-01 1.13e-01 1.11e-01 5.25e-01 5.90e-01 ph/cm2/s
Error 6.49e-02 3.89e-02 3.37e-02 6.61e-02 1.14e-01 1.30e-01 ph/cm2/s
Fluence Cutoff-PL 4.19e-07 5.72e-07 5.16e-07 5.23e-07 1.75e-06 2.00e-06 erg/cm2
Error 5.48e-08 5.11e-08 7.05e-08 4.13e-07 1.72e-07 4.66e-07 erg/cm2
Peak flux Cutoff-PL 1.67e-01 1.93e-01 1.20e-01 4.66e-02 5.11e-01 5.26e-01 ph/cm2/s
Error 7.89e-02 5.12e-02 3.95e-02 8.29e-02 1.18e-01 1.51e-01 ph/cm2/s
Fluence Band 4.16e-07 5.70e-07 5.15e-07 5.23e-07 1.74e-06 2.07e-06 erg/cm2
Error 5.44e-08 5.09e-08 7.04e-08 4.13e-07 1.72e-07 4.56e-07 erg/cm2
Peak flux Band 1.67e-01 1.93e-01 1.20e-01 4.68e-02 5.11e-01 5.26e-01 ph/cm2/s
Error 7.88e-02 5.13e-02 3.95e-02 8.23e-02 1.18e-01 1.04e-01 ph/cm2/s
=== Time-averaged spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 2.096 0.148 - - 8.69e-04 7.89e-05 43.374 57
CPL 1.811 0.427 28.9 4999.4 1.25e-03 8.46e-04 42.555 0
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.642 0.379 - - 4.03e-03 9.44e-04 59.266 57
CPL 0.781 1.774 68.2 5000.0 1.14e-02 9.38e-02 58.426 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: 186.432000 sec.
T50 in the 50-300 keV band: 131.776000 sec.
=== Table of the duration information ==
Value tstart tstop
T100 222.288 -25.568 196.720
T90 189.072 -11.732 177.340
T50 61.976 90.452 152.428
Peak 1.000 130.420 131.420
Image
Pre-slew 15-350 keV image (Event data; bkg subtracted)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
350.9819 -31.5190 0.0221 29.3 13.3 1.0205 8.8 TRIG_00157870
------------------------------------------
Foreground time interval of the image:
-25.568 70.801 (delta_t = 96.369 [sec])
Background time interval of the image:
-299.000 -99.120 (delta_t = 199.880 [sec])
-98.000 -41.749 (delta_t = 56.251 [sec])
-41.000 -25.568 (delta_t = 15.432 [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 -25.568 sec. to 196.720 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 2.09566 ( -0.145312 0.150562 )
Norm@50keV : 8.691431E-04 ( -7.962924E-05 7.816241E-05) )
------------------------------------------------------------
Chi-Squared = 43.37440 using 59 PHA bins.
Reduced chi-squared = 0.7609544 for 57 degrees of freedom
Null hypothesis probability = 0.908
Photon flux (15-150 keV) in 222.3 sec: 0.136446 ( -0.010044 0.010063 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.79457e-06 ( -1.47927e-07 1.49461e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -25.568 sec. to 196.720 sec.
Photon index: 1.81117 ( -0.602787 0.252166 )
Epeak [keV] : 28.8930 ( -27.7670 9971.11 )
Norm@50keV : 1.252091E-03 ( -2.663729E-04 1.426296E-03) )
------------------------------------------------------------
Chi-Squared = 42.55479 using 59 PHA bins.
but latest trial 2.06056 gives Chi-Squared = 0.984451
but latest trial 1.12604 gives Chi-Squared = 3.03547
but latest trial 9.481476E-04 gives Chi-Squared = 3.58297
Reduced chi-squared = 0.7599069 for 56 degrees of freedom
Null hypothesis probability = 0.907
Photon flux (15-150 keV) in 222.3 sec: 0.134387 ( -0.010756 0.005303 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.74656e-06 ( -1.71042e-07 1.72451e-07 ) ergs/cm2
Band function
Time interval is from -25.568 sec. to 196.720 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -1.80741 ( -8.19259 0.550043 )
beta : -9.36726 ( -0.632737 7.39314 )
Epeak [keV] : 29.1873 ( -29.0873 9970.81 )
Norm@50keV : 1.256511E-03 ( -3.875328E-04 1.421697E-03) )
------------------------------------------------------------
Chi-Squared = 42.55508 using 59 PHA bins.
Reduced chi-squared = 0.7737287 for 55 degrees of freedom
Null hypothesis probability = 0.890
Photon flux (15-150 keV) in 222.3 sec: 0.134382 ( -0.010751 0.010729 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.74365e-06 ( -1.7066e-07 1.7327e-07 ) ergs/cm2
Peak spectrum fit using the pre-slew DRM
Power-law model
Time interval is from 130.420 sec. to 131.420 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.64173 ( -0.368251 0.390375 )
Norm@50keV : 4.031337E-03 ( -9.579994E-04 9.308783E-04) )
------------------------------------------------------------
Chi-Squared = 59.26562 using 59 PHA bins.
Reduced chi-squared = 1.039748 for 57 degrees of freedom
Null hypothesis probability = 0.393
Photon flux (15-150 keV) in 1.000 sec: 0.524961 ( -0.11431 0.11445 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.75034e-08 ( -9.2484e-09 9.5103e-09 ) ergs/cm2
Cutoff power-law model
Time interval is from 130.420 sec. to 131.420 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.780927 ( -2.36710 1.18059 )
Epeak [keV] : 68.2053 ( -68.1953 9931.79 )
Norm@50keV : 1.139032E-02 ( -1.139032E-02 0.176227 )
------------------------------------------------------------
Chi-Squared = 58.42587 using 59 PHA bins.
Reduced chi-squared = 1.043319 for 56 degrees of freedom
Null hypothesis probability = 0.386
Photon flux (15-150 keV) in 1.000 sec: 0.511027 ( -0.118908 0.117282 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.56022e-08 ( -9.7241e-09 1.01453e-08 ) ergs/cm2
Band function
Time interval is from 130.420 sec. to 131.420 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.785599 ( -9.21440 1.46692 )
beta : -9.36389 ( -0.636114 11.2128 )
Epeak [keV] : 68.3150 ( -26.5412 9931.68 )
Norm@50keV : 1.132599E-02 ( -1.132599E-02 0.177004 )
------------------------------------------------------------
Chi-Squared = 58.42595 using 59 PHA bins.
Reduced chi-squared = 1.062290 for 55 degrees of freedom
Null hypothesis probability = 0.351
Photon flux (15-150 keV) in 1.000 sec: 0.511152 ( -0.119035 0.117613 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.55834e-08 ( -9.7226e-09 1.01412e-08 ) ergs/cm2
Plot creation:
Wed Jan 9 14:28:15 EST 2008