batgrbproduct Analysis for Trigger=310785
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 May 4 02:44:15 EDT 2008
Host Name: gcn5
Current Working Dir: /local/data/raid2/prebascript/trigger310785/GCN5_download_cron
======================================================================
Trigger: 00310785 Segment: 000
BAT Trigger Time: 231510376.192 [s; MET]
Trigger Stop: 231510376.256 [s; MET]
UTC: 2008-05-03T12:26:13.429140 [includes UTCF correction]
Where From?: (*SHORT BURST*) TDRSS scaled map message
BAT
RA: 286.617169964645 Dec: 68.7780078042036 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 8.79
Image Trigger?: NO
Rate S/N Ratio: 20.1990098767242 [ if not an image trigger ]
Image S/N Ratio: 8.79
Flight Position: [ source = BAT ]
RA: 286.617169964645 Dec: 68.7780078042036 [deg; J2000]
Ground Position: [ source = BAT pre-slew burst ]
RA: 286.67783912342 Dec: 68.8014271042547 [deg; J2000]
{ 19h 06m 42.7s , +68d 48' 05.1" }
+/- 3.41819016841596 [arcmin] (estimated 90% radius based on SNR)
+/- 1.98978578401 [arcmin] (formal 1-sigma fit error)
SNR: 5.25475352765913
RA = 19h 6m 42.7s (286.677839 deg.)
Dec = 68d 48' 5" (68.801427 deg.)
Angular difference between Flight and Ground position is 1.925849 arcmin
Partial Coding Fraction: 0.7578125 [ including projection effects ]
Duration
T90: 167.252000033855 +/- 42.946280877151
Measured from: 10.447999984026
to: 177.700000017881 [s; relative to TRIGTIME]
T50: 50.108000010252 +/- 9.79021307068405
Measured from: 29.1839999854565
to: 79.2919999957085 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 26.6119999885559
to: 27.6119999885559 [s; relative to TRIGTIME]
Total Fluence
Measured from: -0.0480000078678131
to: 231.535999983549 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 1.382794 1.400214 0.731052 0.218263
0.075777 0.075799 0.067314 0.059985 [error]
Peak 0.043236 0.041384 0.017152 0.007203
0.005675 0.005723 0.005109 0.004445 [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 4.49e-07 6.07e-07 6.04e-07 1.08e-06 2.01e-06 2.74e-06 erg/cm2
Error 4.74e-08 4.00e-08 6.64e-08 2.46e-07 1.50e-07 3.08e-07 erg/cm2
Peak flux Power-law 3.88e-01 2.98e-01 1.53e-01 1.13e-01 8.90e-01 9.51e-01 ph/cm2/s
Error 8.81e-02 4.87e-02 4.06e-02 5.65e-02 1.45e-01 1.58e-01 ph/cm2/s
Fluence Cutoff-PL 4.34e-07 6.24e-07 6.04e-07 6.97e-07 1.96e-06 2.36e-06 erg/cm2
Error 5.50e-08 5.09e-08 6.97e-08 4.86e-07 1.73e-07 5.34e-07 erg/cm2
Peak flux Cutoff-PL 3.57e-01 3.42e-01 1.44e-01 2.56e-02 8.65e-01 8.69e-01 ph/cm2/s
Error 1.00e-01 7.15e-02 5.23e-02 6.81e-02 1.48e-01 1.56e-01 ph/cm2/s
Fluence Band 4.29e-07 6.22e-07 6.01e-07 7.99e-07 1.96e-06 2.43e-06 erg/cm2
Error 5.33e-08 4.83e-08 7.16e-08 3.38e-07 1.72e-07 4.51e-07 erg/cm2
Peak flux Band 3.61e-01 3.38e-01 1.43e-01 4.34e-02 8.69e-01 9.00e-01 ph/cm2/s
Error 1.03e-01 7.03e-02 5.13e-02 5.67e-02 1.46e-01 1.62e-01 ph/cm2/s
=== Time-averaged spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 2.006 0.132 - - 9.41e-04 7.38e-05 60.906 57
CPL 1.748 0.460 43.9 4999.2 1.30e-03 8.96e-04 60.094 0
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.963 0.294 - - 6.04e-03 1.23e-03 75.554 57
CPL 0.795 1.587 41.0 5000.0 3.02e-02 2.00e-01 73.343 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: 67.264000 sec.
T50 in the 50-300 keV band: 33.856000 sec.
=== Table of the duration information ==
Value tstart tstop
T100 231.584 -0.048 231.536
T90 167.252 10.448 177.700
T50 50.108 29.184 79.292
Peak 1.000 26.612 27.612
Image
Pre-slew 15-350 keV image (Event data; bkg subtracted)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
286.6778 +68.8014 0.0368 32.3 -6.8 0.1824 5.3 TRIG_00310785
------------------------------------------
Foreground time interval of the image:
-0.048 10.409 (delta_t = 10.457 [sec])
Background time interval of the image:
-239.192 -0.048 (delta_t = 239.144 [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 -0.048 sec. to 231.536 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 2.00650 ( -0.130461 0.134068 )
Norm@50keV : 9.413347E-04 ( -7.433892E-05 7.321173E-05) )
------------------------------------------------------------
Chi-Squared = 60.90557 using 59 PHA bins.
Reduced chi-squared = 1.068519 for 57 degrees of freedom
Null hypothesis probability = 0.337
Photon flux (15-150 keV) in 231.6 sec: 0.141624 ( -0.009665 0.009687 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.01117e-06 ( -1.49259e-07 1.50783e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.048 sec. to 231.536 sec.
Parameters : value lower 90% higher 90%
Photon index: 1.74837 ( -0.553464 0.365775 )
Epeak [keV] : 43.9140 ( -42.2407 9956.09 )
Norm@50keV : 1.300608E-03 ( -5.238078E-04 1.267241E-03) )
------------------------------------------------------------
Chi-Squared = 60.09415 using 59 PHA bins.
but latest trial 2.08896 gives Chi-Squared = 1.34307
but latest trial 7.022442E-04 gives Chi-Squared = 27.4092
Reduced chi-squared = 1.073110 for 56 degrees of freedom
Null hypothesis probability = 0.330
Photon flux (15-150 keV) in 231.6 sec: 0.139564 ( -0.010382 0.01031 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.96324e-06 ( -1.73517e-07 1.72382e-07 ) ergs/cm2
Band function
Time interval is from -0.048 sec. to 231.536 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -1.46942 ( -8.53058 2.50055 )
beta : -2.03401 ( -7.48306 0.619723 )
Epeak [keV] : 28.5085 ( -43.8742 367.044 )
Norm@50keV : 2.211531E-03 ( -4.779229E-04 66.2823 )
------------------------------------------------------------
Chi-Squared = 60.67352 using 59 PHA bins.
Reduced chi-squared = 1.103155 for 55 degrees of freedom
Null hypothesis probability = 0.279
Photon flux (15-150 keV) in 231.6 sec: 0.139495 ( -0.009784 0.010385 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.95889e-06 ( -1.68058e-07 1.75743e-07 ) ergs/cm2
Peak spectrum fit using the pre-slew DRM
Power-law model
Time interval is from 26.612 sec. to 27.612 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.96281 ( -0.282960 0.304590 )
Norm@50keV : 6.036251E-03 ( -1.250981E-03 1.216671E-03) )
------------------------------------------------------------
Chi-Squared = 75.55443 using 59 PHA bins.
Reduced chi-squared = 1.325516 for 57 degrees of freedom
Null hypothesis probability = 5.056E-02
Photon flux (15-150 keV) in 1.000 sec: 0.890325 ( -0.145483 0.145495 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.55325e-08 ( -1.07723e-08 1.12036e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 26.612 sec. to 27.612 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.794925 ( -1.86302 1.31051 )
Epeak [keV] : 41.0083 ( -40.9983 9958.99 )
Norm@50keV : 3.015079E-02 ( -3.015079E-02 0.368857 )
------------------------------------------------------------
Chi-Squared = 73.34299 using 59 PHA bins.
Reduced chi-squared = 1.309696 for 56 degrees of freedom
Null hypothesis probability = 5.981E-02
Photon flux (15-150 keV) in 1.000 sec: 0.864617 ( -0.148166 0.148283 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.97329e-08 ( -1.09841e-08 1.27662e-08 ) ergs/cm2
Band function
Time interval is from 26.612 sec. to 27.612 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.849403 ( -9.15060 2.39767 )
beta : -4.06765 ( -5.93235 13.7761 )
Epeak [keV] : 41.4365 ( -41.3365 125.252 )
Norm@50keV : 2.776191E-02 ( -804.770 340.473 )
------------------------------------------------------------
Chi-Squared = 73.32513 using 59 PHA bins.
Reduced chi-squared = 1.333184 for 55 degrees of freedom
Null hypothesis probability = 4.989E-02
Photon flux (15-150 keV) in 1.000 sec: 0.869094 ( -0.146211 0.145836 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.13209e-08 ( -9.4862e-09 1.24867e-08 ) ergs/cm2
Plot creation:
Mon May 5 22:36:24 EDT 2008