Analysis Summary

Notes:

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Mon Jan 20 01:57:16 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger311874
======================================================================

  Trigger: 00311874      Segment: 000

  BAT Trigger Time: 232752174.784   [s; MET]
      Trigger Stop: 232752182.976   [s; MET]
               UTC: 2008-05-17T21:22:51.986120    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 102.254712634596   Dec: 50.7307421877239  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    9.81
     Image Trigger?:     NO
     Rate S/N Ratio:     11.8321595661992  [ if not an image trigger ]
     Image S/N Ratio:    9.81

  Analysis Position:   [ source = BAT ]
    RA: 102.254712634596   Dec: 50.7307421877239  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 102.278442458184   Dec: 50.7460113143002  [deg; J2000]  
        { 06h 49m 06.8s , +50d 44' 45.6" }
         +/- 2.30377997269376 [arcmin] (estimated 90% radius based on SNR)
         +/- 1.35506563531954 [arcmin] (formal 1-sigma fit error)
    SNR: 9.23305717576612
 
  Angular difference between the analysis and refined position is 1.285006 arcmin
 
  Partial Coding Fraction: 0.5    [ including projection effects ]

  Duration
     T90: 64.5079999864101 +/- 22.3013869451639
        Measured from: 0.543999999761581
                   to: 65.0519999861717     [s; relative to TRIGTIME]
     T50: 25.5960000157356 +/- 18.8237293691574
        Measured from: 4.53999999165535
                   to: 30.136000007391     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 3.88400000333786     
                   to: 4.88400000333786     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -0.763999998569489     
                   to: 68.3879999816418     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.244035   0.314499   0.306645   0.076972
           0.055703   0.058259   0.052203   0.047391 [error]
 Peak      0.022649   0.031192   0.016279   0.003404
           0.007024   0.007344   0.006567   0.005729 [error]

     [ fluence units of on-axis counts / fully illuminated detector ] 

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   69.152   -0.764   68.388
T90    64.508    0.544   65.052
T50    25.596    4.540   30.136
Peak    1.000    3.884    4.884
 
 
====== Spectral Analysis Summary =====================================
 
Model      : spectral model: simple power-law (PL) and cutoff power-law (CPL)
Ph_index   : photon index: E^{Ph_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 both the PL model and CPL model
Nomr_90err : 90% error of the normalization
chi2       : Chi-Squared
dof        : degree of freedo
 
=== Time-averaged spectral analysis ===
(Best model with acceptable fit: PL)
 
Model Ph_index Ph_90err_low Ph_90err_hi  Epeak  Epeak_90err_low  Epeak_90err_hi  Norm       Nomr_90err_low    Norm_90err_hi    chi2    dof
PL      -1.428    -0.320      0.317       -           -               -         8.83e-04     -1.67e-04          1.66e-04      54.310   57
CPL     -0.817    -0.887      1.735       94.566     -41.190       -94.566      1.82e-03     -1.12e-03          1.16e-02      53.670   56
 
 
=== 1-s peak spectral analysis ===
(Best model with acceptable fit: PL)
 
Model Ph_index Ph_90err_low Ph_90err_hi  Epeak  Epeak_90err_low  Epeak_90err_hi  Norm       Nomr_90err_low    Norm_90err_hi    chi2    dof
PL      -1.776     -0.505     0.461       -           -               -         4.37e-03     -1.50e-03          1.46e-03      67.090   57
CPL      0.724     -2.431     8.127       41.402      -7.208        88.945      1.47e-01     -1.47e-01          2.31e+04      64.020   56
 
 
=== 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         PL   7.28e-08  1.40e-07  2.08e-07  6.66e-07  5.87e-07  1.09e-06   erg/cm2
      90%_error_low -2.16e-08 -2.71e-08 -5.06e-08 -2.87e-07 -1.22e-07 -3.37e-07   erg/cm2
      90%_error_hi   2.33e-08  2.67e-08  5.03e-08  4.09e-07  1.25e-07  4.38e-07   erg/cm2
Peak flux       PL   2.34e-01  2.00e-01  1.17e-01  1.02e-01  5.96e-01  6.54e-01   ph/cm2/s
      90%_error_low -9.01e-02 -5.84e-02 -4.90e-02 -6.26e-02 -1.74e-01 -1.94e-01   ph/cm2/s
      90%_error_hi   9.65e-02  5.84e-02  5.15e-02  1.04e-01  1.74e-01  1.98e-01   ph/cm2/s
 
Fluence        CPL   6.64e-08  1.50e-07  2.14e-07  2.74e-07  5.57e-07  7.04e-07   erg/cm2
      90%_error_low -2.64e-08 -3.33e-08 -5.55e-08 -2.23e-07 -1.36e-07 -2.67e-07   erg/cm2
      90%_error_hi   2.67e-08  3.58e-08  5.66e-08  6.62e-07  1.39e-07  5.25e-07   erg/cm2
Peak flux      CPL   1.97e-01  2.72e-01  8.66e-02  3.31e-03  5.59e-01  5.60e-01   ph/cm2/s
      90%_error_low -1.06e-01 -9.26e-02 -8.66e-02 -3.31e-03 -1.71e-01 -1.71e-01   ph/cm2/s
      90%_error_hi   1.08e-01  1.03e-01  7.84e-02  8.94e-02  1.74e-01  1.77e-01   ph/cm2/s
 
======================================================================
  • Special notes of this burst




    Image

    Pre-slew 15.0-350.0 keV image (Event data)

    #   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  102.2784    50.7460   0.0208    29.1612   -68.1976         0.9886091      9.233 TRIG_00311874                 
 
Foreground time interval of the image:
 -0.764  54.517 (delta_t =  55.281 [sec])
Background time interval of the image:
-239.784  -0.764 (delta_t = 239.020 [sec])




    Light Curves

    Note: The mask-weighted lightcurves have units of either count/det or counts/sec/det, where a det is 0.4 x 0.4 = 0.16 sq cm.

    Full-time range; 1 s binning

    Bokeh Plot

    Other quick-look light curves:




    Spectra

    Notes:

    Time averaged spectrum fit using the average DRM

    Power-law model
    Time interval is from   -0.764 sec. to   68.388 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.42775     ( -0.319741   0.317377 )
Norm@50keV  : 8.82617E-04    ( -0.000167269   0.000165719 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          54.31 using 59 PHA bins.
# Reduced chi-squared =         0.9528 for     57 degrees of freedom 
# Null hypothesis probability =   5.765862e-01
 
Photon flux (15-150 keV)    in 69.15 sec: 0.108185 ( -0.0200879  0.020121 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.86573e-07 ( -1.22194e-07  1.24677e-07 ) ergs/cm2
    Cutoff power-law model
    Time interval is from   -0.764 sec. to   68.388 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.816949     ( -0.887221   1.73459 )
Epeak [keV] : 94.5655      ( -41.1858 -94.5617 )
Norm@50keV  : 1.82368E-03    ( -0.00112412   0.0115822 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          53.67 using 59 PHA bins.
# Reduced chi-squared =         0.9584 for     56 degrees of freedom 
# Null hypothesis probability =   5.634678e-01
 
Photon flux (15-150 keV)    in 69.15 sec: 0.105498 ( -0.0211112  0.020932 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.56765e-07 ( -1.35717e-07  1.39079e-07 ) ergs/cm2

    1-s peak spectrum fit

    Power-law model
    Time interval is from    3.884 sec. to    4.884 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.77574     ( -0.50456   0.46145 )
Norm@50keV  : 4.36814E-03    ( -0.00150359   0.00146456 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          67.09 using 59 PHA bins.
# Reduced chi-squared =          1.177 for     57 degrees of freedom 
# Null hypothesis probability =   1.695447e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.596384 ( -0.173615  0.173616 ) ph/cm2/s
Energy fluence (15-150 keV)             : 4.02513e-08 ( -1.36342e-08  1.44818e-08 ) ergs/cm2
    Cutoff power-law model
    Time interval is from    3.884 sec. to    4.884 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.723689     ( -2.48336   8.07501 )
Epeak [keV] : 41.4016      ( -6.91803 89.2351 )
Norm@50keV  : 0.146702    ( -0.179963   23063 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          64.02 using 59 PHA bins.
# Reduced chi-squared =          1.143 for     56 degrees of freedom 
# Null hypothesis probability =   2.158029e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.559436 ( -0.170742  0.174438 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.10249e-08 ( -1.11763e-08  1.6049e-08 ) ergs/cm2

    Time-resolved spectra




    Distribution

    T90 vs. Hardness ratio plot 

    T90                                   = 64.508 sec.
Hardness ratio (energy fluence ratio) = 1.48689402047

    S(15-50 keV) vs. S(50-150 keV) plot 

    S(15-50 keV)  = 2.1271086e-07
S(50-150 keV) = 3.738644e-07

    The dash-dotted line and the dashed line traces the fluences calculated from the Band function with Epeak = 15 and 150 keV, respectively. Both lines assume a canonical values of alpha = -1 and beta = -2.5.




    Mask shadow pattern 

    IMX = 2.072424406940372E-01, IMY = 5.180804300206198E-01

    Spacecraft aspect plot

    Bright source in the pre-burst/pre-slew/post-slew images

    Pre-burst image of 15-350 keV band 

    Time interval of the image:
-239.784000 -0.764000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
149.6315  32.6804    2.7  11.1   78.1   0.7454   4.3 ------	UNKNOWN                       
125.6552  15.2709    2.4  22.2 -172.2   0.8125   4.9 ------	UNKNOWN                       
237.5247  77.4892    3.2  58.1   -6.6   3.7424   4.1 ------	UNKNOWN                       
237.7363  77.7405    3.5  58.0   -6.9   3.9758   4.3 ------	UNKNOWN

    Pre-slew background subtracted image of 15-350 keV band 

    Time interval of the image:
-0.764000 54.516600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
173.6700  18.0428    2.6  37.0   86.6   1.0559   4.4 ------	UNKNOWN                       
134.0828 -19.3465    2.7  54.6  161.8   1.8673   4.3 ------	UNKNOWN                       
189.0158  62.6614    2.4  42.2   11.6   0.6226   4.8 ------	UNKNOWN                       
121.1178 -14.6083    2.2  51.9  178.0   1.0905   5.1 ------	UNKNOWN                       
102.2785  50.7460    1.2  29.2  -68.2   0.9923   9.3 ------	UNKNOWN                       
354.8515  85.8788    2.8  58.1  -24.2   1.8782   4.1 ------	UNKNOWN

    Post-slew image of 15-350 keV band 

    Time interval of the image:
109.116590 917.316600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6239  22.0145    0.2  32.2 -123.8  33.6420  49.3    0.5	Crab                          
121.6043  -3.7240    4.5  56.9  179.2   7.6114   2.6 ------	UNKNOWN                       
340.2034  66.7391    3.7  54.6   -1.8   4.6975   3.1 ------	UNKNOWN                       
 13.4787  55.6433    2.8  49.7  -25.2   4.2904   4.2 ------	UNKNOWN