Analysis Summary

Notes:

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Mon Jan 20 08:19:54 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger285948
======================================================================

  Trigger: 00285948      Segment: 000

  BAT Trigger Time: 206967232.32   [s; MET]
      Trigger Stop: 206967232.832   [s; MET]
               UTC: 2007-07-24T10:53:50.211640    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 27.8178746741569   Dec: -18.6216425472074  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    8.71
     Image Trigger?:     NO
     Rate S/N Ratio:     13.0384048104053  [ if not an image trigger ]
     Image S/N Ratio:    8.71

  Analysis Position:   [ source = BAT ]
    RA: 27.8178746741569   Dec: -18.6216425472074  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 27.8221260545431   Dec: -18.606926437213  [deg; J2000]  
        { 01h 51m 17.3s , -18d 36' 24.9" }
         +/- 2.25588103450103 [arcmin] (estimated 90% radius based on SNR)
         +/- 1.14066683450112 [arcmin] (formal 1-sigma fit error)
    SNR: 9.51439026023414
 
  Angular difference between the analysis and refined position is 0.915460 arcmin
 
  Partial Coding Fraction: 0.9140625    [ including projection effects ]

  Duration
     T90: 0.432000011205673 +/- 0.0863712981793007
        Measured from: 0.00400000810623169
                   to: 0.436000019311905     [s; relative to TRIGTIME]
     T50: 0.227999985218048 +/- 0.0712179940465239
        Measured from: 0.112000018358231
                   to: 0.340000003576279     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: -0.282000005245209     
                   to: 0.717999994754791     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -0.0279999971389771     
                   to: 0.46000000834465     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.022668   0.022279   0.013210   0.001359
           0.003570   0.003682   0.003239   0.002554 [error]
 Peak      0.025876   0.026933   0.013150   0.001302
           0.004844   0.004973   0.004343   0.003612 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100    0.488   -0.028    0.460
T90     0.432    0.004    0.436
T50     0.228    0.112    0.340
Peak    1.000   -0.282    0.718
 
 
====== 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      -1.861    -0.324      0.296       -           -               -         6.88e-03     -1.53e-03          1.48e-03      53.110   57
CPL     -0.680    -1.309      1.823       45.854     -17.118       -45.854      3.39e-02     -3.39e-02          3.82e-01      50.880   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      -1.940     -0.373     0.335       -           -               -         3.73e-03     -9.98e-04          9.75e-04      48.990   57
CPL      0.407     -1.821     2.898       38.773      -9.035        16.149      1.01e-01     -1.01e-01          7.43e+00      43.700   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   6.02e-09  8.89e-09  9.79e-09  2.03e-08  3.09e-08  4.50e-08   erg/cm2
      90%_error_low -1.41e-09 -1.58e-09 -2.82e-09 -9.48e-09 -6.64e-09 -1.32e-08   erg/cm2
      90%_error_hi   1.45e-09  1.58e-09  2.91e-09  1.37e-08  6.88e-09  1.65e-08   erg/cm2
Peak flux       PL   2.35e-01  1.82e-01  9.49e-02  7.14e-02  5.44e-01  5.83e-01   ph/cm2/s
      90%_error_low -6.19e-02 -3.83e-02 -3.14e-02 -3.61e-02 -1.13e-01 -1.24e-01   ph/cm2/s
      90%_error_hi   6.43e-02  3.82e-02  3.30e-02  5.31e-02  1.13e-01  1.26e-01   ph/cm2/s
 
Fluence        CPL   6.35e-09  8.68e-09  9.06e-09  2.08e-08  3.01e-08  4.51e-08   erg/cm2
      90%_error_low -1.68e-09 -6.13e-10 -3.65e-09 -2.04e-08 -9.12e-09 -1.39e-08   erg/cm2
      90%_error_hi   1.49e-09  4.00e-09  3.63e-09  2.97e-09  5.16e-09  8.37e-09   erg/cm2
Peak flux      CPL   2.05e-01  2.37e-01  7.74e-02  4.49e-03  5.23e-01  5.23e-01   ph/cm2/s
      90%_error_low -7.11e-02 -5.62e-02 -4.52e-02 -4.49e-03 -1.10e-01 -1.10e-01   ph/cm2/s
      90%_error_hi   7.19e-02  5.87e-02  4.51e-02  3.21e-02  1.11e-01  1.12e-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
   27.8221   -18.6069   0.0201    17.2333    33.3837         0.0623730      9.514 TRIG_00285948                 
 
Foreground time interval of the image:
 -0.028   0.460 (delta_t =   0.488 [sec])
Background time interval of the image:
-239.320  -0.028 (delta_t = 239.292 [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   -0.028 sec. to    0.460 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.86112     ( -0.323942   0.29613 )
Norm@50keV  : 6.88163E-03    ( -0.00152562   0.00147839 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          53.11 using 59 PHA bins.
# Reduced chi-squared =         0.9318 for     57 degrees of freedom 
# Null hypothesis probability =   6.216334e-01
 
Photon flux (15-150 keV)    in 0.488 sec: 0.971741 ( -0.171439  0.171439 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.08802e-08 ( -6.64373e-09  6.87529e-09 ) ergs/cm2
    Cutoff power-law model
    Time interval is from   -0.028 sec. to    0.460 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.679947     ( -1.31018   1.82233 )
Epeak [keV] : 45.8539      ( -17.1125 -45.8482 )
Norm@50keV  : 3.39427E-02    ( -0.0339871   0.382067 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          50.88 using 59 PHA bins.
# Reduced chi-squared =         0.9086 for     56 degrees of freedom 
# Null hypothesis probability =   6.685518e-01
 
Photon flux (15-150 keV)    in 0.488 sec: 0.943885 ( -0.172674  0.174005 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.01453e-08 ( -9.11965e-09  5.15753e-09 ) ergs/cm2

    1-s peak spectrum fit

    Power-law model
    Time interval is from   -0.282 sec. to    0.718 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.94013     ( -0.372436   0.335688 )
Norm@50keV  : 3.72782E-03    ( -0.000997297   0.000975628 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          48.99 using 59 PHA bins.
# Reduced chi-squared =         0.8596 for     57 degrees of freedom 
# Null hypothesis probability =   7.657147e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.544355 ( -0.11317  0.113223 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.42941e-08 ( -8.6404e-09  9.08694e-09 ) ergs/cm2
    Cutoff power-law model
    Time interval is from   -0.282 sec. to    0.718 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.40708     ( -1.84809   2.87089 )
Epeak [keV] : 38.7735      ( -8.95256 16.2315 )
Norm@50keV  : 0.101304    ( -0.108343   7.42331 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          43.70 using 59 PHA bins.
# Reduced chi-squared =         0.7803 for     56 degrees of freedom 
# Null hypothesis probability =   8.842305e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.522898 ( -0.109749  0.111378 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.84702e-08 ( -7.29049e-09  8.95809e-09 ) ergs/cm2

    Time-resolved spectra




    Distribution

    T90 vs. Hardness ratio plot 

    T90                                   = 0.432 sec.
Hardness ratio (energy fluence ratio) = 1.10113385547

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

    S(15-50 keV)  = 1.4914042e-08
S(50-150 keV) = 1.5966301e-08

    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 = 2.590083416516621E-01, IMY = -1.706787245475634E-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:
-239.320000 -0.028000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
352.2981  21.1616    2.6  46.3  138.4   2.6501   4.4 ------	UNKNOWN                       
 40.5937 -45.9086    2.1  44.2    8.6   1.3562   5.5 ------	UNKNOWN                       
 51.6974 -52.0151    2.3  52.2    1.7   1.9803   5.0 ------	UNKNOWN                       
 70.5903 -44.2242    2.1  53.5  -16.8   2.2608   5.5 ------	UNKNOWN                       
 56.7410  49.1281    3.3  55.2 -145.4   3.7331   3.5 ------	UNKNOWN

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

    Time interval of the image:
-0.028000 0.460000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
357.5338  10.9544    3.0  37.8  127.1   0.0574   3.8 ------	UNKNOWN                       
 27.8221 -18.6069    1.2  17.2   33.4   0.0624   9.5 ------	UNKNOWN                       
 60.6673  12.2643    2.4  30.9 -102.6   0.0440   4.8 ------	UNKNOWN                       
 67.8758  25.9324    1.8  43.8 -116.3   0.1554   6.4 ------	UNKNOWN

    Post-slew image of 15-350 keV band 

    Time interval of the image:
55.780650 938.580610
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 78.9924 -61.7347    3.1  55.8   -9.1   4.4029   3.7 ------	UNKNOWN                       
 23.8223  40.2677    3.5  59.0 -166.1   9.0244   3.3 ------	UNKNOWN