Analysis Summary

Notes:

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Mon Jan 20 11:19:39 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger261880
======================================================================

  Trigger: 00261880      Segment: 000

  BAT Trigger Time: 194041680   [s; MET]
      Trigger Stop: 194041744   [s; MET]
               UTC: 2007-02-24T20:27:58.214180    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 178.989686201408   Dec: -13.3399298580834  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.5
     Image Trigger?:     YES
     Rate S/N Ratio:     0  [ if not an image trigger ]
     Image S/N Ratio:    7.5

  Analysis Position:   [ source = BAT ]
    RA: 178.989686201408   Dec: -13.3399298580834  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 178.99720195201   Dec: -13.373545725744  [deg; J2000]  
        { 11h 55m 59.3s , -13d 22' 24.8" }
         +/- 2.29129570710923 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.910543767147948 [arcmin] (formal 1-sigma fit error)
    SNR: 9.30500796835042
 
  Angular difference between the analysis and refined position is 2.064121 arcmin
 
  Partial Coding Fraction: 1    [ including projection effects ]

  Duration
     T90: 48 +/- 35.7770876399966
        Measured from: -15
                   to: 33     [s; relative to TRIGTIME]
     T50: 16 +/- 16
        Measured from: -15
                   to: 1     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: -7.5     
                   to: -6.5     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -15     
                   to: 49     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.361915   0.289511   0.112186   0.027142
           0.037197   0.038685   0.033804   0.030114 [error]
 Peak      0.009983   0.014453  -0.004225   0.000578
           0.004767   0.004912   0.004304   0.003772 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   64.000  -15.000   49.000
T90    48.000  -15.000   33.000
T50    16.000  -15.000    1.000
Peak    1.000   -7.500   -6.500
 
 
====== 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      -2.289    -0.300      0.270       -           -               -         6.05e-04     -1.32e-04          1.30e-04      61.380   57
CPL     -1.510    -0.827      1.509       22.576     -19.385        14.938      1.89e-03     -1.08e-03          1.57e-02      60.220   56
 
 
=== 1-s peak spectral analysis ===
(Best model with acceptable fit: N/A)
 
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      -2.157     -1.223     0.757       -           -               -         1.22e-03     -8.85e-04          8.57e-04      51.040   57
CPL      3.008     -3.196    -3.008       32.226      -7.286         8.711      3.04e+00     -3.04e+00          2.16e+05      46.190   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   1.04e-07  1.19e-07  9.75e-08  1.34e-07  3.70e-07  4.55e-07   erg/cm2
      90%_error_low -1.72e-08 -1.81e-08 -2.76e-08 -6.04e-08 -6.45e-08 -1.02e-07   erg/cm2
      90%_error_hi   1.74e-08  1.77e-08  2.99e-08  8.81e-08  6.76e-08  1.24e-07   erg/cm2
Peak flux       PL   9.72e-02  6.37e-02  2.71e-02  1.59e-02  1.96e-01  2.04e-01   ph/cm2/s
      90%_error_low -5.77e-02 -3.72e-02 -2.71e-02 -1.59e-02 -1.07e-01 -1.13e-01   ph/cm2/s
      90%_error_hi   6.14e-02  3.69e-02  2.90e-02  4.31e-02  1.08e-01  1.17e-01   ph/cm2/s
 
Fluence        CPL   1.02e-07  1.30e-07   N/A     1.11e-07  3.38e-07  3.81e-07   erg/cm2
      90%_error_low -1.87e-08    N/A    -2.76e-08 -9.20e-08 -6.58e-08 -1.08e-07   erg/cm2
      90%_error_hi   1.83e-08    N/A     2.99e-08  4.35e-07  8.11e-08  1.89e-07   erg/cm2
Peak flux      CPL   7.66e-02  1.24e-01  7.39e-03  4.66e-07  2.08e-01  2.09e-01   ph/cm2/s
      90%_error_low -5.41e-02 -6.00e-02 -7.39e-03 -4.66e-07 -9.39e-02 -9.47e-02   ph/cm2/s
      90%_error_hi   7.20e-02  6.08e-02  2.77e-02  1.60e-03  9.82e-02  9.73e-02   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
      178.9972   -13.3735   0.0206    12.2877    -0.4991         0.7773800      9.305 TRIG_00261880                 
     
    Foreground time interval of the image:
    -15.000  49.000 (delta_t =  64.000 [sec])
    Background time interval of the image:
    -239.000 -15.000 (delta_t = 224.000 [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  -15.000 sec. to   49.000 sec.
     
    Spectral model in power-law:
    ------------------------------------------------------------
    Parameters  : value       lower 90%   higher 90%
    Photon index: -2.28896     ( -0.300418   0.270033 )
    Norm@50keV  : 6.05476E-04    ( -0.000131605   0.000129548 )
    ------------------------------------------------------------
    #Fit statistic : Chi-Squared =          61.38 using 59 PHA bins.
    # Reduced chi-squared =          1.077 for     57 degrees of freedom 
    # Null hypothesis probability =   3.219588e-01
     
    Photon flux (15-150 keV)    in 64 sec: 0.105178 ( -0.0140851  0.014092 ) ph/cm2/s
    Energy fluence (15-150 keV)             : 3.69641e-07 ( -6.44864e-08  6.76493e-08 ) ergs/cm2
     
    
    Cutoff power-law model
    Time interval is from  -15.000 sec. to   49.000 sec.
    Spectral model in the cutoff power-law:
    ------------------------------------------------------------
    Parameters  : value       lower 90%   higher 90%
    Photon index: -1.50955     ( -0.826979   1.50891 )
    Epeak [keV] : 22.5761      ( -19.3854 14.9369 )
    Norm@50keV  : 1.89164E-03    ( -0.00108141   0.0157306 )
    ------------------------------------------------------------
    #Fit statistic : Chi-Squared =          60.22 using 59 PHA bins.
    # Reduced chi-squared =          1.075 for     56 degrees of freedom 
    # Null hypothesis probability =   3.255668e-01
     
    Photon flux (15-150 keV)    in 64 sec: 0.105400 ( -0.0141073  0.013968 ) ph/cm2/s
    Energy fluence (15-150 keV)             : 3.38057e-07 ( -6.57619e-08  8.1113e-08 ) ergs/cm2
     
    

    1-s peak spectrum fit

    Power-law model
    Time interval is from   -7.500 sec. to   -6.500 sec.
     
    Spectral model in power-law:
    ------------------------------------------------------------
    Parameters  : value       lower 90%   higher 90%
    Photon index: -2.15739     ( -1.08746   0.89301 )
    Norm@50keV  : 1.21692E-03    ( -0.000872113   0.000869417 )
    ------------------------------------------------------------
    #Fit statistic : Chi-Squared =          51.04 using 59 PHA bins.
    # Reduced chi-squared =         0.8954 for     57 degrees of freedom 
    # Null hypothesis probability =   6.972080e-01
     
    Photon flux (15-150 keV)    in 1 sec: 0.195904 ( -0.107346  0.108216 ) ph/cm2/s
    Energy fluence (15-150 keV)             : 1.10438e-08 ( -6.75101e-09  8.03276e-09 ) ergs/cm2
     
    
    Cutoff power-law model
    Time interval is from   -7.500 sec. to   -6.500 sec.
    Spectral model in the cutoff power-law:
    ------------------------------------------------------------
    Parameters  : value       lower 90%   higher 90%
    Photon index: 6.44076     ( -6.67693   -6.48918 )
    Epeak [keV] : 32.0866      ( -7.14227 8.85436 )
    Norm@50keV  : 569.343    ( -661.529   215516 )
    ------------------------------------------------------------
    #Fit statistic : Chi-Squared =          45.50 using 59 PHA bins.
    # Reduced chi-squared =         0.8126 for     56 degrees of freedom 
    # Null hypothesis probability =   8.407542e-01
     
    Photon flux (15-150 keV)    in 1 sec: 0.207664 ( -0.09389  0.098156 ) ph/cm2/s
    Energy fluence (15-150 keV)             : 9.86938e-09 ( -4.50326e-09  4.92681e-09 ) ergs/cm2
     
    

    Time-resolved spectra




    Distribution

    T90 vs. Hardness ratio plot

    T90                                   = 48.0 sec.
    Hardness ratio (energy fluence ratio) = 0.818540397333
    

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

    S(15-50 keV)  = 2.235241e-07
    S(50-150 keV) = 1.4612069e-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 = 2.178018704812982E-01, IMY = 1.897387479609091E-03
    

    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:
    -239.000000 -15.000000
     
    # RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
    #  [deg]    [deg]    ['] [deg]  [deg]                   [']
    179.6562  43.9069    2.9  45.0  173.7   1.1662   3.9 ------	UNKNOWN                       
    197.6841  42.0144    2.2  46.0 -167.6   1.4909   5.2 ------	UNKNOWN                       
    194.4151  14.4744    2.1  21.1 -144.1   0.9032   5.5 ------	UNKNOWN                       
    

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

    Time interval of the image:
    -15.000000 49.000000
     
    # RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
    #  [deg]    [deg]    ['] [deg]  [deg]                   [']
    154.5690  42.7021    1.9  49.5  149.6   1.9876   6.0 ------	UNKNOWN                       
    176.8772 -11.6020    2.5  11.0   11.3   0.3707   4.7 ------	UNKNOWN                       
    178.9972 -13.3736    1.2  12.3   -0.5   0.7776   9.4 ------	UNKNOWN                       
    

    Post-slew image of 15-350 keV band

    Time interval of the image:
    129.100590 963.100000
     
    # RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
    #  [deg]    [deg]    ['] [deg]  [deg]                   [']
    135.6042 -40.5968    5.1  46.6   -0.0   1.8253   2.2    4.3	Vela X-1                      
    170.2892 -60.6424    5.7  47.7  -40.2   2.7231   2.0    1.4	Cen X-3                       
    159.7756   0.1318    2.7  23.3   78.0   2.0529   4.3 ------	UNKNOWN                       
    174.5395  -1.3048    2.9  12.8  113.9   1.4027   4.0 ------	UNKNOWN                       
    145.3789 -33.3172    3.0  36.5    5.2   1.9049   3.8 ------	UNKNOWN                       
    189.5516   1.6451    3.0  18.3  170.0   1.3517   3.8 ------	UNKNOWN                       
    143.4278 -50.4883    2.4  47.0  -15.5   3.4858   4.7 ------	UNKNOWN                       
    231.4595  15.4639    3.7  59.4 -163.2  11.2082   3.2 ------	UNKNOWN