Analysis Summary

Notes:

Special note: Due to the low partial coding fraction, the refined position is found using the DETECTION mask. Therefore, the refined position and the mask shadow pattern shown here are from analyses with DETECTION mask, everything else uses the FLUX mask.

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Sun May 10 03:57:53 EDT 2015
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger548760
======================================================================

  Trigger: 00548760      Segment: 000

  BAT Trigger Time: 382584700.416   [s; MET]
      Trigger Stop: 382584716.8   [s; MET]
               UTC: 2013-02-15T01:31:30.197800    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 43.4794556448911   Dec: 13.3706926231607  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    8.16
     Image Trigger?:     NO
     Rate S/N Ratio:     19.6468827043885  [ if not an image trigger ]
     Image S/N Ratio:    8.16

  Analysis Position:   [ source = BAT ]
    RA: 43.4794556448911   Dec: 13.3706926231607  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 43.486816900885   Dec: 13.3875384675329  [deg; J2000]  
        { 02h 53m 56.8s , +13d 23' 15.1" }
         +/- 1.47862085532387 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.622661696834093 [arcmin] (formal 1-sigma fit error)
    SNR: 17.396655739627
 
  Angular difference between the analysis and refined position is 1.098294 arcmin
 
  Partial Coding Fraction: 0.08398438    [ including projection effects ]

  Duration
     T90: 66.2240000367165 +/- 10.6648491081526
        Measured from: -3.0799999833107
                   to: 63.1440000534058     [s; relative to TRIGTIME]
     T50: 28.0640000104904 +/- 7.6662042961526
        Measured from: 6.68000000715256
                   to: 34.744000017643     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 11.1639999747276     
                   to: 12.1639999747276     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -6.16799998283386     
                   to: 73.3840000033379     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     1.741688   2.736699   2.383794   0.598929
           0.187482   0.200999   0.184906   0.165851 [error]
 Peak      0.053623   0.123665   0.084582   0.028675
           0.022442   0.023873   0.022467   0.020077 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   79.552   -6.168   73.384
T90    66.224   -3.080   63.144
T50    28.064    6.680   34.744
Peak    1.000   11.164   12.164
 
 
====== 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      -1.605    -0.136      0.135       -           -               -         7.26e-03     -5.79e-04          5.78e-04      66.540   57
CPL     -1.179    -0.482      0.578      101.572     -33.866      -101.572      1.17e-02     -4.71e-03          1.02e-02      64.570   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      -1.627     -0.455     0.432       -           -               -         1.99e-02     -5.22e-03          5.18e-03      58.950   57
CPL     -0.994     -1.651     3.410       84.021      N/A           N/A         4.04e-02        N/A               N/A         58.660   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   8.15e-07  1.40e-06  1.85e-06  4.93e-06  5.40e-06  8.99e-06   erg/cm2
      90%_error_low -1.10e-07 -1.19e-07 -1.86e-07 -9.83e-07 -4.52e-07 -1.14e-06   erg/cm2
      90%_error_hi   1.14e-07  1.18e-07  1.85e-07  1.13e-06  4.54e-07  1.25e-06   erg/cm2
Peak flux       PL   9.24e-01  8.63e-01  5.59e-01  5.58e-01  2.58e+00  2.90e+00   ph/cm2/s
      90%_error_low -3.81e-01 -2.45e-01 -1.80e-01 -2.94e-01 -6.98e-01 -7.47e-01   ph/cm2/s
      90%_error_hi   4.38e-01  2.40e-01  1.74e-01  4.18e-01  7.05e-01  7.47e-01   ph/cm2/s
 
Fluence        CPL   7.49e-07  1.46e-06  1.92e-06  2.85e-06  5.29e-06  6.98e-06   erg/cm2
      90%_error_low -1.33e-07 -1.37e-07 -2.08e-07 -1.31e-06 -4.77e-07 -1.39e-06   erg/cm2
      90%_error_hi   1.37e-07  1.41e-07  2.13e-07  2.45e-06  4.76e-07  2.51e-06   erg/cm2
Peak flux      CPL   8.11e-01  9.09e-01  5.99e-01  3.17e-01  2.51e+00  2.64e+00   ph/cm2/s
      90%_error_low -8.11e-01 -2.78e-01     N/A   -3.17e-01 -7.40e-01 -8.53e-01   ph/cm2/s
      90%_error_hi   5.25e-01  3.11e-01     N/A    3.43e-01  7.33e-01  9.56e-01   ph/cm2/s
 
======================================================================
  • Special notes of this burst




    Image

    Pre-slew 15.0-350.0 keV image (Event data; DETECTION mask)

    #   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
   43.4818    13.3906   0.0113    53.8855   -31.5773         7.9354411     17.017 TRIG_00548760                 
 
Foreground time interval of the image:
 -6.136 102.472 (delta_t = 108.608 [sec])
Background time interval of the image:
-239.416  -6.136 (delta_t = 233.280 [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   -6.168 sec. to   73.384 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.60548     ( -0.136244   0.134709 )
Norm@50keV  : 7.26353E-03    ( -0.000579458   0.000578118 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          66.54 using 59 PHA bins.
# Reduced chi-squared =          1.167 for     57 degrees of freedom 
# Null hypothesis probability =   1.814761e-01
 
Photon flux (15-150 keV)    in 79.55 sec: 0.935017 ( -0.077859  0.078123 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.40095e-06 ( -4.52035e-07  4.54227e-07 ) ergs/cm2
    Cutoff power-law model
    Time interval is from   -6.168 sec. to   73.384 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.17896     ( -0.482186   0.577609 )
Epeak [keV] : 101.572      ( -33.8657 -101.572 )
Norm@50keV  : 1.16915E-02    ( -0.00471181   0.0101825 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          64.57 using 59 PHA bins.
# Reduced chi-squared =          1.153 for     56 degrees of freedom 
# Null hypothesis probability =   2.021598e-01
 
Photon flux (15-150 keV)    in 79.55 sec: 0.916143 ( -0.080923  0.081201 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.29005e-06 ( -4.77336e-07  4.76022e-07 ) ergs/cm2

    1-s peak spectrum fit

    Power-law model
    Time interval is from   11.164 sec. to   12.164 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.62711     ( -0.454516   0.431896 )
Norm@50keV  : 1.98715E-02    ( -0.00522379   0.00518065 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          58.95 using 59 PHA bins.
# Reduced chi-squared =          1.034 for     57 degrees of freedom 
# Null hypothesis probability =   4.040835e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.57559 ( -0.69839  0.70457 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.85285e-07 ( -5.04788e-08  5.08661e-08 ) ergs/cm2
    Cutoff power-law model
    Time interval is from   11.164 sec. to   12.164 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.13634     ( -0.50922   4.55228 )
Epeak [keV] : 53.9386      (   )
Norm@50keV  : 8.84908E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          58.48 using 59 PHA bins.
# Reduced chi-squared =          1.044 for     56 degrees of freedom 
# Null hypothesis probability =   3.844470e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.51069 ( -0.7396  0.73264 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.80892e-07 ( -5.60847e-08  5.29971e-08 ) ergs/cm2

    Time-resolved spectra




    Distribution

    T90 vs. Hardness ratio plot 

    T90                                   = 66.224 sec.
Hardness ratio (energy fluence ratio) = 1.31455838243

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

    S(15-50 keV)  = 2.2182011e-06
S(50-150 keV) = 3.182806e-06

    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 (with DETECTION mask) 

    IMX = 1.167673035019286E+00, IMY = 7.177203054069740E-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:
-239.416000 -6.168000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6425  22.0351    0.4  35.4   19.3   9.1168  31.3    1.3	Crab                          
135.5257 -40.5453    1.5  47.8  165.4   4.9710   7.9    0.6	Vela X-1                      
 67.8630  20.1642    2.7  40.0   -4.0   1.3049   4.2 ------	UNKNOWN                       
 85.0156 -18.0662    2.4   8.0 -102.5   0.9605   4.8 ------	UNKNOWN                       
 68.4790   9.7126    2.4  31.7  -15.0   1.1251   4.8 ------	UNKNOWN                       
 72.8708 -33.8943    2.7  27.0 -113.9   1.1192   4.2 ------	UNKNOWN                       
 42.4046   2.8102    3.5  50.8  -44.4   4.2434   3.3 ------	UNKNOWN

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

    Time interval of the image:
-6.168000 73.384000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6594  22.1952    0.0  35.6   19.3  -0.5752  -3.6   10.9	Crab                          
135.5349 -40.4136    5.6  47.8  165.2  -0.6049  -2.1    8.5	Vela X-1                      
116.2548   6.7520    2.5  31.6   84.9   0.8974   4.6 ------	UNKNOWN                       
 43.4866  13.3871    0.7  53.9  -31.6   8.0857  17.3 ------	UNKNOWN

    Post-slew image of 15-350 keV band 

    Time interval of the image:
903.084600 962.625800
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.5274 -40.5150    1.8  24.4   68.2   0.6467   6.3    2.4	Vela X-1                      
170.7274 -60.6837    0.0   8.3 -170.7   0.0123   0.2   12.6	Cen X-3                       
187.1054 -62.7763    0.0  15.2 -150.3   0.0357   0.5   12.3	GX 301-2                      
 63.8157 -36.4710    2.3  58.2   -5.7   2.3597   5.0 ------	UNKNOWN                       
254.1571 -55.8680    2.3  46.7 -126.1   1.7990   5.1 ------	UNKNOWN                       
284.0619 -72.5256    3.1  41.0  -97.2   1.3418   3.7 ------	UNKNOWN