Analysis Summary

Notes:

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Wed May  3 17:07:05 EDT 2017
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger748898
======================================================================

  Trigger: 00748898      Segment: 000

  BAT Trigger Time: 514301219.136   [s; MET]
      Trigger Stop: 514301220.16   [s; MET]
               UTC: 2017-04-19T13:26:40.202980    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 79.8660177495021   Dec: -21.4203767383782  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.66
     Image Trigger?:     NO
     Rate S/N Ratio:     11.5325625946708  [ if not an image trigger ]
     Image S/N Ratio:    7.66

  Analysis Position:   [ source = BAT ]
    RA: 79.8660177495021   Dec: -21.4203767383782  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 79.8540155717891   Dec: -21.4339573708003  [deg; J2000]  
        { 05h 19m 25.0s , -21d 26' 02.2" }
         +/- 1.71630048690819 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.608855590440741 [arcmin] (formal 1-sigma fit error)
    SNR: 14.0599914817981
 
  Angular difference between the analysis and refined position is 1.055149 arcmin
 
  Partial Coding Fraction: 0.53125    [ including projection effects ]

  Duration
     T90: 7.77600002288818 +/- 1.75110480013101
        Measured from: -0.0719999670982361
                   to: 7.70400005578995     [s; relative to TRIGTIME]
     T50: 2.97600001096725 +/- 1.9597224220684
        Measured from: 0.760000050067902
                   to: 3.73600006103516     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 0.460000038146973     
                   to: 1.46000003814697     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -0.375999987125397     
                   to: 8.58400005102158     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.198783   0.211268   0.104903   0.027769
           0.024177   0.025470   0.022347   0.019252 [error]
 Peak      0.057119   0.062026   0.035233   0.009921
           0.008633   0.009203   0.008042   0.006499 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100    8.960   -0.376    8.584
T90     7.776   -0.072    7.704
T50     2.976    0.760    3.736
Peak    1.000    0.460    1.460
 
 
====== 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      -2.039    -0.272      0.249       -           -               -         3.61e-03     -6.40e-04          6.17e-04      53.200   57
CPL     -1.701    -0.431      1.188       37.979     -35.487       -37.979      5.62e-03        N/A               N/A         52.860   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      -1.915     -0.305     0.280       -           -               -         1.01e-02     -1.99e-03          1.92e-03      50.260   57
CPL     -1.396     -0.782     1.597       50.555      N/A           N/A         1.98e-02        N/A               N/A         49.790   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   6.87e-08  9.10e-08  8.86e-08  1.54e-07  2.99e-07  4.03e-07   erg/cm2
      90%_error_low -1.28e-08 -1.24e-08 -2.10e-08 -6.20e-08 -4.81e-08 -8.85e-08   erg/cm2
      90%_error_hi   1.32e-08  1.23e-08  2.14e-08  8.39e-08  4.92e-08  1.05e-07   erg/cm2
Peak flux       PL   6.19e-01  4.88e-01  2.59e-01  1.99e-01  1.46e+00  1.56e+00   ph/cm2/s
      90%_error_low -1.41e-01 -7.77e-02 -6.54e-02 -8.29e-02 -2.33e-01 -2.51e-01   ph/cm2/s
      90%_error_hi   1.47e-01  7.77e-02  6.58e-02  1.11e-01  2.33e-01  2.52e-01   ph/cm2/s
 
Fluence        CPL    N/A      N/A      N/A      N/A      N/A      N/A      erg/cm2
      90%_error_low -1.28e-08 -1.24e-08 -2.10e-08 -6.20e-08 -4.81e-08 -8.85e-08   erg/cm2
      90%_error_hi   1.32e-08  1.23e-08  2.14e-08  8.39e-08  4.92e-08  1.05e-07   erg/cm2
Peak flux      CPL   5.86e-01  5.19e-01  2.61e-01  1.02e-01  1.43e+00  1.47e+00   ph/cm2/s
      90%_error_low -1.67e-01 -1.01e-01     N/A   -1.02e-01 -2.41e-01 -2.67e-01   ph/cm2/s
      90%_error_hi   1.65e-01  1.13e-01     N/A    1.24e-01  2.40e-01  3.21e-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
   79.8540   -21.4340   0.0138    40.0591     5.0169         0.6543633     14.060 TRIG_00748898                 
 
Foreground time interval of the image:
 -0.376   8.584 (delta_t =   8.960 [sec])
Background time interval of the image:
-769.835 -715.357 (delta_t =  54.479 [sec])
-239.136  -0.376 (delta_t = 238.760 [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   -0.376 sec. to    8.584 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.03879     ( -0.271912   0.249121 )
Norm@50keV  : 3.61102E-03    ( -0.000639877   0.000617274 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          53.20 using 59 PHA bins.
# Reduced chi-squared =         0.9334 for     57 degrees of freedom 
# Null hypothesis probability =   6.183075e-01
 
Photon flux (15-150 keV)    in 8.96 sec: 0.551587 ( -0.074119  0.074138 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.99136e-07 ( -4.81103e-08  4.92158e-08 ) ergs/cm2
    Cutoff power-law model
    Time interval is from   -0.376 sec. to    8.584 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.70143     ( -0.431479   1.18845 )
Epeak [keV] : 37.9792      ( -35.4881 -37.9799 )
Norm@50keV  : 5.62370E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          52.86 using 59 PHA bins.
# Reduced chi-squared =         0.9439 for     56 degrees of freedom 
# Null hypothesis probability =   5.945111e-01
 
Photon flux (15-150 keV)    in 8.96 sec: 0.545214 ( -0.076473  0.076294 ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

    1-s peak spectrum fit

    Power-law model
    Time interval is from    0.460 sec. to    1.460 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.91506     ( -0.304743   0.280225 )
Norm@50keV  : 1.00803E-02    ( -0.00198561   0.00191511 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          50.26 using 59 PHA bins.
# Reduced chi-squared =         0.8817 for     57 degrees of freedom 
# Null hypothesis probability =   7.240580e-01
 
Photon flux (15-150 keV)    in 1 sec: 1.45607 ( -0.23283  0.2329 ) ph/cm2/s
Energy fluence (15-150 keV)             : 9.27065e-08 ( -1.74403e-08  1.78285e-08 ) ergs/cm2
    Cutoff power-law model
    Time interval is from    0.460 sec. to    1.460 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.39564     ( -0.782181   1.59647 )
Epeak [keV] : 50.5547      (   )
Norm@50keV  : 1.98453E-02    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          49.79 using 59 PHA bins.
# Reduced chi-squared =         0.8890 for     56 degrees of freedom 
# Null hypothesis probability =   7.077547e-01
 
Photon flux (15-150 keV)    in 1 sec: 1.43300 ( -0.24111  0.23984 ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

    Time-resolved spectra




    Distribution

    T90 vs. Hardness ratio plot 

    T90                                   = 7.776 sec.
Hardness ratio (energy fluence ratio) = 0.973531994392

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

    S(15-50 keV)  = 1.5974184e-07
S(50-150 keV) = 1.3939456e-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 = 8.376373229670094E-01, IMY = -7.353312053587659E-02

    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:
-769.835400 -715.356900
-239.136000 -0.376000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 69.6355 -61.8594    3.2  33.9   75.6   1.4973   3.6 ------	UNKNOWN                       
 81.3259  -1.9153    3.0  53.0  -15.4   2.0399   3.9 ------	UNKNOWN                       
 67.2309  -0.4078    3.6  44.8  -30.8   1.2484   3.2 ------	UNKNOWN                       
  0.7514  -0.5465    3.5  48.0 -129.1   3.3561   3.3   55.7	UNKNOWN

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

    Time interval of the image:
-0.376000 8.584000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 79.8534 -21.4346    0.8  40.1    5.0   0.6479  14.0 ------	UNKNOWN                       
 71.4886  -1.3798    2.3  46.7  -25.3   0.2944   5.1 ------	UNKNOWN                       
339.5288 -14.3546    2.3  55.0 -160.1   0.6980   5.1 ------	UNKNOWN                       
341.8434  -9.2211    2.0  56.1 -153.4   1.0652   5.7 ------	UNKNOWN

    Post-slew image of 15-350 keV band 

    Time interval of the image:
84.764600 962.894000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6310  22.0196    0.4  43.6  -22.2  35.7643  31.0    0.3	Crab                          
109.2153  25.9792    3.0  55.3    5.2   9.7864   3.9 ------	UNKNOWN                       
 22.0750 -63.9782    3.8  56.9  179.0  13.9550   3.0 ------	UNKNOWN                       
 92.8647  11.2536    2.9  35.1   -4.7   3.3898   3.9 ------	UNKNOWN                       
 37.9362 -32.8217    3.1  38.7 -143.5   4.2829   3.7 ------	UNKNOWN                       
 29.0834 -34.5063    2.9  46.2 -145.1   6.3945   3.9 ------	UNKNOWN