Analysis Summary

Notes:

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Sun Mar 17 22:45:22 EDT 2019
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger883818
======================================================================

  Trigger: 00883818      Segment: 000

  BAT Trigger Time: 569187094.336   [s; MET]
      Trigger Stop: 569187110.72   [s; MET]
               UTC: 2019-01-14T19:31:12.086340    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 174.882937593776   Dec: 18.8766590141854  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.12
     Image Trigger?:     NO
     Rate S/N Ratio:     9.48683298050514  [ if not an image trigger ]
     Image S/N Ratio:    7.12

  Analysis Position:   [ source = BAT ]
    RA: 174.882937593776   Dec: 18.8766590141854  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 174.86793074047   Dec: 18.8814949319361  [deg; J2000]  
        { 11h 39m 28.3s , +18d 52' 53.4" }
         +/- 2.2922620327574 [arcmin] (estimated 90% radius based on SNR)
         +/- 1.20712298966811 [arcmin] (formal 1-sigma fit error)
    SNR: 9.29940473488376
 
  Angular difference between the analysis and refined position is 0.900026 arcmin
 
  Partial Coding Fraction: 0.6328125    [ including projection effects ]

  Duration
     T90: 26.4919999837875 +/- 6.69042210499976
        Measured from: 0.167999982833862
                   to: 26.6599999666214     [s; relative to TRIGTIME]
     T50: 13.0479999780655 +/- 4.12861484108176
        Measured from: 4.44400000572205
                   to: 17.4919999837875     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 3.62400007247925     
                   to: 4.62400007247925     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -1.16399991512299     
                   to: 27.8999999761581     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.309884   0.423022   0.143154   0.045916
           0.046547   0.049057   0.044696   0.043927 [error]
 Peak      0.028981   0.013750   0.017731   0.025360
           0.008819   0.009573   0.008593   0.008429 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   29.064   -1.164   27.900
T90    26.492    0.168   26.660
T50    13.048    4.444   17.492
Peak    1.000    3.624    4.624
 
 
====== 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      -1.977    -0.294      0.273       -           -               -         1.91e-03     -3.79e-04          3.68e-04      54.720   57
CPL     -1.324    -0.813      2.698       39.231     -36.235       -39.231      4.83e-03     -4.83e-03          2.64e-01      54.120   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      -2.004     -1.362     1.036       -           -               -         3.56e-03     -3.56e-03          2.08e-03      60.730   57
CPL     -2.068     -0.938     2.068       41.305      N/A           N/A         3.30e-03        N/A               N/A         60.620   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   1.11e-07  1.53e-07  1.56e-07  2.88e-07  5.12e-07  7.08e-07   erg/cm2
      90%_error_low -2.25e-08 -2.34e-08 -4.07e-08 -1.25e-07 -9.42e-08 -1.78e-07   erg/cm2
      90%_error_hi   2.30e-08  2.32e-08  4.24e-08  1.77e-07  9.76e-08  2.19e-07   erg/cm2
Peak flux       PL   2.38e-01  1.78e-01  8.88e-02  6.31e-02  5.35e-01  5.69e-01   ph/cm2/s
      90%_error_low -2.38e-01 -8.75e-02 -8.88e-02 -6.31e-02 -2.31e-01 -2.52e-01   ph/cm2/s
      90%_error_hi   1.59e-01  7.79e-02  7.83e-02  1.99e-01  2.31e-01  2.58e-01   ph/cm2/s
 
Fluence        CPL   1.08e-07  1.66e-07  1.43e-07  8.02e-08  4.67e-07  4.99e-07   erg/cm2
      90%_error_low -2.47e-08 -4.68e-08 -7.80e-08 -7.82e-08 -1.25e-07 -1.56e-07   erg/cm2
      90%_error_hi   2.42e-08  4.12e-08  5.14e-08  2.42e-07  1.27e-07  3.49e-07   erg/cm2
Peak flux      CPL   2.13e-01  1.56e-01  7.87e-02  6.68e-02  4.76e-01  5.14e-01   ph/cm2/s
      90%_error_low     N/A   -1.56e-01 -7.87e-02 -6.68e-02 -4.76e-01     N/A     ph/cm2/s
      90%_error_hi      N/A    9.61e-02  5.18e-02  3.56e-02  2.86e-01     N/A     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
  174.8679    18.8815   0.0207    35.8443     2.3629         0.9408097      9.299 TRIG_00883818                 
 
Foreground time interval of the image:
 -1.164  27.900 (delta_t =  29.064 [sec])
Background time interval of the image:
-239.336  -1.164 (delta_t = 238.172 [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   -1.164 sec. to   27.900 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.97693     ( -0.293731   0.272865 )
Norm@50keV  : 1.91405E-03    ( -0.00037894   0.000367713 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          54.72 using 59 PHA bins.
# Reduced chi-squared =         0.9599 for     57 degrees of freedom 
# Null hypothesis probability =   5.612851e-01
 
Photon flux (15-150 keV)    in 29.06 sec: 0.284124 ( -0.042406  0.042407 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.12467e-07 ( -9.42178e-08  9.76393e-08 ) ergs/cm2
    Cutoff power-law model
    Time interval is from   -1.164 sec. to   27.900 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.32448     ( -0.818616   2.69269 )
Epeak [keV] : 39.2310      ( -36.1731 -39.1694 )
Norm@50keV  : 4.83357E-03    ( -0.00491556   0.263807 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          54.12 using 59 PHA bins.
# Reduced chi-squared =         0.9664 for     56 degrees of freedom 
# Null hypothesis probability =   5.464953e-01
 
Photon flux (15-150 keV)    in 29.06 sec: 0.277288 ( -0.046203  0.045038 ) ph/cm2/s
Energy fluence (15-150 keV)             : 4.67041e-07 ( -1.24781e-07  1.26644e-07 ) ergs/cm2

    1-s peak spectrum fit

    Power-law model
    Time interval is from    3.624 sec. to    4.624 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.00433     ( -1.3614   1.03696 )
Norm@50keV  : 3.55813E-03    ( -0.00355692   0.00208544 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          60.73 using 59 PHA bins.
# Reduced chi-squared =          1.065 for     57 degrees of freedom 
# Null hypothesis probability =   3.431013e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.534821 ( -0.231008  0.23098 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.28148e-08 ( -1.82095e-08  2.05457e-08 ) ergs/cm2
    Cutoff power-law model
    Time interval is from    3.624 sec. to    4.624 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.10573     ( -0.900979   2.10575 )
Epeak [keV] : 44.4878      (   )
Norm@50keV  : 2.75659E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          60.46 using 59 PHA bins.
# Reduced chi-squared =          1.080 for     56 degrees of freedom 
# Null hypothesis probability =   3.178922e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.475655 ( -0.475655  0.28638 ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

    Time-resolved spectra




    Distribution

    T90 vs. Hardness ratio plot 

    T90                                   = 26.492 sec.
Hardness ratio (energy fluence ratio) = 1.01615538305

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

    S(15-50 keV)  = 2.64565e-07
S(50-150 keV) = 2.4790747e-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 = 7.217858374019105E-01, IMY = -2.978403258128292E-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:
-239.336000 -1.164000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 41.0282  61.3932    2.5  55.9 -178.3   5.1531   4.5 ------	UNKNOWN                       
174.0115  32.8705    2.9  22.7   -8.0   0.9473   4.0 ------	UNKNOWN                       
180.6633  32.6107    2.4  26.0  -19.1   1.2548   4.7 ------	UNKNOWN

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

    Time interval of the image:
-1.164000 27.900000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
174.8681  18.8814    1.2  35.8    2.4   0.9520   9.4 ------	UNKNOWN                       
131.3818  68.8508    2.2  20.9 -172.0   0.3915   5.3 ------	UNKNOWN                       
181.6292  14.3285    2.1  42.5   -4.6   0.6392   5.4 ------	UNKNOWN                       
148.7744  69.5958    2.3  18.3 -155.2   0.3558   5.0 ------	UNKNOWN                       
187.6714  11.7017    1.9  47.3  -10.6   0.7837   6.1 ------	UNKNOWN                       
181.3797  51.6652    2.4  15.5  -66.8   0.3612   4.8 ------	UNKNOWN                       
 27.3035  64.0473    2.3  57.7 -170.5   2.0904   5.0 ------	UNKNOWN

    Post-slew image of 15-350 keV band 

    Time interval of the image:
141.164620 962.714000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
144.1040  -3.4900    3.1  37.7   43.7   4.4730   3.7 ------	UNKNOWN                       
235.2149  52.5725    3.9  57.2 -154.1  14.8196   3.0 ------	UNKNOWN