Analysis Summary

Notes:

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Mon Aug  6 18:32:54 EDT 2018
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger846868
======================================================================

  Trigger: 00846868      Segment: 000

  BAT Trigger Time: 552826341.504   [s; MET]
      Trigger Stop: 552826349.696   [s; MET]
               UTC: 2018-07-09T10:52:00.268380    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 38.1190695176549   Dec: 60.3717433056486  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    9.13
     Image Trigger?:     NO
     Rate S/N Ratio:     15.556349186104  [ if not an image trigger ]
     Image S/N Ratio:    9.13

  Analysis Position:   [ source = BAT ]
    RA: 38.1190695176549   Dec: 60.3717433056486  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 38.0855238153814   Dec: 60.333308454253  [deg; J2000]  
        { 02h 32m 20.5s , +60d 19' 59.9" }
         +/- 1.55996534289738 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.668667851786314 [arcmin] (formal 1-sigma fit error)
    SNR: 16.1153551191521
 
  Angular difference between the analysis and refined position is 2.511838 arcmin
 
  Partial Coding Fraction: 0.8125    [ including projection effects ]

  Duration
     T90: 194.807999968529 +/- 31.2153429769643
        Measured from: 2.74800002574921
                   to: 197.555999994278     [s; relative to TRIGTIME]
     T50: 98.3200000524521 +/- 67.6398104335087
        Measured from: 10.3799999952316
                   to: 108.700000047684     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 8.73199999332428     
                   to: 9.73199999332428     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: 0.596000075340271     
                   to: 223.72000002861     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.562713   0.695017   0.666130   0.113794
           0.090902   0.093747   0.082761   0.075497 [error]
 Peak      0.018102   0.024548   0.028868   0.011033
           0.007027   0.006986   0.006393   0.005653 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100  223.124    0.596  223.720
T90   194.808    2.748  197.556
T50    98.320   10.380  108.700
Peak    1.000    8.732    9.732
 
 
====== 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      -1.323    -0.238      0.240       -           -               -         6.19e-04     -8.03e-05          8.00e-05      53.130   57
CPL     -1.319    -0.240      0.304     9999.350    -9999.350      -9999.350      6.21e-04     -5.42e-04          4.81e-04      53.140   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      -1.011     -0.486     0.526       -           -               -         5.10e-03     -1.38e-03          1.36e-03      63.440   57
CPL     -0.817      0.817     1.962      362.169    -362.169      -362.169      6.17e-03     -2.35e-03          2.56e-02      63.450   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   1.49e-07  3.06e-07  4.89e-07  1.74e-06  1.36e-06  2.69e-06   erg/cm2
      90%_error_low -3.45e-08 -4.31e-08 -8.25e-08 -5.73e-07 -2.00e-07 -6.41e-07   erg/cm2
      90%_error_hi   3.64e-08  4.23e-08  8.14e-08  7.53e-07  2.03e-07  7.93e-07   erg/cm2
Peak flux       PL   1.32e-01  1.77e-01  1.76e-01  3.15e-01  5.88e-01  8.00e-01   ph/cm2/s
      90%_error_low -6.70e-02 -6.20e-02 -5.15e-02 -1.64e-01 -1.60e-01 -2.24e-01   ph/cm2/s
      90%_error_hi   8.29e-02  5.95e-02  5.01e-02  2.59e-01  1.61e-01  2.47e-01   ph/cm2/s
 
Fluence        CPL   1.49e-07  3.06e-07  4.89e-07  1.91e-06  1.36e-06  2.73e-06   erg/cm2
      90%_error_low    N/A       N/A       N/A       N/A    -2.00e-07 -1.11e-06   erg/cm2
      90%_error_hi     N/A       N/A       N/A       N/A     2.03e-07  2.85e-07   erg/cm2
Peak flux      CPL   1.28e-01  1.78e-01  1.78e-01  2.88e-01  5.85e-01  7.72e-01   ph/cm2/s
      90%_error_low -8.60e-02 -6.40e-02 -5.29e-02 -2.88e-01 -1.66e-01 -3.04e-01   ph/cm2/s
      90%_error_hi   8.50e-02  6.28e-02  6.21e-02  2.02e-01  1.64e-01  2.61e-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
   38.0855    60.3333   0.0119    20.0126  -117.5140         1.4856785     16.115 TRIG_00846868                 
 
Foreground time interval of the image:
  0.596  49.597 (delta_t =  49.001 [sec])
Background time interval of the image:
-239.504   0.596 (delta_t = 240.100 [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    0.596 sec. to  223.720 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.32301     ( -0.237634   0.239965 )
Norm@50keV  : 6.18759E-04    ( -8.0287e-05   7.99674e-05 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          53.13 using 59 PHA bins.
# Reduced chi-squared =         0.9320 for     57 degrees of freedom 
# Null hypothesis probability =   6.211805e-01
 
Photon flux (15-150 keV)    in 223.1 sec: 7.41425E-02 ( -0.0096543  0.0096772 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.35681e-06 ( -2.00141e-07  2.02919e-07 ) ergs/cm2
    Cutoff power-law model
    Time interval is from    0.596 sec. to  223.720 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.31865     ( -0.239747   0.30439 )
Epeak [keV] : 9999.35      ( -9999.36 -9999.36 )
Norm@50keV  : 6.21270E-04    ( -0.00054213   0.000480762 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          53.14 using 59 PHA bins.
# Reduced chi-squared =         0.9489 for     56 degrees of freedom 
# Null hypothesis probability =   5.839117e-01
 
Photon flux (15-150 keV)    in 223.1 sec: 7.41348E-02 ( -0.0096658  0.0096687 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.35622e-06 ( -2.00001e-07  2.02866e-07 ) ergs/cm2

    1-s peak spectrum fit

    Power-law model
    Time interval is from    8.732 sec. to    9.732 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.01119     ( -0.48564   0.525557 )
Norm@50keV  : 5.10118E-03    ( -0.00137742   0.00135702 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          63.44 using 59 PHA bins.
# Reduced chi-squared =          1.113 for     57 degrees of freedom 
# Null hypothesis probability =   2.597716e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.587655 ( -0.160047  0.161359 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.49503e-08 ( -1.56958e-08  1.5965e-08 ) ergs/cm2
    Cutoff power-law model
    Time interval is from    8.732 sec. to    9.732 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.817251     ( 0.830448   1.97513 )
Epeak [keV] : 362.169      ( -407.436 -407.436 )
Norm@50keV  : 6.17468E-03    ( -0.00214252   0.0258468 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          63.45 using 59 PHA bins.
# Reduced chi-squared =          1.133 for     56 degrees of freedom 
# Null hypothesis probability =   2.305513e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.584936 ( -0.166451  0.163565 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.47344e-08 ( -1.62398e-08  1.6096e-08 ) ergs/cm2

    Time-resolved spectra




    Distribution

    T90 vs. Hardness ratio plot 

    T90                                   = 194.808 sec.
Hardness ratio (energy fluence ratio) = 1.5988218372

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

    S(15-50 keV)  = 4.552618e-07
S(50-150 keV) = 9.015375e-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 = -1.682567517699103E-01, IMY = 3.230260812799193E-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:
-239.504000 0.596000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
307.9621  40.9557    6.4  46.6  134.5   2.0582   1.8    6.7	Cyg X-3                       
326.1276  38.5227    7.8  35.5  121.1   0.7779   1.5   12.2	Cyg X-2                       
 43.5284  -1.3199    3.4  54.3  -11.6   2.2636   3.4 ------	UNKNOWN                       
 40.9030  61.4447    1.5  21.8 -118.0   2.0672   7.7 ------	UNKNOWN                       
108.4153  71.7943    4.4  48.0 -129.2   3.1107   2.6 ------	UNKNOWN                       
124.8305  74.6978    2.7  50.9 -135.4   6.5034   4.3 ------	UNKNOWN

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

    Time interval of the image:
0.596000 49.596610
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
308.0649  40.8255   10.4  46.6  134.3  -0.4669  -1.1    7.9	Cyg X-3                       
326.1156  38.1769    5.5  35.7  120.5   0.4072   2.1    9.1	Cyg X-2                       
 38.0855  60.3333    0.7  20.0 -117.5   1.4859  16.1 ------	UNKNOWN

    Post-slew image of 15-350 keV band 

    Time interval of the image:
93.596600 962.592600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
  5.2484  22.5557    3.2  44.2   40.9   5.8738   3.6 ------	UNKNOWN                       
 13.1586  11.0476    3.1  52.6   26.3  11.4157   3.8 ------	UNKNOWN                       
 24.2261  49.3771    3.2  13.5   36.8   2.2738   3.7 ------	UNKNOWN                       
 40.8688  61.4354    0.8   1.7 -134.4   9.2940  13.6 ------	UNKNOWN