GRB171020A: Summary Image Light curves Spectra Distribution Others

Analysis Summary

Notes:

• 1) No attempt has been made to eliminate the non-significant decimal places.
• 2) This batgrbproduct analysis is done using the HEASARC data.
• 3) This batgrbproduct analysis is using the flight position for the mask-weighting calculation.

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Sat Jan 20 05:10:05 EST 2018
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger780845
======================================================================

  Trigger: 00780845      Segment: 000

  BAT Trigger Time: 530233650.624   [s; MET]
      Trigger Stop: 530233658.816   [s; MET]
               UTC: 2017-10-20T23:07:10.751760    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 39.2624242628798   Dec: 15.1860174459639  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    8.64
     Image Trigger?:     NO
     Rate S/N Ratio:     17.464249196573  [ if not an image trigger ]
     Image S/N Ratio:    8.64

  Analysis Position:   [ source = BAT ]
    RA: 39.2624242628798   Dec: 15.1860174459639  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 39.2594004674261   Dec: 15.1993590075078  [deg; J2000]  
        { 02h 37m 02.3s , +15d 11' 57.7" }
         +/- 1.80894193723606 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.601104503476604 [arcmin] (formal 1-sigma fit error)
    SNR: 13.0427422685848
 
  Angular difference between the analysis and refined position is 0.819418 arcmin
 
  Partial Coding Fraction: 0.4804688    [ including projection effects ]

  Duration
     T90: 41.8560000061989 +/- 9.19157878695337
        Measured from: 0.247999966144562
                   to: 42.1039999723434     [s; relative to TRIGTIME]
     T50: 17.727999985218 +/- 4.11358723729074
        Measured from: 7.09600001573563
                   to: 24.8240000009537     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 19.9399999976158     
                   to: 20.9399999976158     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -0.967999994754791     
                   to: 46.6480000019073     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.347207   0.461168   0.557084   0.250698
           0.062298   0.064489   0.054786   0.048090 [error]
 Peak      0.019563   0.038286   0.025938   0.010278
           0.008990   0.009323   0.007852   0.006996 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   47.616   -0.968   46.648
T90    41.856    0.248   42.104
T50    17.728    7.096   24.824
Peak    1.000   19.940   20.940
 
 
====== 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      -1.033    -0.198      0.207       -           -               -         2.29e-03     -2.62e-04          2.60e-04      66.610   57
CPL     -0.844    -0.368      0.966      354.479    -354.479      -354.479      2.77e-03     -7.14e-04          4.29e-03      66.460   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      -1.308     -0.475     0.492       -           -               -         6.11e-03     -1.72e-03          1.72e-03      73.820   57
CPL     -0.116     -1.583     3.955       82.729     -59.377       -82.729      2.29e-02     -2.29e-02          1.26e+00      73.000   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   8.99e-08  2.20e-07  4.30e-07  2.08e-06  1.16e-06  2.82e-06   erg/cm2
      90%_error_low -2.09e-08 -3.19e-08 -5.18e-08 -5.28e-07 -1.35e-07 -5.57e-07   erg/cm2
      90%_error_hi   2.27e-08  3.13e-08  5.13e-08  6.57e-07  1.36e-07  6.67e-07   erg/cm2
Peak flux       PL   2.09e-01  2.36e-01  1.91e-01  2.57e-01  7.30e-01  8.93e-01   ph/cm2/s
      90%_error_low -9.89e-02 -7.75e-02 -6.29e-02 -1.38e-01 -2.12e-01 -2.56e-01   ph/cm2/s
      90%_error_hi   1.15e-01  7.52e-02  6.16e-02  2.14e-01  2.14e-01  2.61e-01   ph/cm2/s
 
Fluence        CPL   8.57e-08  2.23e-07  4.39e-07  1.61e-06  1.15e-06  2.36e-06   erg/cm2
      90%_error_low -2.75e-08 -3.35e-08 -5.86e-08 -1.02e-06 -1.46e-07 -1.02e-06   erg/cm2
      90%_error_hi   2.61e-08  3.46e-08  6.49e-08  5.99e-07  1.43e-07  4.82e-07   erg/cm2
Peak flux      CPL   1.63e-01  2.57e-01  2.11e-01  9.16e-02  6.95e-01  7.23e-01   ph/cm2/s
      90%_error_low -1.22e-01 -8.94e-02 -7.42e-02 -9.16e-02 -2.28e-01 -2.53e-01   ph/cm2/s
      90%_error_hi   1.42e-01  9.61e-02  8.00e-02  2.24e-01  2.25e-01  3.20e-01   ph/cm2/s
 
======================================================================

Image

Pre-slew 15.0-350.0 keV image (Event data)

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
   39.2594    15.1994   0.0148    28.2642    74.6097         1.6979571     13.043 TRIG_00780845                 
 
Foreground time interval of the image:
 -0.968  46.648 (delta_t =  47.616 [sec])
Background time interval of the image:
-222.123  -0.968 (delta_t = 221.155 [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

Other quick-look light curves:

• 64 ms binning (zoomed)
• 16 ms binning (zoomed)
• 8 ms binning (zoomed)
• 2 ms binning (zoomed)
• SN=5 or 10 s binning (full-time range)
• Raw light curve

Spectra

Notes:

• 1) The fitting includes the systematic errors.
• 2) When the burst includes telescope slew time periods, the fitting uses an average response file made from multiple 5-s response files through out the slew time plus single time preiod for the non-slew times, and weighted by the total counts in the corresponding time period using addrmf. An average response file is needed becuase a spectral fit using the pre-slew DRM will introduce some errors in both a spectral shape and a normalization if the PHA file contains a lot of the slew/post-slew time interval.
• 3) For fits to more complicated models (e.g. a power-law over a cutoff power-law), the BAT team has decided to require a chi-square improvement of more than 6 for each extra dof.

Time averaged spectrum fit using the average DRM

Power-law model

Time interval is from   -0.968 sec. to   46.648 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.03304     ( -0.19824   0.207175 )
Norm@50keV  : 2.28507E-03    ( -0.000261864   0.000259613 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          66.61 using 59 PHA bins.
# Reduced chi-squared =          1.169 for     57 degrees of freedom 
# Null hypothesis probability =   1.799329e-01
 
Photon flux (15-150 keV)    in 47.62 sec: 0.263600 ( -0.031096  0.03127 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.16332e-06 ( -1.35351e-07  1.35892e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -0.968 sec. to   46.648 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.844352     ( -0.368182   0.966446 )
Epeak [keV] : 354.479      ( -354.69 -354.69 )
Norm@50keV  : 2.76835E-03    ( -0.000713439   0.00429516 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          66.46 using 59 PHA bins.
# Reduced chi-squared =          1.187 for     56 degrees of freedom 
# Null hypothesis probability =   1.598903e-01
 
Photon flux (15-150 keV)    in 47.62 sec: 0.261282 ( -0.032862  0.032553 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.15244e-06 ( -1.46462e-07  1.42587e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   19.940 sec. to   20.940 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.30789     ( -0.475409   0.492457 )
Norm@50keV  : 6.11356E-03    ( -0.00172137   0.00172082 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          73.82 using 59 PHA bins.
# Reduced chi-squared =          1.295 for     57 degrees of freedom 
# Null hypothesis probability =   6.637389e-02
 
Photon flux (15-150 keV)    in 1 sec: 0.730443 ( -0.212249  0.213786 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.03045e-08 ( -1.82841e-08  1.86251e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   19.940 sec. to   20.940 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.116008     ( -1.58273   3.95522 )
Epeak [keV] : 82.7290      ( -59.3761 -82.7281 )
Norm@50keV  : 2.29400E-02    ( -0.022941   1.2592 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          73.00 using 59 PHA bins.
# Reduced chi-squared =          1.303 for     56 degrees of freedom 
# Null hypothesis probability =   6.314319e-02
 
Photon flux (15-150 keV)    in 1 sec: 0.694741 ( -0.227602  0.225139 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.59887e-08 ( -1.92562e-08  2.03456e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 41.856 sec.
Hardness ratio (energy fluence ratio) = 1.95474412038

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

S(15-50 keV)  = 3.1003586e-07
S(50-150 keV) = 8.532783e-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 = 1.426852745462230E-01, IMY = -5.183595386081318E-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:
-222.123400 -0.968000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6323  22.0152    0.7  42.6    0.7   8.9216  17.3    0.1	Crab                          
326.0768  38.3765   27.6  53.5 -173.5   0.4219   0.4    5.5	Cyg X-2                       
 75.7324   2.1585    2.5  52.6   26.4   8.3757   4.6 ------	UNKNOWN                       
 40.9161  61.4295    0.2  18.0 -101.9  25.2126  75.4 ------	UNKNOWN                       
 18.3178  67.2981    2.6  26.3 -122.8   1.6749   4.5 ------	UNKNOWN                       

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

Time interval of the image:
-0.968000 46.648000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.7957  21.9756    4.4  42.7    0.6  -0.3594  -2.6    9.3	Crab                          
326.1118  38.4004   15.1  53.5 -173.5  -0.2196  -0.8    5.5	Cyg X-2                       
354.8875  18.8278    2.8  44.3  145.7   1.0212   4.2 ------	UNKNOWN                       
 39.2594  15.1994    0.9  28.3   74.6   1.6978  13.0 ------	UNKNOWN                       
 97.2749  13.2727    2.3  58.0   -2.2   2.8901   5.0 ------	UNKNOWN                       
 36.6480  62.8086    3.1  19.4 -108.1   0.3653   3.7 ------	UNKNOWN                       
333.1448  63.4855    2.5  41.6 -142.7   0.7719   4.7 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
127.076590 962.535500
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
349.2157  45.8783    2.9  51.7  154.7  13.2938   3.9 ------	UNKNOWN                       
 21.5963 -13.0659    3.2  33.2   50.2   4.3117   3.6 ------	UNKNOWN                       
 19.1953   3.1815    3.0  23.1   78.3   3.5177   3.9 ------	UNKNOWN                       
  1.9855  42.5380    3.3  42.0  155.7   5.6344   3.5 ------	UNKNOWN                       
 40.9557  61.4308    0.3  46.3 -161.3  76.6161  42.8 ------	UNKNOWN                       
 79.9785 -28.6636    3.3  58.9  -24.4  19.3733   3.5 ------	UNKNOWN