GRB181020A: 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: Mon Dec 17 17:56:18 EST 2018
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger867987
======================================================================

  Trigger: 00867987      Segment: 000

  BAT Trigger Time: 561754855.296   [s; MET]
      Trigger Stop: 561754855.424   [s; MET]
               UTC: 2018-10-20T19:00:33.510100    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 13.9670984422145   Dec: -47.3799961910664  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    8.26
     Image Trigger?:     NO
     Rate S/N Ratio:     28.9309522829789  [ if not an image trigger ]
     Image S/N Ratio:    8.26

  Analysis Position:   [ source = BAT ]
    RA: 13.9670984422145   Dec: -47.3799961910664  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 13.9856438394844   Dec: -47.3719623592739  [deg; J2000]  
        { 00h 55m 56.6s , -47d 22' 19.1" }
         +/- 0.564057571401366 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.137267062245579 [arcmin] (formal 1-sigma fit error)
    SNR: 68.9240229394993
 
  Angular difference between the analysis and refined position is 0.894508 arcmin
 
  Partial Coding Fraction: 0.9453125    [ including projection effects ]

  Duration
     T90: 238.015999913216 +/- 11.5988104904574
        Measured from: 0.796000003814697
                   to: 238.81199991703     [s; relative to TRIGTIME]
     T50: 16.0719999074936 +/- 4.86733609384869
        Measured from: 4.51999998092651
                   to: 20.5919998884201     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 7.26399993896484     
                   to: 8.26399993896484     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -1.44799995422363     
                   to: 271.203999996185     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     3.022382   4.375695   3.958866   1.073056
           0.110750   0.117662   0.108420   0.104210 [error]
 Peak      0.174326   0.335363   0.390363   0.129826
           0.010213   0.012815   0.013912   0.011623 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100  272.652   -1.448  271.204
T90   238.016    0.796  238.812
T50    16.072    4.520   20.592
Peak    1.000    7.264    8.264
 
 
====== 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      -1.254    -0.060      0.060       -           -               -         2.96e-03     -9.07e-05          9.07e-05      52.470   57
CPL     -1.159    -0.121      0.238      495.380    -495.380      -495.380      3.27e-03     -4.92e-04          8.88e-04      51.970   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      -0.863     -0.074     0.075       -           -               -         6.67e-02     -2.72e-03          2.71e-03      67.150   57
CPL     -0.687     -0.224     0.305      437.420    -437.420      -437.420      7.96e-02     -1.50e-02          2.73e-02      66.060   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   8.19e-07  1.75e-06  2.94e-06  1.13e-05  8.08e-06  1.68e-05   erg/cm2
      90%_error_low -5.23e-08 -6.43e-08 -1.10e-07 -9.68e-07 -2.73e-07 -1.03e-06   erg/cm2
      90%_error_hi   5.36e-08  6.40e-08  1.09e-07  1.03e-06  2.74e-07  1.08e-06   erg/cm2
Peak flux       PL   1.50e+00  2.21e+00  2.42e+00  5.01e+00  7.66e+00  1.11e+01   ph/cm2/s
      90%_error_low -1.28e-01 -1.13e-01 -1.09e-01 -4.89e-01 -3.11e-01 -5.47e-01   ph/cm2/s
      90%_error_hi   1.32e-01  1.13e-01  1.08e-01  5.24e-01  3.11e-01  5.62e-01   ph/cm2/s
 
Fluence        CPL   8.00e-07  1.76e-06  2.96e-06  9.83e-06  8.02e-06  1.53e-05   erg/cm2
      90%_error_low -6.83e-08 -6.45e-08 -1.22e-07 -2.68e-06 -3.07e-07 -2.68e-06   erg/cm2
      90%_error_hi   5.48e-08  6.84e-08  1.23e-07  1.23e-06  3.04e-07  1.71e-06   erg/cm2
Peak flux      CPL   1.43e+00  2.22e+00  2.48e+00  4.16e+00  7.60e+00  1.03e+01   ph/cm2/s
      90%_error_low -1.69e-01 -1.18e-01 -1.35e-01 -1.06e+00 -3.25e-01 -1.11e+00   ph/cm2/s
      90%_error_hi   2.39e-01  1.18e-01  1.36e-01  1.05e+00  3.25e-01  1.06e+00   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
   13.9856   -47.3720   0.0028    12.1465    64.7027         8.2385229     68.924 TRIG_00867987                 
 
Foreground time interval of the image:
 -1.448  11.005 (delta_t =  12.453 [sec])
Background time interval of the image:
-239.296  -1.448 (delta_t = 237.848 [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   -1.448 sec. to  271.204 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.25351     ( -0.0597708   0.0599395 )
Norm@50keV  : 2.96169E-03    ( -9.0685e-05   9.06772e-05 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          52.47 using 59 PHA bins.
# Reduced chi-squared =         0.9204 for     57 degrees of freedom 
# Null hypothesis probability =   6.456573e-01
 
Photon flux (15-150 keV)    in 272.7 sec: 0.350492 ( -0.011384  0.011419 ) ph/cm2/s
Energy fluence (15-150 keV)             : 8.07634e-06 ( -2.72735e-07  2.73829e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -1.448 sec. to  271.204 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.15908     ( -0.120567   0.238084 )
Epeak [keV] : 495.380      ( -495.441 -495.441 )
Norm@50keV  : 3.26734E-03    ( -0.000491682   0.000888183 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          51.97 using 59 PHA bins.
# Reduced chi-squared =         0.9280 for     56 degrees of freedom 
# Null hypothesis probability =   6.281245e-01
 
Photon flux (15-150 keV)    in 272.7 sec: 0.348155 ( -0.012633  0.012598 ) ph/cm2/s
Energy fluence (15-150 keV)             : 8.0191e-06 ( -3.06599e-07  3.0381e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from    7.264 sec. to    8.264 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.863463     ( -0.0741684   0.0746961 )
Norm@50keV  : 6.67121E-02    ( -0.00271614   0.00271093 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          67.15 using 59 PHA bins.
# Reduced chi-squared =          1.178 for     57 degrees of freedom 
# Null hypothesis probability =   1.682389e-01
 
Photon flux (15-150 keV)    in 1 sec: 7.65685 ( -0.3106  0.3107 ) ph/cm2/s
Energy fluence (15-150 keV)             : 7.59626e-07 ( -3.51233e-08  3.52694e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from    7.264 sec. to    8.264 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.687076     ( -0.223742   0.304523 )
Epeak [keV] : 437.420      ( -437.42 -437.42 )
Norm@50keV  : 7.95734E-02    ( -0.0150474   0.0272596 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          66.06 using 59 PHA bins.
# Reduced chi-squared =          1.180 for     56 degrees of freedom 
# Null hypothesis probability =   1.682605e-01
 
Photon flux (15-150 keV)    in 1 sec: 7.59784 ( -0.32508  0.32453 ) ph/cm2/s
Energy fluence (15-150 keV)             : 7.52749e-07 ( -3.72978e-08  3.70926e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 238.016 sec.
Hardness ratio (energy fluence ratio) = 1.67776164318

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

S(15-50 keV)  = 2.5695544e-06
S(50-150 keV) = 5.506902e-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

IMX = 9.197117906108621E-02, IMY = -1.945902495346681E-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:
-239.296000 -1.448000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 63.0943 -21.5448    2.2  47.8  145.0   4.9395   5.1 ------	UNKNOWN                       
 32.0144 -48.1610    3.3  12.5  124.0   0.8567   3.5 ------	UNKNOWN                       
112.2376 -41.0770    3.0  56.4 -157.2   5.2494   3.9 ------	UNKNOWN                       
290.4717 -77.2096    2.4  33.6  -68.8   2.1381   4.7 ------	UNKNOWN                       

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

Time interval of the image:
-1.448000 11.004600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 35.7417 -19.5622    2.0  40.7  109.3   2.4738   5.7 ------	UNKNOWN                       
 13.9856 -47.3720    0.2  12.1   64.7   8.2383  68.9 ------	UNKNOWN                       
 19.3493 -62.0110    2.3   3.3  -79.5   0.5192   4.9 ------	UNKNOWN                       
 86.0326 -61.8494    2.2  31.0 -148.6   0.6875   5.3 ------	UNKNOWN                       
103.4378 -42.9839    1.9  50.8 -161.9   1.7003   6.1 ------	UNKNOWN                       
273.6128 -62.5031    2.7  46.6  -55.1   2.0185   4.2 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
44.404600 962.793300
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
328.6638  -9.0594    2.6  54.1   17.0  12.6998   4.4 ------	UNKNOWN                       
106.2724 -80.8487    3.4  43.8 -116.2  10.9764   3.5 ------	UNKNOWN