GRB191218A: 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 v2.47
    Process Start Time: Mon May 18 15:20:18 EDT 2020
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger944916
======================================================================

  Trigger: 00944916      Segment: 000

  BAT Trigger Time: 598329787.968   [s; MET]
      Trigger Stop: 598329788.992   [s; MET]
               UTC: 2019-12-18T02:42:43.860860    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 301.077639808073   Dec: -40.2740100040986  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    8.88
     Image Trigger?:     NO
     Rate S/N Ratio:     51.8652099195598  [ if not an image trigger ]
     Image S/N Ratio:    8.88

  Analysis Position:   [ source = BAT ]
    RA: 301.077639808073   Dec: -40.2740100040986  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 301.06871575253   Dec: -40.2771831067954  [deg; J2000]  
        { 20h 04m 16.5s , -40d 16' 37.9" }
         +/- 1.35991615543344 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.580356676801513 [arcmin] (formal 1-sigma fit error)
    SNR: 19.605899010128
 
  Angular difference between the analysis and refined position is 0.450699 arcmin
 
  Partial Coding Fraction: 0.09472656    [ including projection effects ]

  Duration
     T90: 44.6640000343323 +/- 0.739134655826652
        Measured from: 0.543999910354614
                   to: 45.2079999446869     [s; relative to TRIGTIME]
     T50: 37.5799999237061 +/- 2.84478753699162
        Measured from: 3.1159999370575
                   to: 40.6959998607635     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 0.663999915122986     
                   to: 1.66399991512299     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -0.232000112533569     
                   to: 46.0319999456406     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     1.925889   2.968141   3.859860   1.520604
           0.165957   0.182856   0.173696   0.146838 [error]
 Peak      0.089643   0.263583   0.341827   0.138872
           0.028434   0.034025   0.036650   0.032122 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   46.264   -0.232   46.032
T90    44.664    0.544   45.208
T50    37.580    3.116   40.696
Peak    1.000    0.664    1.664
 
 
====== 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      -1.119    -0.096      0.098       -           -               -         1.63e-02     -9.17e-04          9.13e-04      64.540   57
CPL     -0.979    -0.184      0.391      455.826    -455.826      -455.826      1.86e-02     -2.91e-03          7.89e-03      64.120   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      -0.998     -0.221     0.227       -           -               -         5.71e-02     -7.78e-03          7.72e-03      51.040   57
CPL     -0.395     -0.702     1.026      165.338      N/A           N/A         1.01e-01        N/A               N/A         49.560   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   6.75e-07  1.57e-06  2.89e-06  1.27e-05  7.84e-06  1.79e-05   erg/cm2
      90%_error_low -7.88e-08 -1.12e-07 -1.66e-07 -1.62e-06 -4.33e-07 -1.69e-06   erg/cm2
      90%_error_hi   8.25e-08  1.11e-07  1.65e-07  1.78e-06  4.33e-07  1.82e-06   erg/cm2
Peak flux       PL   1.28e-04  1.42e-03  4.29e-02  4.08e+00  1.93e-01  3.64e+00   ph/cm2/s
      90%_error_low 1.68e-04     N/A   -1.53e-03 -4.90e-01 -5.32e-03 -1.70e-03   ph/cm2/s
      90%_error_hi   5.90e-04     N/A    4.12e-02  2.17e+00  1.72e-01  2.72e+00   ph/cm2/s
 
Fluence        CPL   6.47e-07  1.58e-06  2.94e-06  1.09e-05  7.82e-06  1.60e-05   erg/cm2
      90%_error_low -1.05e-07 -1.15e-07 -1.04e-07 -3.61e-06 -4.39e-07 -3.58e-06   erg/cm2
      90%_error_hi   7.73e-08  1.15e-07  2.14e-07  3.50e-06  4.39e-07  2.41e-06   erg/cm2
Peak flux      CPL   1.21e+00  2.01e+00  2.15e+00  2.25e+00  6.43e+00  7.61e+00   ph/cm2/s
      90%_error_low -4.75e-01 -3.69e-01 -3.60e-01 -1.06e+00 -9.27e-01 -1.47e+00   ph/cm2/s
      90%_error_hi   5.30e-01  3.66e-01  3.73e-01  1.69e+00  9.32e-01  2.09e+00   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  301.0687   -40.2772   0.0098    50.3266  -139.2491        10.7672757     19.606 TRIG_00944916                 
 
Foreground time interval of the image:
 -0.232  46.032 (delta_t =  46.264 [sec])
Background time interval of the image:
-239.968  -0.232 (delta_t = 239.736 [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   -0.232 sec. to   46.032 sec.
XSPEC12>exit
 XSPEC: quit
 
 
Photon index: -1.11887     ( -0.0964863   0.0980118 )
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.11887     ( -0.0980118   0.0964863 )
Norm@50keV  : 1.63122E-02    ( -0.000917367   0.000912762 )
------------------------------------------------------------
 
Photon flux (15-150 keV)    in 46.26 sec: 1.89571 ( -0.11333  0.11382 ) ph/cm2/s
Energy fluence (15-150 keV)             : 7.84361e-06 ( -4.33146e-07  4.33437e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -0.232 sec. to   46.032 sec.
 XSPEC: quit
 
 
Photon index: -0.979057     ( -0.18364   0.390564 )
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.979057     ( -0.390564   0.18364 )
Epeak [keV] : 455.826      ( -455.81 -455.81 )
Norm@50keV  : 1.86104E-02    ( -0.00291383   0.00788763 )
------------------------------------------------------------
 
Photon flux (15-150 keV)    in 46.26 sec: 0.428375 ( -0.126256  0.118343 ) ph/cm2/s
Energy fluence (15-150 keV)             : 7.81928e-06 ( -4.39464e-07  4.38733e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from    0.664 sec. to    1.664 sec.
XSPEC12>exit
 XSPEC: quit
 
 
Photon index: -0.998036     ( -0.221112   0.226996 )
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.998036     ( -0.226996   0.221112 )
Norm@50keV  : 5.70676E-02    ( -0.00777835   0.0077242 )
------------------------------------------------------------
 
Photon flux (15-150 keV)    in 1 sec: 0.192837 ( -0.005321  0.172412 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.1759e-07 ( -8.62898e-08  8.65516e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from    0.664 sec. to    1.664 sec.
 XSPEC: quit
 
 
Photon index: -0.395289     ( -0.702376   1.02611 )
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.395289     ( -1.02611   0.702376 )
Epeak [keV] : 165.338      (   )
Norm@50keV  : 0.101229    (     )
------------------------------------------------------------
 
Photon flux (15-150 keV)    in 1 sec: 6.43127 ( -0.92692  0.9324 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.12125e-07 ( -8.88982e-08  8.83457e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 44.664 sec.
Hardness ratio (energy fluence ratio) = 1.84183176874

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

S(15-50 keV)  = 2.2428675e-06
S(50-150 keV) = 5.600694e-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 = -9.133415072618881E-01, IMY = 7.870104577881698E-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:
-239.968000 -0.232000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
288.7966  10.9408   20.6  34.1  -60.0   0.2061   0.6    0.3	GRS 1915+105                  
299.6360  35.2437    4.3  36.4  -13.9   0.7669   2.7    3.4	Cyg X-1                       
308.0989  40.9705    2.5  37.5    0.6   1.5399   4.7    1.2	Cyg X-3                       
326.1364  38.4657    7.3  32.7   23.8   0.5143   1.6    8.8	Cyg X-2                       
312.8292  59.1044    3.1  53.8   12.7   5.0835   3.7 ------	UNKNOWN                       
306.2907  58.0759    3.2  53.8    8.3   4.4209   3.6 ------	UNKNOWN                       
290.1508  -9.6908    2.5  36.2  -96.2   2.4810   4.6 ------	UNKNOWN                       
286.0522 -13.1906    2.7  41.3  -98.6   4.4316   4.3 ------	UNKNOWN                       
291.7774 -28.2418    2.4  45.4 -121.1   4.5570   4.8 ------	UNKNOWN                       

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

Time interval of the image:
-0.232000 46.032000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
288.7124  10.9037    9.8  34.2  -60.1   0.1992   1.2    5.7	GRS 1915+105                  
299.6993  35.2891   17.4  36.4  -13.7   0.0810   0.7    7.5	Cyg X-1                       
307.9978  40.8543    5.1  37.4    0.4  -0.3112  -2.3    7.8	Cyg X-3                       
326.1702  38.3069    7.7  32.6   23.9   0.1902   1.5    0.9	Cyg X-2                       
343.7987 -39.4645    2.6  49.3  177.8   1.0372   4.5 ------	UNKNOWN                       
283.0837  34.5377    2.5  46.6  -27.5   0.8475   4.7 ------	UNKNOWN                       
286.5286   9.1594    2.6  36.2  -63.4   0.9352   4.4 ------	UNKNOWN                       
271.7409  39.8707    2.1  57.0  -26.3   2.7270   5.6 ------	UNKNOWN                       
301.0687 -40.2772    0.6  50.3 -139.2  10.7691  19.6 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image: