GRB170921A

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: Fri Oct 20 14:34:01 EDT 2017
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger773509
======================================================================

  Trigger: 00773509      Segment: 000

  BAT Trigger Time: 527696948.224   [s; MET]
      Trigger Stop: 527696952.32   [s; MET]
               UTC: 2017-09-21T14:28:48.502900    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 26.8495479369481   Dec: 30.8742207954133  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    10.2
     Image Trigger?:     NO
     Rate S/N Ratio:     16.8819430161341  [ if not an image trigger ]
     Image S/N Ratio:    10.2

  Analysis Position:   [ source = BAT ]
    RA: 26.8495479369481   Dec: 30.8742207954133  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 26.8406911730994   Dec: 30.8796537098092  [deg; J2000]  
        { 01h 47m 21.8s , +30d 52' 46.8" }
         +/- 1.8530781230834 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.805485407365669 [arcmin] (formal 1-sigma fit error)
    SNR: 12.6012333217451
 
  Angular difference between the analysis and refined position is 0.560605 arcmin
 
  Partial Coding Fraction: 0.8671875    [ including projection effects ]

  Duration
     T90: 28.8000000119209 +/- 5.92553253459488
        Measured from: -18.2960000038147
                   to: 10.5040000081062     [s; relative to TRIGTIME]
     T50: 7.74400001764297 +/- 5.94959091543058
        Measured from: -1.84799998998642
                   to: 5.89600002765656     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 2.74000000953674     
                   to: 3.74000000953674     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -21.8159999847412     
                   to: 13     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.357408   0.539242   0.235640   0.043104
           0.041420   0.042598   0.037101   0.032268 [error]
 Peak      0.038391   0.030822   0.029113   0.010913
           0.007219   0.007705   0.006851   0.005700 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   34.816  -21.816   13.000
T90    28.800  -18.296   10.504
T50     7.744   -1.848    5.896
Peak    1.000    2.740    3.740
 
 
====== 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      -1.759    -0.176      0.170       -           -               -         2.08e-03     -2.44e-04          2.41e-04      58.760   57
CPL     -0.067    -0.926      1.183       48.528      -6.701         8.226      1.89e-02     -1.89e-02          7.06e-02      47.220   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      -1.659     -0.454     0.418       -           -               -         5.98e-03     -1.61e-03          1.50e-03      67.290   57
CPL     -1.668     -1.344     0.897     9999.290      N/A           N/A         5.97e-03        N/A               N/A         67.290   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   1.18e-07  1.85e-07  2.19e-07  5.01e-07  6.67e-07  1.02e-06   erg/cm2
      90%_error_low -1.69e-08 -1.87e-08 -3.39e-08 -1.39e-07 -8.03e-08 -1.78e-07   erg/cm2
      90%_error_hi   1.74e-08  1.87e-08  3.43e-08  1.70e-07  8.17e-08  2.03e-07   erg/cm2
Peak flux       PL   2.87e-01  2.63e-01  1.66e-01  1.61e-01  7.83e-01  8.78e-01   ph/cm2/s
      90%_error_low -9.71e-02 -5.82e-02 -5.78e-02 -8.94e-02 -1.72e-01 -2.02e-01   ph/cm2/s
      90%_error_hi   1.03e-01  5.81e-02  5.71e-02  1.38e-01  1.72e-01  2.06e-01   ph/cm2/s
 
Fluence        CPL   9.99e-08  2.23e-07  2.05e-07  5.78e-08  5.75e-07  5.86e-07   erg/cm2
      90%_error_low -2.01e-08 -2.74e-08 -4.64e-08 -4.02e-08 -8.09e-08 -8.95e-08   erg/cm2
      90%_error_hi   2.01e-08  2.85e-08  4.35e-08  1.05e-07  8.90e-08  1.30e-07   erg/cm2
Peak flux      CPL   2.74e-01  2.04e-01  1.05e-01  9.25e-02  6.21e-01  6.76e-01   ph/cm2/s
      90%_error_low     N/A   -8.77e-02 -4.04e-02 -3.87e-02 -2.65e-01 -2.78e-01   ph/cm2/s
      90%_error_hi      N/A    8.34e-02  2.43e-02  3.07e-02  1.82e-01  2.65e-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
   26.8407    30.8797   0.0153    14.0080    86.4636         1.0985798     12.601 TRIG_00773509                 
 
Foreground time interval of the image:
-21.816  13.000 (delta_t =  34.816 [sec])
Background time interval of the image:
-239.224 -21.816 (delta_t = 217.408 [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:

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  -21.816 sec. to   13.000 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.75914     ( -0.175926   0.169665 )
Norm@50keV  : 2.07772E-03    ( -0.000244199   0.000240883 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          58.76 using 59 PHA bins.
# Reduced chi-squared =          1.031 for     57 degrees of freedom 
# Null hypothesis probability =   4.107819e-01
 
Photon flux (15-150 keV)    in 34.82 sec: 0.281908 ( -0.028606  0.028614 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.67357e-07 ( -8.02611e-08  8.17417e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from  -21.816 sec. to   13.000 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.0665121     ( -0.926106   1.18272 )
Epeak [keV] : 48.5278      ( -6.70072 8.22668 )
Norm@50keV  : 1.88750E-02    ( -0.0188772   0.0706181 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          47.22 using 59 PHA bins.
# Reduced chi-squared =         0.8432 for     56 degrees of freedom 
# Null hypothesis probability =   7.920156e-01
 
Photon flux (15-150 keV)    in 34.82 sec: 0.266217 ( -0.029455  0.029566 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.74857e-07 ( -8.09008e-08  8.89602e-08 ) ergs/cm2

1-s peak spectrum fit

Power-law model

Time interval is from    2.740 sec. to    3.740 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.65938     ( -0.453788   0.417728 )
Norm@50keV  : 5.98108E-03    ( -0.00160672   0.00150309 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          67.29 using 59 PHA bins.
# Reduced chi-squared =          1.181 for     57 degrees of freedom 
# Null hypothesis probability =   1.653594e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.783444 ( -0.172347  0.172354 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.55815e-08 ( -1.52829e-08  1.58106e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from    2.740 sec. to    3.740 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.24371     ( -0.767739   1.4725 )
Epeak [keV] : 90.6312      (   )
Norm@50keV  : 3.02449E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          67.17 using 59 PHA bins.
# Reduced chi-squared =          1.200 for     56 degrees of freedom 
# Null hypothesis probability =   1.457616e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.621499 ( -0.26491  0.182075 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.88562e-08 ( -1.57792e-08  9.73974e-09 ) ergs/cm2

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 28.8 sec.
Hardness ratio (energy fluence ratio) = 1.18184368685

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

S(15-50 keV)  = 3.028617e-07
S(50-150 keV) = 3.645038e-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 = 1.538833695729371E-02, IMY = -2.490014657164326E-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:
-239.224000 -21.816000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6175  21.9941    0.6  44.8  -24.2   8.3999  20.6    1.5	Crab                          
325.9375  38.4099    0.0  51.5  163.7   3.1532   3.4   12.2	Cyg X-2                       
 64.6359  -3.8586    2.5  53.7   16.7   4.6732   4.6 ------	UNKNOWN                       
 72.6056  -1.4005    2.5  55.4    6.7   5.0672   4.7 ------	UNKNOWN

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

Time interval of the image:
-21.816000 13.000000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6491  22.1945    6.0  44.7  -24.4   0.2748   1.9   10.8	Crab                          
326.1750  38.3138  134.5  51.4  163.5   0.0276   0.1    0.5	Cyg X-2                       
 46.0415   6.5880    2.6  37.6   36.5   0.5916   4.5 ------	UNKNOWN                       
 26.8407  30.8796    0.9  14.0   86.5   1.0983  12.6 ------	UNKNOWN                       
 92.1097  12.5773    2.2  57.1  -22.0   1.9253   5.2 ------	UNKNOWN

Post-slew image of 15-350 keV band

Time interval of the image:
81.076600 962.796400
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
326.3497  38.1678    0.0  49.5  160.6  -3.0032  -1.4   12.5	Cyg X-2                       
321.2868  37.4888    3.7  53.6  160.8  11.4237   3.2 ------	UNKNOWN

Analysis Summary

Notes:

Image

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

Light Curves

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:

Time averaged spectrum fit using the average DRM

Power-law model

Cutoff power-law model

1-s peak spectrum fit

Power-law model

Cutoff power-law model

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

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

Mask shadow pattern

Spacecraft aspect plot

Bright source in the pre-burst/pre-slew/post-slew images

Pre-burst image of 15-350 keV band

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

Post-slew image of 15-350 keV band

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