GRB230903A: 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 v2.48
    Process Start Time: Fri Sep 29 23:23:01 EDT 2023
             Host Name: batproc1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger1189514
======================================================================

  Trigger: 01189514      Segment: 000

  BAT Trigger Time: 715454608.192   [s; MET]
      Trigger Stop: 715454610.24   [s; MET]
               UTC: 2023-09-03T17:22:56.248260    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 9.92619753724725   Dec: -40.9238279211701  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.63
     Image Trigger?:     NO
     Rate S/N Ratio:     11.6619037896906  [ if not an image trigger ]
     Image S/N Ratio:    7.63

  Analysis Position:   [ source = BAT ]
    RA: 9.92619753724725   Dec: -40.9238279211701  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 9.897540336889   Dec: -40.9088789038754  [deg; J2000]  
        { 00h 39m 35.4s , -40d 54' 32.0" }
         +/- 1.85317230060731 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.624442800687011 [arcmin] (formal 1-sigma fit error)
    SNR: 12.6003184888947
 
  Angular difference between the analysis and refined position is 1.578838 arcmin
 
  Partial Coding Fraction: 0.40625    [ including projection effects ]

  Duration
     T90: 2.53599989414215 +/- 0.269429022393487
        Measured from: 0.276000022888184
                   to: 2.81199991703033     [s; relative to TRIGTIME]
     T50: 1.57999992370605 +/- 0.544249932404332
        Measured from: 0.679999947547913
                   to: 2.25999987125397     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 0.495999932289124     
                   to: 1.49599993228912     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: 0.195999979972839     
                   to: 2.93199992179871     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.080541   0.160312   0.111503   0.027623
           0.016930   0.017991   0.016133   0.013339 [error]
 Peak      0.039378   0.068104   0.051960   0.015583
           0.010591   0.010974   0.010193   0.008028 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100    2.736    0.196    2.932
T90     2.536    0.276    2.812
T50     1.580    0.680    2.260
Peak    1.000    0.496    1.496
 
 
====== 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      -1.401    -0.210      0.209       -           -               -         9.21e-03     -1.27e-03          1.26e-03      54.650   57
CPL      0.678    -1.221      1.772       63.179     -10.648        24.407      1.05e-01     -1.05e-01          6.93e-01      44.260   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      -1.444     -0.291     0.287       -           -               -         1.07e-02     -2.11e-03          2.10e-03      63.400   57
CPL      0.611     -1.507     2.466       61.212     -13.450        42.017      1.24e-01     -1.24e-01          2.14e+00      57.220   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   2.93e-08  5.73e-08  8.67e-08  2.85e-07  2.43e-07  4.58e-07   erg/cm2
      90%_error_low -6.23e-09 -8.19e-09 -1.46e-08 -8.73e-08 -3.64e-08 -1.02e-07   erg/cm2
      90%_error_hi   6.56e-09  8.13e-09  1.46e-08  1.09e-07  3.68e-08  1.19e-07   erg/cm2
Peak flux       PL   4.17e-01  4.34e-01  3.19e-01  3.78e-01  1.32e+00  1.55e+00   ph/cm2/s
      90%_error_low -1.22e-01 -8.91e-02 -7.45e-02 -1.46e-01 -2.57e-01 -3.04e-01   ph/cm2/s
      90%_error_hi   1.32e-01  8.84e-02  7.41e-02  1.89e-01  2.58e-01  3.07e-01   ph/cm2/s
 
Fluence        CPL   2.09e-08  7.00e-08  9.50e-08  3.64e-08  2.15e-07  2.22e-07   erg/cm2
      90%_error_low -7.67e-09 -1.13e-08 -1.92e-08 -2.57e-08 -3.79e-08 -4.43e-08   erg/cm2
      90%_error_hi   8.03e-09  1.20e-08  1.85e-08  6.56e-08  4.01e-08  7.03e-08   erg/cm2
Peak flux      CPL   3.01e-01  5.31e-01  3.62e-01  7.05e-02  1.25e+00  1.26e+00   ph/cm2/s
      90%_error_low -1.43e-01 -1.19e-01 -1.02e-01 -7.05e-02 -2.63e-01 -2.71e-01   ph/cm2/s
      90%_error_hi   1.55e-01  1.28e-01  9.77e-02  1.60e-01  2.64e-01  2.85e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
    9.8975   -40.9089   0.0153    28.6584    93.7422         0.4120037     12.600 TRIG_01189514                 
 
Foreground time interval of the image:
  0.196   2.932 (delta_t =   2.736 [sec])
Background time interval of the image:
-344.192 -254.138 (delta_t =  90.054 [sec])
-239.192   0.196 (delta_t = 239.388 [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    0.196 sec. to    2.932 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.40144     ( -0.210199   0.209397 )
Norm@50keV  : 9.21022E-03    ( -0.00126762   0.0012641 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   54.65     using 59 bins.
 Reduced chi-squared = 0.958772
# Null hypothesis probability of 5.64e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 2.736 sec: 1.12203 ( -0.154298  0.15456 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.43442e-07 ( -3.63967e-08  3.6782e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from    0.196 sec. to    2.932 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.677504     ( -1.22073   1.77143 )
Epeak [keV] : 63.1787      ( -10.6464 24.4082 )
Norm@50keV  : 0.104702    ( -0.104718   0.692852 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   44.26     using 59 bins.
 Reduced chi-squared = 0.790357
# Null hypothesis probability of 8.72e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 2.736 sec: 1.05189 ( -0.161075  0.16068 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.14633e-07 ( -3.79453e-08  4.00829e-08 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from    0.496 sec. to    1.496 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.44404     ( -0.291337   0.286498 )
Norm@50keV  : 1.07037E-02    ( -0.00210759   0.00209862 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   63.40     using 59 bins.
 Reduced chi-squared = 1.11228
# Null hypothesis probability of 2.61e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 1.31709 ( -0.25746  0.25794 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.0257e-07 ( -2.16436e-08  2.19331e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from    0.496 sec. to    1.496 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.610635     ( -1.51318   2.4589 )
Epeak [keV] : 61.2124      ( -13.3617 42.1045 )
Norm@50keV  : 0.124388    ( -0.125894   2.14179 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   57.22     using 59 bins.
 Reduced chi-squared = 1.02179
# Null hypothesis probability of 4.30e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 1.25430 ( -0.263157  0.26357 ) ph/cm2/s
Energy fluence (15-150 keV)             : 9.12935e-08 ( -2.21868e-08  2.38448e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 2.536 sec.
Hardness ratio (energy fluence ratio) = 1.51411922278

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

S(15-50 keV)  = 8.660901e-08
S(50-150 keV) = 1.5683614e-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 = -3.567144706682876E-02, IMY = -5.453748491462346E-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:
-344.192000 -254.138200
-239.192000 0.196000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
298.4262 -62.6125    2.7  43.5   13.3   3.6914   4.2 ------	UNKNOWN                       
191.4203 -84.6742    2.6  33.1  -32.1   2.6472   4.5 ------	UNKNOWN                       
 81.4884 -25.7539    3.0  44.2 -153.3   3.1476   3.9 ------	UNKNOWN                       
123.5538 -64.0929    2.7  34.4  -76.7   3.4448   4.3 ------	UNKNOWN                       
100.9292 -30.9553    2.3  48.0 -129.0  10.4959   5.2 ------	UNKNOWN                       

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

Time interval of the image:
0.196000 2.932000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
  9.8975 -40.9089    0.9  28.7   93.7   0.4121  12.6 ------	UNKNOWN                       
 69.9783  -8.7153    2.6  56.5 -174.4   0.3447   4.5 ------	UNKNOWN                       
171.3015 -81.5121    2.3  34.3  -38.9   0.1280   5.1 ------	UNKNOWN                       
101.2771 -35.0241    2.3  44.8 -125.6   0.3295   4.9 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
94.908590 961.808600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
345.9990 -33.1766    2.6  20.5   58.5   5.3695   4.3 ------	UNKNOWN                       
308.2330 -47.7598    2.6  43.4   13.3   9.0753   4.4 ------	UNKNOWN                       
345.1778 -71.6926    2.4  33.1  -32.1   6.4403   4.8 ------	UNKNOWN                       
342.8014 -75.5913    2.5  36.7  -35.1   6.7678   4.7 ------	UNKNOWN