GRB240222A: 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: Sat Mar  9 13:54:13 EST 2024
             Host Name: batproc1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger1216804
======================================================================

  Trigger: 01216804      Segment: 000

  BAT Trigger Time: 730284724.288   [s; MET]
      Trigger Stop: 730284725.312   [s; MET]
               UTC: 2024-02-22T08:51:31.328680    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 143.247834483184   Dec: -68.0289508826161  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    9.35
     Image Trigger?:     NO
     Rate S/N Ratio:     29.2232783924049  [ if not an image trigger ]
     Image S/N Ratio:    9.35

  Analysis Position:   [ source = BAT ]
    RA: 143.247834483184   Dec: -68.0289508826161  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 143.207833587025   Dec: -68.0314074925631  [deg; J2000]  
        { 09h 32m 49.9s , -68d 01' 53.1" }
         +/- 1.82535659216322 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.80098663106405 [arcmin] (formal 1-sigma fit error)
    SNR: 12.8755116540803
 
  Angular difference between the analysis and refined position is 0.909921 arcmin
 
  Partial Coding Fraction: 0.9453125    [ including projection effects ]

  Duration
     T90: 3.94399988651276 +/- 2.33488331466837
        Measured from: -2.66799998283386
                   to: 1.27599990367889     [s; relative to TRIGTIME]
     T50: 0.979999899864197 +/- 2.36447378531799
        Measured from: -0.0759999752044678
                   to: 0.903999924659729     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: -0.203999996185303     
                   to: 0.796000003814697     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -2.7039999961853     
                   to: 1.36800003051758     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.041681   0.107525   0.133828   0.042187
           0.013519   0.014185   0.012804   0.011111 [error]
 Peak      0.019692   0.060968   0.061661   0.032709
           0.006878   0.007470   0.007353   0.006351 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100    4.072   -2.704    1.368
T90     3.944   -2.668    1.276
T50     0.980   -0.076    0.904
Peak    1.000   -0.204    0.796
 
 
====== 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      -0.751    -0.215      0.229       -           -               -         5.29e-03     -7.12e-04          6.98e-04      54.210   57
CPL      0.046    -0.868      1.169      161.653     -64.644      -161.653      1.09e-02     -5.91e-03          1.79e-02      51.960   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      -0.830     -0.226     0.237       -           -               -         1.08e-02     -1.51e-03          1.50e-03      53.350   57
CPL      0.137     -0.956     1.251      129.992     -43.373      1795.508      2.82e-02     -1.70e-02          6.16e-02      50.360   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   1.37e-08  4.00e-08  9.51e-08  6.20e-07  2.57e-07  7.69e-07   erg/cm2
      90%_error_low -3.71e-09 -6.92e-09 -1.17e-08 -1.62e-07 -3.21e-08 -1.67e-07   erg/cm2
      90%_error_hi   4.16e-09  6.84e-09  1.16e-08  2.04e-07  3.22e-08  2.05e-07   erg/cm2
Peak flux       PL   2.36e-01  3.54e-01  3.98e-01  8.50e-01  1.24e+00  1.84e+00   ph/cm2/s
      90%_error_low -6.43e-02 -6.33e-02 -5.56e-02 -2.30e-01 -1.71e-01 -2.74e-01   ph/cm2/s
      90%_error_hi   7.18e-02  6.26e-02  5.53e-02  2.83e-01  1.71e-01  2.92e-01   ph/cm2/s
 
Fluence        CPL   1.06e-08  4.06e-08  1.04e-07  2.71e-07  2.50e-07  4.26e-07   erg/cm2
      90%_error_low -4.64e-09 -7.80e-09 -1.50e-08 -1.49e-07 -3.42e-08 -1.50e-07   erg/cm2
      90%_error_hi   5.32e-09  7.64e-09  1.55e-08  3.48e-07  3.38e-08  3.38e-07   erg/cm2
Peak flux      CPL   1.79e-01  3.66e-01  4.43e-01  3.79e-01  1.20e+00  1.37e+00   ph/cm2/s
      90%_error_low -7.67e-02 -7.15e-02 -7.08e-02 -1.99e-01 -1.77e-01 -2.73e-01   ph/cm2/s
      90%_error_hi   8.64e-02  7.16e-02  7.32e-02  4.77e-01  1.77e-01  4.88e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  143.2078   -68.0314   0.0150    24.2829  -157.8715         0.3472245     12.876 TRIG_01216804                 
 
Foreground time interval of the image:
 -2.704   1.368 (delta_t =   4.072 [sec])
Background time interval of the image:
-132.387  -2.704 (delta_t = 129.683 [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   -2.704 sec. to    1.368 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.751449     ( -0.214506   0.22918 )
Norm@50keV  : 5.29051E-03    ( -0.000712003   0.000697735 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   54.21     using 59 bins.
 Reduced chi-squared = 0.951053
# Null hypothesis probability of 5.80e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 4.072 sec: 0.609401 ( -0.077689  0.07827 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.57062e-07 ( -3.20697e-08  3.21842e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -2.704 sec. to    1.368 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.0455262     ( -0.867725   1.1695 )
Epeak [keV] : 161.653      ( -64.6433 -161.653 )
Norm@50keV  : 1.09455E-02    ( -0.00591274   0.0178782 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   51.96     using 59 bins.
 Reduced chi-squared = 0.927857
# Null hypothesis probability of 6.28e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 4.072 sec: 0.587961 ( -0.081304  0.081871 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.49861e-07 ( -3.4152e-08  3.37598e-08 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   -0.204 sec. to    0.796 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.830411     ( -0.226152   0.237274 )
Norm@50keV  : 1.08310E-02    ( -0.00151184   0.00149737 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   53.35     using 59 bins.
 Reduced chi-squared = 0.935965
# Null hypothesis probability of 6.13e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 1.24373 ( -0.17053  0.17117 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.24994e-07 ( -1.78766e-08  1.8004e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -0.204 sec. to    0.796 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.136557     ( -0.956426   1.25104 )
Epeak [keV] : 129.992      ( -43.3731 1795.5 )
Norm@50keV  : 2.81848E-02    ( -0.0169593   0.0615694 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   50.36     using 59 bins.
 Reduced chi-squared = 0.899286
# Null hypothesis probability of 6.87e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 1.19732 ( -0.17676  0.17724 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.19286e-07 ( -1.96836e-08  1.93736e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 3.944 sec.
Hardness ratio (energy fluence ratio) = 2.37607420594

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

S(15-50 keV)  = 5.373976e-08
S(50-150 keV) = 2.033195e-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 = -4.179265294965571E-01, IMY = 1.699443114918553E-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:
-132.387400 -2.704000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.6249 -40.6323    1.5  15.4  115.1   1.6751   7.5    6.4	Vela X-1                      
170.5731 -60.6268    3.0  32.8  179.3   1.0479   3.9    7.6	Cen X-3                       
186.3543 -62.8329   21.8  40.0 -175.5  -0.1754  -0.5    9.1	GX 301-2                      
175.1695 -54.5732    2.2  36.2  169.4   1.5401   5.3 ------	UNKNOWN                       

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

Time interval of the image:
-2.704000 1.368000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.4961 -40.5505    5.1  15.4  115.1   0.0631   2.3    1.5	Vela X-1                      
170.2053 -60.7319   34.6  32.8  179.6  -0.0106  -0.3    7.3	Cen X-3                       
186.6504 -62.7740  182.2  40.3 -175.5  -0.0025  -0.1    0.3	GX 301-2                      
152.3573 -32.0503    2.8  31.3  119.2   0.1597   4.1 ------	UNKNOWN                       
143.2078 -68.0314    0.9  24.3 -157.9   0.3474  12.9 ------	UNKNOWN                       
241.7167 -70.6547    2.1  55.2 -153.0   0.6246   5.4 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
76.812600 962.802000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.5439 -40.5254    1.3  27.8   65.7  17.1011   8.6    1.9	Vela X-1                      
170.3291 -60.6092    1.8  13.7  148.7   8.3280   6.4    0.9	Cen X-3                       
186.6303 -62.7625    3.6  18.4  172.6   3.9785   3.2    0.9	GX 301-2                      
 92.2156 -35.4871    4.0  43.1   10.4   6.2802   2.9 ------	UNKNOWN                       
186.7872 -80.4846    3.2  16.4 -125.6   4.3866   3.6 ------	UNKNOWN