GRB240912A: 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 Oct 19 14:44:41 EDT 2024
             Host Name: batproc1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger1253910
======================================================================

  Trigger: 01253910      Segment: 000

  BAT Trigger Time: 747798433.344   [s; MET]
      Trigger Stop: 747798433.856   [s; MET]
               UTC: 2024-09-12T01:46:39.185300    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 124.63322615577   Dec: 33.9949552639727  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.78
     Image Trigger?:     NO
     Rate S/N Ratio:     13  [ if not an image trigger ]
     Image S/N Ratio:    7.78

  Analysis Position:   [ source = BAT ]
    RA: 124.63322615577   Dec: 33.9949552639727  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 124.622721747922   Dec: 33.9949849621564  [deg; J2000]  
        { 08h 18m 29.5s , +33d 59' 41.9" }
         +/- 1.04079011498913 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.36010956312302 [arcmin] (formal 1-sigma fit error)
    SNR: 28.7285606334815
 
  Angular difference between the analysis and refined position is 0.522547 arcmin
 
  Partial Coding Fraction: 0.8671875    [ including projection effects ]

  Duration
     T90: 114.931999921799 +/- 8.08011290348459
        Measured from: 20.6000000238419
                   to: 135.531999945641     [s; relative to TRIGTIME]
     T50: 25.2079999446869 +/- 0.475394495726533
        Measured from: 62.1160000562668
                   to: 87.3240000009537     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 76.0520000457764     
                   to: 77.0520000457764     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -3.64800000190735     
                   to: 373.027999997139     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total    17.062591  21.642468  15.397990   3.356233
           0.128313   0.135199   0.115625   0.086841 [error]
 Peak      0.510251   0.717492   0.528835   0.132137
           0.012611   0.014688   0.013176   0.008178 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100  376.676   -3.648  373.028
T90   114.932   20.600  135.532
T50    25.208   62.116   87.324
Peak    1.000   76.052   77.052
 
 
====== 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: CPL)
 
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      -1.625    -0.026      0.026       -           -               -         9.60e-03     -1.32e-04          1.32e-04      36.540   57
CPL     -1.450    -0.106      0.108      193.985     -50.561       191.316      1.13e-02     -1.04e-03          1.17e-03      28.630   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      -1.497     -0.048     0.048       -           -               -         1.20e-01     -3.14e-03          3.14e-03      54.320   57
CPL     -1.224     -0.193     0.202      154.422     -43.355       221.114      1.60e-01     -2.93e-02          3.78e-02      48.410   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   5.19e-06  8.84e-06  1.15e-05  3.01e-05  3.37e-05  5.56e-05   erg/cm2
      90%_error_low -1.59e-07 -1.60e-07 -1.63e-07 -1.00e-06 -4.45e-07 -1.03e-06   erg/cm2
      90%_error_hi   1.61e-07  1.60e-07  1.63e-07  1.03e-06  4.46e-07  1.05e-06   erg/cm2
Peak flux       PL   4.91e+00  4.95e+00  3.51e+00  3.95e+00  1.49e+01  1.73e+01   ph/cm2/s
      90%_error_low -2.50e-01 -1.51e-01 -1.11e-01 -2.62e-01 -4.24e-01 -4.54e-01   ph/cm2/s
      90%_error_hi   2.55e-01  1.51e-01  1.11e-01  2.73e-01  4.24e-01  4.54e-01   ph/cm2/s
 
Fluence        CPL   4.91e-06  8.86e-06  1.17e-05  2.51e-05  3.34e-05  5.05e-05   erg/cm2
      90%_error_low -2.26e-07 -1.62e-07 -2.05e-07 -2.55e-06 -4.83e-07 -2.61e-06   erg/cm2
      90%_error_hi   2.31e-07  1.62e-07  2.06e-07  2.92e-06  4.83e-07  2.97e-06   erg/cm2
Peak flux      CPL   4.59e+00  5.02e+00  3.60e+00  3.00e+00  1.47e+01  1.62e+01   ph/cm2/s
      90%_error_low -3.24e-01 -1.62e-01 -1.30e-01 -5.19e-01 -4.58e-01 -7.37e-01   ph/cm2/s
      90%_error_hi   3.30e-01  1.63e-01  1.31e-01  6.51e-01  4.60e-01  8.28e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  124.6227    33.9950   0.0067    29.0863  -165.3448         1.4673395     28.729 TRIG_01253910                 
 
Foreground time interval of the image:
 -3.648  10.157 (delta_t =  13.805 [sec])
Background time interval of the image:
-156.443  -3.648 (delta_t = 152.795 [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   -3.648 sec. to  373.028 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.62451     ( -0.0255143   0.0255764 )
Norm@50keV  : 9.60437E-03    ( -0.000131926   0.000131782 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   36.54     using 59 bins.
 Reduced chi-squared = 0.641053
# Null hypothesis probability of 9.84e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 376.7 sec: 1.24380 ( -0.02216  0.02227 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.37439e-05 ( -4.45346e-07  4.45806e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -3.648 sec. to  373.028 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.45014     ( -0.105988   0.108286 )
Epeak [keV] : 193.985      ( -50.5613 191.316 )
Norm@50keV  : 1.13027E-02    ( -0.00104296   0.00117146 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   28.63     using 59 bins.
 Reduced chi-squared = 0.51125
# Null hypothesis probability of 9.99e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 376.7 sec: 1.21947 ( -0.02603  0.02626 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.34261e-05 ( -4.82911e-07  4.82952e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   76.052 sec. to   77.052 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.49701     ( -0.0482754   0.0481667 )
Norm@50keV  : 0.119582    ( -0.00314338   0.00314291 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   54.32     using 59 bins.
 Reduced chi-squared = 0.952982
# Null hypothesis probability of 5.76e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 14.9170 ( -0.4235  0.4243 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.13512e-06 ( -3.1753e-08  3.1824e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   76.052 sec. to   77.052 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.22362     ( -0.193412   0.20228 )
Epeak [keV] : 154.422      ( -43.3565 221.113 )
Norm@50keV  : 0.160274    ( -0.0293128   0.0377613 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   48.41     using 59 bins.
 Reduced chi-squared = 0.864464
# Null hypothesis probability of 7.54e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 14.6529 ( -0.4584  0.4598 ) ph/cm2/s
Energy fluence (15-150 keV)             : 7.13724e-07 ( -3.84034e-08  3.19002e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 114.932 sec.
Hardness ratio (energy fluence ratio) = 1.31956343762

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

S(15-50 keV)  = 1.3760625e-05
S(50-150 keV) = 1.966551e-05

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 = -5.381822438423821E-01, IMY = 1.407399230798909E-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:
-156.443400 -3.648000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6361  22.0239    1.4  39.9  127.2   6.0964   8.5    0.6	Crab                          
135.4504 -40.5079    5.5  47.5   -6.3   0.8386   2.1    4.5	Vela X-1                      
 89.4123  -3.7321    2.5  32.8   83.5   2.1224   4.7 ------	UNKNOWN                       
129.0911 -38.8238    2.6  44.6   -0.4   1.6968   4.5 ------	UNKNOWN                       

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

Time interval of the image:
-3.648000 10.156600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.5955  21.8556   14.9  39.9  127.0   0.1000   0.8    9.8	Crab                          
135.4464 -40.5222    3.5  47.5   -6.3   0.2931   3.3    4.2	Vela X-1                      
 99.8233  50.8858    2.1  49.1  171.0   0.6639   5.5 ------	UNKNOWN                       
127.5182   2.9374    2.6   6.8  -63.2   0.2003   4.5 ------	UNKNOWN                       
124.6227  33.9950    0.4  29.1 -165.3   1.4675  28.7 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
93.356590 962.717100
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6423  21.9963    1.2  37.9   58.0  30.4852   9.3    1.2	Crab                          
 95.2701  60.7696    2.8  32.8  129.3   8.1617   4.1 ------	UNKNOWN                       
 98.3355  20.4023    3.2  26.9   42.1   5.0300   3.6 ------	UNKNOWN                       
124.6507  33.9904    1.3   0.0 -157.0  11.1924   9.0 ------	UNKNOWN                       
181.5906  36.0673    2.7  46.0 -134.1  12.5323   4.3 ------	UNKNOWN