GRB250312A: 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: Thu Jun 19 21:22:02 EDT 2025
             Host Name: batproc1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger1294765
======================================================================

  Trigger: 01294765      Segment: 000

  BAT Trigger Time: 763478692.864   [s; MET]
      Trigger Stop: 763478694.912   [s; MET]
               UTC: 2025-03-12T13:24:17.633320    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 29.5098301429752   Dec: -42.4044965663019  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.99
     Image Trigger?:     NO
     Rate S/N Ratio:     14.4913767461894  [ if not an image trigger ]
     Image S/N Ratio:    7.99

  Analysis Position:   [ source = BAT ]
    RA: 29.5098301429752   Dec: -42.4044965663019  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 29.5152574583294   Dec: -42.3434792030045  [deg; J2000]  
        { 01h 58m 03.7s , -42d 20' 36.5" }
         +/- 2.93238627602947 [arcmin] (estimated 90% radius based on SNR)
         +/- 1.31051201728423 [arcmin] (formal 1-sigma fit error)
    SNR: 6.54123201811011
 
  Angular difference between the analysis and refined position is 3.668937 arcmin
 
  Partial Coding Fraction: 0.6328125    [ including projection effects ]

  Duration
     T90: 222.211999893188 +/- 13.4695562051199
        Measured from: 0.172000050544739
                   to: 222.383999943733     [s; relative to TRIGTIME]
     T50: 181.911999940872 +/- 138.468649210829
        Measured from: 2.73199999332428
                   to: 184.643999934196     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 0.684000015258789     
                   to: 1.68400001525879     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -0.916000008583069     
                   to: 231.332000017166     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.852274   1.237559   0.795715  -0.050995
           0.110012   0.118336   0.107040   0.095976 [error]
 Peak      0.020510   0.056347   0.078091   0.032738
           0.009895   0.011440   0.011134   0.009611 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100  232.248   -0.916  231.332
T90   222.212    0.172  222.384
T50   181.912    2.732  184.644
Peak    1.000    0.684    1.684
 
 
====== 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      -1.823    -0.222      0.209       -           -               -         7.86e-04     -1.10e-04          1.07e-04      56.900   57
CPL     -1.692    -0.514      0.784      105.605    -105.590      -105.605      9.28e-04     -5.78e-04          1.55e-03      56.800   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      -0.802     -0.336     0.369       -           -               -         1.24e-02     -2.52e-03          2.42e-03      50.510   57
CPL     -0.794     -0.339     0.408     9999.290    -9999.290      -9999.290      1.24e-02     -2.32e-03          2.60e-02      50.510   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   3.16e-07  4.77e-07  5.39e-07  1.16e-06  1.68e-06  2.49e-06   erg/cm2
      90%_error_low -5.16e-08 -5.36e-08 -1.02e-07 -3.91e-07 -2.34e-07 -5.07e-07   erg/cm2
      90%_error_hi   5.31e-08  5.36e-08  1.04e-07  5.04e-07  2.39e-07  5.98e-07   erg/cm2
Peak flux       PL   2.62e-01  4.00e-01  4.59e-01  1.01e+00  1.42e+00  2.13e+00   ph/cm2/s
      90%_error_low -1.07e-01 -1.10e-01 -8.42e-02 -3.66e-01 -2.74e-01 -4.19e-01   ph/cm2/s
      90%_error_hi   1.27e-01  1.07e-01  8.36e-02  4.96e-01  2.76e-01  4.58e-01   ph/cm2/s
 
Fluence        CPL   3.11e-07  4.84e-07  5.39e-07  9.12e-07  1.66e-06  2.25e-06   erg/cm2
      90%_error_low -5.72e-08 -6.04e-08 -1.05e-07 -6.44e-07 -2.58e-07 -7.17e-07   erg/cm2
      90%_error_hi   5.71e-08  6.89e-08  1.06e-07  3.41e-07  2.55e-07  4.17e-07   erg/cm2
Peak flux      CPL   2.71e-01  4.00e-01  4.58e-01  1.05e+00  1.42e+00  2.15e+00   ph/cm2/s
      90%_error_low -1.17e-01 -1.12e-01 -8.31e-02 -2.28e-01 -2.93e-01 -7.57e-01   ph/cm2/s
      90%_error_hi   1.18e-01  1.08e-01  1.09e-01  4.41e-01  2.80e-01  4.29e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
   29.5153   -42.3435   0.0293    37.9761   -14.5892         0.9199883      6.541 TRIG_01294765                 
 
Foreground time interval of the image:
 -0.916  29.837 (delta_t =  30.753 [sec])
Background time interval of the image:
-119.864  -0.916 (delta_t = 118.948 [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   -0.916 sec. to  231.332 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.82255     ( -0.221531   0.209404 )
Norm@50keV  : 7.85626E-04    ( -0.000109854   0.000106766 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   56.90     using 59 bins.
 Reduced chi-squared = 0.998246
# Null hypothesis probability of 4.79e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 232.2 sec: 0.109224 ( -0.0122761  0.012278 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.6785e-06 ( -2.33556e-07  2.38938e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -0.916 sec. to  231.332 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.69231     ( -0.513775   0.783968 )
Epeak [keV] : 105.605      ( -105.697 -105.712 )
Norm@50keV  : 9.27914E-04    ( -0.000577673   0.00155418 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   56.80     using 59 bins.
 Reduced chi-squared = 1.01429
# Null hypothesis probability of 4.45e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 232.2 sec: 0.108657 ( -0.0126232  0.012601 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.65704e-06 ( -2.58281e-07  2.54586e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from    0.684 sec. to    1.684 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.802057     ( -0.335983   0.368981 )
Norm@50keV  : 1.23577E-02    ( -0.00251845   0.00241834 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   50.51     using 59 bins.
 Reduced chi-squared = 0.88614
# Null hypothesis probability of 7.16e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 1.42018 ( -0.27398  0.27606 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.44301e-07 ( -2.71462e-08  2.72013e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from    0.684 sec. to    1.684 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.793521     ( -0.338828   0.408295 )
Epeak [keV] : 9999.29      ( -9999.36 -9999.36 )
Norm@50keV  : 1.24314E-02    ( -0.00233367   0.025985 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   50.51     using 59 bins.
 Reduced chi-squared = 0.901964
# Null hypothesis probability of 6.82e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 1.42493 ( -0.29329  0.28016 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.44261e-07 ( -2.58287e-08  2.72176e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 222.212 sec.
Hardness ratio (energy fluence ratio) = 1.13091508366

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

S(15-50 keV)  = 7.921436e-07
S(50-150 keV) = 8.863611e-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 = 7.554453377773364E-01, IMY = 1.966264557379882E-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:
-119.864000 -0.916000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
264.6692 -44.6081    4.9  45.9  133.8   5.1617   2.3   10.0	4U 1735-44                    
270.4088 -25.7098    8.4  54.2  156.9   2.7407   1.4    6.1	GRS 1758-258                  
275.8902 -30.3623    5.5  47.4  156.8   3.2419   2.1    1.8	H1820-303                     
285.1214 -24.9624    6.0  45.3  170.0  -2.2622  -1.9    5.3	HT1900.1-2455                 
280.7367 -28.3496    3.2  45.7  162.8   4.8355   3.6 ------	UNKNOWN                       

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

Time interval of the image:
-0.916000 29.836600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
264.7163 -44.5951    4.1  45.9  133.8  -1.2877  -2.9    8.8	4U 1735-44                    
270.3724 -25.6496    7.9  54.2  156.9  -0.8928  -1.5    6.8	GRS 1758-258                  
275.8673 -30.5671   14.0  47.3  156.6  -0.2843  -0.8   12.4	H1820-303                     
285.1909 -24.9523    5.8  45.3  170.1   0.4646   2.0    8.6	HT1900.1-2455                 
  1.4154 -78.8956    2.1  30.4   55.4   0.8361   5.6 ------	UNKNOWN                       
 58.6218 -39.4475    1.7  57.5   -0.4   4.0012   6.9 ------	UNKNOWN                       
 29.5153 -42.3435    1.8  38.0  -14.6   0.9196   6.5 ------	UNKNOWN                       
347.1655 -26.7116    2.3  25.2  -87.4   0.6846   5.1 ------	UNKNOWN                       
 31.3879 -26.0142    2.0  49.4  -31.9   1.4994   5.8 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
123.036600 962.304800
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 55.4590 -57.8803    3.4  22.5  102.7   5.3601   3.4 ------	UNKNOWN                       
313.7154 -73.5062    3.2  45.7  162.8  12.1491   3.6 ------	UNKNOWN                       
 59.8069 -10.9916    2.9  41.0    9.2   6.9643   4.0 ------	UNKNOWN                       
305.2132 -59.2052    2.9  51.9 -179.5  13.4765   4.0 ------	UNKNOWN                       
357.8685 -57.7075    3.3  25.1 -178.4   4.1151   3.5 ------	UNKNOWN