batgrbproduct analysis for trigger=1426088

batgrbproduct Analysis for Trigger=1426088

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 (local time): Sat Feb 28 17:47:17 EST 2026
             Host Name: batproc1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger1426088
======================================================================

  Trigger: 01426088      Segment: 000

  BAT Trigger Time: 787987508.864   [s; MET]
      Trigger Stop: 787987512.96   [s; MET]
               UTC: 2025-12-21T05:24:31.965060    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 101.408459383592   Dec: 0.729192803908108  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.35
     Image Trigger?:     NO
     Rate S/N Ratio:     13.9642400437689  [ if not an image trigger ]
     Image S/N Ratio:    7.35

  Flight Position:   [ source = BAT ]
    RA: 101.408459383592   Dec: 0.729192803908108  [deg; J2000]

  Ground Position:   [ source = BAT pre-slew burst ]
    RA: 101.422318443239   Dec: 0.737713396285322  [deg; J2000]  
        { 06h 45m 41.4s , +00d 44' 15.8" }
         +/- 1.41412613105958 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.547047653536818 [arcmin] (formal 1-sigma fit error)
    SNR: 18.5410921399077
 
  Angular difference between Flight and Ground position is 0.976070 arcmin
 
  Partial Coding Fraction: 0.4296875    [ including projection effects ]

  Duration
     T90: 56.864000082016 +/- 7.0481272127273
        Measured from: -35.5920000076294
                   to: 21.2720000743866     [s; relative to TRIGTIME]
     T50: 20.9759999513626 +/- 11.2270445163436
        Measured from: -15.1439999341965
                   to: 5.83200001716614     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 2.90799999237061     
                   to: 3.90799999237061     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -38.1039999723434     
                   to: 27.7360000610352     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.608569   1.087964   1.015174   0.275365
           0.075700   0.080363   0.069525   0.057548 [error]
 Peak      0.026973   0.045111   0.057839   0.019973
           0.009761   0.010305   0.009590   0.007883 [error]

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

======================================================================
 
=== 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   Power-law 2.05e-07 4.41e-07 7.44e-07 2.86e-06 2.04e-06 4.25e-06   erg/cm2
              Error 2.99e-08 3.86e-08 6.59e-08 5.65e-07 1.67e-07 6.04e-07   erg/cm2
Peak flux Power-law 2.49e-01 3.30e-01 3.21e-01 5.59e-01 1.09e+00 1.46e+00   ph/cm2/s
              Error 1.12e-01 8.99e-02 7.18e-02 2.78e-01 2.38e-01 3.25e-01   ph/cm2/s
 
Fluence   Cutoff-PL 1.85e-07 4.60e-07 7.77e-07 1.49e-06 1.98e-06 2.91e-06   erg/cm2
              Error 3.65e-08 4.51e-08 7.70e-08 1.10e-06 1.81e-07 1.04e-06   erg/cm2
Peak flux Cutoff-PL 2.47e-01 3.31e-01 3.22e-01 5.48e-01 1.09e+00 1.45e+00   ph/cm2/s
              Error 1.29e-01 9.15e-02 8.28e-02 3.66e-01 2.40e-01 3.98e-01   ph/cm2/s
 
Fluence        Band -------- -------- -------- -------- -------- --------   erg/cm2
              Error -------- -------- -------- -------- -------- --------   erg/cm2
Peak flux      Band -------- -------- -------- -------- -------- --------   ph/cm2/s
              Error -------- -------- -------- -------- -------- --------   ph/cm2/s

 
=== Time-averaged spectral analysis ===
 
Model Ph_index Ph_90err Epeak  Epeak_90err Norm     Nomr_90err chi2   dof
PL    1.248    0.131    -      -           3.10e-03 2.35e-04   58.350 57
CPL   0.748    0.572     135.3  -44.2      5.34e-03 3.54e-03   55.800 56
 
 
=== 1-s peak spectral analysis ===
 
Model Ph_index Ph_90err Epeak  Epeak_90err Norm     Nomr_90err chi2   dof
PL    1.039    0.381    -      -           9.40e-03 2.00e-03   58.780 57
CPL   1.033    2.591    9998.6    0.0      9.46e-03 1.40e-02   58.780 56
 
Model      : spectral model: simple power-law (PL) and cutoff power-law (CPL)
Ph_index   : photon index: E^-{Ph_index} (minus sign is not included in the 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 PL model and at 1 keV in CPL model
Nomr_90err : 90% error of the normalization
chi2       : Chi-Squared
dof        : degree of freedom

 
=== T90/T50 calculation in the 50-300 keV band (BATSE band) using 64 ms lc ===
 
T90 in the 50-300 keV band: 55.488000 sec.
T50 in the 50-300 keV band: 16.384000 sec.

 
=== Table of the duration information ==
 
        Value   tstart    tstop
T100   65.840  -38.104   27.736
T90    56.864  -35.592   21.272
T50    20.976  -15.144    5.832
Peak    1.000    2.908    3.908

Click here for the BAT GCN circular template

Estimated redshift from machine learning (Ukwatta et al. 2016) - may take a few minute to calcaulte

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  101.4223     0.7377   0.0103    28.6670    82.0255         2.9995362     18.541 TRIG_01426088                 
 
Foreground time interval of the image:
-38.104  27.736 (delta_t =  65.840 [sec])
Background time interval of the image:
-239.864 -38.104 (delta_t = 201.760 [sec])

Lightcurves

Notes:

1) The mask-weighted light curves are using the flight position.
2) Multiple plots of different time binning/intervals are shown to cover all scenarios of short/long GRBs, rate/image triggers, and real/false positives.
3) For all the mask-weighted lightcurves, the y-axis units are counts/sec/det where a det is 0.4 x 0.4 = 0.16 sq cm.
4) The verticle lines correspond to following: green dotted lines are T50 interval, black dotted lines are T90 interval, blue solid line(s) is a spacecraft slew start time, and orange solid line(s) is a spacecraft slew end time.
5) Time of each bin is in the middle of the bin.

1 s binning

From T0-310 s to T0+310 s

From T100_start - 20 s to T100_end + 30 s

Full time interval

64 ms binning

Full time interval

From T100_start to T100_end

From T0-5 sec to T0+5 sec

16 ms binning

From T100_start-5 s to T100_start+5 s

8 ms binning

From T100_start-3 s to T100_start+3 s

2 ms binning

From T100_start-1 s to T100_start+1 s

SN=5 or 10 sec. binning (whichever binning is satisfied first)

SN=5 or 10 sec. binning (T < 200 sec)

Quad-rate summed light curves (from T0-300s to T0+1000s)

Spectral Evolution

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  -38.104 sec. to   27.736 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.24811     ( -0.131383   0.129703 )
Norm@50keV  : 3.09614E-03    ( -0.00023458   0.000234535 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   58.35     using 59 bins.
 Reduced chi-squared = 1.02368
# Null hypothesis probability of 4.26e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 65.84 sec: 0.366080 ( -0.029013  0.029081 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.04136e-06 ( -1.66887e-07  1.67811e-07 ) ergs/cm2

Cutoff power-law model

Time interval is from  -38.104 sec. to   27.736 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.747676     ( -0.610207   0.533795 )
Epeak [keV] : 135.317      ( -47.0126 -135.317 )
Norm@50keV  : 5.33530E-03    ( -0.00228836   0.00478168 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   55.80     using 59 bins.
 Reduced chi-squared = 0.996429
# Null hypothesis probability of 4.82e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 65.84 sec: 0.358251 ( -0.03031  0.030265 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.9824e-06 ( -1.81786e-07  1.8057e-07 ) ergs/cm2

Band function

Time interval is from  -38.104 sec. to   27.736 sec.
 
 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       :    (     )
beta        :     (     )
Epeak [keV] :       (   )
Norm@50keV   :     (     )
------------------------------------------------------------
 
Photon flux (15-150 keV)    in  sec:  (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

Single BB

 
Spectral model blackbody:
------------------------------------------------------------
Parameters  : value    Lower 90%  Upper 90%
kT [keV]    : 18.2340  (-1.67561  1.91454)
R^2/D10^2   : 2.27383E-02  (-0.00654874   0.00885911)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   80.01     using 59 bins.
 Reduced chi-squared = 
# Null hypothesis probability of 2.39e-02 with 57 degrees of freedom
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  9.924e-08   1.560e-08
25- 50  4.634e-07   5.057e-08
50-150  1.122e-06   1.501e-07
15-150  1.685e-06   1.597e-07

Thermal bremsstrahlung (OTTB)

 
 
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT [keV]    : 200.000       (-18.5804      -200)
Norm        : 1.53585       (-0.11799     0.11799)
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   71.80     using 59 bins.
 Reduced chi-squared = 
# Null hypothesis probability of 8.97e-02 with 57 degrees of freedom
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  2.518e-07   2.476e-08
25- 50  4.843e-07   5.982e-08
50-150  1.062e-06   3.476e-07
15-150  1.798e-06   3.598e-07

Double BB

 
 
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT1 [keV]   : 8.53841        (-3.72349      4.51621)
R1^2/D10^2  : 0.149682        (-0.0762933      0.416358)
kT2 [keV]   : 28.8360        (-9.45069      102.878)
R2^2/D10^2  : 3.82350E-03    (-0.002603   0.00754932)
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   57.39     using 59 bins.
 Reduced chi-squared = 
# Null hypothesis probability of 3.87e-01 with 55 degrees of freedom
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  1.693e-07   8.703e-08
25- 50  4.688e-07   2.272e-07
50-150  1.299e-06   6.612e-07
15-150  1.937e-06   9.419e-07

Peak spectrum fit

Power-law model

Time interval is from    2.908 sec. to    3.908 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.03949     ( -0.39163   0.370408 )
Norm@50keV  : 9.40402E-03    ( -0.00201246   0.00198721 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   58.78     using 59 bins.
 Reduced chi-squared = 1.03123
# Null hypothesis probability of 4.10e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 1.08530 ( -0.237225  0.23874 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.00314e-07 ( -2.21998e-08  2.23028e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from    2.908 sec. to    3.908 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.03348     ( -1.47142   3.71149 )
Epeak [keV] : 9998.59      ( -9998.58 -9998.58 )
Norm@50keV  : 9.45844E-03    ( -0.00198332   0.0260524 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   58.78     using 59 bins.
 Reduced chi-squared = 1.04964
# Null hypothesis probability of 3.74e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 1.08518 ( -0.241947  0.23852 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.01559e-07 ( -2.37786e-08  2.07955e-08 ) ergs/cm2

Band function

Time interval is from    2.908 sec. to    3.908 sec.
 
 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       :    (     )
beta        :     (     )
Epeak [keV] :       (   )
Norm@50keV   :     (     )
------------------------------------------------------------
 
Photon flux (15-150 keV)    in  sec:  (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

Single BB

 
Spectral model blackbody:
------------------------------------------------------------
Parameters  : value    Lower 90%  Upper 90%
kT [keV]    : 26.3244  (-6.47333  9.73015)
R^2/D10^2   : 2.21221E-02  (-0.0134369   0.0306276)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   63.38     using 59 bins.
 Reduced chi-squared = 
# Null hypothesis probability of 2.62e-01 with 57 degrees of freedom
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  2.589e-09   1.321e-09
25- 50  1.507e-08   7.071e-09
50-150  7.674e-08   3.580e-08
15-150  9.440e-08   3.854e-08

Thermal bremsstrahlung (OTTB)

 
 
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT [keV]    : 200.000       (-64.1645      -200)
Norm        : 4.51314       (-0.979433     0.979433)
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   64.40     using 59 bins.
 Reduced chi-squared = 
# Null hypothesis probability of 2.34e-01 with 57 degrees of freedom
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  1.124e-08   6.600e-09
25- 50  2.162e-08   1.232e-08
50-150  4.741e-08   2.710e-08
15-150  8.027e-08   4.639e-08

Double BB

 
 
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT1 [keV]   : 5.92548        (-1.97165      3.27583)
R1^2/D10^2  : 1.75428        (-1.51913      5.40932)
kT2 [keV]   : 34.1764        (-9.7449      22.9447)
R2^2/D10^2  : 9.10687E-03    (-0.00689131   0.0130233)
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   55.64     using 59 bins.
 Reduced chi-squared = 
# Null hypothesis probability of 4.50e-01 with 55 degrees of freedom
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  9.567e-09   6.275e-09
25- 50  1.772e-08   9.890e-09
50-150  7.760e-08   4.472e-08
15-150  1.049e-07   5.725e-08

Pre-slew spectrum (Pre-slew PHA with pre-slew DRM)

Power-law model

 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.24811     ( -0.131383   0.129703 )
Norm@50keV  : 3.09614E-03    ( -0.00023458   0.000234535 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   58.35     using 59 bins.
 Reduced chi-squared = 
# Null hypothesis probability of 4.26e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 65.84 sec: 0.366078 ( -0.0290119  0.0290785 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.04114e-06 ( -1.67108e-07  1.6781e-07 ) ergs/cm2

Cutoff power-law model

Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.747673     ( -0.610204   0.533797 )
Epeak [keV] : 135.317      ( -47.0122 -135.317 )
Norm@50keV  : 5.33532E-03    ( -0.00228803   0.00478166 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   55.80     using 59 bins.
 Reduced chi-squared = 
# Null hypothesis probability of 4.82e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 65.84 sec: 0.358227 ( -0.030303  0.030269 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.98324e-06 ( -1.82186e-07  1.80704e-07 ) ergs/cm2

Band function

 
 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       :    (     )
beta        :     (     )
Epeak [keV] :       (   )
Norm@50keV   :     (     )
------------------------------------------------------------
 
Photon flux (15-150 keV)    in  sec:  (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

S(25-50 keV) vs. S(50-100 keV) plot

S(25-50 keV)  = 4.41e-07
S(50-100 keV) = 7.44e-07

T90 vs. Hardness ratio plot

T90                                   = 56.864000082016 sec.
Hardness ratio (energy fluence ratio) = 1.68707

Color vs. Color plot

Count Ratio  (25-50 keV) / (15-25 keV) = 1.78774
Count Ratio (50-100 keV) / (15-25 keV) = 1.66813

Mask shadow pattern

IMX = 7.584960979595232E-02, IMY = -5.414494923853239E-01

TIME vs. PHA plot around the trigger time

TIME vs. DetID plot around the trigger time

100 us light curve (15-350 keV)

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:
-239.864000 -38.104000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.5715 -40.6025    7.4  29.8  -44.4   0.5757   1.6    3.5	Vela X-1                      
123.9868  31.1749    2.2  43.0  143.8   4.0232   5.3 ------	UNKNOWN                       
168.1186 -25.7933    2.6  40.8  -95.8   6.2776   4.4 ------	UNKNOWN

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

Time interval of the image:
-38.104000 27.736000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.6319 -40.5657    5.1  29.8  -44.5   0.3071   2.2    4.8	Vela X-1                      
101.4223   0.7377    0.6  28.7   82.0   2.9987  18.6 ------	UNKNOWN                       
108.4376 -46.6094    2.5  38.4  -10.8   0.6771   4.6 ------	UNKNOWN                       
124.9006 -32.7352    2.4  21.2  -26.0   0.4778   4.8 ------	UNKNOWN

Post-slew image of 15-350 keV band

Time interval of the image:
119.836570 962.216000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6171  22.0329    0.6  27.4   78.3  34.3602  19.5    1.4	Crab                          
 65.1104  -7.5688    2.8  37.1   12.6   7.0479   4.2 ------	UNKNOWN                       
 96.0068 -17.6157    2.7  19.1  -48.0   5.1116   4.3 ------	UNKNOWN                       
148.5026  -3.7379    3.0  47.3 -148.0   9.8156   3.8 ------	UNKNOWN                       
156.0112  -6.5088    2.7  55.0 -145.3  26.2142   4.2 ------	UNKNOWN

Plot creation:
Sun Mar  1 23:10:09 EST 2026