batgrbproduct analysis for trigger=1516664

batgrbproduct Analysis for Trigger=1516664

Analysis Summary

Notes:

1) No attempt has been made to eliminate the non-significant decimal places.
2) This batgrbproduct analysis is done of the amount of data for this trigger downloaded to date.
3) This batgrbproduct analysis is using the flight position for the mask-weighting calculation.
4) This page will be updated for up to 15 downlinks after the trigger.

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.48
    Process Start Time (local time): Mon Oct 12 16:41:38 EDT 2026
             Host Name: batproc1
   Current Working Dir: /local/data/bat1/prebascript/trigger1516664/batgroup_hand_proc
======================================================================

  Trigger: 01516664      Segment: 000

  BAT Trigger Time: 813419240   [s; MET]
      Trigger Stop: 813419440   [s; MET]
               UTC: 2026-10-11T13:46:41.386400    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 21.9249299867221   Dec: -21.5287283535641  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    10.92
     Image Trigger?:     YES
     Rate S/N Ratio:     0  [ if not an image trigger ]
     Image S/N Ratio:    10.92

  Flight Position:   [ source = BAT ]
    RA: 21.9249299867221   Dec: -21.5287283535641  [deg; J2000]

  Ground Position:   [ source = BAT pre-slew burst ]
    RA: 21.9110460363436   Dec: -21.5502077381543  [deg; J2000]  
        { 01h 27m 38.7s , -21d 33' 00.7" }
         +/- 1.02421549523504 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.231273245897613 [arcmin] (formal 1-sigma fit error)
    SNR: 29.3950095614199
 
  Angular difference between Flight and Ground position is 1.503769 arcmin
 
  Partial Coding Fraction: 0.296875    [ including projection effects ]

  Duration
     T90: 78.8960000276566 +/- 18.4929702170934
        Measured from: 125.639999985695
                   to: 204.536000013351     [s; relative to TRIGTIME]
     T50: 28.9919999837875 +/- 2.26240234179747
        Measured from: 157.960000038147
                   to: 186.952000021935     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 171.740000009537     
                   to: 172.740000009537     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: 103.608000040054     
                   to: 208.743999958038     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     2.521649   3.574844   2.699858   0.746800
           0.119443   0.127541   0.106840   0.082737 [error]
 Peak      0.085390   0.130776   0.119527   0.029607
           0.013901   0.015993   0.014018   0.010945 [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 8.38e-07 1.54e-06 2.19e-06 6.51e-06 6.25e-06 1.11e-05   erg/cm2
              Error 6.41e-08 7.00e-08 1.07e-07 7.12e-07 2.65e-07 7.76e-07   erg/cm2
Peak flux Power-law 9.20e-01 9.86e-01 7.51e-01 9.32e-01 3.01e+00 3.59e+00   ph/cm2/s
              Error 1.93e-01 1.33e-01 1.13e-01 2.77e-01 3.81e-01 4.58e-01   ph/cm2/s
 
Fluence   Cutoff-PL 7.89e-07 1.58e-06 2.24e-06 4.48e-06 6.15e-06 9.09e-06   erg/cm2
              Error 7.98e-08 7.90e-08 1.22e-07 -------- 2.85e-07 1.67e-06   erg/cm2
Peak flux Cutoff-PL 7.93e-01 1.08e+00 8.12e-01 3.84e-01 2.94e+00 3.07e+00   ph/cm2/s
              Error 2.27e-01 1.70e-01 1.34e-01 -------- 3.90e-01 5.20e-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    1.498    0.072    -      -           6.26e-03 2.51e-04   70.500 57
CPL   1.217    0.289     150.5 1191.2      8.49e-03 2.70e-03   67.630 56
 
 
=== 1-s peak spectral analysis ===
 
Model Ph_index Ph_90err Epeak  Epeak_90err Norm     Nomr_90err chi2   dof
PL    1.393    0.198    -      -           2.48e-02 3.11e-03   64.900 57
CPL   0.499    0.974      83.7  232.1      7.09e-02 1.12e-01   61.690 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: 58.624000 sec.
T50 in the 50-300 keV band: 25.536000 sec.

 
=== Table of the duration information ==
 
        Value   tstart    tstop
T100  105.136  103.608  208.744
T90    78.896  125.640  204.536
T50    28.992  157.960  186.952
Peak    1.000  171.740  172.740

Click here for the BAT GCN circular template

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

Image

Pre-slew 15-350 keV image (Event data; bkg subtracted)

#   RAcent  DECcent POSerr  Theta    Phi     Peak Cts     SNR  Name
   21.9110 -21.5502 0.0066   34.6  129.5      10.0510    29.4  TRIG_01516664       
------------------------------------------
 
Foreground time interval of the image:
103.608 208.301 (delta_t = 104.693 [sec])
Background time interval of the image:
-179.000 103.608 (delta_t = 282.608 [sec])

Lightcurves

Notes:

1) All plots contain as much data as has been downloaded to date.
2) The mask-weighted light curves are using the flight position.
3) Multiple plots of different time binning/intervals are shown to cover all scenarios of short/long GRBs, rate/image triggers, and real/false positives.
4) 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.
5) 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.
6) 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)

Spectra

Notes:

1) The fitting includes the systematic errors.
2) For long bursts, a spectral fit of 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.
4) For short bursts (T90<1sec), the specrtum is also fit with Blackbody, OTTB, and Double Blackbody.

Time averaged spectrum fit using the pre-slew DRM

Power-law model

Time interval is from  103.608 sec. to  208.744 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.49759     ( -0.071882   0.0718477 )
Norm@50keV  : 6.26222E-03    ( -0.000251451   0.000251399 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          70.50 using 59 PHA bins.
# Reduced chi-squared =          1.237 for     57 degrees of freedom 
# Null hypothesis probability =   1.078846e-01
 
Photon flux (15-150 keV)    in 105.1 sec: 0.781264 ( -0.0339995  0.0340926 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.24608e-06 ( -2.64907e-07  2.65373e-07 ) ergs/cm2

Cutoff power-law model

Time interval is from  103.608 sec. to  208.744 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.21701     ( -0.301121   0.275904 )
Epeak [keV] : 150.466      ( -51.3994 2331.06 )
Norm@50keV  : 8.49253E-03    ( -0.00220842   0.00318163 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          67.63 using 59 PHA bins.
# Reduced chi-squared =          1.208 for     56 degrees of freedom 
# Null hypothesis probability =   1.372496e-01
 
Photon flux (15-150 keV)    in 105.1 sec: 0.768552 ( -0.036127  0.036218 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.14777e-06 ( -2.86114e-07  2.84853e-07 ) ergs/cm2

Band function

Time interval is from  103.608 sec. to  208.744 sec.
 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       : -0.905014   ( -0.473556   1.69976 )
beta        : -1.62915    ( 1.62957   0.139816 )
Epeak [keV] : 79.7924      ( -46.0989 243.256 )
Norm@50keV   : 1.31013E-02    ( -0.00669592   0.100511 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          67.12 using 59 PHA bins.
# Reduced chi-squared =          1.220 for     55 degrees of freedom 
# Null hypothesis probability =   1.266486e-01
 
Photon flux (15-150 keV)    in 105.1 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]    : 16.3922  (  )
R^2/D10^2   : 6.40720E-02  (   )
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared =         196.17 using 59 PHA bins.
# Reduced chi-squared =         3.4415 for     57 degrees of freedom 
# Null hypothesis probability =   3.579540e-17
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  3.720e-07   2.959e-08
25- 50  1.598e-06   8.776e-08
50-150  3.028e-06   2.091e-07
15-150  4.998e-06   2.107e-07

Thermal bremsstrahlung (OTTB)

XSPEC12>exit
 XSPEC: quit
 
 
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT [keV]    : 200.000       (-17.2758      -200)
Norm        : 3.21761       (-0.12902     0.12902)
------------------------------------------------------------
 Reduced chi-squared = 
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  8.421e-07   4.078e-08
25- 50  1.620e-06   6.674e-08
50-150  3.553e-06   1.619e-07
15-150  6.015e-06   2.628e-07

Double BB

XSPEC12>exit
 XSPEC: quit
 
 
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT1 [keV]   : 7.99989        (-1.20875      1.26619)
R1^2/D10^2  : 0.497047        (-0.181827      0.35185)
kT2 [keV]   : 29.0074        (-4.21615      6.62353)
R2^2/D10^2  : 6.78237E-03    (-0.00347361   0.00539267)
------------------------------------------------------------
 Reduced chi-squared = 
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  7.003e-07   1.059e-07
25- 50  1.641e-06   1.939e-07
50-150  3.783e-06   6.464e-07
15-150  6.124e-06   7.982e-07

Peak spectrum fit

Power-law model

Time interval is from  171.740 sec. to  172.740 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.39308     ( -0.19845   0.198472 )
Norm@50keV  : 2.47545E-02    ( -0.00311233   0.00310471 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          64.90 using 59 PHA bins.
# Reduced chi-squared =          1.139 for     57 degrees of freedom 
# Null hypothesis probability =   2.206734e-01
 
Photon flux (15-150 keV)    in 1 sec: 3.00994 ( -0.380997  0.381458 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.39534e-07 ( -3.28306e-08  3.31025e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from  171.740 sec. to  172.740 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.499191     ( -1.09462   0.853745 )
Epeak [keV] : 83.7004      ( -23.4528 440.81 )
Norm@50keV  : 7.09249E-02    ( -0.0443754   0.180297 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          61.69 using 59 PHA bins.
# Reduced chi-squared =          1.102 for     56 degrees of freedom 
# Null hypothesis probability =   2.799177e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.93932 ( -0.39048  0.38934 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.26817e-07 ( -3.5798e-08  3.5859e-08 ) ergs/cm2

Band function

Time interval is from  171.740 sec. to  172.740 sec.
 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       : 3.97008E-02   ( -1.12706   -0.036437 )
beta        : -1.98112    ( 1.97493   0.58454 )
Epeak [keV] : 64.0061      ( -38.0073 108.716 )
Norm@50keV   : 0.146950    ( -0.14538   435.344 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          60.95 using 59 PHA bins.
# Reduced chi-squared =          1.108 for     55 degrees of freedom 
# Null hypothesis probability =   2.706826e-01
 
Photon flux (15-150 keV)    in 1 sec:  (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.28371e-07 ( -2.28364e-07  -3.4277e-08 ) ergs/cm2

Single BB

 XSPEC: quit
 
 
Spectral model blackbody:
------------------------------------------------------------
Parameters  : value    Lower 90%  Upper 90%
kT [keV]    : 15.3310  (-2.02547  2.45589)
R^2/D10^2   : 0.339113  (-0.138654   0.218953)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
 Reduced chi-squared = 
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  1.662e-08   4.400e-09
25- 50  6.738e-08   1.230e-08
50-150  1.088e-07   2.543e-08
15-150  1.928e-07   3.130e-08

Thermal bremsstrahlung (OTTB)

XSPEC12>exit
 XSPEC: quit
 
 
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT [keV]    : 200.000       (-58.5943      -200)
Norm        : 12.5189       (-1.55361     1.55361)
------------------------------------------------------------
 Reduced chi-squared = 
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  3.118e-08   1.743e-08
25- 50  5.997e-08   3.306e-08
50-150  1.315e-07   7.270e-08
15-150  2.227e-07   1.227e-07

Double BB

XSPEC12>exit
 XSPEC: quit
 
 
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT1 [keV]   : 10.7744        (-6.15286      3.81111)
R1^2/D10^2  : 0.837641        (-0.475214      0.797044)
kT2 [keV]   : 37.8117        (-33.4584      -38.0073)
R2^2/D10^2  : 9.20810E-03    (-0.0088781   0.19225)
------------------------------------------------------------
 Reduced chi-squared = 
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  2.222e-08   1.206e-08
25- 50  6.725e-08   3.652e-08
50-150  1.412e-07   7.539e-08
15-150  2.307e-07   1.118e-07

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: 1.49264     ( -0.0721367   0.0720887 )
Norm@50keV  : 6.25094E-03    ( -0.000251718   0.000251675 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          68.44 using 59 PHA bins.
# Reduced chi-squared =          1.201 for     57 degrees of freedom 
# Null hypothesis probability =   1.426666e-01
 
Photon flux (15-150 keV)    in 104.7 sec: 0.778828 ( -0.0340093  0.0341023 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.21619e-06 ( -2.64423e-07  2.64877e-07 ) ergs/cm2

Cutoff power-law model

Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.22005     ( -0.301464   0.27343 )
Epeak [keV] : 154.485      ( -54.1515 -154.485 )
Norm@50keV  : 8.40130E-03    ( -0.00217701   0.00314709 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          65.74 using 59 PHA bins.
# Reduced chi-squared =          1.174 for     56 degrees of freedom 
# Null hypothesis probability =   1.752520e-01
 
Photon flux (15-150 keV)    in 104.7 sec: 0.766521 ( -0.03613  0.036259 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.12154e-06 ( -2.85297e-07  2.84135e-07 ) ergs/cm2

Band function

 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       : -0.913031   ( -0.450005   1.95714 )
beta        : -1.61902    ( 1.62055   0.139653 )
Epeak [keV] : 80.7516      ( -47.8081 300.159 )
Norm@50keV   : 1.28821E-02    ( -0.00647194   0.0969661 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          65.26 using 59 PHA bins.
# Reduced chi-squared =          1.186 for     55 degrees of freedom 
# Null hypothesis probability =   1.621749e-01
 
Photon flux (15-150 keV)    in 104.7 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)  = 1.54e-06
S(50-100 keV) = 2.19e-06

T90 vs. Hardness ratio plot

T90                                   = 78.8960000276566 sec.
Hardness ratio (energy fluence ratio) = 1.42208

Color vs. Color plot

Count Ratio  (25-50 keV) / (15-25 keV) = 1.41766
Count Ratio (50-100 keV) / (15-25 keV) = 1.07067

Mask shadow pattern

IMX = -4.390715900811846E-01, IMY = -5.332293944345299E-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:
-179.000000 103.608000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
320.7229   2.3833    2.8  41.0    9.0   2.3493   4.1 ------	UNKNOWN                       
289.9725 -20.0633    2.7  50.0  -43.3   6.5367   4.3 ------	UNKNOWN                       
289.2242 -22.8347    2.4  49.5  -47.0   7.8165   4.8 ------	UNKNOWN

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

Time interval of the image:
103.608000 208.300600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 21.9109 -21.5501    0.4  34.6  129.5  10.0465  29.4 ------	UNKNOWN                       
 48.7024 -55.2112    2.6  49.9 -174.9   1.5194   4.4 ------	UNKNOWN                       
305.1827   1.3143    2.4  49.9   -9.0   1.5300   4.9 ------	UNKNOWN

Post-slew image of 15-350 keV band

Time interval of the image:
300.500600 723.183100
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
320.6510 -20.0910    2.6  56.9    0.0   9.3981   4.4 ------	UNKNOWN                       
331.2579 -54.2039    2.3  50.0  -43.2  10.9900   4.9 ------	UNKNOWN                       
327.6689 -53.2669    2.3  51.7  -41.2  13.2003   5.1 ------	UNKNOWN

Plot creation:
Mon Oct 12 16:48:40 EDT 2026