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