batgrbproduct analysis for trigger=1516528
batgrbproduct Analysis for Trigger=1516528
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): Sun Oct 11 19:24:46 EDT 2026
Host Name: batproc1
Current Working Dir: /local/data/bat1/prebascript/trigger1516528/batgroup_hand_proc
======================================================================
Trigger: 01516528 Segment: 000
BAT Trigger Time: 813352665.92 [s; MET]
Trigger Stop: 813352666.432 [s; MET]
UTC: 2026-10-10T19:17:07.310880 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 248.751603809033 Dec: 26.6091767045418 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 8.94
Image Trigger?: NO
Rate S/N Ratio: 26.944387170615 [ if not an image trigger ]
Image S/N Ratio: 8.94
Flight Position: [ source = BAT ]
RA: 248.751603809033 Dec: 26.6091767045418 [deg; J2000]
Ground Position: [ source = BAT pre-slew burst ]
RA: 248.767294556298 Dec: 26.600367773935 [deg; J2000]
{ 16h 35m 04.2s , +26d 36' 01.3" }
+/- 1.75333806837667 [arcmin] (estimated 90% radius based on SNR)
+/- 0.715467885208547 [arcmin] (formal 1-sigma fit error)
SNR: 13.637628710311
Angular difference between Flight and Ground position is 0.993938 arcmin
Partial Coding Fraction: 0.8359375 [ including projection effects ]
Duration
T90: 71.5040000677109 +/- 14.0730278203181
Measured from: -4.28799998760223
to: 67.2160000801086 [s; relative to TRIGTIME]
T50: 36.3999999761581 +/- 4.65542952101428
Measured from: 1.39200007915497
to: 37.7920000553131 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 0.259999990463257
to: 1.25999999046326 [s; relative to TRIGTIME]
Total Fluence
Measured from: -9.27999997138977
to: 76.4480000734329 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 1.434306 1.819950 1.369880 0.514249
0.116889 0.142888 0.161924 0.136316 [error]
Peak 0.066844 0.168029 0.178290 0.087524
0.013311 0.016498 0.018498 0.015749 [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 3.82e-07 7.30e-07 1.08e-06 3.43e-06 3.05e-06 5.63e-06 erg/cm2
Error 5.29e-08 6.40e-08 1.53e-07 1.02e-06 3.65e-07 1.16e-06 erg/cm2
Peak flux Power-law 6.80e-01 1.02e+00 1.15e+00 2.44e+00 3.58e+00 5.29e+00 ph/cm2/s
Error 1.44e-01 1.32e-01 1.38e-01 6.35e-01 3.86e-01 7.20e-01 ph/cm2/s
Fluence Cutoff-PL 3.85e-07 7.31e-07 1.07e-06 3.09e-06 3.03e-06 5.21e-06 erg/cm2
Error 5.49e-08 5.31e-08 1.53e-07 1.65e-06 3.88e-07 1.56e-06 erg/cm2
Peak flux Cutoff-PL 5.94e-01 1.07e+00 1.22e+00 1.34e+00 3.52e+00 4.22e+00 ph/cm2/s
Error 1.77e-01 1.51e-01 1.74e-01 1.06e+00 3.97e-01 1.15e+00 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 1.435 0.168 - - 3.71e-03 3.73e-04 49.400 57
CPL 1.439 0.170 9999.4 0.0 3.71e-03 2.81e-03 49.410 56
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 0.832 0.184 - - 3.12e-02 3.37e-03 46.260 57
CPL 0.250 0.807 167.2 0.0 5.80e-02 0.00e+00 44.550 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: 37.632000 sec.
T50 in the 50-300 keV band: 20.736000 sec.
=== Table of the duration information ==
Value tstart tstop
T100 85.728 -9.280 76.448
T90 71.504 -4.288 67.216
T50 36.400 1.392 37.792
Peak 1.000 0.260 1.260
Image
Pre-slew 15-350 keV image (Event data; bkg subtracted)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
248.7673 +26.6004 0.0141 15.3 63.1 4.2449 13.6 TRIG_01516528
------------------------------------------
Foreground time interval of the image:
-9.280 33.381 (delta_t = 42.661 [sec])
Background time interval of the image:
-119.920 -9.280 (delta_t = 110.640 [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 -9.280 sec. to 76.448 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.43470 ( -0.165699 0.1712 )
Norm@50keV : 3.70930E-03 ( -0.000376917 0.000369627 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 49.40 using 59 PHA bins.
# Reduced chi-squared = 0.8667 for 57 degrees of freedom
# Null hypothesis probability = 7.525997e-01
Photon flux (15-150 keV) in 85.73 sec: 0.455411 ( -0.0400195 0.0400385 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.05174e-06 ( -3.59911e-07 3.69232e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -9.280 sec. to 76.448 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.43942 ( -0.171625 0.167704 )
Epeak [keV] : 9999.36 ( -9999.36 -9999.36 )
Norm@50keV : 3.70732E-03 ( -0.00200828 0.00362152 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 49.41 using 59 PHA bins.
# Reduced chi-squared = 0.8823 for 56 degrees of freedom
# Null hypothesis probability = 7.207724e-01
Photon flux (15-150 keV) in 85.73 sec: 0.455211 ( -0.039895 0.039763 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.0311e-06 ( -3.86368e-07 3.89746e-07 ) ergs/cm2
Band function
Time interval is from -9.280 sec. to 76.448 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : 3.99566 ( -3.99562 -3.99562 )
beta : -1.48089 ( -0.240061 0.181571 )
Epeak [keV] : 22.7985 ( -22.7966 85.4881 )
Norm@50keV : 107.670 ( -107.697 341576 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.90 using 59 PHA bins.
# Reduced chi-squared = 0.8890 for 55 degrees of freedom
# Null hypothesis probability = 7.056568e-01
Photon flux (15-150 keV) in 85.73 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] : 12.9812 (-1.79 2.12311)
R^2/D10^2 : 8.27708E-02 (-0.0325178 0.0537423)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 84.95 using 59 PHA bins.
# Reduced chi-squared = 1.490 for 57 degrees of freedom
# Null hypothesis probability = 9.592452e-03
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 2.536e-07 4.505e-08
25- 50 8.721e-07 1.055e-07
50-150 9.283e-07 2.241e-07
15-150 2.054e-06 2.799e-07
Thermal bremsstrahlung (OTTB)
XSPEC12>exit
XSPEC: quit
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 200.000 (-55.9143 -200)
Norm : 1.83220 (-0.160855 0.160855)
------------------------------------------------------------
Reduced chi-squared =
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 3.919e-07 1.286e-07
25- 50 7.538e-07 4.044e-07
50-150 1.653e-06 8.743e-07
15-150 2.799e-06 1.483e-06
Double BB
XSPEC12>exit
XSPEC: quit
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 6.60892 (-1.4626 1.72005)
R1^2/D10^2 : 0.597236 (-0.316053 0.470959)
kT2 [keV] : 29.7008 (-7.85193 18.9837)
R2^2/D10^2 : 4.22100E-03 (-0.00321591 0.00449355)
------------------------------------------------------------
Reduced chi-squared =
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 3.874e-07 1.367e-07
25- 50 7.206e-07 2.591e-07
50-150 1.986e-06 1.079e-06
15-150 3.094e-06 1.259e-06
Peak spectrum fit
Power-law model
Time interval is from 0.260 sec. to 1.260 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.831760 ( -0.185612 0.182122 )
Norm@50keV : 3.12026E-02 ( -0.00337388 0.00336745 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 46.26 using 59 PHA bins.
# Reduced chi-squared = 0.8115 for 57 degrees of freedom
# Null hypothesis probability = 8.447117e-01
Photon flux (15-150 keV) in 1 sec: 3.58294 ( -0.385749 0.385799 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.59851e-07 ( -4.49562e-08 4.54281e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.260 sec. to 1.260 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.249804 ( -0.904125 0.709725 )
Epeak [keV] : 167.237 ( )
Norm@50keV : 5.79713E-02 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 44.55 using 59 PHA bins.
# Reduced chi-squared = 0.7956 for 56 degrees of freedom
# Null hypothesis probability = 8.646830e-01
Photon flux (15-150 keV) in 1 sec: 3.51837 ( -0.39832 0.39619 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.47437e-07 ( -5.0121e-08 4.915e-08 ) ergs/cm2
Band function
Time interval is from 0.260 sec. to 1.260 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.967864 ( 0.967696 0.967696 )
beta : -0.831760 ( -0.182143 0.18571 )
Epeak [keV] : 15.3470 ( -15.3465 -15.3465 )
Norm@50keV : 4.34170E-02 ( -0.0155773 789625 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 46.26 using 59 PHA bins.
# Reduced chi-squared = 0.8410 for 55 degrees of freedom
# Null hypothesis probability = 7.933312e-01
Photon flux (15-150 keV) in 1 sec: ( ) ph/cm2/s
Energy fluence (15-150 keV) : 0 ( 0 0 ) ergs/cm2
Single BB
XSPEC: quit
Spectral model blackbody:
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 22.2188 (-3.08717 3.81126)
R^2/D10^2 : 0.130681 (-0.0489854 0.0740071)
(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 1.189e-08 2.655e-09
25- 50 6.321e-08 9.420e-09
50-150 2.332e-07 4.265e-08
15-150 3.083e-07 4.860e-08
Thermal bremsstrahlung (OTTB)
XSPEC12>exit
XSPEC: quit
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 200.000 (-21.5482 -200)
Norm : 12.9981 (-1.51595 1.51595)
------------------------------------------------------------
Reduced chi-squared =
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 3.234e-08 1.790e-08
25- 50 6.222e-08 3.428e-08
50-150 1.365e-07 7.600e-08
15-150 2.310e-07 1.285e-07
Double BB
XSPEC12>exit
XSPEC: quit
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 12.3050 (-5.62794 6.45)
R1^2/D10^2 : 0.452954 (-0.271651 1.36502)
kT2 [keV] : 46.9207 (-27.4173 -49.7786)
R2^2/D10^2 : 1.08268E-02 (-0.00819763 0.0628861)
------------------------------------------------------------
Reduced chi-squared =
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.726e-08 9.645e-09
25- 50 6.654e-08 3.687e-08
50-150 2.665e-07 1.363e-07
15-150 3.503e-07 1.741e-07
Plot creation:
Sun Oct 11 19:32:08 EDT 2026