Analysis for Ground-detected GRB160819A
Analysis Summary
Notes:
- 1) No attempt has been made to eliminate the non-significant decimal places.
- 2) This is a special analysis for ground-detected GRB. The event data duration is likely to be shorter than the burst duration. In such cases, the burst durations are found using the quad-rate data, and spectral analyses are only available for event data range.
- 3) When spectral analysis covers slew times, the analysis uses an average response file made by some sub-response-files with a 5-s time interval during slew times.
==========================================================================
BAT GROUND-DETECTED GRB DATA PROCESSING REPORT
(This burst occurred during telescope slew)
Process Script Ver: batgrbproduct v2.46
Process Start Time: Sat Aug 20 12:52:11 EDT 2016
Host Name: bat1
Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/GRB160819A
======================================================================
Trigger: 00086022 Segment: 006
BAT Trigger Time: 493331254.4
UTC: 20160819T20:27:30.400 [includes UTCF correction]
Where From?: Ground analysis (best_duration.txt)
NOTE: BAT trigger time for ground-detected burst during slew is the T100 start time.
Analysis Position: [ source = GCN ]
RA: 114.13494286 Dec: -22.35165385 [deg; J2000]
Refined Position: [ source = BAT mosaic image ]
RA: 114.138948096313 Dec: -22.3472685705862 [deg; J2000]
{ 07h 36m 33.3s , -22d -20' -50.2" }
+/- 1.01533632758 [arcmin] (estimated 90% radius based on SNR)
SNR: 29.7668204346
Angular difference between the GCN position (ra=114.13494286, dec=-22.35165385 deg) and this refined position is 0.344 arcmin
Partial Coding Fraction: Unavailable because the burst occurred during slew.
Duration
T90: 67.1999999880791 +/- 1.6
Measured from: 3.2
to: 70.4 [s; relative to TRIGTIME]
T50: 35.1999999880791 +/- 1.6
Measured from: 19.2
to: 54.4 [s; relative to TRIGTIME]
=== 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 1.29e-06 2.10e-06 2.59e-06 6.30e-06 7.76e-06 1.23e-05 erg/cm2
Error 7.02e-08 6.68e-08 9.17e-08 5.00e-07 2.25e-07 5.53e-07 erg/cm2
Peak flux Power-law 3.58e+00 3.94e+00 3.09e+00 3.99e+00 1.21e+01 1.46e+01 ph/cm2/s
Error 3.37e-01 2.30e-01 1.82e-01 4.83e-01 6.43e-01 7.54e-01 ph/cm2/s
Fluence Cutoff-PL 1.23e-06 2.12e-06 2.63e-06 4.79e-06 7.66e-06 1.08e-05 erg/cm2
Error 8.96e-08 7.30e-08 1.03e-07 1.27e-06 2.45e-07 1.29e-06 erg/cm2
Peak flux Cutoff-PL 3.30e+00 4.06e+00 3.23e+00 2.74e+00 1.19e+01 1.33e+01 ph/cm2/s
Error 4.20e-01 2.63e-01 2.28e-01 9.86e-01 6.59e-01 1.18e+00 ph/cm2/s
Fluence Band 1.24e-06 2.13e-06 2.70e-06 2.83e-06 3.21e-06 2.27e-06 erg/cm2
Error 4.50e-08 6.49e-08 8.00e-08 -------- -------- -------- erg/cm2
Peak flux Band 1.23e-04 1.65e-05 5.58e-02 1.30e+00 8.75e-02 3.57e+00 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 1.697 0.053 - - 1.78e-02 5.04e-04 48.820 57
CPL 1.489 0.208 133.0 452.8 2.23e-02 4.89e-03 45.770 56
The chi2 of BB fit is Chi-Squared which shows a significant improvement in the fit over a PL.
Check the BB fit.
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.351 0.085 - - 1.00e-01 5.10e-03 65.080 57
CPL 0.972 0.373 147.3 475.2 1.52e-01 6.33e-02 61.820 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
=== Table of the duration information ==
Value tstart tstop
T100 73.600 0.000 73.600
T90 67.200 3.200 70.400
T50 35.200 19.200 54.400
Peak 1.000 46.700 47.700
Image
Note1: The mosaic image is made with timebin = 0.3 s; energybin = 15-350 keV
Note2: The mosaic image uses Galactic coordinate.
#RAcent DECcent POSerr Theta Phi Peak_Cts SNR Name
114.139 -22.347 0.002 29.001 178.669 0.112 29.767 UNKNOWN
Image time interval: 26.600 to 73.600 [sec]
Lightcurves
Notes:
- 1) 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.
- 2) 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 (for the best duration plot, slew times are marked by green arrows).
- 3) For lightcurves in unit of count rate, time of each bin is in the middle of the bin.
Best duration plot
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)
Spectral Evolution
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 26.600 sec. to 73.600 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.69657 ( -0.0524359 0.0525741 )
Norm@50keV : 1.78057E-02 ( -0.000504166 0.000504032 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.82 using 59 PHA bins.
# Reduced chi-squared = 0.8566 for 57 degrees of freedom
# Null hypothesis probability = 7.710943e-01
Photon flux (15-150 keV) in 47 sec: 2.36206 ( -0.07592 0.07622 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.75171e-06 ( -2.2478e-07 2.24891e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 26.600 sec. to 73.600 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.48874 ( -0.212321 0.20291 )
Epeak [keV] : 133.047 ( -41.3425 864.209 )
Norm@50keV : 2.22618E-02 ( -0.00423646 0.00553706 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 45.77 using 59 PHA bins.
# Reduced chi-squared = 0.8173 for 56 degrees of freedom
# Null hypothesis probability = 8.336603e-01
Photon flux (15-150 keV) in 47 sec: 2.32507 ( -0.08324 0.08366 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.6531e-06 ( -2.45157e-07 2.44182e-07 ) ergs/cm2
Band function
Time interval is from 26.600 sec. to 73.600 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.373279 ( -1.65595 3.11713 )
beta : -1.75724 ( 1.75721 0.0730109 )
Epeak [keV] : 39.0868 ( -14.4641 144.013 )
Norm@50keV : 0.127248 ( -0.127458 498.01 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 43.88 using 59 PHA bins.
# Reduced chi-squared = 0.7978 for 55 degrees of freedom
# Null hypothesis probability = 8.592240e-01
Photon flux (15-150 keV) in 47 sec: 2.36206 ( -0.07592 0.07622 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.21253e-06 ( 0 0 ) ergs/cm2
Single BB
Spectral model blackbody:
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 15.2832 ( )
R^2/D10^2 : 0.228953 ( )
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 345.74 using 59 PHA bins.
# Reduced chi-squared = 6.0656 for 57 degrees of freedom
# Null hypothesis probability = 5.978517e-43
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 5.245e-07 3.078e-08
25- 50 2.120e-06 8.836e-08
50-150 3.398e-06 1.732e-07
15-150 6.042e-06 1.950e-07
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 150.425 (-17.2751 26.3228)
Norm : 9.60523 (-0.38292 0.359655)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.37 using 59 PHA bins.
# Reduced chi-squared = 0.8486 for 57 degrees of freedom
# Null hypothesis probability = 7.851994e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.141e-06 6.674e-08
25- 50 2.129e-06 1.177e-07
50-150 4.277e-06 9.670e-07
15-150 7.548e-06 1.072e-06
Double BB
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 7.10152 (-0.638211 0.68636)
R1^2/D10^2 : 2.50730 (-0.696423 1.03782)
kT2 [keV] : 26.1640 (-2.28608 2.92225)
R2^2/D10^2 : 2.54902E-02 (-0.00830269 0.0106717)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 46.98 using 59 PHA bins.
# Reduced chi-squared = 0.8542 for 55 degrees of freedom
# Null hypothesis probability = 7.706377e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.108e-06 1.100e-07
25- 50 2.171e-06 1.321e-07
50-150 4.300e-06 3.194e-07
15-150 7.579e-06 4.841e-07
Peak spectrum fit
Power-law model
Time interval is from 0.000 sec. to 0.000 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.35150 ( -0.0850684 0.0850586 )
Norm@50keV : 0.100350 ( -0.00510207 0.00510169 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 65.08 using 59 PHA bins.
# Reduced chi-squared = 1.142 for 57 degrees of freedom
# Null hypothesis probability = 2.159656e-01
Photon flux (15-150 keV) in 1 sec: 12.0931 ( -0.6426 0.6435 ) ph/cm2/s
Energy fluence (15-150 keV) : 9.79873e-07 ( -5.37045e-08 5.38639e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.000 sec. to 0.000 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.972296 ( -0.38815 0.357201 )
Epeak [keV] : 147.328 ( -48.7398 901.706 )
Norm@50keV : 0.152053 ( -0.048305 0.0782101 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 61.82 using 59 PHA bins.
# Reduced chi-squared = 1.104 for 56 degrees of freedom
# Null hypothesis probability = 2.761495e-01
Photon flux (15-150 keV) in 1 sec: 11.9369 ( -0.659 0.6596 ) ph/cm2/s
Energy fluence (15-150 keV) : 9.64784e-07 ( -5.65244e-08 5.6226e-08 ) ergs/cm2
Band function
Time interval is from 0.000 sec. to 0.000 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.582486 ( -0.577629 1.09719 )
beta : -1.61025 ( -0.701648 0.214493 )
Epeak [keV] : 86.8396 ( -39.8932 109.719 )
Norm@50keV : 0.250466 ( -0.128598 1.11684 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 59.51 using 59 PHA bins.
# Reduced chi-squared = 1.082 for 55 degrees of freedom
# Null hypothesis probability = 3.150191e-01
Photon flux (15-150 keV) in 1 sec: 8.74677E-02 ( ) ph/cm2/s
Energy fluence (15-150 keV) : 7.1715e-08 ( 0 0 ) ergs/cm2
Single BB
Spectral model blackbody:
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 17.1731 ( )
R^2/D10^2 : 0.916710 ( )
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 129.29 using 59 PHA bins.
# Reduced chi-squared = 2.2682 for 57 degrees of freedom
# Null hypothesis probability = 1.546874e-07
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 5.490e-08 5.435e-09
25- 50 2.449e-07 1.945e-08
50-150 5.173e-07 4.715e-08
15-150 8.171e-07 4.905e-08
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 200.000 (-11.5965 -200)
Norm : 50.5890 (-2.58867 2.58867)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 79.61 using 59 PHA bins.
# Reduced chi-squared = 1.397 for 57 degrees of freedom
# Null hypothesis probability = 2.561814e-02
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.260e-07 7.450e-09
25- 50 2.424e-07 1.305e-08
50-150 5.316e-07 2.950e-08
15-150 9.000e-07 5.325e-08
Double BB
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 10.7467 (-2.13645 1.95883)
R1^2/D10^2 : 3.18651 (-1.06765 2.28842)
kT2 [keV] : 44.0721 (-16.3219 96.0422)
R2^2/D10^2 : 2.75511E-02 (-0.0191559 0.0719467)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 63.91 using 59 PHA bins.
# Reduced chi-squared = 1.162 for 55 degrees of freedom
# Null hypothesis probability = 1.920471e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 8.294e-08 1.602e-08
25- 50 2.549e-07 4.290e-08
50-150 6.172e-07 2.433e-07
15-150 9.551e-07 2.695e-07
Webpage updated on:
Sat Aug 20 14:36:16 EDT 2016