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 v2.46
Process Start Time: Thu May 31 13:23:52 EDT 2018
Host Name: bat1
Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger831816
======================================================================
Trigger: 00831816 Segment: 000
BAT Trigger Time: 547676163.2 [s; MET]
Trigger Stop: 547676167.296 [s; MET]
UTC: 2018-05-10T20:15:42.277740 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 77.9887913665582 Dec: -62.3350422840413 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 9.44
Image Trigger?: NO
Rate S/N Ratio: 9.64365076099295 [ if not an image trigger ]
Image S/N Ratio: 9.44
Analysis Position: [ source = BAT ]
RA: 77.9887913665582 Dec: -62.3350422840413 [deg; J2000]
Refined Position: [ source = BAT pre-slew burst ]
RA: 77.9617891654031 Dec: -62.3194091474247 [deg; J2000]
{ 05h 11m 50.8s , -62d 19' 09.9" }
+/- 1.67525278281714 [arcmin] (estimated 90% radius based on SNR)
+/- 0.627700451976007 [arcmin] (formal 1-sigma fit error)
SNR: 14.5547113561785
Angular difference between the analysis and refined position is 1.202482 arcmin
Partial Coding Fraction: 0.4101562 [ including projection effects ]
Duration
T90: 134.016000032425 +/- 52.9225468980937
Measured from: -13.1680001020432
to: 120.847999930382 [s; relative to TRIGTIME]
T50: 28.8639999628067 +/- 7.80978659114986
Measured from: 0.991999983787537
to: 29.8559999465942 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 0.96399998664856
to: 1.96399998664856 [s; relative to TRIGTIME]
Total Fluence
Measured from: -19.9200000762939
to: 137.103999972343 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 1.355591 1.686391 0.775132 0.207374
0.121460 0.123199 0.103869 0.088842 [error]
Peak 0.040811 0.059284 0.044886 -0.002253
0.010340 0.010709 0.009052 0.007472 [error]
[ fluence units of on-axis counts / fully illuminated detector ]
======================================================================
====== Table of the duration information =============================
Value tstart tstop
T100 157.024 -19.920 137.104
T90 134.016 -13.168 120.848
T50 28.864 0.992 29.856
Peak 1.000 0.964 1.964
====== Spectral Analysis Summary =====================================
Model : spectral model: simple power-law (PL) and cutoff power-law (CPL)
Ph_index : photon index: E^{Ph_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 both the PL model and CPL model
Nomr_90err : 90% error of the normalization
chi2 : Chi-Squared
dof : degree of freedo
=== Time-averaged spectral analysis ===
(Best model with acceptable fit: PL)
Model Ph_index Ph_90err_low Ph_90err_hi Epeak Epeak_90err_low Epeak_90err_hi Norm Nomr_90err_low Norm_90err_hi chi2 dof
PL -2.014 -0.176 0.168 - - - 1.46e-03 -1.68e-04 1.64e-04 46.250 57
CPL -2.012 -0.067 1.299 9999.200 N/A N/A 1.47e-03 N/A N/A 46.250 56
=== 1-s peak spectral analysis ===
(Best model with acceptable fit: N/A)
Model Ph_index Ph_90err_low Ph_90err_hi Epeak Epeak_90err_low Epeak_90err_hi Norm Nomr_90err_low Norm_90err_hi chi2 dof
PL -1.663 -0.360 0.345 - - - 9.28e-03 -2.06e-03 2.01e-03 72.680 57
CPL -1.336 -0.946 1.458 95.411 -95.411 -95.411 1.39e-02 -1.39e-02 7.03e-02 72.470 56
=== 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 PL 4.77e-07 6.42e-07 6.35e-07 1.13e-06 2.12e-06 2.89e-06 erg/cm2
90%_error_low -6.12e-08 -5.79e-08 -9.84e-08 -3.14e-07 -2.26e-07 -4.31e-07 erg/cm2
90%_error_hi 6.26e-08 5.80e-08 1.00e-07 3.87e-07 2.30e-07 4.85e-07 erg/cm2
Peak flux PL 4.47e-01 4.09e-01 2.58e-01 2.49e-01 1.22e+00 1.36e+00 ph/cm2/s
90%_error_low -1.38e-01 -8.53e-02 -7.23e-02 -1.15e-01 -2.50e-01 -2.79e-01 ph/cm2/s
90%_error_hi 1.48e-01 8.46e-02 7.17e-02 1.61e-01 2.50e-01 2.81e-01 ph/cm2/s
Fluence CPL 4.61e-07 6.76e-07 6.18e-07 5.06e-07 2.02e-06 2.26e-06 erg/cm2
90%_error_low -6.71e-08 -8.71e-08 -1.22e-07 -3.64e-07 -2.75e-07 -4.73e-07 erg/cm2
90%_error_hi 6.75e-08 8.30e-08 1.10e-07 9.72e-07 2.79e-07 1.16e-06 erg/cm2
Peak flux CPL 4.28e-01 4.25e-01 2.64e-01 1.66e-01 1.21e+00 1.28e+00 ph/cm2/s
90%_error_low -1.56e-01 -9.81e-02 -7.56e-02 -1.66e-01 -2.53e-01 -3.01e-01 ph/cm2/s
90%_error_hi 1.59e-01 1.08e-01 7.97e-02 1.22e-01 2.54e-01 3.48e-01 ph/cm2/s
======================================================================
Image
Pre-slew 15.0-350.0 keV image (Event data)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name 77.9618 -62.3194 0.0132 29.6528 -103.8504 4.3238461 14.555 TRIG_00831816 Foreground time interval of the image: -19.920 137.104 (delta_t = 157.024 [sec]) Background time interval of the image: -239.200 -19.920 (delta_t = 219.280 [sec])
Light Curves
Note: 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.
Full-time range; 1 s binning
Other quick-look light curves:
- 64 ms binning (zoomed)
- 16 ms binning (zoomed)
- 8 ms binning (zoomed)
- 2 ms binning (zoomed)
- SN=5 or 10 s binning (full-time range)
- Raw light curve
Spectra
- 64 ms binning (zoomed)
- 16 ms binning (zoomed)
- 8 ms binning (zoomed)
- 2 ms binning (zoomed)
- SN=5 or 10 s binning (full-time range)
- Raw light curve
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 -19.920 sec. to 137.104 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -2.01391 ( -0.175944 0.168211 ) Norm@50keV : 1.46460E-03 ( -0.000167575 0.000164254 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 46.25 using 59 PHA bins. # Reduced chi-squared = 0.8113 for 57 degrees of freedom # Null hypothesis probability = 8.449724e-01 Photon flux (15-150 keV) in 157 sec: 0.221123 ( -0.020023 0.020033 ) ph/cm2/s Energy fluence (15-150 keV) : 2.12251e-06 ( -2.25548e-07 2.29715e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -19.920 sec. to 137.104 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.57317 ( -0.504956 0.86097 ) Epeak [keV] : 39.6227 ( ) Norm@50keV : 2.65336E-03 ( ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 45.09 using 59 PHA bins. # Reduced chi-squared = 0.8052 for 56 degrees of freedom # Null hypothesis probability = 8.513575e-01 Photon flux (15-150 keV) in 157 sec: 0.217285 ( -0.02095 0.020906 ) ph/cm2/s Energy fluence (15-150 keV) : 2.01981e-06 ( -2.74667e-07 2.78881e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.964 sec. to 1.964 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.66318 ( -0.360384 0.345225 ) Norm@50keV : 9.28494E-03 ( -0.00206269 0.00201206 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 72.68 using 59 PHA bins. # Reduced chi-squared = 1.275 for 57 degrees of freedom # Null hypothesis probability = 7.874071e-02 Photon flux (15-150 keV) in 1 sec: 1.21775 ( -0.249739 0.25004 ) ph/cm2/s Energy fluence (15-150 keV) : 8.62561e-08 ( -1.98619e-08 2.02464e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.964 sec. to 1.964 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.33604 ( -0.94639 1.45794 ) Epeak [keV] : 95.4111 ( -95.4111 -95.4111 ) Norm@50keV : 1.39286E-02 ( -0.0139286 0.0703357 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 72.47 using 59 PHA bins. # Reduced chi-squared = 1.294 for 56 degrees of freedom # Null hypothesis probability = 6.853521e-02 Photon flux (15-150 keV) in 1 sec: 1.20599 ( -0.253492 0.25354 ) ph/cm2/s Energy fluence (15-150 keV) : 8.41395e-08 ( -2.12845e-08 2.12895e-08 ) ergs/cm2
Time-resolved spectra
Distribution
T90 vs. Hardness ratio plot
T90 = 134.016 sec. Hardness ratio (energy fluence ratio) = 0.990444243983
S(15-50 keV) vs. S(50-150 keV) plot
S(15-50 keV) = 1.1183119e-06 S(50-150 keV) = 1.0042218e-06
The dash-dotted line and the dashed line traces the fluences calculated from the Band function with Epeak = 15 and 150 keV, respectively. Both lines assume a canonical values of alpha = -1 and beta = -2.5.
Mask shadow pattern
IMX = -1.362833035213309E-01, IMY = 5.527449941697828E-01
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: -239.200000 -19.920000 # RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name # [deg] [deg] ['] [deg] [deg] ['] 135.5219 -40.5346 1.5 27.1 -11.7 1.7423 7.5 1.2 Vela X-1 170.2985 -60.6388 1.1 10.7 79.8 2.1104 10.5 1.1 Cen X-3 186.5890 -62.7958 2.3 15.9 107.0 1.1129 5.0 2.4 GX 301-2 243.7065 -54.9592 2.3 42.7 135.2 3.1878 5.0 ------ UNKNOWN 215.3151 -62.6933 1.1 27.0 126.3 3.0266 10.8 ------ UNKNOWN 296.8690 -66.7000 3.1 44.8 175.1 1.6668 3.7 ------ UNKNOWN
Pre-slew background subtracted image of 15-350 keV band
Time interval of the image: -19.920000 137.104000 # RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name # [deg] [deg] ['] [deg] [deg] ['] 135.5888 -40.6253 6.0 27.0 -11.6 0.3952 1.9 5.0 Vela X-1 169.9351 -60.6039 5.1 10.6 79.0 -0.3914 -2.3 11.3 Cen X-3 187.0189 -62.7230 7.8 16.1 107.1 0.2959 1.5 10.3 GX 301-2 241.0123 -54.4339 2.4 42.2 132.9 2.6371 4.8 ------ UNKNOWN 210.8343 -59.1936 2.4 27.5 117.3 1.2840 4.8 ------ UNKNOWN 77.9618 -62.3194 0.8 29.7 -103.9 4.3238 14.5 ------ UNKNOWN
Post-slew image of 15-350 keV band
Time interval of the image: