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 13:25:50 EDT 2018
Host Name: bat1
Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger831810
======================================================================
Trigger: 00831810 Segment: 000
BAT Trigger Time: 547673095.232 [s; MET]
Trigger Stop: 547673096.256 [s; MET]
UTC: 2018-05-10T19:24:34.309920 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 276.318496902141 Dec: -31.9109448076993 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 11.84
Image Trigger?: NO
Rate S/N Ratio: 22.9128784747792 [ if not an image trigger ]
Image S/N Ratio: 11.84
Analysis Position: [ source = BAT ]
RA: 276.318496902141 Dec: -31.9109448076993 [deg; J2000]
Refined Position: [ source = BAT pre-slew burst ]
RA: 276.338636377679 Dec: -31.917968500946 [deg; J2000]
{ 18h 25m 21.3s , -31d 55' 04.7" }
+/- 0.859859238158921 [arcmin] (estimated 90% radius based on SNR)
+/- 0.302521840957937 [arcmin] (formal 1-sigma fit error)
SNR: 37.739277165375
Angular difference between the analysis and refined position is 1.108908 arcmin
Partial Coding Fraction: 0.3789062 [ including projection effects ]
Duration
T90: 64 +/- 16
Measured from: -15.2319999933243
to: 48.7680000066757 [s; relative to TRIGTIME]
T50: 16 +/- 16
Measured from: 0.76800000667572
to: 16.7680000066757 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 8.26800000667572
to: 9.26800000667572 [s; relative to TRIGTIME]
Total Fluence
Measured from: -15.2319999933243
to: 64.7680000066757 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 2.307364 3.447369 2.979017 0.746756
0.097345 0.098385 0.084255 0.062077 [error]
Peak 0.086244 0.154273 0.124640 0.054110
0.014326 0.015080 0.013579 0.009418 [error]
[ fluence units of on-axis counts / fully illuminated detector ]
======================================================================
====== Table of the duration information =============================
Value tstart tstop
T100 80.000 -15.232 64.768
T90 64.000 -15.232 48.768
T50 16.000 0.768 16.768
Peak 1.000 8.268 9.268
====== 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: CPL)
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 -1.458 -0.058 0.058 - - - 8.28e-03 -2.64e-04 2.64e-04 65.360 57
CPL -1.035 -0.234 0.247 127.708 -27.413 84.388 1.29e-02 -2.71e-03 3.64e-03 55.440 56
=== 1-s peak 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 -1.216 -0.183 0.186 - - - 2.88e-02 -3.01e-03 3.00e-03 51.230 57
CPL -1.175 -0.224 0.497 999.907 -999.907 -999.907 3.03e-02 N/A N/A 51.370 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 8.13e-07 1.53e-06 2.23e-06 6.92e-06 6.33e-06 1.15e-05 erg/cm2
90%_error_low -5.07e-08 -5.72e-08 -8.50e-08 -5.76e-07 -2.11e-07 -6.26e-07 erg/cm2
90%_error_hi 5.19e-08 5.70e-08 8.48e-08 6.10e-07 2.12e-07 6.53e-07 erg/cm2
Peak flux PL 9.03e-01 1.08e+00 9.27e-01 1.36e+00 3.39e+00 4.27e+00 ph/cm2/s
90%_error_low -1.85e-01 -1.40e-01 -1.07e-01 -3.12e-01 -3.74e-01 -4.52e-01 ph/cm2/s
90%_error_hi 1.99e-01 1.38e-01 1.06e-01 3.64e-01 3.75e-01 4.55e-01 ph/cm2/s
Fluence CPL 7.32e-07 1.57e-06 2.32e-06 4.16e-06 6.19e-06 8.79e-06 erg/cm2
90%_error_low -6.48e-08 -6.24e-08 -9.93e-08 -9.48e-07 -2.27e-07 -9.63e-07 erg/cm2
90%_error_hi 6.63e-08 6.28e-08 1.00e-07 1.30e-06 2.26e-07 1.30e-06 erg/cm2
Peak flux CPL 9.02e-01 1.07e+00 9.25e-01 1.43e+00 3.40e+00 4.34e+00 ph/cm2/s
90%_error_low N/A -1.51e-01 N/A N/A N/A -8.07e-01 ph/cm2/s
90%_error_hi N/A 1.55e-01 N/A N/A N/A 3.82e-01 ph/cm2/s
======================================================================
Image
Pre-slew 15.0-350.0 keV image (Event data)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name 276.3386 -31.9180 0.0051 34.4327 45.0793 6.0965620 37.739 TRIG_00831810 Foreground time interval of the image: -15.232 11.069 (delta_t = 26.301 [sec]) Background time interval of the image: -239.232 -15.232 (delta_t = 224.000 [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 -15.232 sec. to 64.768 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.45827 ( -0.0575513 0.0575992 ) Norm@50keV : 8.27748E-03 ( -0.000264413 0.00026441 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 65.36 using 59 PHA bins. # Reduced chi-squared = 1.147 for 57 degrees of freedom # Null hypothesis probability = 2.091905e-01 Photon flux (15-150 keV) in 80 sec: 1.02222 ( -0.036004 0.03611 ) ph/cm2/s Energy fluence (15-150 keV) : 6.32805e-06 ( -2.1145e-07 2.11685e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -15.232 sec. to 64.768 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.03482 ( -0.234054 0.246729 ) Epeak [keV] : 127.708 ( -27.4131 84.3873 ) Norm@50keV : 1.28618E-02 ( -0.002713 0.00364041 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 55.44 using 59 PHA bins. # Reduced chi-squared = 0.9899 for 56 degrees of freedom # Null hypothesis probability = 4.961602e-01 Photon flux (15-150 keV) in 80 sec: 0.994243 ( -0.03874 0.038947 ) ph/cm2/s Energy fluence (15-150 keV) : 6.18842e-06 ( -2.26589e-07 2.26034e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 8.268 sec. to 9.268 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.21583 ( -0.183058 0.185889 ) Norm@50keV : 2.87879E-02 ( -0.00300973 0.00299931 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 51.23 using 59 PHA bins. # Reduced chi-squared = 0.8987 for 57 degrees of freedom # Null hypothesis probability = 6.904280e-01 Photon flux (15-150 keV) in 1 sec: 3.38686 ( -0.37412 0.37529 ) ph/cm2/s Energy fluence (15-150 keV) : 2.9081e-07 ( -3.21257e-08 3.21956e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 8.268 sec. to 9.268 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.21137 ( -0.22433 0.496946 ) Epeak [keV] : 1.00000E+04 ( -10000 -10000 ) Norm@50keV : 2.89240E-02 ( ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 51.24 using 59 PHA bins. # Reduced chi-squared = 0.9150 for 56 degrees of freedom # Null hypothesis probability = 6.553400e-01 Photon flux (15-150 keV) in 1 sec: 3.39810 ( ) ph/cm2/s Energy fluence (15-150 keV) : 2.90743e-07 ( 0 0 ) ergs/cm2
Time-resolved spectra
Distribution
T90 vs. Hardness ratio plot
T90 = 64.0 sec. Hardness ratio (energy fluence ratio) = 1.47764440895
S(15-50 keV) vs. S(50-150 keV) plot
S(15-50 keV) = 2.3038148e-06 S(50-150 keV) = 3.884574e-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 = 4.840881543379221E-01, IMY = -4.854305873561023E-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: -239.232000 -15.232000 # RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name # [deg] [deg] ['] [deg] [deg] ['] 254.2724 35.3568 15.0 44.6 174.3 -0.4836 -0.8 9.1 Her X-1 263.0691 -24.7370 3.5 34.0 69.6 -1.8356 -3.3 3.3 GX 1+4 268.2090 -1.4760 11.2 17.5 111.9 -0.3750 -1.0 9.6 SW J1753.5-0127 270.2309 -24.9527 11.7 30.2 59.6 0.4431 1.0 8.1 GX 5-1 270.4290 -25.8400 4.3 30.9 58.4 1.2086 2.7 9.0 GRS 1758-258 274.0398 -14.0424 2.2 19.2 67.2 1.7357 5.2 2.0 GX 17+2 276.1233 -30.3727 11.6 33.0 46.2 0.4832 1.0 10.3 H1820-303 285.0851 -24.9337 8.5 26.3 32.1 0.4727 1.4 2.8 HT1900.1-2455 288.7969 10.9290 1.1 10.1 -129.7 2.8343 10.3 1.0 GRS 1915+105 299.6188 35.2485 3.8 36.3 -129.0 1.5159 3.0 3.1 Cyg X-1 308.0875 40.8999 5.8 44.5 -124.2 2.7613 2.0 3.3 Cyg X-3 262.9420 -33.9756 10.5 41.2 60.1 -1.1630 -1.1 8.8 GX 354-0 239.1378 36.0054 2.2 55.1 165.7 9.4739 5.1 ------ UNKNOWN 275.0850 7.1789 0.2 11.9 150.7 22.5689 76.9 ------ UNKNOWN 310.5032 -3.9349 2.8 25.6 -46.6 1.4012 4.1 ------ UNKNOWN 272.6419 56.9080 2.7 56.4 -157.1 8.1327 4.2 ------ UNKNOWN 306.5206 45.7213 2.4 48.0 -129.0 7.3656 4.9 ------ UNKNOWN
Pre-slew background subtracted image of 15-350 keV band
Time interval of the image: -15.232000 11.068590 # RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name # [deg] [deg] ['] [deg] [deg] ['] 254.4680 35.2667 7.0 44.5 174.4 0.2788 1.6 4.6 Her X-1 262.9289 -24.9144 0.0 34.2 69.5 -0.2343 -1.2 11.0 GX 1+4 268.3486 -1.4579 9.7 17.4 111.9 0.1235 1.2 1.2 SW J1753.5-0127 270.0583 -25.0233 0.0 30.4 59.8 0.2405 1.7 12.7 GX 5-1 270.1462 -25.6582 4.6 30.9 59.0 0.3545 2.5 9.9 GRS 1758-258 273.7952 -13.9858 0.0 19.3 67.8 -0.0475 -0.4 12.6 GX 17+2 275.8630 -30.5368 4.2 33.2 46.5 0.4374 2.7 10.7 H1820-303 285.1028 -24.7620 11.5 26.2 32.1 -0.1021 -1.0 10.2 HT1900.1-2455 288.8810 11.0989 15.3 10.3 -129.6 -0.0582 -0.8 10.4 GRS 1915+105 299.5936 35.1988 24.6 36.3 -129.0 0.0624 0.5 0.2 Cyg X-1 308.3035 40.8610 10.1 44.5 -124.0 0.3672 1.1 10.3 Cyg X-3 263.2298 -33.8916 7.2 41.0 59.9 -0.5293 -1.6 12.5 GX 354-0 276.3386 -31.9180 0.3 34.4 45.1 6.0967 37.6 ------ UNKNOWN 319.8216 -28.1196 2.3 44.2 -14.2 0.6879 5.0 ------ UNKNOWN 320.7015 -23.8997 2.1 42.6 -20.0 0.7171 5.4 ------ UNKNOWN
Post-slew image of 15-350 keV band
Time interval of the image: 76.868590 323.268600 # RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name # [deg] [deg] ['] [deg] [deg] ['] 244.9769 -15.6454 0.5 32.8 106.7 15.7815 23.0 0.3 Sco X-1 255.9501 -37.8602 1.0 17.7 59.0 3.5919 11.0 2.0 4U 1700-377 256.4351 -36.4299 5.2 17.0 63.5 0.7315 2.3 0.4 GX 349+2 263.0398 -24.7067 24.5 13.7 112.7 0.1783 0.5 2.9 GX 1+4 264.5383 -44.4364 7.0 15.5 27.2 0.5599 1.6 8.8 4U 1735-44 268.3188 -1.3545 12.8 31.5 158.9 -0.4401 -0.9 6.6 SW J1753.5-0127 270.3196 -25.0793 2.3 8.6 135.3 1.8923 5.1 1.9 GX 5-1 270.3090 -25.8378 7.0 8.0 132.0 0.5982 1.6 5.7 GRS 1758-258 273.8555 -14.0493 4.0 18.0 166.6 0.9932 2.9 8.8 GX 17+2 275.8075 -30.2057 10.8 1.8 160.3 0.3693 1.1 11.4 H1820-303 285.1972 -25.0744 0.0 10.4 -134.7 0.6199 1.7 12.7 HT1900.1-2455 288.7523 10.9541 2.5 44.5 -168.1 2.8592 4.7 2.8 GRS 1915+105 263.1629 -33.7173 5.3 11.2 71.5 0.7487 2.2 11.2 GX 354-0 275.0765 7.1881 0.3 39.1 172.4 23.8448 44.1 ------ UNKNOWN 183.2047 -86.8680 2.4 58.3 -2.0 9.0636 4.9 ------ UNKNOWN 287.7530 14.2432 2.5 47.4 -170.6 3.1365 4.6 ------ UNKNOWN 304.3883 2.7900 3.2 43.8 -142.9 2.5230 3.7 ------ UNKNOWN 336.8617 -61.4778 3.9 48.4 -39.5 3.8989 3.0 ------ UNKNOWN 314.6948 -0.3046 4.3 48.1 -129.1 5.7508 2.7 ------ UNKNOWN