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: Wed May 30 15:23:21 EDT 2018
Host Name: bat1
Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger821881
======================================================================
Trigger: 00821881 Segment: 000
BAT Trigger Time: 544495556.416 [s; MET]
Trigger Stop: 544495557.44 [s; MET]
UTC: 2018-04-04T00:45:35.686520 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 83.5636225759874 Dec: -37.1698540029188 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 8.76
Image Trigger?: NO
Rate S/N Ratio: 13.856406460551 [ if not an image trigger ]
Image S/N Ratio: 8.76
Analysis Position: [ source = BAT ]
RA: 83.5636225759874 Dec: -37.1698540029188 [deg; J2000]
Refined Position: [ source = BAT pre-slew burst ]
RA: 83.5313008011088 Dec: -37.1695522417724 [deg; J2000]
{ 05h 34m 07.5s , -37d 10' 10.4" }
+/- 1.08541244783242 [arcmin] (estimated 90% radius based on SNR)
+/- 0.417853299211083 [arcmin] (formal 1-sigma fit error)
SNR: 27.0563163836033
Angular difference between the analysis and refined position is 1.545441 arcmin
Partial Coding Fraction: 0.8203125 [ including projection effects ]
Duration
T90: 36.2799999713898 +/- 5.35102610066606
Measured from: -17.1360000371933
to: 19.1439999341965 [s; relative to TRIGTIME]
T50: 10.1959999799728 +/- 1.75672875410864
Measured from: -2.12800002098083
to: 8.067999958992 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 1.99199998378754
to: 2.99199998378754 [s; relative to TRIGTIME]
Total Fluence
Measured from: -22.472000002861
to: 24.1599999666214 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 0.860579 0.849977 0.514605 0.132736
0.042551 0.043873 0.038234 0.033972 [error]
Peak 0.046023 0.061991 0.037731 0.011676
0.006742 0.006809 0.005948 0.005112 [error]
[ fluence units of on-axis counts / fully illuminated detector ]
======================================================================
====== Table of the duration information =============================
Value tstart tstop
T100 46.632 -22.472 24.160
T90 36.280 -17.136 19.144
T50 10.196 -2.128 8.068
Peak 1.000 1.992 2.992
====== 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 -1.949 -0.123 0.119 - - - 2.96e-03 -2.08e-04 2.05e-04 40.530 57
CPL -1.948 -0.484 0.435 9986.040 -9986.030 -9986.040 2.97e-03 -1.20e-03 2.02e-03 40.530 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 -1.674 -0.228 0.223 - - - 1.00e-02 -1.39e-03 1.36e-03 54.340 57
CPL -1.581 -0.826 0.790 202.949 -202.939 -202.949 1.13e-02 N/A N/A 54.380 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 2.69e-07 3.77e-07 3.90e-07 7.42e-07 1.27e-06 1.78e-06 erg/cm2
90%_error_low -2.59e-08 -2.23e-08 -3.83e-08 -1.42e-07 -8.57e-08 -1.79e-07 erg/cm2
90%_error_hi 2.67e-08 2.24e-08 3.85e-08 1.63e-07 8.65e-08 1.95e-07 erg/cm2
Peak flux PL 4.89e-01 4.44e-01 2.78e-01 2.66e-01 1.32e+00 1.48e+00 ph/cm2/s
90%_error_low -9.67e-02 -5.69e-02 -4.96e-02 -8.41e-02 -1.67e-01 -1.87e-01 ph/cm2/s
90%_error_hi 1.01e-01 5.67e-02 4.95e-02 1.06e-01 1.67e-01 1.88e-01 ph/cm2/s
Fluence CPL 2.70e-07 3.76e-07 3.90e-07 7.42e-07 1.27e-06 1.81e-06 erg/cm2
90%_error_low -3.17e-08 -2.15e-08 -4.09e-08 N/A -1.05e-07 -2.36e-07 erg/cm2
90%_error_hi 2.67e-08 2.83e-08 4.13e-08 N/A 8.65e-08 9.19e-08 erg/cm2
Peak flux CPL 4.89e-01 4.44e-01 2.78e-01 2.66e-01 1.32e+00 1.48e+00 ph/cm2/s
90%_error_low -1.06e-01 -5.62e-02 -4.95e-02 -1.68e-01 -1.70e-01 -2.64e-01 ph/cm2/s
90%_error_hi 7.77e-02 7.21e-02 5.13e-02 6.02e-02 1.65e-01 1.86e-01 ph/cm2/s
======================================================================
Image
Pre-slew 15.0-350.0 keV image (Event data)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name 83.5313 -37.1696 0.0071 32.4939 -8.8360 2.2155130 27.056 TRIG_00821881 Foreground time interval of the image: -22.472 17.685 (delta_t = 40.157 [sec]) Background time interval of the image: -168.515 -22.472 (delta_t = 146.043 [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 -22.472 sec. to 24.160 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.94863 ( -0.122586 0.119285 ) Norm@50keV : 2.96201E-03 ( -0.000207822 0.000204804 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 40.53 using 59 PHA bins. # Reduced chi-squared = 0.7111 for 57 degrees of freedom # Null hypothesis probability = 9.513769e-01 Photon flux (15-150 keV) in 46.63 sec: 0.434159 ( -0.026644 0.026731 ) ph/cm2/s Energy fluence (15-150 keV) : 1.27123e-06 ( -8.56938e-08 8.6536e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -22.472 sec. to 24.160 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.94756 ( -0.483438 0.435499 ) Epeak [keV] : 9986.04 ( -9999.35 -9999.36 ) Norm@50keV : 2.96598E-03 ( -0.00119559 0.00202185 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 40.53 using 59 PHA bins. # Reduced chi-squared = 0.7238 for 56 degrees of freedom # Null hypothesis probability = 9.404426e-01 Photon flux (15-150 keV) in 46.63 sec: 0.434460 ( -0.028859 0.026524 ) ph/cm2/s Energy fluence (15-150 keV) : 1.27451e-06 ( -1.0492e-07 8.65084e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 1.992 sec. to 2.992 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.67403 ( -0.227917 0.222956 ) Norm@50keV : 1.00462E-02 ( -0.00138905 0.00136394 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 54.34 using 59 PHA bins. # Reduced chi-squared = 0.9533 for 57 degrees of freedom # Null hypothesis probability = 5.756327e-01 Photon flux (15-150 keV) in 1 sec: 1.32242 ( -0.16719 0.16738 ) ph/cm2/s Energy fluence (15-150 keV) : 9.32331e-08 ( -1.35071e-08 1.3729e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 1.992 sec. to 2.992 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.67255 ( -0.818515 0.797966 ) Epeak [keV] : 9987.16 ( -9988.19 -9988.2 ) Norm@50keV : 1.00658E-02 ( ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 54.34 using 59 PHA bins. # Reduced chi-squared = 0.9703 for 56 degrees of freedom # Null hypothesis probability = 5.380717e-01 Photon flux (15-150 keV) in 1 sec: 1.32235 ( -0.16983 0.1654 ) ph/cm2/s Energy fluence (15-150 keV) : 9.3218e-08 ( -1.55897e-08 1.35989e-08 ) ergs/cm2
Time-resolved spectra
Distribution
T90 vs. Hardness ratio plot
T90 = 36.28 sec. Hardness ratio (energy fluence ratio) = 1.03628709343
S(15-50 keV) vs. S(50-150 keV) plot
S(15-50 keV) = 6.459347e-07 S(50-150 keV) = 6.252902e-07
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 = 6.293607744657843E-01, IMY = 9.783533358478688E-02
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: -168.515400 -22.472000 # RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name # [deg] [deg] ['] [deg] [deg] ['] 135.5295 -40.4988 3.0 40.3 60.6 1.7793 3.9 3.4 Vela X-1 170.0065 -60.7209 17.9 34.8 108.7 -0.2082 -0.6 10.8 Cen X-3 186.7051 -62.7325 4.5 37.8 121.5 0.9481 2.5 2.6 GX 301-2
Pre-slew background subtracted image of 15-350 keV band
Time interval of the image: -22.472000 17.684590 # RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name # [deg] [deg] ['] [deg] [deg] ['] 135.5761 -40.6645 4.1 40.2 60.8 0.6496 2.8 6.9 Vela X-1 170.6322 -60.5262 0.0 35.2 108.9 0.2242 1.3 11.0 Cen X-3 186.9203 -62.9287 8.0 37.7 121.8 -0.2799 -1.4 11.9 GX 301-2 193.6839 -61.2235 2.3 40.8 124.7 1.2011 4.9 ------ UNKNOWN 263.9902 -54.5446 2.9 55.8 169.6 1.7961 4.0 ------ UNKNOWN 83.5318 -37.1693 0.4 32.5 -8.8 2.2289 27.2 ------ UNKNOWN 352.2167 -61.2145 2.6 34.4 -134.0 0.5081 4.5 ------ UNKNOWN 0.0815 -52.4318 2.4 39.1 -119.6 0.8566 4.9 ------ UNKNOWN
Post-slew image of 15-350 keV band
Time interval of the image: 70.484600 842.784000 # RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name # [deg] [deg] ['] [deg] [deg] ['] 83.6459 22.0213 1.8 59.2 -16.3 15.3713 6.6 0.8 Crab 135.3986 -40.5316 7.8 39.9 95.0 2.4005 1.5 6.1 Vela X-1 124.9454 -59.5672 4.0 34.5 127.5 1.9774 2.9 ------ UNKNOWN 90.9563 -31.8608 2.7 8.1 34.7 1.4971 4.3 ------ UNKNOWN 14.4730 -50.3113 2.6 49.7 -144.9 6.4576 4.5 ------ UNKNOWN 48.5580 -12.0954 3.9 40.1 -76.9 4.3454 2.9 ------ UNKNOWN 55.3935 0.1386 3.1 45.5 -57.8 7.5630 3.7 ------ UNKNOWN 21.1709 -39.2988 3.0 48.1 -129.1 8.2787 3.8 ------ UNKNOWN