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 GROUND-DETECTED GRB DATA PROCESSING REPORT
(This burst occurred during telescope slew)
Process Script Ver: batgrbproduct v2.46
Process Start Time: Tue Nov 11 08:47:39 EST 2014
Host Name: bat1
Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/GRB090418B
======================================================================
Trigger: 00090078 Segment: 001
BAT Trigger Time: 261737965.0
UTC: 2009-04-18T08:59:20.331 [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.
Refined Position: [ source = BAT mosaic image ]
RA: 225.914157234555 Dec: 17.2304913823518 [deg; J2000]
{ 15h 03m 39.4s , +17d 13' 49.8" }
+/- 0.392204406676 [arcmin] (estimated 90% radius based on SNR)
SNR: 115.843500037
Angular difference between the analysis and refined position is Usage: arcmin
Partial Coding Fraction: Unavailable because the burst occurred during slew.
Duration
T90: 38. +/- 1.
Measured from: 3
to: 41 [s; relative to TRIGTIME]
T50: 16. +/- 1.
Measured from: 13
to: 29 [s; relative to TRIGTIME]
====== Table of the duration information =============================
Value tstart tstop
T100 89.000 0.000 89.000
T90 38.000 3.000 41.000
T50 16.000 13.000 29.000
Peak 1.000 15.000 16.000
====== 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 -1.684 -0.031 0.031 - - - 2.00e-02 -3.14e-04 3.14e-04 41.620 57
CPL -1.553 -0.121 0.124 200.939 -69.125 4834.961 2.28e-02 -2.46e-03 2.86e-03 38.220 56
=== 1-s peak 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 -1.463 -0.063 0.062 - - - 8.50e-02 -3.11e-03 3.11e-03 68.210 57
CPL -0.955 -0.259 0.275 110.317 -21.388 57.482 1.48e-01 -3.58e-02 5.07e-02 56.370 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 2.71e-06 4.45e-06 5.54e-06 1.37e-05 1.65e-05 2.64e-05 erg/cm2
90%_error_low -9.29e-08 -8.81e-08 -9.92e-08 -5.74e-07 -2.57e-07 -6.04e-07 erg/cm2
90%_error_hi 9.44e-08 8.79e-08 9.91e-08 5.91e-07 2.57e-07 6.16e-07 erg/cm2
Peak flux PL 3.38e+00 3.47e+00 2.52e+00 2.93e+00 1.05e+01 1.23e+01 ph/cm2/s
90%_error_low -2.23e-01 -1.43e-01 -1.11e-01 -2.57e-01 -4.02e-01 -4.50e-01 ph/cm2/s
90%_error_hi 2.28e-01 1.42e-01 1.10e-01 2.72e-01 4.02e-01 4.50e-01 ph/cm2/s
Fluence CPL 2.60e-06 4.46e-06 5.61e-06 1.18e-05 1.64e-05 2.45e-05 erg/cm2
90%_error_low -1.30e-07 -8.97e-08 -1.17e-07 -1.50e-06 -2.85e-07 -1.54e-06 erg/cm2
90%_error_hi 1.32e-07 8.96e-08 1.18e-07 1.76e-06 2.84e-07 1.79e-06 erg/cm2
Peak flux CPL 3.02e+00 3.60e+00 2.66e+00 1.80e+00 1.03e+01 1.11e+01 ph/cm2/s
90%_error_low -2.76e-01 -1.60e-01 -1.32e-01 -3.79e-01 -4.19e-01 -5.84e-01 ph/cm2/s
90%_error_hi 2.82e-01 1.62e-01 1.34e-01 4.94e-01 4.19e-01 6.48e-01 ph/cm2/s
======================================================================
Image
Note1: The mosaic image is made with timebin = 0.10 s; energybin = 15-350 keV
Note2: The mosaic image uses Galactic coordinate.
#RAcent DECcent POSerr Theta Phi Peak_Cts SNR Name 225.914 17.230 0.001 28.908 68.083 0.139 115.844 UNKNOWN Image time interval: 0.000 to 89.000 [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.
Best duration plot
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 0.000 sec. to 89.000 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.68382 ( -0.0306381 0.0306469 ) Norm@50keV : 2.00488E-02 ( -0.000313669 0.000313576 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 41.62 using 59 PHA bins. # Reduced chi-squared = 0.7301 for 57 degrees of freedom # Null hypothesis probability = 9.371782e-01 Photon flux (15-150 keV) in 89 sec: 2.64793 ( -0.05272 0.053 ) ph/cm2/s Energy fluence (15-150 keV) : 1.65451e-05 ( -2.5664e-07 2.56862e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.000 sec. to 89.000 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.55255 ( -0.121193 0.124417 ) Epeak [keV] : 200.939 ( -69.125 4834.97 ) Norm@50keV : 2.27851E-02 ( -0.00245575 0.00286041 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 38.22 using 59 PHA bins. # Reduced chi-squared = 0.6825 for 56 degrees of freedom # Null hypothesis probability = 9.668010e-01 Photon flux (15-150 keV) in 89 sec: 2.61004 ( -0.06209 0.06266 ) ph/cm2/s Energy fluence (15-150 keV) : 1.64093e-05 ( -2.84647e-07 2.84314e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 15.000 sec. to 16.000 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.46322 ( -0.0626628 0.0624189 ) Norm@50keV : 8.50298E-02 ( -0.00311252 0.00311122 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 68.21 using 59 PHA bins. # Reduced chi-squared = 1.197 for 57 degrees of freedom # Null hypothesis probability = 1.469850e-01 Photon flux (15-150 keV) in 1 sec: 10.5138 ( -0.4019 0.4024 ) ph/cm2/s Energy fluence (15-150 keV) : 8.1182e-07 ( -3.1954e-08 3.20392e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 15.000 sec. to 16.000 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -0.954708 ( -0.258845 0.274519 ) Epeak [keV] : 110.317 ( -21.388 57.4822 ) Norm@50keV : 0.148458 ( -0.0358361 0.0506504 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 56.37 using 59 PHA bins. # Reduced chi-squared = 1.007 for 56 degrees of freedom # Null hypothesis probability = 4.610982e-01 Photon flux (15-150 keV) in 1 sec: 10.2651 ( -0.41857 0.4193 ) ph/cm2/s Energy fluence (15-150 keV) : 7.91189e-07 ( -3.41992e-08 3.40695e-08 ) ergs/cm2
Time-resolved spectra
Distribution
T90 vs. Hardness ratio plot
T90 = 38.0 sec. Hardness ratio (energy fluence ratio) = 1.24505914105
S(15-50 keV) vs. S(50-150 keV) plot
S(15-50 keV) = 7.156842e-06 S(50-150 keV) = 9.388445e-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
Mask shadow pattern unavailable because this burst occurs during telescope slews.Spacecraft aspect plot
