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: Mon Mar 23 14:19:40 EDT 2015
Host Name: bat1
Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/GRB090823
======================================================================
Trigger: 00036390 Segment: 005
BAT Trigger Time: 272736676.8
UTC: 2009-08-23T16:11:11.777 [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: 128.701911074135 Dec: 60.6029026479423 [deg; J2000]
{ 08h 34m 48.5s , +60d 36' 10.4" }
+/- 2.06054729292 [arcmin] (estimated 90% radius based on SNR)
SNR: 10.830004702
Angular difference between the analysis and refined position is Usage: arcmin
Partial Coding Fraction: Unavailable because the burst occurred during slew.
Duration
T90: 25.6000000238419 +/- 1.6
Measured from: 0
to: 25.6 [s; relative to TRIGTIME]
T50: 14.4000000357628 +/- 1.6
Measured from: 3.2
to: 17.6 [s; relative to TRIGTIME]
====== Table of the duration information =============================
Value tstart tstop
T100 27.200 0.000 27.200
T90 25.600 0.000 25.600
T50 14.400 3.200 17.600
Peak 1.000 3.500 4.500
====== 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 -2.263 -0.323 0.291 - - - 1.27e-03 -2.92e-04 2.87e-04 43.690 57
CPL -2.352 -0.294 1.870 159.682 N/A N/A 1.11e-03 N/A N/A 43.690 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 N/A N/A N/A - - - N/A N/A N/A N/A N/A
CPL N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A
=== 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 5.32e-08 6.17e-08 5.14e-08 7.22e-08 1.92e-07 2.38e-07 erg/cm2
90%_error_low -9.29e-09 -9.87e-09 -1.55e-08 -3.44e-08 -3.57e-08 -5.74e-08 erg/cm2
90%_error_hi 9.36e-09 9.59e-09 1.69e-08 5.21e-08 3.77e-08 7.18e-08 erg/cm2
Peak flux PL N/A N/A N/A N/A N/A N/A 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 128.702 60.603 0.006 35.833 -119.222 0.024 10.830 UNKNOWN Image time interval: 11.200 to 27.200 [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 11.200 sec. to 27.200 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -2.2629 ( -0.323365 0.290953 ) Norm@50keV : 1.26576E-03 ( -0.000291943 0.000286924 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 43.69 using 59 PHA bins. # Reduced chi-squared = 0.7665 for 57 degrees of freedom # Null hypothesis probability = 9.024593e-01 Photon flux (15-150 keV) in 16 sec: 0.216752 ( -0.030316 0.030339 ) ph/cm2/s Energy fluence (15-150 keV) : 1.92314e-07 ( -3.56962e-08 3.77299e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 11.200 sec. to 27.200 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -2.35236 ( -0.294517 1.8697 ) Epeak [keV] : 159.682 ( ) Norm@50keV : 1.11275E-03 ( ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 43.69 using 59 PHA bins. # Reduced chi-squared = 0.7802 for 56 degrees of freedom # Null hypothesis probability = 8.843664e-01 Photon flux (15-150 keV) in 16 sec: 0.214598 ( -0.0302 0.030024 ) ph/cm2/s Energy fluence (15-150 keV) : 1.93344e-07 ( -3.62933e-08 3.89618e-08 ) ergs/cm2
1-s peak spectrum fit
1-s peak spectrum unavailable, likely because there are no event data in the 1-s peak range.
Time-resolved spectra
Distribution
T90 vs. Hardness ratio plot
T90 = 25.6 sec. Hardness ratio (energy fluence ratio) = 0.833470115945
S(15-50 keV) vs. S(50-150 keV) plot
S(15-50 keV) = 1.1490124e-07 S(50-150 keV) = 7.741131e-08
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
