Analysis for Trigger 652847
Analysis Summary
Notes:
- 1) No attempt has been made to eliminate the non-significant decimal places.
- 2) This is a special analysis for ground-detected GRB. The event data duration is likely to be shorter than the burst duration. In such cases, the burst durations are found using the quad-rate data, and spectral analyses are only available for event data range.
- 3) Some mask-weighted light curve plots might be missing because the time range is not completely covered by the event data range.
Sepcial note:
Due to the low partial coding fraction of this burst, the light curves and burst durations are created using the special DETECTION mask aperture. However, the spectral analysis are done using the default FLUX aperture for more accurate results, and thus the spectral analysis is only available after T+174.24 s (met=461843230.240000 s; see figure below), when the burst came into the BAT calibrated field of view.
FLUX-mask-weighted light curve (pcodethresh=0.05; aperture=CALDB:FLUX)
==========================================================================
BAT GRB DATA PROCESSING REPORT
Process Script Ver: batgrbproduct v2.46
Process Start Time: Sat Aug 22 05:18:10 EDT 2015
Host Name: bat1
Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger652847
======================================================================
Trigger: 00652847 Segment: 000
BAT Trigger Time: 461843056 [s; MET]
Trigger Stop: 461843208 [s; MET]
UTC: 2015-08-21T09:44:00.976460 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 341.905812314366 Dec: -57.8753482469684 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 7.18
Image Trigger?: YES
Rate S/N Ratio: 0 [ if not an image trigger ]
Image S/N Ratio: 7.18
Flight Position: [ source = BAT ]
Refined Position: [ source = BAT pre-slew image ]
RA: 341.912503639 Dec: -57.8829689694 [deg; J2000]
{ 22h 47m 39.0s , -57d -52' -58.7" }
+/- 1.7287765782 [arcmin] (estimated 90% radius based on SNR)
SNR: 13.9170837428
Angular difference between Flight and Ground position is 0.505 arcmin
Partial Coding Fraction: 0 [ including projection effects ]
Duration
T90: 172.128000020981 +/- 99.043754395434
Measured from: 6.528
to: 178.656 [s; relative to TRIGTIME]
T50: 50.5120000243187 +/- 16.0483429909714
Measured from: 18.928
to: 69.44 [s; relative to TRIGTIME]
=== 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 Power-law 1.92e-07 2.45e-07 2.29e-07 3.75e-07 7.92e-07 1.04e-06 erg/cm2
Error 5.13e-08 5.11e-08 8.10e-08 2.57e-07 1.93e-07 3.59e-07 erg/cm2
Peak flux Power-law -------- -------- -------- -------- -------- -------- ph/cm2/s
Error -------- -------- -------- -------- -------- -------- ph/cm2/s
Fluence Cutoff-PL 1.59e-07 3.12e-07 1.92e-07 2.34e-08 6.85e-07 6.87e-07 erg/cm2
Error 6.27e-08 7.58e-08 9.97e-08 9.94e-08 1.76e-07 1.99e-07 erg/cm2
Peak flux Cutoff-PL -------- -------- -------- -------- -------- -------- ph/cm2/s
Error -------- -------- -------- -------- -------- -------- ph/cm2/s
Fluence Band -------- -------- -------- -------- -------- -------- erg/cm2
Error -------- -------- -------- -------- -------- -------- erg/cm2
Peak flux Band -------- -------- -------- -------- -------- -------- ph/cm2/s
Error -------- -------- -------- -------- -------- -------- ph/cm2/s
=== Time-averaged spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 2.099 0.369 - - 5.45e-04 1.44e-04 65.000 57
CPL -0.193 2.409 38.2 14.1 1.21e-02 2.93e-01 60.490 56
(1-s peak is outside the event data range; spectral analysis not available)
Model : spectral model: simple power-law (PL) and cutoff power-law (CPL)
Ph_index : photon index: E^-{Ph_index} (minus sign is not included in the 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 PL model and at 1 keV in CPL model
Nomr_90err : 90% error of the normalization
chi2 : Chi-Squared
dof : degree of freedom
=== Table of the duration information ==
Value tstart tstop
T100 309.648 21.096 330.744
T90 172.128 27.624 199.752
T50 50.512 40.024 90.536
Peak 1.000 34.268 35.268
Image
Pre-slew 15.0-50.0 keV image (Event data with DETECTION mask)
#RAcent DECcent POSerr Theta Phi Peak_Cts SNR Name
341.913 -57.883 0.028 53.909 147.946 15.101 13.917 TRIG_00652847
Image time interval: to [sec]
Lightcurves
Notes:
- 1) 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.
- 2) The verticle lines correspond to following: green dotted lines are T50 interval, black dotted lines are T90 interval, blue solid line(s) is a spacecraft slew start time, and orange solid line(s) is a spacecraft slew end time (for the best duration plot, slew times are marked by green arrows).
- 3) For lightcurves in unit of count rate, time of each bin is in the middle of the bin.
1 s binning
From T0-310 s to T0+310 s
From T100_start - 20 s to T100_end + 30 s
Full time interval
64 ms binning
Full time interval
From T100_start to T100_end
From T0-5 sec to T0+5 sec
16 ms binning
From T100_start-5 s to T100_start+5 s
8 ms binning
From T100_start-3 s to T100_start+3 s
2 ms binning
From T100_start-1 s to T100_start+1 s
SN=5 or 10 sec. binning (whichever binning is satisfied first)
SN=5 or 10 sec. binning (T < 200 sec)
Spectra
Notes:
- 1) The fitting includes the systematic errors.
- 2) For long bursts, a spectral fit of 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.
- 4) For short bursts (T90<1sec), the specrtum is also fit with Blackbody, OTTB, and Double Blackbody.
Time averaged spectrum fit using an average DRM
Power-law model
Time interval is from 174.240 sec. to 330.744 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 2.09941 ( -0.348431 0.388739 )
Norm@50keV : 5.44529E-04 ( -0.000146287 0.000142548 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 65.00 using 59 PHA bins.
# Reduced chi-squared = 1.140 for 57 degrees of freedom
# Null hypothesis probability = 2.181392e-01
Photon flux (15-150 keV) in 156.5 sec: 8.56438E-02 ( -0.0175026 0.0175074 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.91676e-07 ( -1.88736e-07 1.97275e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 174.240 sec. to 330.744 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.193105 ( -2.91242 1.90501 )
Epeak [keV] : 38.2169 ( -15.4654 12.6623 )
Norm@50keV : 1.21186E-02 ( -0.0123846 0.573074 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 60.49 using 59 PHA bins.
# Reduced chi-squared = 1.080 for 56 degrees of freedom
# Null hypothesis probability = 3.169477e-01
Photon flux (15-150 keV) in 156.5 sec: 8.06231E-02 ( -0.0177275 0.0178029 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.84997e-07 ( -1.61137e-07 1.91307e-07 ) ergs/cm2
Band function
Time interval is from 174.240 sec. to 330.744 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : 0.310255 ( -2.79472 2.28419 )
beta : -9.99677 ( 9.97865 19.9785 )
Epeak [keV] : 38.1694 ( -9.33586 12.8508 )
Norm@50keV : 1.41034E-02 ( -0.0134185 0.0125846 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 60.50 using 59 PHA bins.
# Reduced chi-squared = 1.100 for 55 degrees of freedom
# Null hypothesis probability = 2.838734e-01
Photon flux (15-150 keV) in 156.5 sec: ( ) ph/cm2/s
Energy fluence (15-150 keV) : 0 ( 0 0 ) ergs/cm2
Single BB
Spectral model blackbody:
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 9.98056 (-1.77045 2.1074)
R^2/D10^2 : 4.24095E-02 (-0.0224892 0.0477304)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 61.15 using 59 PHA bins.
# Reduced chi-squared = 1.073 for 57 degrees of freedom
# Null hypothesis probability = 3.294808e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.346e-07 5.110e-08
25- 50 3.336e-07 1.142e-07
50-150 1.732e-07 8.888e-08
15-150 6.413e-07 2.196e-07
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 52.5574 (-20.0649 44.397)
Norm : 0.483196 (-0.137356 0.197741)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 62.12 using 59 PHA bins.
# Reduced chi-squared = 1.090 for 57 degrees of freedom
# Null hypothesis probability = 2.987485e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.869e-07 5.244e-08
25- 50 2.732e-07 8.189e-08
50-150 2.778e-07 1.627e-07
15-150 7.379e-07 2.384e-07
Double BB
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 3.25935 (-3.34893 196.101)
R1^2/D10^2 : 1.27285 (-1.28565 -1.28565)
kT2 [keV] : 11.1342 (-3.14447 -11.1449)
R2^2/D10^2 : 2.51740E-02 (-0.0251592 0.0435191)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 59.57 using 59 PHA bins.
# Reduced chi-squared = 1.083 for 55 degrees of freedom
# Null hypothesis probability = 3.129197e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.635e-07 8.326e-08
25- 50 3.056e-07 1.723e-07
50-150 2.076e-07 1.256e-07
15-150 6.767e-07 3.718e-07
Webpage updated on:
Sat Aug 22 06:22:09 EDT 2015