Analysis for Trigger 745797
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.
Special 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 is done using the default FLUX aperture for more accurate results, and thus the spectral analysis is only available after T+56.7 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 EVENT DATA PROCESSING REPORT
Process Script Ver: batgrbproduct v2.46
Process Start Time: Thu Apr 6 15:38:29 EDT 2017
Host Name: bat1
Current Working Dir: /local/data/bat1/prebascript/trigger745797/batgroup_hand_proc
======================================================================
Trigger: 00745797 Segment: 000
BAT Trigger Time: 513110407.296 [s; MET]
Trigger Stop: 513110415.488 [s; MET]
UTC: 2017-04-05T18:39:48.432100 [includes UTCF correction]
Where From?: TDRSS position message
BAT
RA: 219.810293944594 Dec: -25.24359290963 [deg; J2000]
Catalogged Source?: NO
Point Source?: YES
GRB Indicated?: YES [ by BAT flight software ]
Image S/N Ratio: 9.82
Image Trigger?: NO
Rate S/N Ratio: 57.5325994545701 [ if not an image trigger ]
Image S/N Ratio: 9.82
Analysis Position: [ source = BAT ]
RA: 219.810293944594 Dec: -25.24359290963 [deg; J2000]
Refined Position: [ source = BAT pre-slew burst ]
RA: 219.824358637399 Dec: -25.2360176682354 [deg; J2000]
{ 14h 39m 17.8s , -25d 14' 09.7" }
+/- 1.31644644231929 [arcmin] (estimated 90% radius based on SNR)
+/- 0.466748336918744 [arcmin] (formal 1-sigma fit error)
SNR: 20.5372545906635
Partial Coding Fraction: 0.06933594 [ including projection effects ]
Duration
T90: 164.65600001812 +/- 35.3909366653105
Measured from: -16.7680000066757
to: 147.888000011444 [s; relative to TRIGTIME]
T50: 47.4720000624657 +/- 2.35857584961261
Measured from: 0.84799998998642
to: 48.3200000524521 [s; relative to TRIGTIME]
Fluence
Peak Flux (peak 1 second)
Measured from: 4.72399997711182
to: 5.72399997711182 [s; relative to TRIGTIME]
Total Fluence
Measured from: -27.1359999775887
to: 242.495999991894 [s; relative to TRIGTIME]
Band 1 Band 2 Band 3 Band 4
15-25 25-50 50-100 100-350 keV
Total 7.099721 12.100800 11.708993 3.323140
0.314019 0.310126 0.284668 0.222188 [error]
Peak 0.214339 0.309089 0.289326 0.132567
0.035467 0.040904 0.040553 0.029197 [error]
[ fluence units of on-axis counts / fully illuminated detector ]
======================================================================
=== 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 5.51e-07 9.60e-07 1.28e-06 3.48e-06 3.72e-06 6.26e-06 erg/cm2
Error 6.30e-08 6.80e-08 1.10e-07 6.60e-07 2.65e-07 7.45e-07 erg/cm2
Peak flux Power-law -------- -------- -------- -------- -------- -------- ph/cm2/s
Error -------- -------- -------- -------- -------- -------- ph/cm2/s
Fluence Cutoff-PL 5.48e-07 9.63e-07 1.28e-06 3.34e-06 3.71e-06 6.09e-06 erg/cm2
Error 6.50e-08 7.25e-08 1.15e-07 1.07e-06 2.80e-07 1.24e-06 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 1.588 0.119 - - 1.64e-03 1.09e-04 56.630 57
CPL 1.526 0.297 360.8 0.0 1.76e-03 7.56e-04 56.660 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 269.632 -27.136 242.496
T90 164.656 -16.768 147.888
T50 47.472 0.848 48.320
Peak 1.000 4.724 5.724
Image
15.0-350.0 keV image (Event data with DETECTION mask)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
219.8244 -25.2360 0.0095 41.3806 77.7872 28.2578041 20.537 TRIG_00745797
Foreground time interval of the image:
-27.136 50.605 (delta_t = 77.741 [sec])
Background time interval of the image:
-131.195 -27.136 (delta_t = 104.059 [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.
- 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 56.7 sec. to 242.496 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.58757 ( -0.118019 0.119152 )
Norm@50keV : 1.63914E-03 ( -0.000109373 0.000108921 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 56.63 using 59 PHA bins.
# Reduced chi-squared = 0.9934 for 57 degrees of freedom
# Null hypothesis probability = 4.890564e-01
Photon flux (15-150 keV) in 242.5 sec: 0.209841 ( -0.014136 0.014178 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.72368e-06 ( -2.66267e-07 2.67868e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 56.7 sec. to 242.496 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.52642 ( -0.433131 0.161658 )
Epeak [keV] : 360.758 ( -526.878 -526.878 )
Norm@50keV : 1.75714E-03 ( -0.000434013 0.00107773 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 56.66 using 59 PHA bins.
# Reduced chi-squared = 1.012 for 56 degrees of freedom
# Null hypothesis probability = 4.502083e-01
Photon flux (15-150 keV) in 242.5 sec: 0.209475 ( -0.01485 0.01446 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.71493e-06 ( -2.88502e-07 2.73773e-07 ) ergs/cm2
Band function
Time interval is from 56.7 sec. to 242.496 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.695855 ( 1.11047 1.11047 )
beta : -1.61349 ( 1.6061 0.13128 )
Epeak [keV] : 38.8998 ( -38.7872 450.52 )
Norm@50keV : 7.17393E-03 ( -0.00741737 202806 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 56.33 using 59 PHA bins.
# Reduced chi-squared = 1.024 for 55 degrees of freedom
# Null hypothesis probability = 4.247978e-01
Photon flux (15-150 keV) in 242.5 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] : 14.9928 ( )
R^2/D10^2 : 2.26833E-02 ( )
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 127.10 using 59 PHA bins.
# Reduced chi-squared = 2.2297 for 57 degrees of freedom
# Null hypothesis probability = 2.924707e-07
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 2.589e-07 3.477e-08
25- 50 1.028e-06 9.021e-08
50-150 1.573e-06 1.987e-07
15-150 2.860e-06 2.449e-07
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 198.417 (-59.6701 -198.426)
Norm : 0.847144 (-0.0548935 0.0630584)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 57.84 using 59 PHA bins.
# Reduced chi-squared = 1.015 for 57 degrees of freedom
# Null hypothesis probability = 4.439090e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 5.119e-07 4.729e-08
25- 50 9.841e-07 1.434e-07
50-150 2.155e-06 7.692e-07
15-150 3.651e-06 8.608e-07
Double BB
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 6.20653 (-1.08964 1.30078)
R1^2/D10^2 : 0.360540 (-0.179178 0.402715)
kT2 [keV] : 25.7061 (-4.06548 6.40869)
R2^2/D10^2 : 2.79808E-03 (-0.00151034 0.0024379)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 55.71 using 59 PHA bins.
# Reduced chi-squared = 1.013 for 55 degrees of freedom
# Null hypothesis probability = 4.480418e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 5.458e-07 1.479e-07
25- 50 9.445e-07 1.889e-07
50-150 2.206e-06 5.447e-07
15-150 3.697e-06 7.936e-07
Webpage updated on:
Thu Apr 6 21:07:34 EDT 2017