Analysis for Ground-detected GRB: Trigger=848489
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.
==========================================================================
BAT GROUND-DETECTED GRB DATA PROCESSING REPORT
Process Script Ver: batgrbproduct v2.46
Process Start Time: Wed Jul 18 16:04:59 EDT 2018
Host Name: bat1
Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/ground_detect_bursts/scripts
======================================================================
Trigger: 00848489 Segment: 000
BAT Trigger Time: 553571885.816
UTC: 20180718T01:57:44.530 [includes UTCF correction]
Where From?: Ground analysis (best_duration.txt)
NOTE: BAT trigger time for ground-detected burst is the T100 start time.
Analysis Position: [ source = GCN ]
RA: 336.0186 Dec: 2.78980
Refined Position: [ source = BAT pre-slew image ]
RA: 336.019 Dec: 2.7898 [deg; J2000]
{ 22h 24m 04.6s , +02d 47' 23.3" }
+/- 3.00825676649 [arcmin] (estimated 90% radius based on SNR)
SNR: 6.30765882123
Angular difference between the GCN position (ra=357.7188, dec=25.5838 deg) and this refined position is 0.001 arcmin
Partial Coding Fraction: 0.25 [ including projection effects ]
Duration
T90: 0.0839999914169312 +/- 0.0233238752907961
Measured from: 0.00800002
to: 0.092 [s; relative to TRIGTIME]
T50: 0.0519999265670776 +/- 0.0256125023115591
Measured from: 0.016
to: 0.068 [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 2.94e-09 8.58e-10 1.36e-10 2.48e-11 3.95e-09 3.96e-09 erg/cm2
Error 1.99e-09 5.11e-10 9.77e-11 2.53e-11 2.52e-09 2.52e-09 erg/cm2
Peak flux Power-law 3.82e-01 3.31e-01 1.96e-01 1.74e-01 9.83e-01 1.08e+00 ph/cm2/s
Error 1.73e-01 1.04e-01 8.47e-02 1.44e-01 3.09e-01 3.42e-01 ph/cm2/s
Fluence Cutoff-PL 2.32e-09 1.10e-08 2.34e-09 1.94e-12 1.56e-08 1.56e-08 erg/cm2
Error 2.76e-09 4.68e-09 -------- 2.92e-12 5.49e-09 5.50e-09 erg/cm2
Peak flux Cutoff-PL 3.43e-01 3.78e-01 2.02e-01 5.32e-02 9.62e-01 9.75e-01 ph/cm2/s
Error 1.92e-01 1.48e-01 1.53e-01 1.16e-01 3.14e-01 3.54e-01 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 4.657 0.755 - - 1.07e-03 7.05e-04 82.090 57
CPL 1.000 0.000 80.0 0.0 2.10e-04 0.00e+00 88.450 56
=== 1-s peak spectral analysis ===
Model Ph_index Ph_90err Epeak Epeak_90err Norm Nomr_90err chi2 dof
PL 1.757 0.521 - - 7.25e-03 2.53e-03 58.080 57
CPL 0.689 3.189 53.9 -2.2 2.90e-02 1.68e+01 57.300 56
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 0.100 0.000 0.100
T90 0.084 0.008 0.092
T50 0.052 0.016 0.068
Peak 1.000 -0.448 0.552
Image
15.0-150.0 keV image (Event data)
#RAcent DECcent POSerr Theta Phi Peak_Cts SNR Name
336.019 2.790 0.000 34.670 69.207 0.079 6.308 TRIG_00848489
Image time interval: -0.026 to +0.165 [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.
Best duration plot
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)
Spectral Evolution
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 the pre-slew DRM
Power-law model
Time interval is from 0.000 sec. to 0.100 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 4.65650 ( -0.676788 0.833737 )
Norm@50keV : 1.07159E-03 ( -0.000719191 0.000691525 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 82.09 using 59 PHA bins.
# Reduced chi-squared = 1.440 for 57 degrees of freedom
# Null hypothesis probability = 1.642924e-02
Photon flux (15-150 keV) in 0.1 sec: 1.19595 ( -0.785305 0.78978 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.94903e-09 ( -2.51948e-09 2.51674e-09 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.000 sec. to 0.100 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.00000 ( )
Epeak [keV] : 80.0000 ( )
Norm@50keV : 2.09740E-04 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 88.45 using 59 PHA bins.
# Reduced chi-squared = 1.580 for 56 degrees of freedom
# Null hypothesis probability = 3.697836e-03
Photon flux (15-150 keV) in 0.1 sec: ( ) ph/cm2/s
Energy fluence (15-150 keV) : 1.56236e-08 ( -5.04008e-09 5.94341e-09 ) ergs/cm2
Band function
Time interval is from 0.000 sec. to 0.100 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : ( )
beta : ( )
Epeak [keV] : ( )
Norm@50keV : ( )
------------------------------------------------------------
Photon flux (15-150 keV) in 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] : 6.73878 (-0.804494 0.548718)
R^2/D10^2 : 7.82043 (-3.66699 6.32673)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 64.68 using 59 PHA bins.
# Reduced chi-squared = 1.135 for 57 degrees of freedom
# Null hypothesis probability = 2.263707e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 5.475e-09 2.197e-09
25- 50 6.957e-09 2.294e-09
50-150 1.003e-09 5.045e-10
15-150 1.344e-08 4.811e-09
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 13.1584 (-2.56537 2.23146)
Norm : 51.5267 (-25.2283 33.4326)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 73.18 using 59 PHA bins.
# Reduced chi-squared = 1.284 for 57 degrees of freedom
# Null hypothesis probability = 7.307816e-02
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 5.274e-09 2.269e-09
25- 50 3.161e-09 1.366e-09
50-150 4.256e-10 2.234e-10
15-150 8.861e-09 4.013e-09
Double BB
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 6.70894 (-0.804797 0.552108)
R1^2/D10^2 : 8.02102 (-3.66928 6.32862)
kT2 [keV] : 0.209476 (-0.209476 -0.209476)
R2^2/D10^2 : 1.87267E-04 (-0.00018673 -0.00018673)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 64.68 using 59 PHA bins.
# Reduced chi-squared = 1.176 for 55 degrees of freedom
# Null hypothesis probability = 1.744335e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 5.538e-09 2.335e-09
25- 50 6.975e-09 3.103e-09
50-150 9.888e-10 4.956e-10
15-150 1.350e-08 5.755e-09
Peak spectrum fit
Power-law model
Time interval is from -0.448 sec. to 0.552 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.75694 ( -0.492331 0.549084 )
Norm@50keV : 7.25453E-03 ( -0.00257286 0.00247763 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 58.08 using 59 PHA bins.
# Reduced chi-squared = 1.019 for 57 degrees of freedom
# Null hypothesis probability = 4.353983e-01
Photon flux (15-150 keV) in 1 sec: 0.983499 ( -0.309243 0.309631 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.69268e-08 ( -2.34958e-08 2.42701e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.448 sec. to 0.552 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.688847 ( -4.88613 1.4909 )
Epeak [keV] : 53.9330 ( -49.5157 -53.9309 )
Norm@50keV : 2.89871E-02 ( -0.0289904 33.5399 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 57.30 using 59 PHA bins.
# Reduced chi-squared = 1.023 for 56 degrees of freedom
# Null hypothesis probability = 4.268534e-01
Photon flux (15-150 keV) in 1 sec: 0.962432 ( -0.314628 0.313218 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.60544e-08 ( -5.41312e-08 2.39567e-08 ) ergs/cm2
Band function
Time interval is from -0.448 sec. to 0.552 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : ( )
beta : ( )
Epeak [keV] : ( )
Norm@50keV : ( )
------------------------------------------------------------
Photon flux (15-150 keV) in 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] : 10.8727 (-3.35226 5.45948)
R^2/D10^2 : 0.356584 (-0.355971 1.04502)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 58.48 using 59 PHA bins.
# Reduced chi-squared = 1.026 for 57 degrees of freedom
# Null hypothesis probability = 4.209004e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 8.786e-09 5.490e-09
25- 50 2.447e-08 1.503e-08
50-150 1.620e-08 1.185e-08
15-150 4.946e-08 3.054e-08
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 99.9056 (-62.2115 -101.221)
Norm : 4.43969 (-1.5677 2.45497)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 57.48 using 59 PHA bins.
# Reduced chi-squared = 1.008 for 57 degrees of freedom
# Null hypothesis probability = 4.572453e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.160e-08 7.190e-09
25- 50 2.006e-08 1.249e-08
50-150 3.249e-08 2.619e-08
15-150 6.416e-08 4.326e-08
Double BB
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 8.24101 (-7.69457 6.26443)
R1^2/D10^2 : 0.793203 (-0.804761 -0.804761)
kT2 [keV] : 29.7770 (-29.5488 -29.5488)
R2^2/D10^2 : 4.74332E-03 (-0.00500704 0.782214)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 56.72 using 59 PHA bins.
#Fit statistic : Chi-Squared = 56.67 using 59 PHA bins.
# Reduced chi-squared = 1.031 for 55 degrees of freedom
# Reduced chi-squared = 1.030 for 55 degrees of freedom
# Null hypothesis probability = 4.105512e-01
# Null hypothesis probability = 4.124320e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.092e-08 7.160e-09
25- 50 2.205e-08 1.393e-08
50-150 3.087e-08 1.892e-08
15-150 6.384e-08 3.769e-08
Webpage updated on:
Wed Jul 18 17:17:37 EDT 2018