Special notes of this burst
Image
Pre-slew 15.0-350.0 keV image (Event data)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
177.9274 -53.0870 0.0172 45.6740 140.4691 1.1752033 11.199 TRIG_00303631
Foreground time interval of the image:
-0.848 6.576 (delta_t = 7.424 [sec])
Background time interval of the image:
-239.760 -0.848 (delta_t = 238.912 [sec])
Lightcurves
Notes:
- 1) The mask-weighted light curves are using the flight position.
- 2) Multiple plots of different time binning/intervals are shown to cover all scenarios of short/long GRBs, rate/image triggers, and real/false positives.
- 3) For all the mask-weighted lightcurves, the y-axis units are counts/sec/det where a det is 0.4 x 0.4 = 0.16 sq cm.
- 4) 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.
- 5) 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)
Quad-rate summed light curves (from T0-300s to T0+1000s)
Spectral Evolution
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 -0.848 sec. to 6.576 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 2.53099 ( -0.256229 0.285377 )
Norm@50keV : 8.23885E-03 ( -0.0017745 0.00176813 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 61.84 using 59 PHA bins.
# Reduced chi-squared = 1.085 for 57 degrees of freedom
# Null hypothesis probability = 3.074100e-01
Photon flux (15-150 keV) in 7.424 sec: 1.64970 ( -0.222778 0.222781 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.1685e-07 ( -9.91446e-08 1.02553e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.848 sec. to 6.576 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.23768 ( -4.83104 2.16725 )
Epeak [keV] : 27.3693 ( -5.439 3.66893 )
Norm@50keV : 14.3078 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 50.89 using 59 PHA bins.
# Reduced chi-squared = 0.9088 for 56 degrees of freedom
# Null hypothesis probability = 6.680701e-01
Photon flux (15-150 keV) in 7.424 sec: 1.55004 ( -0.22194 0.22365 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.96435e-07 ( -7.85244e-08 9.1777e-08 ) ergs/cm2
Band function
Time interval is from -0.848 sec. to 6.576 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : 2.28903 ( -0.517742 0.225335 )
beta : -10.0000 ( 10 3.78314e-07 )
Epeak [keV] : 27.2252 ( -3.32352 3.67695 )
Norm@50keV : 15.9633 ( -2.08023 501.939 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 50.90 using 59 PHA bins.
# Reduced chi-squared = 0.9254 for 55 degrees of freedom
# Null hypothesis probability = 6.320852e-01
Photon flux (15-150 keV) in 7.424 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] : 6.96524 (-0.804352 0.907082)
R^2/D10^2 : 3.37218 (-1.36728 2.29418)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 50.98 using 59 PHA bins.
# Reduced chi-squared = 0.8943 for 57 degrees of freedom
# Null hypothesis probability = 6.992421e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.941e-07 4.198e-08
25- 50 2.633e-07 5.241e-08
50-150 4.285e-08 1.961e-08
15-150 5.002e-07 9.351e-08
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 29.1218 (-7.20753 10.3861)
Norm : 13.9097 (-3.39561 4.71509)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 55.16 using 59 PHA bins.
# Reduced chi-squared = 0.9677 for 57 degrees of freedom
# Null hypothesis probability = 5.444778e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 2.069e-07 3.560e-08
25- 50 2.326e-07 4.391e-08
50-150 1.224e-07 5.485e-08
15-150 5.619e-07 1.076e-07
Double BB
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 6.61955 (-6.68898 0.491005)
R1^2/D10^2 : 3.98310 (-1.6343 4.25207)
kT2 [keV] : 27.6812 (-27.8459 -27.8459)
R2^2/D10^2 : 2.69221E-03 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 49.51 using 59 PHA bins.
#Fit statistic : Chi-Squared = 49.48 using 59 PHA bins.
# Reduced chi-squared = 0.9002 for 55 degrees of freedom
# Reduced chi-squared = 0.8997 for 55 degrees of freedom
# Null hypothesis probability = 6.835916e-01
# Null hypothesis probability = 6.845525e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.970e-07 4.907e-08
25- 50 2.565e-07 8.044e-08
50-150 1.163e-07 5.247e-08
15-150 5.698e-07 1.507e-07
Peak spectrum fit
Power-law model
Time interval is from 0.412 sec. to 1.412 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 3.26400 ( -0.313263 0.413049 )
Norm@50keV : 7.41514E-03 ( -0.00253738 0.00240295 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 54.63 using 59 PHA bins.
# Reduced chi-squared = 0.9584 for 57 degrees of freedom
# Null hypothesis probability = 5.646130e-01
Photon flux (15-150 keV) in 1 sec: 2.48684 ( -0.56755 0.56757 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.01754e-07 ( -2.37053e-08 2.36959e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.412 sec. to 1.412 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.408938 ( -2.17274 1.59348 )
Epeak [keV] : 24.4286 ( )
Norm@50keV : 0.372416 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 46.74 using 59 PHA bins.
# Reduced chi-squared = 0.8346 for 56 degrees of freedom
# Null hypothesis probability = 8.063577e-01
Photon flux (15-150 keV) in 1 sec: 2.78811 ( -0.59544 0.59576 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.25151e-07 ( -2.79905e-08 2.8151e-08 ) ergs/cm2
Band function
Time interval is from 0.412 sec. to 1.412 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.156119 ( -1.17446 4.82973 )
beta : -9.23415 ( 9.08822 18.2578 )
Epeak [keV] : 25.9128 ( -6.71283 8.49435 )
Norm@50keV : 0.518747 ( -0.436625 1253.18 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 46.79 using 59 PHA bins.
# Reduced chi-squared = 0.8508 for 55 degrees of freedom
# Null hypothesis probability = 7.765881e-01
Photon flux (15-150 keV) in 1 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] : 7.56837 (-1.85568 1.90813)
R^2/D10^2 : 4.12306 (-2.51016 8.94074)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 49.37 using 59 PHA bins.
# Reduced chi-squared = 0.8662 for 57 degrees of freedom
# Null hypothesis probability = 7.535211e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 4.085e-08 1.824e-08
25- 50 6.479e-08 2.514e-08
50-150 1.413e-08 8.938e-09
15-150 1.198e-07 4.732e-08
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 23.6195 (-6.11409 6.1509)
Norm : 28.7728 (-8.82038 13.1754)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 47.60 using 59 PHA bins.
# Reduced chi-squared = 0.8350 for 57 degrees of freedom
# Null hypothesis probability = 8.081232e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 5.072e-08 1.299e-08
25- 50 5.008e-08 1.150e-08
50-150 1.957e-08 9.931e-09
15-150 1.204e-07 3.161e-08
Double BB
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 3.97150 (-3.97076 -3.9715)
R1^2/D10^2 : 32.2479 (-31.0416 -32.2479)
kT2 [keV] : 9.82065 (-2.81357 -9.82062)
R2^2/D10^2 : 0.988717 (-0.988733 3.76161)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 46.43 using 59 PHA bins.
# Reduced chi-squared = 0.8442 for 55 degrees of freedom
# Null hypothesis probability = 7.879662e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 4.762e-08 2.803e-08
25- 50 5.677e-08 3.442e-08
50-150 2.327e-08 1.595e-08
15-150 1.277e-07 7.015e-08
Pre-slew spectrum (Pre-slew PHA with pre-slew DRM)
Power-law model
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 2.53099 ( -0.256229 0.285377 )
Norm@50keV : 8.23885E-03 ( -0.0017745 0.00176813 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 61.84 using 59 PHA bins.
# Reduced chi-squared = 1.085 for 57 degrees of freedom
# Null hypothesis probability = 3.074100e-01
Photon flux (15-150 keV) in 7.424 sec: 1.64970 ( -0.222778 0.222781 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.1685e-07 ( -9.91446e-08 1.02553e-07 ) ergs/cm2
Cutoff power-law model
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.23768 ( -4.83104 2.16725 )
Epeak [keV] : 27.3693 ( -5.439 3.66893 )
Norm@50keV : 14.3078 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 50.89 using 59 PHA bins.
# Reduced chi-squared = 0.9088 for 56 degrees of freedom
# Null hypothesis probability = 6.680701e-01
Photon flux (15-150 keV) in 7.424 sec: 1.55004 ( -0.22194 0.22365 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.96435e-07 ( -7.85244e-08 9.1777e-08 ) ergs/cm2
Band function
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : 2.28903 ( -0.517742 0.225335 )
beta : -10.0000 ( 10 3.78314e-07 )
Epeak [keV] : 27.2252 ( -3.32352 3.67695 )
Norm@50keV : 15.9633 ( -2.08023 501.907 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 50.90 using 59 PHA bins.
# Reduced chi-squared = 0.9254 for 55 degrees of freedom
# Null hypothesis probability = 6.320852e-01
Photon flux (15-150 keV) in 7.424 sec: ( ) ph/cm2/s
Energy fluence (15-150 keV) : 0 ( 0 0 ) ergs/cm2
S(25-50 keV) vs. S(50-100 keV) plot
S(25-50 keV) = 2.05e-07
S(50-100 keV) = 1.42e-07
T90 vs. Hardness ratio plot
T90 = 6.5280000269413 sec.
Hardness ratio (energy fluence ratio) = 0.692683
Color vs. Color plot
Count Ratio (25-50 keV) / (15-25 keV) = 1.10192
Count Ratio (50-100 keV) / (15-25 keV) = 0.20291
Mask shadow pattern
IMX = -7.896449343651111E-01, IMY = -6.516477441098890E-01
TIME vs. PHA plot around the trigger time
TIME vs. DetID plot around the trigger time
100 us light curve (15-350 keV)
Spacecraft aspect plot
Bright source in the pre-burst/pre-slew/post-slew images
Pre-burst image of 15-350 keV band
Time interval of the image:
-239.760000 -0.848000
# RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name
# [deg] [deg] ['] [deg] [deg] [']
170.0455 -60.6471 5.8 37.0 140.8 1.1276 2.0 8.1 Cen X-3
186.1975 -62.7389 0.0 39.3 153.0 -0.9960 -1.9 12.8 GX 301-2
109.6942 -36.0917 4.0 39.1 64.4 2.7340 2.9 ------ UNKNOWN
184.7981 -50.2344 2.7 50.1 143.9 6.0223 4.3 ------ UNKNOWN
73.3186 -21.1485 2.8 48.8 15.0 2.9833 4.1 ------ UNKNOWN
206.3529 -63.4004 2.4 42.7 166.0 2.5363 4.8 ------ UNKNOWN
58.9000 -23.9173 2.6 46.8 -3.2 2.5423 4.5 ------ UNKNOWN
245.9646 -53.6892 2.7 56.2 -170.4 4.6671 4.3 ------ UNKNOWN
280.9373 -53.1322 3.0 55.2 -145.3 6.4991 3.8 ------ UNKNOWN
21.2231 -30.9782 4.0 48.3 -49.8 3.8985 2.9 ------ UNKNOWN
Pre-slew background subtracted image of 15-350 keV band
Time interval of the image:
-0.848000 6.576000
# RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name
# [deg] [deg] ['] [deg] [deg] [']
170.1368 -60.7734 0.0 36.9 140.9 0.1052 1.8 10.4 Cen X-3
186.6124 -62.6592 4.4 39.5 153.2 -0.1351 -2.6 6.8 GX 301-2
177.9275 -53.0871 1.0 45.7 140.5 1.1741 11.2 ------ UNKNOWN
65.4434 -15.5860 2.3 54.6 5.6 0.6821 5.1 ------ UNKNOWN
280.0246 -53.0497 2.5 55.4 -146.0 0.6800 4.6 ------ UNKNOWN
31.3597 -20.5842 2.1 55.3 -34.6 0.8333 5.4 ------ UNKNOWN
0.0620 -46.8166 2.5 41.1 -80.7 0.4832 4.6 ------ UNKNOWN
Post-slew image of 15-350 keV band
Time interval of the image:
98.940600 962.340000
# RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name
# [deg] [deg] ['] [deg] [deg] [']
135.5099 -40.5754 0.8 31.0 34.3 8.9700 13.7 1.5 Vela X-1
170.5279 -60.6649 2.6 8.6 -37.0 2.5080 4.5 6.7 Cen X-3
186.8501 -62.6407 16.8 10.6 -84.9 0.3516 0.7 9.4 GX 301-2
100.0829 -41.3354 3.2 51.5 7.6 5.7162 3.6 ------ UNKNOWN
226.4943 -11.2543 4.7 56.9 179.2 8.9368 2.5 ------ UNKNOWN
236.8705 -65.6079 3.3 31.1 -105.4 3.0644 3.6 ------ UNKNOWN
Plot creation:
Sun May 31 08:17:32 EDT 2015