Special notes of this burst
Image
Pre-slew 15.0-350.0 keV image (Event data; DETECTION mask)
# RAcent DECcent POSerr Theta Phi Peak Cts SNR Name
134.5339 -33.4817 0.0128 42.7103 -110.5366 3.6670870 15.072 TRIG_00557508
Foreground time interval of the image:
-1.544 16.597 (delta_t = 18.141 [sec])
Background time interval of the image:
-196.003 -1.544 (delta_t = 194.459 [sec])
Lightcurves
Notes:
- 1) All plots contain as much data as has been downloaded to date.
- 2) The mask-weighted light curves are using the flight position.
- 3) Multiple plots of different time binning/intervals are shown to cover all scenarios of short/long GRBs, rate/image triggers, and real/false positives.
- 4) 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.
- 5) 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.
- 6) 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
Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000
8 ms binning
From T100_start-3 s to T100_start+3 s
Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000
2 ms binning
From T100_start-1 s to T100_start+1 s
Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000
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) 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 -1.816 sec. to 12.008 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.61968 ( -0.170881 0.174721 )
Norm@50keV : 1.76857E-02 ( -0.00189795 0.00188229 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 73.18 using 59 PHA bins.
# Reduced chi-squared = 1.284 for 57 degrees of freedom
# Null hypothesis probability = 7.315466e-02
Photon flux (15-150 keV) in 13.82 sec: 2.28677 ( -0.237376 0.237711 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.28053e-06 ( -2.59437e-07 2.61769e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -1.816 sec. to 12.008 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.925919 ( -0.837212 0.70163 )
Epeak [keV] : 75.2505 ( -19.9255 1996.42 )
Norm@50keV : 4.05091E-02 ( -0.0226431 0.0680615 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 70.35 using 59 PHA bins.
# Reduced chi-squared = 1.256 for 56 degrees of freedom
# Null hypothesis probability = 9.404477e-02
Photon flux (15-150 keV) in 13.82 sec: 2.22775 ( -0.24539 0.24525 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.17611e-06 ( -2.83186e-07 2.84761e-07 ) ergs/cm2
Band function
Time interval is from -1.816 sec. to 12.008 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.845004 ( -0.675015 0.844407 )
beta : -2.26295 ( 2.27095 0.711628 )
Epeak [keV] : 70.3341 ( -26.7662 756.89 )
Norm@50keV : 4.52998E-02 ( -0.0279797 382.507 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 70.26 using 59 PHA bins.
# Reduced chi-squared = 1.277 for 55 degrees of freedom
# Null hypothesis probability = 8.063952e-02
Photon flux (15-150 keV) in 13.82 sec: 2.22497 ( 4.77503 -0.24462 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.17628e-06 ( 0 0 ) ergs/cm2
Single BB
Spectral model blackbody:
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 13.7433 (-1.63151 1.85955)
R^2/D10^2 : 0.352048 (-0.129464 0.2033)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 86.65 using 59 PHA bins.
# Reduced chi-squared = 1.520 for 57 degrees of freedom
# Null hypothesis probability = 6.875432e-03
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.944e-07 3.773e-08
25- 50 7.098e-07 1.003e-07
50-150 8.743e-07 1.888e-07
15-150 1.778e-06 2.446e-07
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 158.955 (-56.2082 -158.609)
Norm : 9.47105 (-1.05076 0.669534)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 70.93 using 59 PHA bins.
# Reduced chi-squared = 1.244 for 57 degrees of freedom
# Null hypothesis probability = 1.015601e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 3.344e-07 7.401e-08
25- 50 6.250e-07 2.595e-07
50-150 1.263e-06 6.810e-07
15-150 2.222e-06 1.034e-06
Double BB
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 6.96909 (-2.34319 2.98946)
R1^2/D10^2 : 2.34777 (-1.52323 7.19884)
kT2 [keV] : 22.3514 (-5.63693 17.6985)
R2^2/D10^2 : 4.55241E-02 (-0.0403026 0.102889)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 70.11 using 59 PHA bins.
# Reduced chi-squared = 1.275 for 55 degrees of freedom
# Null hypothesis probability = 8.242644e-02
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 3.097e-07 1.653e-07
25- 50 6.503e-07 3.256e-07
50-150 1.206e-06 6.682e-07
15-150 2.166e-06 1.129e-06
Peak spectrum fit
Power-law model
Time interval is from -0.108 sec. to 0.892 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.19547 ( -0.337487 0.355394 )
Norm@50keV : 3.28733E-02 ( -0.00719765 0.00716341 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 66.21 using 59 PHA bins.
# Reduced chi-squared = 1.162 for 57 degrees of freedom
# Null hypothesis probability = 1.889517e-01
Photon flux (15-150 keV) in 1 sec: 3.85615 ( -0.882178 0.887786 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.33946e-07 ( -7.53587e-08 7.52316e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.108 sec. to 0.892 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.818746 ( -8.65068 3.34203 )
Epeak [keV] : 106.183 ( -25.9123 -105.052 )
Norm@50keV : 0.149993 ( -0.164761 35.2796 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 64.47 using 59 PHA bins.
# Reduced chi-squared = 1.151 for 56 degrees of freedom
# Null hypothesis probability = 2.045349e-01
Photon flux (15-150 keV) in 1 sec: 3.49673 ( -1.05483 1.02566 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.60901e-07 ( -8.2823e-08 8.5062e-08 ) ergs/cm2
Band function
Time interval is from -0.108 sec. to 0.892 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : 0.773036 ( -1.35444 -0.106502 )
beta : -10.0000 ( 10 1.42109e-14 )
Epeak [keV] : 106.752 ( -22.4312 228.731 )
Norm@50keV : 0.145952 ( -0.145572 2.38688 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 64.48 using 59 PHA bins.
# Reduced chi-squared = 1.172 for 55 degrees of freedom
# Null hypothesis probability = 1.790471e-01
Photon flux (15-150 keV) in 1 sec: 3.81810 ( ) 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] : 25.6152 (-4.50172 5.59587)
R^2/D10^2 : 9.37854E-02 (-0.0453094 0.0780865)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 64.00 using 59 PHA bins.
# Reduced chi-squared = 1.123 for 57 degrees of freedom
# Null hypothesis probability = 2.442764e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 1.055e-08 4.110e-09
25- 50 6.060e-08 2.000e-08
50-150 2.937e-07 1.017e-07
15-150 3.648e-07 1.238e-07
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 200.000 (-65.0113 -200)
Norm : 16.1993 (-3.6176 3.6176)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 69.88 using 59 PHA bins.
# Reduced chi-squared = 1.226 for 57 degrees of freedom
# Null hypothesis probability = 1.175724e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 4.036e-08 2.417e-08
25- 50 7.764e-08 4.547e-08
50-150 1.703e-07 1.002e-07
15-150 2.883e-07 1.666e-07
Double BB
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 2.85178 (-1.41986 2.00133)
R1^2/D10^2 : 242.733 (-231.424 49928.6)
kT2 [keV] : 27.3232 (-4.91825 6.67518)
R2^2/D10^2 : 7.25103E-02 (-0.0379511 0.064211)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 56.07 using 59 PHA bins.
# Reduced chi-squared = 1.020 for 55 degrees of freedom
# Null hypothesis probability = 4.343904e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 4.185e-08 2.262e-08
25- 50 5.703e-08 2.616e-08
50-150 2.883e-07 1.169e-07
15-150 3.872e-07 1.401e-07
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: 1.61968 ( -0.170881 0.174721 )
Norm@50keV : 1.76857E-02 ( -0.00189795 0.00188229 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 73.18 using 59 PHA bins.
# Reduced chi-squared = 1.284 for 57 degrees of freedom
# Null hypothesis probability = 7.315466e-02
Photon flux (15-150 keV) in 13.82 sec: 2.28677 ( -0.237376 0.237711 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.28053e-06 ( -2.59437e-07 2.61769e-07 ) ergs/cm2
Cutoff power-law model
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.925919 ( -0.837212 0.70163 )
Epeak [keV] : 75.2505 ( -19.9255 2429.28 )
Norm@50keV : 4.05091E-02 ( -0.0226431 0.0680615 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 70.35 using 59 PHA bins.
# Reduced chi-squared = 1.256 for 56 degrees of freedom
# Null hypothesis probability = 9.404477e-02
Photon flux (15-150 keV) in 13.82 sec: 2.22775 ( -0.24539 0.24525 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.17611e-06 ( -2.83186e-07 2.84761e-07 ) ergs/cm2
Band function
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -0.845004 ( -0.67504 0.844407 )
beta : -2.26295 ( 2.27095 0.711862 )
Epeak [keV] : 70.3341 ( -26.7662 756.89 )
Norm@50keV : 4.52998E-02 ( -0.0279797 382.387 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 70.26 using 59 PHA bins.
# Reduced chi-squared = 1.277 for 55 degrees of freedom
# Null hypothesis probability = 8.063952e-02
Photon flux (15-150 keV) in 13.82 sec: 2.22497 ( 4.77503 -0.24462 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.17628e-06 ( 0 0 ) ergs/cm2
S(25-50 keV) vs. S(50-100 keV) plot
S(25-50 keV) = 5.96e-07
S(50-100 keV) = 7.76e-07
T90 vs. Hardness ratio plot
T90 = 10.1759999990463 sec.
Hardness ratio (energy fluence ratio) = 1.30201
Color vs. Color plot
Count Ratio (25-50 keV) / (15-25 keV) = 1.73511
Count Ratio (50-100 keV) / (15-25 keV) = 1.137
Mask shadow pattern (with DETECTION mask)
IMX = -3.238303501896034E-01, IMY = 8.644403243361053E-01
TIME vs. PHA plot around the trigger time
Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000
TIME vs. DetID plot around the trigger time
Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000
100 us light curve (15-350 keV)
Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000
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:
-196.003400 -1.816000
# RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name
# [deg] [deg] ['] [deg] [deg] [']
135.5868 -40.5645 3.9 41.0 -120.9 1.4422 2.9 2.7 Vela X-1
170.4718 -60.6596 7.4 31.1 -169.1 0.3255 1.5 5.1 Cen X-3
186.8793 -62.6817 18.4 31.5 175.4 -0.1440 -0.6 8.1 GX 301-2
210.2346 -54.8845 3.1 29.4 147.3 0.9633 3.7 ------ UNKNOWN
155.7084 -4.1392 2.8 39.0 -55.5 1.5331 4.1 ------ UNKNOWN
Pre-slew background subtracted image of 15-350 keV band
Time interval of the image:
-1.816000 12.008000
# RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name
# [deg] [deg] ['] [deg] [deg] [']
135.4463 -40.3690 5.4 41.1 -120.6 -0.3836 -2.1 11.8 Vela X-1
170.0502 -60.6122 6.8 31.1 -168.7 0.1016 1.7 7.8 Cen X-3
186.5881 -62.7885 4.3 31.6 175.7 -0.1622 -2.7 2.2 GX 301-2
213.1119 2.4936 2.1 42.7 39.5 0.7024 5.5 ------ UNKNOWN
215.2905 -16.1913 2.2 31.0 64.4 0.4457 5.3 ------ UNKNOWN
224.9804 -47.8314 2.7 34.1 127.1 0.3765 4.3 ------ UNKNOWN
125.9260 -60.2450 2.4 48.3 -148.5 0.5825 4.8 ------ UNKNOWN
134.5383 -33.4725 0.9 42.7 -110.5 4.0662 13.5 ------ UNKNOWN
Post-slew image of 15-350 keV band
Time interval of the image:
76.596590 302.356000
# RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name
# [deg] [deg] ['] [deg] [deg] [']
135.6125 -40.7242 4.7 7.3 138.4 0.5251 2.4 10.9 Vela X-1
170.3539 -60.7028 11.7 35.7 115.3 0.4860 1.0 4.9 Cen X-3
138.3952 -63.7793 2.6 30.4 141.3 1.2839 4.4 ------ UNKNOWN
146.6079 -4.5191 2.9 31.1 -11.6 0.9424 4.0 ------ UNKNOWN
157.3279 19.3950 2.7 57.2 -9.6 4.2933 4.2 ------ UNKNOWN
60.2060 -41.3116 2.8 57.8 -156.6 4.7511 4.1 ------ UNKNOWN
87.0374 -20.2945 2.6 44.0 -120.4 4.2593 4.5 ------ UNKNOWN
Plot creation:
Fri Dec 18 19:05:35 EST 2015