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
3.1522 32.5706 0.0140 41.6303 -69.8356 4.6458368 13.708 TRIG_00311658
Foreground time interval of the image:
-10.640 17.088 (delta_t = 27.728 [sec])
Background time interval of the image:
-60.608 -10.640 (delta_t = 49.968 [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
Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 2.048000
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 2.048000
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 2.048000
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 -10.640 sec. to 17.088 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 2.19090 ( -0.151425 0.158906 )
Norm@50keV : 9.90969E-03 ( -0.00108751 0.00107329 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 62.96 using 59 PHA bins.
# Reduced chi-squared = 1.104 for 57 degrees of freedom
# Null hypothesis probability = 2.737814e-01
Photon flux (15-150 keV) in 27.73 sec: 1.63277 ( -0.129703 0.129729 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.58038e-06 ( -2.445e-07 2.49398e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -10.640 sec. to 17.088 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.394165 ( -1.18759 0.955541 )
Epeak [keV] : 33.4651 ( -6.17061 4.63386 )
Norm@50keV : 0.123518 ( -0.123567 0.554639 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 50.28 using 59 PHA bins.
# Reduced chi-squared = 0.8979 for 56 degrees of freedom
# Null hypothesis probability = 6.901307e-01
Photon flux (15-150 keV) in 27.73 sec: 1.53084 ( -0.13648 0.13743 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.19327e-06 ( -2.4558e-07 2.80644e-07 ) ergs/cm2
Band function
Time interval is from -10.640 sec. to 17.088 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -7.19690E-02 ( -1.13892 1.78905 )
beta : -3.20225 ( 3.20521 0.638535 )
Epeak [keV] : 32.6443 ( -4.4204 4.59555 )
Norm@50keV : 0.204840 ( -0.238985 3.42755 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.93 using 59 PHA bins.
# Reduced chi-squared = 0.8896 for 55 degrees of freedom
# Null hypothesis probability = 7.044936e-01
Photon flux (15-150 keV) in 27.73 sec: ( ) ph/cm2/s
Energy fluence (15-150 keV) : 2.2912e-06 ( -2.29101e-06 -2.84621e-07 ) ergs/cm2
Single BB
Spectral model blackbody:
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 8.80855 (-0.694373 0.751822)
R^2/D10^2 : 1.24222 (-0.346236 0.482104)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 57.17 using 59 PHA bins.
# Reduced chi-squared = 1.003 for 57 degrees of freedom
# Null hypothesis probability = 4.687853e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 5.144e-07 6.558e-08
25- 50 1.057e-06 1.020e-07
50-150 3.773e-07 8.911e-08
15-150 1.949e-06 1.926e-07
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 46.1358 (-8.64781 11.9338)
Norm : 9.70804 (-1.28014 1.59598)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 52.78 using 59 PHA bins.
# Reduced chi-squared = 0.9260 for 57 degrees of freedom
# Null hypothesis probability = 6.340161e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 6.453e-07 7.265e-08
25- 50 8.996e-07 8.014e-08
50-150 8.079e-07 1.945e-07
15-150 2.353e-06 2.361e-07
Double BB
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 7.78681 ( )
R1^2/D10^2 : 1.81969 (-0.654782 278.022)
kT2 [keV] : 28.8189 (-27.1673 -29.3049)
R2^2/D10^2 : 4.17547E-03 (-0.00399293 0.826176)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 51.26 using 59 PHA bins.
#Fit statistic : Chi-Squared = 49.91 using 59 PHA bins.
# Reduced chi-squared = 0.9321 for 55 degrees of freedom
# Reduced chi-squared = 0.9074 for 55 degrees of freedom
# Null hypothesis probability = 6.181233e-01
# Null hypothesis probability = 6.690079e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 5.958e-07 3.056e-07
25- 50 9.778e-07 5.144e-07
50-150 5.339e-07 3.084e-07
15-150 2.107e-06 1.074e-06
Peak spectrum fit
Power-law model
Time interval is from 0.868 sec. to 1.868 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 2.02448 ( -0.359672 0.409815 )
Norm@50keV : 2.25215E-02 ( -0.00611301 0.00581383 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 44.39 using 59 PHA bins.
# Reduced chi-squared = 0.7787 for 57 degrees of freedom
# Null hypothesis probability = 8.884304e-01
Photon flux (15-150 keV) in 1 sec: 3.41682 ( -0.679117 0.679121 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.07991e-07 ( -5.06242e-08 5.26477e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.868 sec. to 1.868 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.81753 ( -2.41273 0.303787 )
Epeak [keV] : 35.6885 ( )
Norm@50keV : 2.99387E-02 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 44.33 using 59 PHA bins.
# Reduced chi-squared = 0.7916 for 56 degrees of freedom
# Null hypothesis probability = 8.699873e-01
Photon flux (15-150 keV) in 1 sec: 3.39706 ( -0.69655 0.69038 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.03352e-07 ( -6.2527e-08 5.6441e-08 ) ergs/cm2
Band function
Time interval is from 0.868 sec. to 1.868 sec.
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : 4.49082 ( -4.49082 -4.49082 )
beta : -2.29259 ( -0.741354 0.492657 )
Epeak [keV] : 24.6022 ( -24.6022 6.53916 )
Norm@50keV : 1805.11 ( -356.523 3.96552e+07 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 43.52 using 59 PHA bins.
# Reduced chi-squared = 0.7913 for 55 degrees of freedom
# Null hypothesis probability = 8.678869e-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] : 8.39899 (-1.70761 2.31991)
R^2/D10^2 : 3.12451 (-1.92336 4.52245)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.41 using 59 PHA bins.
# Reduced chi-squared = 0.8493 for 57 degrees of freedom
# Null hypothesis probability = 7.839639e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 4.123e-08 1.779e-08
25- 50 7.838e-08 2.972e-08
50-150 2.409e-08 1.429e-08
15-150 1.437e-07 4.748e-08
Thermal bremsstrahlung (OTTB)
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT [keV] : 61.0116 (-28.1592 77.2343)
Norm : 17.8258 (-5.17714 8.07363)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 44.55 using 59 PHA bins.
# Reduced chi-squared = 0.7815 for 57 degrees of freedom
# Null hypothesis probability = 8.850013e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 4.492e-08 1.343e-08
25- 50 6.872e-08 2.182e-08
50-150 7.928e-08 4.926e-08
15-150 1.929e-07 6.874e-08
Double BB
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters : value Lower 90% Upper 90%
kT1 [keV] : 6.67901 (-2.51014 2.43021)
R1^2/D10^2 : 6.46865 (-3.82144 19.6366)
kT2 [keV] : 29.7915 (-23.0805 -35.9724)
R2^2/D10^2 : 1.44627E-02 (-0.00839899 0.151243)
------------------------------------------------------------
#Fit statistic : Chi-Squared = 43.06 using 59 PHA bins.
# Reduced chi-squared = 0.7829 for 55 degrees of freedom
# Null hypothesis probability = 8.787044e-01
Energy Fluence 90% Error
[keV] [erg/cm2] [erg/cm2]
15- 25 4.605e-08 2.686e-08
25- 50 6.737e-08 3.765e-08
50-150 8.564e-08 5.770e-08
15-150 1.991e-07 1.098e-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: 2.19090 ( -0.151425 0.158906 )
Norm@50keV : 9.90969E-03 ( -0.00108751 0.00107329 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 62.96 using 59 PHA bins.
# Reduced chi-squared = 1.104 for 57 degrees of freedom
# Null hypothesis probability = 2.737814e-01
Photon flux (15-150 keV) in 27.73 sec: 1.63277 ( -0.129703 0.129729 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.58038e-06 ( -2.445e-07 2.49398e-07 ) ergs/cm2
Cutoff power-law model
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.394165 ( -1.18759 0.955541 )
Epeak [keV] : 33.4651 ( -6.17061 4.63386 )
Norm@50keV : 0.123518 ( -0.123567 0.554639 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 50.28 using 59 PHA bins.
# Reduced chi-squared = 0.8979 for 56 degrees of freedom
# Null hypothesis probability = 6.901307e-01
Photon flux (15-150 keV) in 27.73 sec: 1.53084 ( -0.13648 0.13743 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.19327e-06 ( -2.4558e-07 2.80644e-07 ) ergs/cm2
Band function
Spectral model in the Band function:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
alpha : -7.19690E-02 ( -1.13892 1.78905 )
beta : -3.20225 ( 3.20521 0.638535 )
Epeak [keV] : 32.6443 ( -4.4204 4.59555 )
Norm@50keV : 0.204840 ( -0.238985 3.42755 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.93 using 59 PHA bins.
# Reduced chi-squared = 0.8896 for 55 degrees of freedom
# Null hypothesis probability = 7.044936e-01
Photon flux (15-150 keV) in 27.73 sec: ( ) ph/cm2/s
Energy fluence (15-150 keV) : 2.2912e-06 ( -2.29101e-06 -2.84621e-07 ) ergs/cm2
S(25-50 keV) vs. S(50-100 keV) plot
S(25-50 keV) = 8.16e-07
S(50-100 keV) = 7.15e-07
T90 vs. Hardness ratio plot
T90 = 20.8639999628067 sec.
Hardness ratio (energy fluence ratio) = 0.876225
Color vs. Color plot
Count Ratio (25-50 keV) / (15-25 keV) = 1.28466
Count Ratio (50-100 keV) / (15-25 keV) = 0.371962
Mask shadow pattern
IMX = 3.063780646226157E-01, IMY = 8.343104835587968E-01
TIME vs. PHA plot around the trigger time
Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 2.048000
TIME vs. DetID plot around the trigger time
Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 2.048000
100 us light curve (15-350 keV)
Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 2.048000
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:
-60.608000 -10.640000
# RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name
# [deg] [deg] ['] [deg] [deg] [']
288.8315 10.9131 3.7 39.1 57.6 0.7803 3.1 2.8 GRS 1915+105
299.5614 35.1686 0.8 13.2 67.2 1.2512 14.4 2.4 Cyg X-1
308.2873 41.0209 4.2 4.5 50.0 0.2371 2.7 9.0 Cyg X-3
326.1695 38.4728 5.9 12.9 -43.6 0.1747 2.0 9.1 Cyg X-2
266.2364 34.5228 2.9 35.6 110.2 0.7914 4.0 ------ UNKNOWN
55.1677 72.5245 2.5 51.5 -136.8 2.2202 4.6 ------ UNKNOWN
Pre-slew background subtracted image of 15-350 keV band
Time interval of the image:
-10.640000 17.088000
# RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name
# [deg] [deg] ['] [deg] [deg] [']
288.8168 10.9391 808.5 39.1 57.6 -0.0029 -0.0 1.2 GRS 1915+105
299.5894 35.2639 3.0 13.1 67.4 0.3146 3.9 3.7 Cyg X-1
308.2918 41.0131 6.7 4.5 49.9 -0.1313 -1.7 9.0 Cyg X-3
326.0529 38.1501 8.9 13.1 -42.2 0.1024 1.3 11.7 Cyg X-2
3.1522 32.5706 0.9 41.6 -69.8 4.6475 13.4 ------ UNKNOWN
Post-slew image of 15-350 keV band
Time interval of the image:
408.692600 962.479700
# RAcent DECcent POSerr Theta Phi PeakCts SNR AngSep Name
# [deg] [deg] ['] [deg] [deg] [']
135.5172 -40.5552 1.3 54.3 1.2 10.5726 8.9 0.5 Vela X-1
170.4433 -60.6023 6.6 44.0 37.9 1.6259 1.8 4.0 Cen X-3
186.5133 -62.7529 5.9 44.2 49.2 2.6096 2.0 4.1 GX 301-2
181.6077 -65.4801 2.5 41.0 47.2 3.7067 4.6 ------ UNKNOWN
354.1833 -42.5534 2.5 35.8 -171.5 1.8333 4.7 ------ UNKNOWN
43.3470 -58.3822 3.1 13.1 -98.3 1.2377 3.7 ------ UNKNOWN
70.6287 -58.2760 2.8 18.6 -48.1 1.2598 4.1 ------ UNKNOWN
116.5239 -42.7869 2.7 46.3 -14.4 2.5637 4.3 ------ UNKNOWN
17.5131 -21.6902 6.8 51.0 -135.5 2.9995 1.7 ------ UNKNOWN
Plot creation:
Sun May 31 07:37:55 EDT 2015