GRB151027B: Summary Image Light curves Spectra Distribution Others

Analysis Summary

Notes:

• 1) No attempt has been made to eliminate the non-significant decimal places.
• 2) This batgrbproduct analysis is done using the HEASARC data.
• 3) This batgrbproduct analysis is using the flight position for the mask-weighting calculation.

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Mon Nov 16 01:08:56 EST 2015
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger661869
======================================================================

  Trigger: 00661869      Segment: 000

  BAT Trigger Time: 467678456   [s; MET]
      Trigger Stop: 467678576   [s; MET]
               UTC: 2015-10-27T22:40:40.667480    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 76.2377464873154   Dec: -6.42683741237344  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    8.49
     Image Trigger?:     YES
     Rate S/N Ratio:     0  [ if not an image trigger ]
     Image S/N Ratio:    8.49

  Analysis Position:   [ source = BAT ]
    RA: 76.2377464873154   Dec: -6.42683741237344  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 76.1894059584858   Dec: -6.42844068456665  [deg; J2000]  
        { 05h 04m 45.5s , -06d 25' 42.4" }
         +/- 2.45869500206442 [arcmin] (estimated 90% radius based on SNR)
         +/- 1.40470053168154 [arcmin] (formal 1-sigma fit error)
    SNR: 8.41334829114635
 
  Angular difference between the analysis and refined position is 2.883805 arcmin
 
  Partial Coding Fraction: 0.1738281    [ including projection effects ]

  Duration
     T90: 80 +/- 35.7770876399966
        Measured from: 1
                   to: 81     [s; relative to TRIGTIME]
     T50: 16 +/- 35.7770876399966
        Measured from: 33
                   to: 49     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 40.5     
                   to: 41.5     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: 1     
                   to: 97     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.928979   0.769479   0.763373   0.023569
           0.119891   0.125099   0.109895   0.098764 [error]
 Peak      0.023380   0.013316   0.008950  -0.012960
           0.012491   0.012556   0.011858   0.010579 [error]

     [ fluence units of on-axis counts / fully illuminated detector ] 

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   96.000    1.000   97.000
T90    80.000    1.000   81.000
T50    16.000   33.000   49.000
Peak    1.000   40.500   41.500
 
 
====== Spectral Analysis Summary =====================================
 
Model      : spectral model: simple power-law (PL) and cutoff power-law (CPL)
Ph_index   : photon index: E^{Ph_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 both the PL model and CPL model
Nomr_90err : 90% error of the normalization
chi2       : Chi-Squared
dof        : degree of freedo
 
=== Time-averaged spectral analysis ===
(Best model with acceptable fit: PL)
 
Model Ph_index Ph_90err_low Ph_90err_hi  Epeak  Epeak_90err_low  Epeak_90err_hi  Norm       Nomr_90err_low    Norm_90err_hi    chi2    dof
PL      -1.817    -0.282      0.265       -           -               -         1.67e-03     -2.89e-04          2.79e-04      58.800   57
CPL     -1.664    -0.628      0.971      104.510    -104.495      -104.510      2.01e-03     -2.01e-03          4.27e-03      58.700   56
 
 
=== 1-s peak spectral analysis ===
(Best model with acceptable fit: N/A)
 
Model Ph_index Ph_90err_low Ph_90err_hi  Epeak  Epeak_90err_low  Epeak_90err_hi  Norm       Nomr_90err_low    Norm_90err_hi    chi2    dof
PL      -2.110      2.110     2.110       -           -               -         1.61e-03     -1.61e-03          2.59e-03      45.810   57
CPL      0.006      N/A       N/A          35.515      N/A           N/A         3.21e-02        N/A               N/A         45.700   56
 
 
=== 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         PL   2.75e-07  4.17e-07  4.74e-07  1.02e-06  1.47e-06  2.19e-06   erg/cm2
      90%_error_low -5.96e-08 -6.06e-08 -1.10e-07 -4.15e-07 -2.53e-07 -5.39e-07   erg/cm2
      90%_error_hi   6.22e-08  6.06e-08  1.11e-07  5.66e-07  2.58e-07  6.56e-07   erg/cm2
Peak flux       PL   1.19e-01  8.39e-02  3.90e-02  2.53e-02  2.54e-01  2.67e-01   ph/cm2/s
      90%_error_low -1.19e-01 -8.39e-02 -3.90e-02 -2.53e-02 -2.54e-01 -2.67e-01   ph/cm2/s
      90%_error_hi   2.05e-01  1.07e-01  8.79e-02  7.62e-01  3.19e-01  3.47e-01   ph/cm2/s
 
Fluence        CPL   2.70e-07  4.25e-07  4.77e-07  7.98e-07  1.46e-06  1.97e-06   erg/cm2
      90%_error_low -6.87e-08 -6.72e-08 -1.13e-07 -5.82e-07 -2.65e-07 -6.70e-07   erg/cm2
      90%_error_hi   6.77e-08  7.52e-08  1.17e-07  3.30e-07  2.61e-07  4.04e-07   erg/cm2
Peak flux      CPL   1.01e-01  1.07e-01  2.96e-02  1.29e-03  2.40e-01  2.40e-01   ph/cm2/s
      90%_error_low -1.01e-01     N/A   -2.96e-02     N/A   -2.40e-01     N/A     ph/cm2/s
      90%_error_hi   2.25e-01     N/A    1.19e-01     N/A    3.26e-01     N/A     ph/cm2/s
 
======================================================================

Image

Pre-slew 15.0-350.0 keV image (Event data)

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
   76.1894    -6.4284   0.0228    37.3753   118.1370         2.3288620      8.413 TRIG_00661869                 
 
Foreground time interval of the image:
  1.000  97.000 (delta_t =  96.000 [sec])
Background time interval of the image:
-239.000   1.000 (delta_t = 240.000 [sec])

Light Curves

Note: 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.

Full-time range; 1 s binning

Other quick-look light curves:

• 64 ms binning (zoomed)
• 16 ms binning (zoomed)
• 8 ms binning (zoomed)
• 2 ms binning (zoomed)
• SN=5 or 10 s binning (full-time range)
• Raw light curve

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    1.000 sec. to   97.000 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.81721     ( -0.282463   0.26495 )
Norm@50keV  : 1.66723E-03    ( -0.000288695   0.000279106 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          58.80 using 59 PHA bins.
# Reduced chi-squared =          1.032 for     57 degrees of freedom 
# Null hypothesis probability =   4.094122e-01
 
Photon flux (15-150 keV)    in 96 sec: 0.231303 ( -0.033851  0.033878 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.47289e-06 ( -2.53166e-07  2.58247e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from    1.000 sec. to   97.000 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.66425     ( -0.629094   0.97038 )
Epeak [keV] : 104.510      ( -104.298 -104.313 )
Norm@50keV  : 2.01004E-03    ( -0.00201156   0.00426857 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          58.70 using 59 PHA bins.
# Reduced chi-squared =          1.048 for     56 degrees of freedom 
# Null hypothesis probability =   3.766614e-01
 
Photon flux (15-150 keV)    in 96 sec: 0.229923 ( -0.034696  0.034628 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.4572e-06 ( -2.65492e-07  2.61303e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   40.500 sec. to   41.500 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.10979     ( 2.10699   2.10699 )
Norm@50keV  : 1.60831E-03    ( -0.00160976   0.00258621 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          45.81 using 59 PHA bins.
# Reduced chi-squared =         0.8038 for     57 degrees of freedom 
# Null hypothesis probability =   8.558133e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.254284 ( -0.254284  0.319004 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.49727e-08 ( 1  2.50577e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   40.500 sec. to   41.500 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 10     (       )
Epeak [keV] : 40.8213      (   )
Norm@50keV  : 6795.54    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          45.67 using 59 PHA bins.
# Reduced chi-squared =         0.8155 for     56 degrees of freedom 
# Null hypothesis probability =   8.364178e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.239613 ( -0.239613  0.325663 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.23928e-08 ( 1  2.30649e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 80.0 sec.
Hardness ratio (energy fluence ratio) = 1.13511537219

S(15-50 keV) vs. S(50-150 keV) plot

S(15-50 keV)  = 6.928603e-07
S(50-150 keV) = 7.800346e-07

The dash-dotted line and the dashed line traces the fluences calculated from the Band function with Epeak = 15 and 150 keV, respectively. Both lines assume a canonical values of alpha = -1 and beta = -2.5.

Mask shadow pattern

IMX = -3.602301433771306E-01, IMY = -6.736029410987967E-01

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:
-239.000000 1.000000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.4507 -40.5442    3.4  34.3 -116.6   1.0651   3.3    3.6	Vela X-1                      
 52.3804 -17.7056    2.3  39.7   76.2   3.4876   5.0 ------	UNKNOWN                       
 25.2412 -33.7544    3.0  50.0   37.1   3.6788   3.9 ------	UNKNOWN                       
 45.1844 -34.9603    2.6  34.8   46.6   1.2711   4.4 ------	UNKNOWN                       
101.5367   4.0535    2.3  47.3  156.6   2.4561   5.0 ------	UNKNOWN                       
 71.6697 -36.2584    2.5  14.8   66.8   0.7903   4.6 ------	UNKNOWN                       
357.2594 -78.1398    2.5  49.5  -24.5   1.7715   4.7 ------	UNKNOWN                       
145.8728 -27.1456    3.4  48.0 -129.2   2.8144   3.4 ------	UNKNOWN                       
148.9548 -49.6272    4.9  41.2  -98.2   2.1857   2.4 ------	UNKNOWN                       

Pre-slew background subtracted image of 15-350 keV band

Time interval of the image:
1.000000 97.000000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.5177 -40.5034    4.7  34.4 -116.7   0.4398   2.4    3.1	Vela X-1                      
 76.1894  -6.4284    1.4  37.4  118.1   2.3264   8.4 ------	UNKNOWN                       
148.0289 -64.0324    2.3  39.7  -76.0   1.7274   5.1 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
189.500590 417.900590
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6216  22.0224    0.3  29.4  170.5   9.9218  42.3    0.8	Crab                          
 29.7133 -18.7454    2.2  46.9   46.7   4.4664   5.2 ------	UNKNOWN                       
107.3423   2.2668    3.1  32.3 -128.3   1.0017   3.7 ------	UNKNOWN                       
106.5528 -46.5971    2.5  47.8  -51.5   4.8841   4.6 ------	UNKNOWN