GRB131227A: 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 Mar  3 23:29:19 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger582184
======================================================================

  Trigger: 00582184      Segment: 000

  BAT Trigger Time: 409812302.656   [s; MET]
      Trigger Stop: 409812303.168   [s; MET]
               UTC: 2013-12-27T04:44:51.212140    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 67.3857857931921   Dec: 28.8645303957545  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.87
     Image Trigger?:     NO
     Rate S/N Ratio:     13.5646599662505  [ if not an image trigger ]
     Image S/N Ratio:    7.87

  Analysis Position:   [ source = BAT ]
    RA: 67.3857857931921   Dec: 28.8645303957545  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 67.3659981459722   Dec: 28.8775730325598  [deg; J2000]  
        { 04h 29m 27.8s , +28d 52' 39.3" }
         +/- 1.29866666048165 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.410235495073138 [arcmin] (formal 1-sigma fit error)
    SNR: 20.940103350303
 
  Angular difference between the analysis and refined position is 1.301291 arcmin
 
  Partial Coding Fraction: 0.90625    [ including projection effects ]

  Duration
     T90: 17.9879999756813 +/- 1.55097383208861
        Measured from: -0.340000033378601
                   to: 17.6479999423027     [s; relative to TRIGTIME]
     T50: 10.41999989748 +/- 1.68187513846769
        Measured from: 2.00400000810623
                   to: 12.4239999055862     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 1.60799998044968     
                   to: 2.60799998044968     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -1.18800002336502     
                   to: 19.227999985218     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.369747   0.476384   0.405377   0.092055
           0.028105   0.029707   0.026495   0.022306 [error]
 Peak      0.046184   0.049559   0.043969   0.006605
           0.006512   0.006988   0.006193   0.005376 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   20.416   -1.188   19.228
T90    17.988   -0.340   17.648
T50    10.420    2.004   12.424
Peak    1.000    1.608    2.608
 
 
====== 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      -1.353    -0.122      0.122       -           -               -         4.22e-03     -2.81e-04          2.81e-04      61.100   57
CPL     -1.341    -0.133      0.418     9967.950    -9967.950      -9967.950      4.27e-03     -3.21e-04          2.40e-03      61.170   56
 
 
=== 1-s peak 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      -1.534     -0.251     0.242       -           -               -         9.12e-03     -1.37e-03          1.34e-03      31.940   57
CPL     -1.254     -0.515     0.993      131.541    -131.541      -131.541      1.27e-02     -1.27e-02          2.68e-02      31.630   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   9.58e-08  1.93e-07  3.02e-07  1.04e-06  8.41e-07  1.63e-06   erg/cm2
      90%_error_low -1.16e-08 -1.39e-08 -2.59e-08 -1.87e-07 -6.31e-08 -2.06e-07   erg/cm2
      90%_error_hi   1.20e-08  1.38e-08  2.58e-08  2.14e-07  6.36e-08  2.29e-07   erg/cm2
Peak flux       PL   3.88e-01  3.83e-01  2.64e-01  2.88e-01  1.15e+00  1.32e+00   ph/cm2/s
      90%_error_low -8.41e-02 -5.40e-02 -5.13e-02 -9.86e-02 -1.58e-01 -1.89e-01   ph/cm2/s
      90%_error_hi   8.88e-02  5.36e-02  5.07e-02  1.25e-01  1.58e-01  1.92e-01   ph/cm2/s
 
Fluence        CPL   9.58e-08  1.93e-07  3.01e-07  1.08e-06  8.43e-07  1.68e-06   erg/cm2
      90%_error_low    N/A    -1.38e-08 -2.69e-08    N/A    -7.26e-08 -5.32e-07   erg/cm2
      90%_error_hi     N/A     1.57e-08  3.00e-08    N/A     6.55e-08  1.06e-08   erg/cm2
Peak flux      CPL   3.70e-01  3.94e-01  2.70e-01  2.06e-01  1.14e+00  1.24e+00   ph/cm2/s
      90%_error_low     N/A   -6.18e-02 -5.45e-02 -1.30e-01 -1.62e-01 -2.21e-01   ph/cm2/s
      90%_error_hi      N/A    6.55e-02  5.69e-02  1.20e-01  1.62e-01  2.56e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
   67.3660    28.8776   0.0092    14.0972   -70.6305         0.9028433     20.940 TRIG_00582184                 
 
Foreground time interval of the image:
 -1.188  10.045 (delta_t =  11.233 [sec])
Background time interval of the image:
-239.656  -1.188 (delta_t = 238.468 [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   -1.188 sec. to   19.228 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.35321     ( -0.121943   0.121854 )
Norm@50keV  : 4.21747E-03    ( -0.000281327   0.000280541 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          61.10 using 59 PHA bins.
# Reduced chi-squared =          1.072 for     57 degrees of freedom 
# Null hypothesis probability =   3.307946e-01
 
Photon flux (15-150 keV)    in 20.42 sec: 0.508428 ( -0.03438  0.03444 ) ph/cm2/s
Energy fluence (15-150 keV)             : 8.40612e-07 ( -6.31201e-08  6.36324e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -1.188 sec. to   19.228 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.34071     ( -0.123375   0.427669 )
Epeak [keV] : 9967.95      ( -9999.36 -9999.36 )
Norm@50keV  : 4.27227E-03    ( -0.000282059   0.00244036 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          61.17 using 59 PHA bins.
# Reduced chi-squared =          1.092 for     56 degrees of freedom 
# Null hypothesis probability =   2.958037e-01
 
Photon flux (15-150 keV)    in 20.42 sec: 0.509273 ( -0.037734  0.035009 ) ph/cm2/s
Energy fluence (15-150 keV)             : 8.42666e-07 ( -7.25862e-08  6.55429e-08 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from    1.608 sec. to    2.608 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.53424     ( -0.25083   0.241638 )
Norm@50keV  : 9.12013E-03    ( -0.00136803   0.00134162 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          31.94 using 59 PHA bins.
# Reduced chi-squared =         0.5603 for     57 degrees of freedom 
# Null hypothesis probability =   9.970679e-01
 
Photon flux (15-150 keV)    in 1 sec: 1.14939 ( -0.157745  0.1578 ) ph/cm2/s
Energy fluence (15-150 keV)             : 8.60677e-08 ( -1.41145e-08  1.43846e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from    1.608 sec. to    2.608 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.25405     ( -0.515296   0.99208 )
Epeak [keV] : 131.541      ( -131.372 -131.372 )
Norm@50keV  : 1.27145E-02    ( -0.0127228   0.0267471 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          31.63 using 59 PHA bins.
# Reduced chi-squared =         0.5648 for     56 degrees of freedom 
# Null hypothesis probability =   9.964774e-01
 
Photon flux (15-150 keV)    in 1 sec: 1.13716 ( -0.162205  0.16194 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.60132e-08 ( -1.33395e-08  9.3149e-09 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 17.988 sec.
Hardness ratio (energy fluence ratio) = 1.56570584593

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

S(15-50 keV)  = 2.885415e-07
S(50-150 keV) = 5.520839e-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 = 8.328994264363478E-02, IMY = 2.369173205339976E-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:
-239.656000 -1.188000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6358  22.0139    0.2   3.1   57.8   9.9504  47.4    0.2	Crab                          
 96.7573  17.5866    2.7  15.8   84.1   0.9867   4.3 ------	UNKNOWN                       
 35.9365  28.9454    2.0  40.8  -86.1   5.6271   5.8 ------	UNKNOWN                       

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

Time interval of the image:
-1.188000 10.044590
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.7951  21.9921    4.7   3.2   58.9   0.1004   2.4    9.1	Crab                          
 74.2050 -25.4852    2.3  47.1  171.4   0.4513   4.9 ------	UNKNOWN                       
 67.3660  28.8776    0.5  14.1  -70.6   0.9029  20.9 ------	UNKNOWN                       
 55.7342  18.7838    2.9  23.3 -107.8   0.1989   4.0 ------	UNKNOWN                       
 36.8910  71.8233    2.4  56.3  -31.2   1.1115   4.8 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
46.044610 838.865900
840.344000 962.379100
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6403  22.0145    0.2  16.2  106.1  39.0140  49.9    0.4	Crab                          
 63.9811  37.9038    3.1   9.5  -21.9   2.5092   3.7 ------	UNKNOWN                       
 61.7705   3.6223    3.4  25.8 -172.3   2.4579   3.4 ------	UNKNOWN                       
 57.3295  18.8256    3.6  13.6 -140.6   2.2928   3.2 ------	UNKNOWN                       
 53.1627 -10.3451    2.8  41.6 -163.9   5.1452   4.1 ------	UNKNOWN                       
351.0732  74.5252    3.0  58.6  -23.0  21.7799   3.9 ------	UNKNOWN                       
 29.2680  -2.2677    2.7  48.0 -129.1  17.4311   4.3 ------	UNKNOWN