GRB091018

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: Sun Jan 19 13:35:36 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger373172
======================================================================

  Trigger: 00373172      Segment: 000

  BAT Trigger Time: 277591704.768   [s; MET]
      Trigger Stop: 277591705.024   [s; MET]
               UTC: 2009-10-18T20:48:19.585200    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 32.2106435093656   Dec: -57.526501145527  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    11.47
     Image Trigger?:     NO
     Rate S/N Ratio:     29.7153159162073  [ if not an image trigger ]
     Image S/N Ratio:    11.47

  Analysis Position:   [ source = BAT ]
    RA: 32.2106435093656   Dec: -57.526501145527  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 32.1911174548272   Dec: -57.5461837742416  [deg; J2000]  
        { 02h 08m 45.9s , -57d 32' 46.3" }
         +/- 0.605207853845408 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.195793938013885 [arcmin] (formal 1-sigma fit error)
    SNR: 62.3280157415109
 
  Angular difference between the analysis and refined position is 1.337953 arcmin
 
  Partial Coding Fraction: 0.84375    [ including projection effects ]

  Duration
     T90: 4.36799991130829 +/- 0.597126457364303
        Measured from: 0.240000009536743
                   to: 4.60799992084503     [s; relative to TRIGTIME]
     T50: 1.55999994277954 +/- 0.078790888946051
        Measured from: 0.995999991893768
                   to: 2.55599993467331     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 0.800000011920929     
                   to: 1.80000001192093     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -0.26800000667572     
                   to: 7.74799996614456     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     1.303209   1.230202   0.484412   0.074576
           0.022100   0.022398   0.018385   0.016636 [error]
 Peak      0.446662   0.490489   0.204968   0.028382
           0.010884   0.011349   0.008530   0.006127 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100    8.016   -0.268    7.748
T90     4.368    0.240    4.608
T50     1.560    0.996    2.556
Peak    1.000    0.800    1.800
 
 
====== 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      -2.305    -0.062      0.061       -           -               -         1.98e-02     -6.61e-04          6.58e-04      52.810   57
CPL     -1.758    -0.180      0.291       19.425      N/A           N/A         3.90e-02        N/A               N/A         40.100   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      -2.193     -0.064     0.063       -           -               -         6.29e-02     -2.36e-03          2.35e-03      86.410   57
CPL     -1.298     -0.293     0.316       35.062      -5.928         4.093      1.91e-01     -5.76e-02          9.12e-02      55.280   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   4.34e-07  4.91e-07  3.97e-07  5.35e-07  1.52e-06  1.86e-06   erg/cm2
      90%_error_low -2.14e-08 -1.40e-08 -1.88e-08 -5.19e-08 -4.38e-08 -6.93e-08   erg/cm2
      90%_error_hi   2.18e-08  1.40e-08  1.89e-08  5.57e-08  4.39e-08  7.14e-08   erg/cm2
Peak flux       PL   5.06e+00  3.39e+00  1.48e+00  8.95e-01  1.04e+01  1.08e+01   ph/cm2/s
      90%_error_low -2.74e-01 -1.14e-01 -7.32e-02 -8.45e-02 -3.76e-01 -3.72e-01   ph/cm2/s
      90%_error_hi   2.79e-01  1.14e-01  7.33e-02  8.98e-02  3.77e-01  3.73e-01   ph/cm2/s
 
Fluence        CPL    N/A      N/A      N/A      N/A      N/A      N/A      erg/cm2
      90%_error_low -2.14e-08 -1.40e-08 -1.88e-08 -5.19e-08 -4.38e-08 -6.93e-08   erg/cm2
      90%_error_hi   2.18e-08  1.40e-08  1.89e-08  5.57e-08  4.39e-08  7.14e-08   erg/cm2
Peak flux      CPL   4.40e+00  3.64e+00  1.49e+00  3.48e-01  9.80e+00  9.89e+00   ph/cm2/s
      90%_error_low -3.33e-01 -1.40e-01 -8.36e-02 -9.04e-02 -4.11e-01 -4.30e-01   ph/cm2/s
      90%_error_hi   3.38e-01  1.42e-01  8.29e-02  1.17e-01  4.13e-01  4.37e-01   ph/cm2/s
 
======================================================================

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
   32.1911   -57.5462   0.0031    15.9048   107.0354         3.1889414     62.328 TRIG_00373172                 
 
Foreground time interval of the image:
 -0.268   7.748 (delta_t =   8.016 [sec])
Background time interval of the image:
-194.467  -0.268 (delta_t = 194.199 [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

Bokeh Plot

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   -0.268 sec. to    7.748 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.30533     ( -0.0618704   0.0611911 )
Norm@50keV  : 1.97914E-02    ( -0.000661361   0.000657676 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          52.81 using 59 PHA bins.
# Reduced chi-squared =         0.9264 for     57 degrees of freedom 
# Null hypothesis probability =   6.330687e-01
 
Photon flux (15-150 keV)    in 8.016 sec: 3.46940 ( -0.11329  0.114 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.51788e-06 ( -4.3843e-08  4.39306e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from   -0.268 sec. to    7.748 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.75839     ( -0.179916   0.291029 )
Epeak [keV] : 19.4255      (   )
Norm@50keV  : 3.89938E-02    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          40.10 using 59 PHA bins.
# Reduced chi-squared =         0.7160 for     56 degrees of freedom 
# Null hypothesis probability =   9.462677e-01
 
Photon flux (15-150 keV)    in 8.016 sec: 3.31149 ( -0.13398  0.13477 ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

1-s peak spectrum fit

Power-law model

Time interval is from    0.800 sec. to    1.800 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.19323     ( -0.0635088   0.0626933 )
Norm@50keV  : 6.29420E-02    ( -0.0023644   0.00235209 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          86.41 using 59 PHA bins.
# Reduced chi-squared =          1.516 for     57 degrees of freedom 
# Null hypothesis probability =   7.216812e-03
 
Photon flux (15-150 keV)    in 1 sec: 10.3843 ( -0.3756  0.377 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.91344e-07 ( -2.01811e-08  2.02314e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from    0.800 sec. to    1.800 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.29822     ( -0.293489   0.315513 )
Epeak [keV] : 35.0618      ( -5.92761 4.09311 )
Norm@50keV  : 0.191167    ( -0.057644   0.0911828 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          55.28 using 59 PHA bins.
# Reduced chi-squared =         0.9871 for     56 degrees of freedom 
# Null hypothesis probability =   5.021020e-01
 
Photon flux (15-150 keV)    in 1 sec: 9.80284 ( -0.41101  0.41296 ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 4.368 sec.
Hardness ratio (energy fluence ratio) = 0.809300913862

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

S(15-50 keV)  = 9.247455e-07
S(50-150 keV) = 5.931611e-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 = -8.347940129779462E-02, IMY = -2.724465592529742E-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:
-194.467410 -0.268000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
124.4538 -38.3966    4.4  59.1 -166.2   3.2210   2.6 ------	UNKNOWN

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

Time interval of the image:
-0.268000 7.748000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 32.1911 -57.5462    0.2  15.9  107.0   3.1890  62.3 ------	UNKNOWN                       
323.4794 -32.2878    2.6  48.2    9.7   0.4774   4.5 ------	UNKNOWN                       
209.6002 -66.6184    3.2  41.1  -97.9   0.6566   3.6 ------	UNKNOWN

Post-slew image of 15-350 keV band

Time interval of the image:
49.932600 962.283400
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
322.2071 -42.6595    2.6  45.0   -3.1   4.0582   4.4 ------	UNKNOWN                       
107.9095 -28.0875    3.6  59.1 -166.2  11.7139   3.2 ------	UNKNOWN

Analysis Summary

Notes:

Image

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

Light Curves

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:

Time averaged spectrum fit using the average DRM

Power-law model

Cutoff power-law model

1-s peak spectrum fit

Power-law model

Cutoff power-law model

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

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

Mask shadow pattern

Spacecraft aspect plot

Bright source in the pre-burst/pre-slew/post-slew images

Pre-burst image of 15-350 keV band

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

Post-slew image of 15-350 keV band

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