GRB081127: 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: Sun Jan 19 20:22:17 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger335715
======================================================================

  Trigger: 00335715      Segment: 000

  BAT Trigger Time: 249462312.192   [s; MET]
      Trigger Stop: 249462320.384   [s; MET]
               UTC: 2008-11-27T07:05:08.903800    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 332.09265321205   Dec: 6.85939107792509  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.25
     Image Trigger?:     NO
     Rate S/N Ratio:     8.42614977317636  [ if not an image trigger ]
     Image S/N Ratio:    7.25

  Analysis Position:   [ source = BAT ]
    RA: 332.09265321205   Dec: 6.85939107792509  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 332.0823951619   Dec: 6.84381693017392  [deg; J2000]  
        { 22h 08m 19.8s , +06d 50' 37.7" }
         +/- 2.33254644561019 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.991046344579726 [arcmin] (formal 1-sigma fit error)
    SNR: 9.07081944969431
 
  Angular difference between the analysis and refined position is 1.116523 arcmin
 
  Partial Coding Fraction: 0.515625    [ including projection effects ]

  Duration
     T90: 17.3000000119209 +/- 3.54516966255674
        Measured from: -9.21999999880791
                   to: 8.08000001311302     [s; relative to TRIGTIME]
     T50: 8.54800000786781 +/- 3.52388478836441
        Measured from: -4.03999999165535
                   to: 4.50800001621246     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: -4.59200000762939     
                   to: -3.59200000762939     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -10.7120000123978     
                   to: 8.53599998354912     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.287636   0.227198   0.171459   0.009593
           0.034745   0.036179   0.032935   0.030583 [error]
 Peak      0.041736   0.017142   0.012955   0.011269
           0.008060   0.008059   0.007650   0.007142 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   19.248  -10.712    8.536
T90    17.300   -9.220    8.080
T50     8.548   -4.040    4.508
Peak    1.000   -4.592   -3.592
 
 
====== 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      -2.044    -0.318      0.290       -           -               -         2.26e-03     -4.52e-04          4.30e-04      48.930   57
CPL     -2.113    -0.308      0.716       60.636      N/A           N/A         2.03e-03        N/A               N/A         48.770   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      -2.288     -0.803     0.620       -           -               -         4.04e-03     -2.01e-03          1.91e-03      66.350   57
CPL     -1.987     -0.024     1.987        1.817      N/A           N/A         6.00e-03        N/A               N/A         66.470   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   9.27e-08  1.22e-07  1.19e-07  2.06e-07  4.02e-07  5.40e-07   erg/cm2
      90%_error_low -1.92e-08 -1.81e-08 -3.21e-08 -9.32e-08 -7.16e-08 -1.33e-07   erg/cm2
      90%_error_hi   1.98e-08  1.79e-08  3.30e-08  1.34e-07  7.38e-08  1.64e-07   erg/cm2
Peak flux       PL   3.57e-01  2.26e-01  9.27e-02  5.15e-02  7.02e-01  7.27e-01   ph/cm2/s
      90%_error_low -1.40e-01 -7.70e-02 -5.49e-02 -5.15e-02 -2.12e-01 -2.23e-01   ph/cm2/s
      90%_error_hi   1.46e-01  7.26e-02  6.33e-02  8.94e-02  2.12e-01  2.26e-01   ph/cm2/s
 
Fluence        CPL   9.18e-08  1.08e-07  1.15e-07  2.27e-07  3.84e-07  5.56e-07   erg/cm2
      90%_error_low -2.30e-08 -5.85e-08 -9.40e-08 -1.10e-07    N/A       N/A      erg/cm2
      90%_error_hi   2.08e-08  3.07e-08  2.92e-08  7.82e-08    N/A       N/A      erg/cm2
Peak flux      CPL   3.58e-01  2.24e-01  9.25e-02  5.92e-02  7.03e-01  7.35e-01   ph/cm2/s
      90%_error_low -1.33e-01     N/A       N/A   -5.92e-02     N/A       N/A     ph/cm2/s
      90%_error_hi   1.45e-01     N/A       N/A    8.09e-02     N/A       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
  332.0824     6.8438   0.0212    42.4819  -171.4140         0.6596626      9.071 TRIG_00335715                 
 
Foreground time interval of the image:
-10.712   8.536 (delta_t =  19.248 [sec])
Background time interval of the image:
-239.192 -10.712 (delta_t = 228.480 [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  -10.712 sec. to    8.536 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.04359     ( -0.317987   0.289721 )
Norm@50keV  : 2.25716E-03    ( -0.000452062   0.00043018 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          48.93 using 59 PHA bins.
# Reduced chi-squared =         0.8584 for     57 degrees of freedom 
# Null hypothesis probability =   7.677471e-01
 
Photon flux (15-150 keV)    in 19.25 sec: 0.345568 ( -0.050034  0.050055 ) ph/cm2/s
Energy fluence (15-150 keV)             : 4.01855e-07 ( -7.16373e-08  7.37654e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from  -10.712 sec. to    8.536 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.2738     ( -0.146558   0.876995 )
Epeak [keV] : 113.046      (   )
Norm@50keV  : 1.70229E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          48.69 using 59 PHA bins.
# Reduced chi-squared =         0.8695 for     56 degrees of freedom 
# Null hypothesis probability =   7.452199e-01
 
Photon flux (15-150 keV)    in 19.25 sec: 0.305494 (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.8361e-07 ( 0  0 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   -4.592 sec. to   -3.592 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.28805     ( -0.803295   0.620107 )
Norm@50keV  : 4.04305E-03    ( -0.00201273   0.00191088 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          66.35 using 59 PHA bins.
# Reduced chi-squared =          1.164 for     57 degrees of freedom 
# Null hypothesis probability =   1.856650e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.701969 ( -0.212395  0.212455 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.85603e-08 ( -1.46651e-08  1.6193e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -4.592 sec. to   -3.592 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.36261     ( -0.0238239   1.98724 )
Epeak [keV] : 178.003      (   )
Norm@50keV  : 3.63389E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          66.34 using 59 PHA bins.
# Reduced chi-squared =          1.185 for     56 degrees of freedom 
# Null hypothesis probability =   1.622784e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.702733 (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 17.3 sec.
Hardness ratio (energy fluence ratio) = 0.97026421737

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

S(15-50 keV)  = 2.1514691e-07
S(50-150 keV) = 1.8670246e-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 = -9.054860239403703E-01, IMY = 1.367151129898282E-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:
-239.192000 -10.712000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
299.5958  35.2016    0.3  22.2  -97.4   8.2143  38.9    0.3	Cyg X-1                       
308.0861  40.8143    7.9  13.5  -98.9   0.2656   1.5    8.4	Cyg X-3                       
326.1306  38.2875    3.2  10.6 -169.9   0.6907   3.6    2.8	Cyg X-2                       
333.9836  53.1449    2.6   7.9   73.2   0.7471   4.4 ------	UNKNOWN                       
278.0933  27.2273    3.1  41.0  -83.6   2.9663   3.8 ------	UNKNOWN                       
298.0759   8.3950    2.0  45.7 -122.3   4.7971   5.7 ------	UNKNOWN                       

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

Time interval of the image:
-10.712000 8.536000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
299.5434  35.2406   15.1  22.2  -97.2  -0.0428  -0.8    3.3	Cyg X-1                       
307.8582  41.0059    4.9  13.5  -97.8  -0.1089  -2.4   11.9	Cyg X-3                       
325.9791  38.3061    4.9  10.5 -169.2  -0.1010  -2.4    9.1	Cyg X-2                       
 53.2118  70.7070    2.1  44.7   49.2   1.0952   5.6 ------	UNKNOWN                       
 16.0232  63.5023    2.2  31.6   63.6   0.3982   5.2 ------	UNKNOWN                       
332.0824   6.8438    1.3  42.5 -171.4   0.6597   9.1 ------	UNKNOWN                       
317.9253  -6.2731    2.3  55.2 -152.0   0.9820   5.1 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
111.108600 784.239000
785.808000 962.864000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
288.7508  10.9009    1.8  43.0  -60.0  10.9442   6.3    3.9	GRS 1915+105                  
299.5907  35.2137    0.3  41.1  -20.4  29.8264  44.1    0.7	Cyg X-1                       
307.9250  41.0283   28.6  40.4   -7.1  -0.2908  -0.4    9.5	Cyg X-3                       
326.2464  38.2327    7.5  31.8   12.7   0.8127   1.5    6.4	Cyg X-2                       
350.9950  40.6969    2.8  37.8   45.0   3.8214   4.2 ------	UNKNOWN                       
340.8826  12.3138    3.8  10.2   78.6   1.2438   3.1 ------	UNKNOWN                       
358.5853 -41.5010    3.8  54.1  177.0   6.4730   3.0 ------	UNKNOWN                       
282.3449  23.2865    3.0  50.5  -44.0   9.6578   3.8 ------	UNKNOWN