GRB091221: 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 12:17:19 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger380311
======================================================================

  Trigger: 00380311      Segment: 000

  BAT Trigger Time: 283121577.664   [s; MET]
      Trigger Stop: 283121578.688   [s; MET]
               UTC: 2009-12-21T20:52:52.295660    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 55.7537241011415   Dec: 23.2118519779555  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.54
     Image Trigger?:     NO
     Rate S/N Ratio:     9.38083151964686  [ if not an image trigger ]
     Image S/N Ratio:    7.54

  Analysis Position:   [ source = BAT ]
    RA: 55.7537241011415   Dec: 23.2118519779555  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 55.7985302009096   Dec: 23.2435055774166  [deg; J2000]  
        { 03h 43m 11.6s , +23d 14' 36.6" }
         +/- 1.31015159961929 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.42040496043359 [arcmin] (formal 1-sigma fit error)
    SNR: 20.6783634160631
 
  Angular difference between the analysis and refined position is 3.116119 arcmin
 
  Partial Coding Fraction: 0.6171875    [ including projection effects ]

  Duration
     T90: 62.8999999165535 +/- 5.65931623683356
        Measured from: -27.7439999580383
                   to: 35.1559999585152     [s; relative to TRIGTIME]
     T50: 17.7159999608994 +/- 1.19157041331859
        Measured from: 10.5120000243187
                   to: 28.227999985218     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 20.6960000395775     
                   to: 21.6960000395775     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -43.5839999914169     
                   to: 41.0840000510216     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     2.689412   3.378063   2.433448   0.624446
           0.075465   0.076489   0.063955   0.052681 [error]
 Peak      0.087862   0.115148   0.128133   0.046834
           0.009206   0.009744   0.008807   0.006987 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   84.668  -43.584   41.084
T90    62.900  -27.744   35.156
T50    17.716   10.512   28.228
Peak    1.000   20.696   21.696
 
 
====== 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      -1.576    -0.056      0.056       -           -               -         7.06e-03     -1.96e-04          1.96e-04      30.150   57
CPL     -1.553    -0.077      0.105      996.012    -996.012      -996.012      7.25e-03     -3.64e-04          6.55e-04      30.660   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      -1.158     -0.137     0.139       -           -               -         2.55e-02     -1.93e-03          1.93e-03      43.320   57
CPL     -1.083     -0.201     0.487      687.739    -687.739      -687.739      2.76e-02     -3.89e-03          1.71e-02      43.380   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   8.20e-07  1.44e-06  1.93e-06  5.31e-06  5.61e-06  9.50e-06   erg/cm2
      90%_error_low -4.69e-08 -4.69e-08 -6.80e-08 -4.26e-07 -1.63e-07 -4.60e-07   erg/cm2
      90%_error_hi   4.81e-08  4.67e-08  6.78e-08  4.52e-07  1.64e-07  4.80e-07   erg/cm2
Peak flux       PL   7.56e-01  9.33e-01  8.36e-01  1.30e+00  2.97e+00  3.82e+00   ph/cm2/s
      90%_error_low -1.16e-01 -8.81e-02 -7.17e-02 -2.28e-01 -2.35e-01 -3.03e-01   ph/cm2/s
      90%_error_hi   1.22e-01  8.70e-02  7.10e-02  2.59e-01  2.36e-01  3.07e-01   ph/cm2/s
 
Fluence        CPL   8.19e-07  1.44e-06  1.92e-06  5.93e-06  5.66e-06  9.56e-06   erg/cm2
      90%_error_low    N/A    -4.69e-08 -5.32e-08    N/A    -2.13e-07 -1.03e-06   erg/cm2
      90%_error_hi     N/A     4.67e-08  8.28e-08    N/A     1.14e-07  1.54e-07   erg/cm2
Peak flux      CPL   7.55e-01  9.33e-01  8.37e-01  1.29e+00  2.97e+00  3.82e+00   ph/cm2/s
      90%_error_low -1.16e-01 -8.14e-02 -7.08e-02 -5.52e-01 -2.41e-01 -6.22e-01   ph/cm2/s
      90%_error_hi   1.22e-01  9.29e-02  8.72e-02  2.55e-01  2.35e-01  2.87e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
   55.7985    23.2435   0.0092    27.2618   -56.9795         2.6428095     20.678 TRIG_00380311                 
 
Foreground time interval of the image:
-43.584  11.837 (delta_t =  55.421 [sec])
Background time interval of the image:
-200.963 -43.584 (delta_t = 157.379 [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  -43.584 sec. to   41.084 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.5758     ( -0.0556834   0.0556686 )
Norm@50keV  : 7.06112E-03    ( -0.0001965   0.000196475 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          30.15 using 59 PHA bins.
# Reduced chi-squared =         0.5289 for     57 degrees of freedom 
# Null hypothesis probability =   9.986921e-01
 
Photon flux (15-150 keV)    in 84.67 sec: 0.900746 ( -0.028512  0.028634 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.60918e-06 ( -1.6316e-07  1.63523e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from  -43.584 sec. to   41.084 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.57355     ( -0.0773558   0.104844 )
Epeak [keV] : 9999.27      ( -9999.29 -9999.29 )
Norm@50keV  : 7.07891E-03    ( -0.000196829   0.000822381 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          30.19 using 59 PHA bins.
# Reduced chi-squared =         0.5391 for     56 degrees of freedom 
# Null hypothesis probability =   9.981258e-01
 
Photon flux (15-150 keV)    in 84.67 sec: 0.911101 ( -0.039028  0.018131 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.6573e-06 ( -2.12532e-07  1.14209e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   20.696 sec. to   21.696 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.15788     ( -0.136717   0.138942 )
Norm@50keV  : 2.54788E-02    ( -0.00193442   0.00193161 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          43.32 using 59 PHA bins.
# Reduced chi-squared =         0.7601 for     57 degrees of freedom 
# Null hypothesis probability =   9.093661e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.97417 ( -0.2353  0.23607 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.61698e-07 ( -2.15716e-08  2.16956e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   20.696 sec. to   21.696 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.08332     ( -0.130665   0.557608 )
Epeak [keV] : 687.739      ( -9999.24 -9999.24 )
Norm@50keV  : 2.75672E-02    ( -0.0019336   0.0191019 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          43.38 using 59 PHA bins.
# Reduced chi-squared =         0.7746 for     56 degrees of freedom 
# Null hypothesis probability =   8.910160e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.97369 ( -0.241  0.23456 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.6165e-07 ( -2.28634e-08  1.96502e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 62.9 sec.
Hardness ratio (energy fluence ratio) = 1.34186939465

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

S(15-50 keV)  = 2.2578427e-06
S(50-150 keV) = 3.351428e-06

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 = 2.808043337596885E-01, IMY = 4.320614184541564E-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:
-200.963400 -43.584000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6378  22.0209    0.3   8.5   14.0   6.6004  37.0    0.5	Crab                          
122.4246  42.8422    2.2  44.9   49.8   4.4097   5.3 ------	UNKNOWN                       
 84.7257  26.3181    0.2  12.9   16.4  13.6714  74.4 ------	UNKNOWN                       
 43.5735  13.7130    3.6  38.0  -76.7   1.7942   3.2 ------	UNKNOWN                       

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

Time interval of the image:
-43.584000 11.836600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.7834  22.0894   10.4   8.6   14.9  -0.1062  -1.1    9.5	Crab                          
 94.5817 -18.4724    2.3  34.1  167.9   0.6679   4.9 ------	UNKNOWN                       
 73.3891  61.5421    2.2  48.5    2.4   1.0690   5.1 ------	UNKNOWN                       
 55.7985  23.2435    0.6  27.3  -57.0   2.6429  20.7 ------	UNKNOWN                       
 63.9829 -11.7810    2.1  31.4 -134.6   0.7223   5.4 ------	UNKNOWN                       
 63.9834 -26.1202    2.1  43.7 -147.0   0.9877   5.4 ------	UNKNOWN                       
 32.7628  36.4570    2.3  50.0  -45.2   2.4253   5.0 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
61.436600 294.436590
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6420  22.0102    0.6  25.7   94.8   9.6615  20.8    0.6	Crab                          
 84.7305  26.3226    0.2  26.4   84.8  27.5325  54.7 ------	UNKNOWN                       
 67.7393 -31.5763    2.9  56.0  175.3   6.1113   3.9 ------	UNKNOWN                       
 21.1797  -5.7577    2.8  44.5 -118.7   6.9023   4.1 ------	UNKNOWN