Analysis Summary

Notes:

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Mon Jan 20 09:32:02 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger279898
======================================================================

  Trigger: 00279898      Segment: 000

  BAT Trigger Time: 201375895.232   [s; MET]
      Trigger Stop: 201375899.328   [s; MET]
               UTC: 2007-05-20T17:44:53.264200    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 121.951513642403   Dec: 57.6167755712018  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.32
     Image Trigger?:     NO
     Rate S/N Ratio:     10  [ if not an image trigger ]
     Image S/N Ratio:    7.32

  Analysis Position:   [ source = BAT ]
    RA: 121.951513642403   Dec: 57.6167755712018  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 121.884543601363   Dec: 57.6040422374475  [deg; J2000]  
        { 08h 07m 32.3s , +57d 36' 14.6" }
         +/- 2.05374278052933 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.827842339031581 [arcmin] (formal 1-sigma fit error)
    SNR: 10.87987794157
 
  Angular difference between the analysis and refined position is 2.284012 arcmin
 
  Partial Coding Fraction: 0.59375    [ including projection effects ]

  Duration
     T90: 96 +/- 35.7770876399966
        Measured from: -15.2319999933243
                   to: 80.7680000066757     [s; relative to TRIGTIME]
     T50: 48 +/- 16
        Measured from: 0.76800000667572
                   to: 48.7680000066757     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 8.26800000667572     
                   to: 9.26800000667572     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -15.2319999933243     
                   to: 96.7680000066757     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.338528   0.460883   0.520753   0.164677
           0.055549   0.058019   0.051689   0.044368 [error]
 Peak     -0.000480   0.017660   0.012065   0.003589
           0.005980   0.006183   0.005571   0.004629 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100  112.000  -15.232   96.768
T90    96.000  -15.232   80.768
T50    48.000    0.768   48.768
Peak    1.000    8.268    9.268
 
 
====== 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      -1.130    -0.206      0.212       -           -               -         9.24e-04     -1.03e-04          1.02e-04      70.650   57
CPL     -1.123    -0.210      0.212     9999.300    -9999.300      -9999.300      9.29e-04     -1.02e-04          5.54e-04      70.670   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      -0.871     -0.853     1.239       -           -               -         2.34e-03     -2.34e-03          1.23e-03      39.430   57
CPL     -0.650      2.904     5.296      340.158      N/A           N/A         2.97e-03        N/A               N/A         39.420   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   9.36e-08  2.16e-07  3.95e-07  1.72e-06  1.07e-06  2.42e-06   erg/cm2
      90%_error_low -2.12e-08 -2.97e-08 -5.06e-08 -4.66e-07 -1.28e-07 -4.97e-07   erg/cm2
      90%_error_hi   2.28e-08  2.89e-08  4.97e-08  5.84e-07  1.29e-07  5.98e-07   erg/cm2
Peak flux       PL   5.30e-02  7.77e-02  8.50e-02  1.74e-01  2.69e-01  3.90e-01   ph/cm2/s
      90%_error_low -5.30e-02 -5.58e-02 -4.26e-02 -1.74e-01 -1.41e-01 -1.96e-01   ph/cm2/s
      90%_error_hi   7.16e-02  5.39e-02  4.20e-02  3.26e-01  1.45e-01  2.47e-01   ph/cm2/s
 
Fluence        CPL   9.35e-08  2.14e-07  3.88e-07  1.73e-06  1.08e-06  2.29e-06   erg/cm2
      90%_error_low    N/A    -3.93e-08 -6.40e-08 -8.63e-07 -1.81e-07 -7.18e-07   erg/cm2
      90%_error_hi     N/A     4.12e-08  7.74e-08  5.78e-07  1.73e-07  7.11e-07   erg/cm2
Peak flux      CPL   5.04e-02  7.91e-02  8.74e-02  1.36e-01  2.68e-01  3.53e-01   ph/cm2/s
      90%_error_low -5.04e-02 -5.67e-02 -4.50e-02 -1.36e-01 -1.39e-01 -2.20e-01   ph/cm2/s
      90%_error_hi   7.36e-02  6.90e-02  5.66e-02  2.18e-01  1.46e-01  2.37e-01   ph/cm2/s
 
======================================================================




Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  121.8845    57.6040   0.0177    30.7140  -132.9350         0.9447114     10.880 TRIG_00279898                 
 
Foreground time interval of the image:
-15.232  35.669 (delta_t =  50.901 [sec])
Background time interval of the image:
-239.232 -15.232 (delta_t = 224.000 [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

Bokeh Plot

Other quick-look light curves:




Spectra

Notes:

Time averaged spectrum fit using the average DRM

Power-law model
Time interval is from  -15.232 sec. to   96.768 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.12997     ( -0.20622   0.212101 )
Norm@50keV  : 9.24477E-04    ( -0.000102547   0.00010226 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          70.65 using 59 PHA bins.
# Reduced chi-squared =          1.239 for     57 degrees of freedom 
# Null hypothesis probability =   1.056422e-01
 
Photon flux (15-150 keV)    in 112 sec: 0.107566 ( -0.0124632  0.012506 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.07253e-06 ( -1.28448e-07  1.29152e-07 ) ergs/cm2
 
Cutoff power-law model
Time interval is from  -15.232 sec. to   96.768 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.12307     ( -0.209488   0.212088 )
Epeak [keV] : 9999.30      ( -9999.36 -9999.36 )
Norm@50keV  : 9.29080E-04    ( -0.000101956   0.000553726 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          70.67 using 59 PHA bins.
# Reduced chi-squared =          1.262 for     56 degrees of freedom 
# Null hypothesis probability =   8.967404e-02
 
Photon flux (15-150 keV)    in 112 sec: 0.107541 ( -0.0124639  0.012504 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.07765e-06 ( -1.80908e-07  1.72776e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model
Time interval is from    8.268 sec. to    9.268 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.870843     ( -0.852867   1.23875 )
Norm@50keV  : 2.34332E-03    ( -0.00234332   0.00122923 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          39.43 using 59 PHA bins.
# Reduced chi-squared =         0.6917 for     57 degrees of freedom 
# Null hypothesis probability =   9.632290e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.268940 ( -0.140622  0.14533 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.66042e-08 ( -1.3311e-08  1.34714e-08 ) ergs/cm2
 
Cutoff power-law model
Time interval is from    8.268 sec. to    9.268 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -4.32574     ( 6.57997   8.9722 )
Epeak [keV] : 340.158      (   )
Norm@50keV  : 2.02619E-11    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          39.30 using 59 PHA bins.
# Reduced chi-squared =         0.7017 for     56 degrees of freedom 
# Null hypothesis probability =   9.559061e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.267587 ( -0.138906  0.145531 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.63263e-08 ( -1.54758e-08  1.36811e-08 ) ergs/cm2
 

Time-resolved spectra




Distribution

T90 vs. Hardness ratio plot

T90                                   = 96.0 sec.
Hardness ratio (energy fluence ratio) = 1.82772169537

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

S(15-50 keV)  = 3.0945819e-07
S(50-150 keV) = 7.630813e-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 = -4.046736628681478E-01, IMY = 4.349471981261410E-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:
-239.232000 -15.232000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
163.8851  23.0641    2.5  54.1  164.9   3.3149   4.7 ------	UNKNOWN                       
185.4765  52.5562    3.1  22.7  143.5   0.5592   3.7 ------	UNKNOWN                       
301.1099  57.9528    2.4  39.0    4.4   1.0452   4.8 ------	UNKNOWN                       
135.0757  57.6315    2.5  27.3 -145.7   0.7291   4.6 ------	UNKNOWN                       
 14.6201  56.6865    2.8  48.3  -49.9   3.3428   4.2 ------	UNKNOWN                       
 19.0011  57.7697    3.5  47.2  -53.1   2.4888   3.3 ------	UNKNOWN                       

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

Time interval of the image:
-15.232000 35.668600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
151.8699  69.7939    2.2  13.2 -140.8   0.3325   5.1 ------	UNKNOWN                       
121.8845  57.6040    1.1  30.7 -132.9   0.9447  10.9 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
86.868590 489.968590
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 75.5849  61.7247    3.1  23.2  -50.0   0.8626   3.8 ------	UNKNOWN