GRB090812: 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 14:37:43 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger359711
======================================================================

  Trigger: 00359711      Segment: 000

  BAT Trigger Time: 271749733.888   [s; MET]
      Trigger Stop: 271749734.912   [s; MET]
               UTC: 2009-08-12T06:02:08.897520    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 353.194081792447   Dec: -10.5945573605417  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    10.25
     Image Trigger?:     NO
     Rate S/N Ratio:     23.388031127053  [ if not an image trigger ]
     Image S/N Ratio:    10.25

  Analysis Position:   [ source = BAT ]
    RA: 353.194081792447   Dec: -10.5945573605417  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 353.200640692419   Dec: -10.6103031693898  [deg; J2000]  
        { 23h 32m 48.2s , -10d 36' 37.1" }
         +/- 0.736804038461972 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.217492457408143 [arcmin] (formal 1-sigma fit error)
    SNR: 47.0560562478732
 
  Angular difference between the analysis and refined position is 1.020870 arcmin
 
  Partial Coding Fraction: 0.78125    [ including projection effects ]

  Duration
     T90: 74.4959999918938 +/- 15.2868744039961
        Measured from: -1.74800002574921
                   to: 72.7479999661446     [s; relative to TRIGTIME]
     T50: 24.2639999389648 +/- 1.34571912144514
        Measured from: 7.68400001525879
                   to: 31.9479999542236     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 26.8240000009537     
                   to: 27.8240000009537     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -5.43999999761581     
                   to: 113.884000003338     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     1.835128   2.946024   2.635923   0.899099
           0.062624   0.064592   0.059081   0.051420 [error]
 Peak      0.080606   0.136323   0.174052   0.075662
           0.007078   0.008251   0.008537   0.007089 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100  119.324   -5.440  113.884
T90    74.496   -1.748   72.748
T50    24.264    7.684   31.948
Peak    1.000   26.824   27.824
 
 
====== 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      -1.218    -0.050      0.050       -           -               -         4.76e-03     -1.23e-04          1.23e-04      51.520   57
CPL     -1.217    -0.047      0.054     9999.360    -9999.360      -9999.360      4.78e-03     -1.20e-04          5.06e-04      51.620   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      -0.862     -0.103     0.105       -           -               -         3.09e-02     -1.78e-03          1.77e-03      43.040   57
CPL     -0.858     -0.102     0.190     9999.360    -9999.360      -9999.360      3.11e-02     -1.75e-03          1.04e-02      43.070   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   5.57e-07  1.22e-06  2.09e-06  8.31e-06  5.73e-06  1.22e-05   erg/cm2
      90%_error_low -3.13e-08 -3.95e-08 -6.15e-08 -5.79e-07 -1.56e-07 -6.04e-07   erg/cm2
      90%_error_hi   3.21e-08  3.94e-08  6.14e-08  6.10e-07  1.56e-07  6.31e-07   erg/cm2
Peak flux       PL   6.93e-01  1.02e+00  1.12e+00  2.32e+00  3.55e+00  5.16e+00   ph/cm2/s
      90%_error_low -8.45e-02 -7.63e-02 -6.80e-02 -3.04e-01 -2.03e-01 -3.39e-01   ph/cm2/s
      90%_error_hi   8.85e-02  7.55e-02  6.76e-02  3.34e-01  2.03e-01  3.50e-01   ph/cm2/s
 
Fluence        CPL   5.56e-07  1.22e-06  2.09e-06  8.26e-06  5.77e-06  1.26e-05   erg/cm2
      90%_error_low    N/A    -3.96e-08    N/A       N/A    -1.93e-07 -1.56e-06   erg/cm2
      90%_error_hi     N/A     3.94e-08    N/A       N/A     1.18e-07  7.23e-08   erg/cm2
Peak flux      CPL   6.92e-01  1.02e+00  1.11e+00  2.31e+00  3.56e+00  5.37e+00   ph/cm2/s
      90%_error_low     N/A   -7.24e-02     N/A       N/A       N/A   -9.18e-01   ph/cm2/s
      90%_error_hi      N/A    7.95e-02     N/A       N/A       N/A    5.18e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  353.2006   -10.6103   0.0041    26.5164   -36.6891         2.8026076     47.056 TRIG_00359711                 
 
Foreground time interval of the image:
 -5.440  12.413 (delta_t =  17.853 [sec])
Background time interval of the image:
-239.888  -5.440 (delta_t = 234.448 [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   -5.440 sec. to  113.884 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.21816     ( -0.0499509   0.0501944 )
Norm@50keV  : 4.75791E-03    ( -0.000123078   0.000122919 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          51.52 using 59 PHA bins.
# Reduced chi-squared =         0.9039 for     57 degrees of freedom 
# Null hypothesis probability =   6.799890e-01
 
Photon flux (15-150 keV)    in 119.3 sec: 0.559954 ( -0.01569  0.015749 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.73021e-06 ( -1.55647e-07  1.56068e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -5.440 sec. to  113.884 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.21661     ( -0.0481708   0.0529067 )
Epeak [keV] : 9999.36      ( -9999.36 -9999.36 )
Norm@50keV  : 4.77778E-03    ( -0.000122499   0.000503098 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          51.62 using 59 PHA bins.
# Reduced chi-squared =         0.9218 for     56 degrees of freedom 
# Null hypothesis probability =   6.412306e-01
 
Photon flux (15-150 keV)    in 119.3 sec: 0.564065 ( -0.019974  0.011445 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.76582e-06 ( -1.93055e-07  1.18424e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   26.824 sec. to   27.824 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.862179     ( -0.103147   0.104912 )
Norm@50keV  : 3.09051E-02    ( -0.00177817   0.00177152 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          43.04 using 59 PHA bins.
# Reduced chi-squared =         0.7551 for     57 degrees of freedom 
# Null hypothesis probability =   9.144651e-01
 
Photon flux (15-150 keV)    in 1 sec: 3.54715 ( -0.20289  0.20314 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.52087e-07 ( -2.19076e-08  2.19977e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   26.824 sec. to   27.824 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.857521     ( -0.102026   0.189385 )
Epeak [keV] : 9999.36      ( -9999.36 -9999.36 )
Norm@50keV  : 3.11046E-02    ( -0.00176833   0.0103368 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          43.07 using 59 PHA bins.
# Reduced chi-squared =         0.7691 for     56 degrees of freedom 
# Null hypothesis probability =   8.973803e-01
 
Photon flux (15-150 keV)    in 1 sec: 3.55904 (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.53248e-07 ( -2.50167e-08  2.25634e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 74.496 sec.
Hardness ratio (energy fluence ratio) = 1.71937281308

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

S(15-50 keV)  = 1.7735367e-06
S(50-150 keV) = 3.956765e-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 = 4.000946854737244E-01, IMY = 2.981031347701597E-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:
-239.888000 -5.440000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
288.8472  11.0122    4.9  41.1  136.3   1.3139   2.4    4.9	GRS 1915+105                  
299.5852  35.1962    0.5  44.5  174.7   8.1539  21.2    0.4	Cyg X-1                       
308.1010  40.9352    3.4  45.1 -172.8   1.2289   3.4    1.1	Cyg X-3                       
326.1336  38.3503    4.8  38.5 -154.0   0.7256   2.4    2.5	Cyg X-2                       
326.7038 -14.0430    2.8  14.1   37.2   0.8042   4.1 ------	UNKNOWN                       
322.3076   7.4779    2.5   9.9  169.4   0.8512   4.6 ------	UNKNOWN                       
349.8392  16.1781    2.6  26.5  -99.8   1.1320   4.4 ------	UNKNOWN                       
321.3945  54.1162    2.3  54.6 -156.0   3.5816   5.0 ------	UNKNOWN                       
354.5164  37.2697    2.4  44.4 -121.1   4.7078   4.8 ------	UNKNOWN                       
  8.2062  11.0605    3.1  40.8  -78.0   3.0376   3.7 ------	UNKNOWN                       

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

Time interval of the image:
-5.440000 12.412590
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
288.8113  10.9378    4.2  41.2  136.1  -0.3742  -2.7    0.9	GRS 1915+105                  
299.5911  35.3807   23.7  44.7  174.9  -0.0485  -0.5   10.7	Cyg X-1                       
308.1139  40.9047    4.0  45.1 -172.8  -0.2719  -2.9    2.9	Cyg X-3                       
326.4283  38.2562    0.0  38.4 -153.6  -0.1371  -1.8   12.7	Cyg X-2                       
295.7883  32.1724    2.7  44.8  168.5   0.4371   4.2 ------	UNKNOWN                       
347.6830 -17.5540    2.3  25.5  -16.8   0.2845   5.0 ------	UNKNOWN                       
353.2006 -10.6103    0.2  26.5  -36.7   2.8027  47.1 ------	UNKNOWN                       
312.9077  47.2515    2.1  49.3 -164.9   0.6484   5.4 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
65.612600 962.222000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
326.1496  38.3443   41.2  55.1  165.8   0.8708   0.3    1.7	Cyg X-2                       
 26.2690  19.4009    4.4  44.3 -120.9   6.1408   2.6 ------	UNKNOWN                       
 23.7158  27.1608    3.4  48.0 -130.9   7.7839   3.4 ------	UNKNOWN