GRB050824: 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: Wed Jan 22 20:38:06 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger151905
======================================================================

  Trigger: 00151905      Segment: 000

  BAT Trigger Time: 146617936   [s; MET]
      Trigger Stop: 146618000   [s; MET]
               UTC: 2005-08-24T23:12:16.307660    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 12.2370524365621   Dec: 22.592045480018  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    8.76
     Image Trigger?:     YES
     Rate S/N Ratio:     0  [ if not an image trigger ]
     Image S/N Ratio:    8.76

  Analysis Position:   [ source = BAT ]
    RA: 12.2370524365621   Dec: 22.592045480018  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 12.2653228188403   Dec: 22.5985296617261  [deg; J2000]  
        { 00h 49m 03.7s , +22d 35' 54.7" }
         +/- 1.96949307934943 [arcmin] (estimated 90% radius based on SNR)
         +/- 1.05836823392072 [arcmin] (formal 1-sigma fit error)
    SNR: 11.5507985557348
 
  Angular difference between the analysis and refined position is 1.613627 arcmin
 
  Partial Coding Fraction: 0.75    [ including projection effects ]

  Duration
     T90: 25.0079999566078 +/- 5.55366545321555
        Measured from: 38.4880000054836
                   to: 63.4959999620914     [s; relative to TRIGTIME]
     T50: 11.9199999570847 +/- 3.72841197195518
        Measured from: 44.1200000047684
                   to: 56.039999961853     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 53.1319999992847     
                   to: 54.1319999992847     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: 37.3840000033379     
                   to: 64.5360000133514     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.335506   0.198524   0.067381   0.007278
           0.030180   0.031668   0.028922   0.028556 [error]
 Peak      0.021931   0.016105   0.013275   0.001563
           0.005840   0.006210   0.005452   0.005668 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   27.152   37.384   64.536
T90    25.008   38.488   63.496
T50    11.920   44.120   56.040
Peak    1.000   53.132   54.132
 
 
====== 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      -2.793    -0.392      0.338       -           -               -         9.31e-04     -2.70e-04          2.80e-04      48.030   57
CPL     -1.000     N/A        N/A          80.000      N/A           N/A         2.89e-03        N/A               N/A         91.000   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      -1.778     -0.613     0.559       -           -               -         3.53e-03     -1.34e-03          1.27e-03      54.990   57
CPL     -1.528     -0.741     4.167       76.233      N/A           N/A         4.98e-03        N/A               N/A         54.960   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   1.11e-07  9.36e-08  5.40e-08  4.64e-08  2.78e-07  3.05e-07   erg/cm2
      90%_error_low -1.76e-08 -1.79e-08 -1.98e-08 -2.55e-08 -4.98e-08 -6.34e-08   erg/cm2
      90%_error_hi   1.76e-08  1.71e-08  2.33e-08  4.29e-08  5.33e-08  7.69e-08   erg/cm2
Peak flux       PL   1.90e-01  1.62e-01  9.45e-02  8.23e-02  4.82e-01  5.28e-01   ph/cm2/s
      90%_error_low -8.30e-02 -5.02e-02 -4.44e-02 -5.59e-02 -1.49e-01 -1.67e-01   ph/cm2/s
      90%_error_hi   8.92e-02  5.02e-02  4.62e-02  1.04e-01  1.49e-01  1.71e-01   ph/cm2/s
 
Fluence        CPL   1.09e-07  1.10e-07   N/A     7.97e-09  2.56e-07  2.59e-07   erg/cm2
      90%_error_low -1.76e-08 -1.68e-08 -1.98e-08    N/A    -4.50e-08    N/A      erg/cm2
      90%_error_hi   1.70e-08  1.38e-08  2.33e-08    N/A     5.60e-08    N/A      erg/cm2
Peak flux      CPL   1.87e-01  1.67e-01  9.36e-02  5.42e-02  4.77e-01  5.02e-01   ph/cm2/s
      90%_error_low -8.92e-02     N/A   -9.36e-02 -5.42e-02 -1.54e-01 -1.77e-01   ph/cm2/s
      90%_error_hi   9.16e-02     N/A    4.83e-02  8.44e-02  1.51e-01  1.89e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
   12.2653    22.5985   0.0167    32.5743   -22.5000         0.7085219     11.551 TRIG_00151905                 
 
Foreground time interval of the image:
 37.384  64.536 (delta_t =  27.152 [sec])
Background time interval of the image:
-196.099  37.384 (delta_t = 233.483 [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   37.384 sec. to   64.536 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.79307     ( -0.392067   0.338135 )
Norm@50keV  : 9.31185E-04    ( -0.000270382   0.000279757 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          48.03 using 59 PHA bins.
# Reduced chi-squared =         0.8426 for     57 degrees of freedom 
# Null hypothesis probability =   7.954379e-01
 
Photon flux (15-150 keV)    in 27.15 sec: 0.221308 ( -0.030304  0.030334 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.7838e-07 ( -4.97727e-08  5.32547e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   37.384 sec. to   64.536 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1     (       )
Epeak [keV] : 80.0000      (   )
Norm@50keV  : 2.89288E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          91.00 using 59 PHA bins.
# Reduced chi-squared =          1.625 for     56 degrees of freedom 
# Null hypothesis probability =   2.152585e-03
 
Photon flux (15-150 keV)    in 27.15 sec: 0.216495 ( -0.029606  0.029767 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.55741e-07 ( -4.49995e-08  5.59901e-08 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   53.132 sec. to   54.132 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.77779     ( -0.61254   0.559214 )
Norm@50keV  : 3.52560E-03    ( -0.00134266   0.00127092 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          54.99 using 59 PHA bins.
# Reduced chi-squared =         0.9648 for     57 degrees of freedom 
# Null hypothesis probability =   5.506838e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.481724 ( -0.149269  0.149292 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.24915e-08 ( -1.19501e-08  1.27805e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   53.132 sec. to   54.132 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.52776     ( -0.740327   4.16761 )
Epeak [keV] : 76.2329      (   )
Norm@50keV  : 4.97600E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          54.96 using 59 PHA bins.
# Reduced chi-squared =         0.9814 for     56 degrees of freedom 
# Null hypothesis probability =   5.143973e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.477271 ( -0.153907  0.151361 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.13249e-08 ( -1.42747e-08  1.19574e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 25.008 sec.
Hardness ratio (energy fluence ratio) = 0.57716489589

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

S(15-50 keV)  = 2.0411046e-07
S(50-150 keV) = 7.427399e-08

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 = 5.902618446927571E-01, IMY = 2.444946922291937E-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:
-196.099400 37.384000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
288.9094  10.8690    6.3  47.5  166.0  -0.8821  -1.8    8.0	GRS 1915+105                  
299.5835  35.2126    0.4  36.8 -157.7   8.5636  32.4    0.7	Cyg X-1                       
308.0971  40.9991    1.8  32.9 -143.7   1.5031   6.5    2.9	Cyg X-3                       
326.1286  38.3774    3.6  21.2 -126.0   0.6328   3.2    3.9	Cyg X-2                       
 26.0022  -6.9126    2.7  54.6   13.3   4.7844   4.2 ------	UNKNOWN                       
305.8942  34.5037    2.7  31.6 -156.1   0.9721   4.2 ------	UNKNOWN                       
 11.0191  48.9089    4.1  39.8  -66.3   1.5777   2.8 ------	UNKNOWN                       

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

Time interval of the image:
37.384000 64.536000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
288.6865  10.8475    6.4  47.7  166.1  -0.2581  -1.8    8.8	GRS 1915+105                  
299.5523  35.0674   11.6  36.8 -158.0   0.0734   1.0    8.3	Cyg X-1                       
308.1710  40.8672   23.2  32.8 -143.9   0.0327   0.5    5.8	Cyg X-3                       
326.0121  38.4759    0.0  21.4 -126.1  -0.0752  -1.3   11.9	Cyg X-2                       
 12.2653  22.5985    1.0  32.6  -22.5   0.7085  11.6 ------	UNKNOWN                       
281.8315  49.3064    2.6  53.1 -143.2   1.2306   4.5 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image: