GRB051221B: 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 19:20:02 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger173904
======================================================================

  Trigger: 00173904      Segment: 000

  BAT Trigger Time: 156888200   [s; MET]
      Trigger Stop: 156888392   [s; MET]
               UTC: 2005-12-21T20:03:20.090560    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 312.395437708596   Dec: 53.0538094719893  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.45
     Image Trigger?:     YES
     Rate S/N Ratio:     0  [ if not an image trigger ]
     Image S/N Ratio:    7.45

  Analysis Position:   [ source = BAT ]
    RA: 312.395437708596   Dec: 53.0538094719893  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 312.384013273902   Dec: 53.0424027507575  [deg; J2000]  
        { 20h 49m 32.2s , +53d 02' 32.6" }
         +/- 1.64171136435465 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.669486708358259 [arcmin] (formal 1-sigma fit error)
    SNR: 14.9813695291972
 
  Angular difference between the analysis and refined position is 0.798877 arcmin
 
  Partial Coding Fraction: 0.4492188    [ including projection effects ]

  Duration
     T90: 42.5720000267029 +/- 5.87969658803675
        Measured from: 51.6999999880791
                   to: 94.272000014782     [s; relative to TRIGTIME]
     T50: 24.0160000026226 +/- 4.88270417274367
        Measured from: 61.2360000014305
                   to: 85.2520000040531     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 58.891999989748     
                   to: 59.891999989748     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: 48.527999997139     
                   to: 98.1040000021458     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.323248   0.517578   0.455272   0.102745
           0.051697   0.053580   0.046351   0.037965 [error]
 Peak      0.014431   0.016365   0.032531   0.010467
           0.007575   0.007935   0.007002   0.005789 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   49.576   48.528   98.104
T90    42.572   51.700   94.272
T50    24.016   61.236   85.252
Peak    1.000   58.892   59.892
 
 
====== 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      -1.314    -0.184      0.187       -           -               -         2.01e-03     -2.13e-04          2.13e-04      53.170   57
CPL     -0.983    -0.425      0.854      169.239    -169.239      -169.239      2.86e-03     -1.11e-03          4.01e-03      52.580   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      -0.856     -0.586     0.732       -           -               -         4.90e-03     -1.86e-03          1.65e-03      56.160   57
CPL     -0.858     -0.582     1.455     9999.360    -9999.360      -9999.360      4.95e-03     -1.71e-03          2.76e-02      56.170   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   1.07e-07  2.20e-07  3.54e-07  1.27e-06  9.80e-07  1.95e-06   erg/cm2
      90%_error_low -2.12e-08 -2.73e-08 -4.43e-08 -3.20e-07 -1.11e-07 -3.52e-07   erg/cm2
      90%_error_hi   2.26e-08  2.69e-08  4.38e-08  3.88e-07  1.11e-07  4.06e-07   erg/cm2
Peak flux       PL   1.09e-01  1.62e-01  1.79e-01  3.72e-01  5.63e-01  8.21e-01   ph/cm2/s
      90%_error_low -7.34e-02 -8.05e-02 -5.37e-02 -2.05e-01 -1.91e-01 -2.53e-01   ph/cm2/s
      90%_error_hi   1.02e-01  7.69e-02  5.33e-02  3.64e-01  1.95e-01  2.86e-01   ph/cm2/s
 
Fluence        CPL   9.92e-08  2.26e-07  3.66e-07  8.24e-07  9.64e-07  1.51e-06   erg/cm2
      90%_error_low -2.68e-08 -3.03e-08 -5.13e-08 -4.78e-07 -1.18e-07 -4.87e-07   erg/cm2
      90%_error_hi   2.54e-08  3.13e-08  5.29e-08  8.35e-07  1.17e-07  5.77e-07   erg/cm2
Peak flux      CPL   1.09e-01  1.62e-01  1.79e-01  3.68e-01  5.63e-01  8.70e-01   ph/cm2/s
      90%_error_low     N/A       N/A       N/A       N/A   -1.91e-01 -4.14e-01   ph/cm2/s
      90%_error_hi      N/A       N/A       N/A       N/A    1.95e-01  1.87e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  312.3840    53.0424   0.0129    38.3252    17.3836         1.5005010     14.981 TRIG_00173904                 
 
Foreground time interval of the image:
 48.528  98.104 (delta_t =  49.576 [sec])
Background time interval of the image:
-299.000  48.528 (delta_t = 347.528 [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   48.528 sec. to   98.104 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.31404     ( -0.18388   0.186771 )
Norm@50keV  : 2.00578E-03    ( -0.00021341   0.00021334 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          53.17 using 59 PHA bins.
# Reduced chi-squared =         0.9327 for     57 degrees of freedom 
# Null hypothesis probability =   6.196839e-01
 
Photon flux (15-150 keV)    in 49.58 sec: 0.239928 ( -0.027102  0.027213 ) ph/cm2/s
Energy fluence (15-150 keV)             : 9.79502e-07 ( -1.11009e-07  1.11452e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   48.528 sec. to   98.104 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.982516     ( -0.424687   0.853837 )
Epeak [keV] : 169.239      ( -169.239 -169.239 )
Norm@50keV  : 2.86122E-03    ( -0.00110659   0.00400845 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          52.58 using 59 PHA bins.
# Reduced chi-squared =         0.9390 for     56 degrees of freedom 
# Null hypothesis probability =   6.049967e-01
 
Photon flux (15-150 keV)    in 49.58 sec: 0.236360 ( -0.028369  0.028316 ) ph/cm2/s
Energy fluence (15-150 keV)             : 9.638e-07 ( -1.18119e-07  1.16953e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   58.892 sec. to   59.892 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.856312     ( -0.586516   0.731692 )
Norm@50keV  : 4.90138E-03    ( -0.00186363   0.00164763 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          56.16 using 59 PHA bins.
# Reduced chi-squared =         0.9854 for     57 degrees of freedom 
# Null hypothesis probability =   5.063922e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.562587 ( -0.191165  0.195485 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.59706e-08 ( -1.69979e-08  1.70188e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   58.892 sec. to   59.892 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.858422     ( -0.582113   1.45469 )
Epeak [keV] : 9999.36      ( -9999.36 -9999.36 )
Norm@50keV  : 4.94721E-03    ( -0.00170657   0.0276423 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          56.17 using 59 PHA bins.
# Reduced chi-squared =          1.003 for     56 degrees of freedom 
# Null hypothesis probability =   4.683400e-01
 
Photon flux (15-150 keV)    in 1 sec: 0.562623 ( -0.191199  0.19532 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.5892e-08 ( -2.18943e-08  2.20551e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 42.572 sec.
Hardness ratio (energy fluence ratio) = 1.60882950992

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

S(15-50 keV)  = 3.264366e-07
S(50-150 keV) = 6.530689e-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 = 7.543637651388493E-01, IMY = -2.361660840860857E-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:
-299.000000 48.528000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
288.7781  10.9292    1.5  39.1  -60.2   4.3364   7.8    1.5	GRS 1915+105                  
299.5853  35.2029    0.2  31.7  -16.0  12.0926  52.9    0.3	Cyg X-1                       
308.1349  40.9341    1.9  29.8    1.0   1.4375   6.2    1.6	Cyg X-3                       
326.1258  38.3846    4.3  21.6   27.7   0.5627   2.7    4.3	Cyg X-2                       
305.4647  58.7415    3.4  45.2   16.4   1.5559   3.4 ------	UNKNOWN                       
308.0655  37.6562    1.7  27.6   -3.9   1.6338   6.9 ------	UNKNOWN                       
343.1975 -25.4403    2.7  44.6 -165.6   1.5582   4.3 ------	UNKNOWN                       
350.0530 -38.5854    3.5  59.0 -166.2   5.6272   3.3 ------	UNKNOWN                       
275.0447  20.0557    2.6  50.8  -44.4   4.8002   4.5 ------	UNKNOWN                       
292.3019  -2.9067    2.7  41.0  -82.3   4.2985   4.3 ------	UNKNOWN                       

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

Time interval of the image:
48.528000 98.104000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
288.7192  10.8606   10.5  39.2  -60.3   0.1575   1.1    6.9	GRS 1915+105                  
299.6897  35.0694    4.3  31.6  -16.1   0.1977   2.7    9.3	Cyg X-1                       
307.9042  41.0120    5.6  30.0    0.8   0.1578   2.1   10.0	Cyg X-3                       
325.9293  38.3751    6.7  21.6   27.3  -0.1147  -1.7   11.8	Cyg X-2                       
312.3840  53.0424    0.8  38.3   17.4   1.5006  15.0 ------	UNKNOWN                       
294.9230  47.6007    1.8  41.3   -1.4   0.5788   6.4 ------	UNKNOWN                       
338.3740 -29.4951    2.4  47.3 -158.3   0.6179   4.8 ------	UNKNOWN                       
335.2208 -31.4162    2.0  48.7 -154.2   0.7987   5.7 ------	UNKNOWN                       
269.8112  27.5848    1.8  55.0  -34.6   2.3306   6.3 ------	UNKNOWN                       
276.7105  18.0097    2.5  49.4  -47.3   1.4238   4.7 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
259.700600 303.058700
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
254.3876  35.4736    8.3  43.7  -38.0  -0.1573  -1.4    8.6	Her X-1                       
299.5944  35.2007    0.5  20.0  -96.4   1.6065  25.1    0.2	Cyg X-1                       
308.0301  40.8958    4.1  12.5 -112.9   0.1697   2.8    5.0	Cyg X-3                       
326.2622  38.4568    4.3  17.5 -167.0   0.1513   2.7    9.2	Cyg X-2                       
346.3521   5.3702    2.6  55.2 -170.9   0.8012   4.4 ------	UNKNOWN