GRB080725: 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 23:55:42 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger317888
======================================================================

  Trigger: 00317888      Segment: 000

  BAT Trigger Time: 238674377.6   [s; MET]
      Trigger Stop: 238674378.624   [s; MET]
               UTC: 2008-07-25T10:26:14.632460    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 121.714820861025   Dec: -13.9900040898407  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.58
     Image Trigger?:     NO
     Rate S/N Ratio:     21.9772609758359  [ if not an image trigger ]
     Image S/N Ratio:    7.58

  Analysis Position:   [ source = BAT ]
    RA: 121.714820861025   Dec: -13.9900040898407  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 121.699301450399   Dec: -13.9858420682984  [deg; J2000]  
        { 08h 06m 47.8s , -13d 59' 09.0" }
         +/- 1.30881518320677 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.441947850853826 [arcmin] (formal 1-sigma fit error)
    SNR: 20.7085335054254
 
  Angular difference between the analysis and refined position is 0.937426 arcmin
 
  Partial Coding Fraction: 0.4257812    [ including projection effects ]

  Duration
     T90: 92.7360000014305 +/- 49.4991723464123
        Measured from: -62.4039999842644
                   to: 30.3320000171661     [s; relative to TRIGTIME]
     T50: 14.8560000360012 +/- 2.44769279383054
        Measured from: -2.63600000739098
                   to: 12.2200000286102     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 3.54800000786781     
                   to: 4.54800000786781     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -105.516000002623     
                   to: 50.0240000188351     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     1.381168   2.003122   1.752158   0.497299
           0.100696   0.104945   0.092372   0.080217 [error]
 Peak      0.056803   0.096957   0.104863   0.021063
           0.009234   0.010108   0.009616   0.007693 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100  155.540 -105.516   50.024
T90    92.736  -62.404   30.332
T50    14.856   -2.636   12.220
Peak    1.000    3.548    4.548
 
 
====== 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      -1.421    -0.098      0.099       -           -               -         2.57e-03     -1.41e-04          1.41e-04      38.440   57
CPL     -1.353    -0.159      0.340      469.163    -469.163      -469.163      2.78e-03     -3.23e-04          1.19e-03      38.450   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      -1.300     -0.177     0.177       -           -               -         1.97e-02     -2.09e-03          2.09e-03      70.070   57
CPL     -0.497     -0.727     0.874      100.433     -27.982       343.185      4.74e-02     -2.56e-02          7.03e-02      66.470   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   4.75e-07  9.15e-07  1.37e-06  4.41e-06  3.85e-06  7.17e-06   erg/cm2
      90%_error_low -4.84e-08 -5.63e-08 -9.25e-08 -6.30e-07 -2.27e-07 -6.94e-07   erg/cm2
      90%_error_hi   5.00e-08  5.59e-08  9.21e-08  7.01e-07  2.28e-07  7.51e-07   erg/cm2
Peak flux       PL   6.68e-01  7.58e-01  6.15e-01  8.34e-01  2.35e+00  2.88e+00   ph/cm2/s
      90%_error_low -1.24e-01 -9.11e-02 -7.75e-02 -1.97e-01 -2.55e-01 -3.16e-01   ph/cm2/s
      90%_error_hi   1.32e-01  9.01e-02  7.68e-02  2.31e-01  2.56e-01  3.19e-01   ph/cm2/s
 
Fluence        CPL   4.70e-07  9.19e-07  1.37e-06  4.44e-06  3.84e-06  6.89e-06   erg/cm2
      90%_error_low -5.76e-08 -5.90e-08 -4.99e-08 -1.95e-06 -2.42e-07 -1.62e-06   erg/cm2
      90%_error_hi   4.72e-08  6.29e-08  1.02e-07  3.77e-07  2.36e-07  5.17e-07   erg/cm2
Peak flux      CPL   5.61e-01  8.04e-01  6.68e-01  4.01e-01  2.27e+00  2.43e+00   ph/cm2/s
      90%_error_low -1.55e-01 -1.04e-01 -9.28e-02 -1.88e-01 -2.65e-01 -3.38e-01   ph/cm2/s
      90%_error_hi   1.61e-01  1.07e-01  9.56e-02  3.83e-01  2.64e-01  4.41e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  121.6993   -13.9858   0.0093    38.0321  -134.6840         5.9565465     20.709 TRIG_00317888                 
 
Foreground time interval of the image:
-105.516  50.024 (delta_t = 155.540 [sec])
Background time interval of the image:
-239.600 -105.516 (delta_t = 134.084 [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 -105.516 sec. to   50.024 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.42058     ( -0.0981488   0.0985692 )
Norm@50keV  : 2.57467E-03    ( -0.000140589   0.000140526 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          38.44 using 59 PHA bins.
# Reduced chi-squared =         0.6743 for     57 degrees of freedom 
# Null hypothesis probability =   9.719174e-01
 
Photon flux (15-150 keV)    in 155.5 sec: 0.315049 ( -0.018211  0.018268 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.8531e-06 ( -2.26999e-07  2.27932e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from -105.516 sec. to   50.024 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.35263     ( -0.135764   0.363345 )
Epeak [keV] : 469.163      ( -740.235 -740.235 )
Norm@50keV  : 2.77536E-03    ( -0.000252849   0.00126412 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          38.45 using 59 PHA bins.
# Reduced chi-squared =         0.6865 for     56 degrees of freedom 
# Null hypothesis probability =   9.646906e-01
 
Photon flux (15-150 keV)    in 155.5 sec: 0.314330 ( -0.018983  0.018274 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.8422e-06 ( -2.42054e-07  2.36015e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from    3.548 sec. to    4.548 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.30006     ( -0.176604   0.176997 )
Norm@50keV  : 1.96657E-02    ( -0.00209386   0.00209153 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          70.07 using 59 PHA bins.
# Reduced chi-squared =          1.229 for     57 degrees of freedom 
# Null hypothesis probability =   1.145962e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.34622 ( -0.25513  0.25557 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.94352e-07 ( -2.27746e-08  2.29381e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from    3.548 sec. to    4.548 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.497443     ( -0.727409   0.87405 )
Epeak [keV] : 100.433      ( -27.9815 343.185 )
Norm@50keV  : 4.73573E-02    ( -0.0255862   0.0703118 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          66.47 using 59 PHA bins.
# Reduced chi-squared =          1.187 for     56 degrees of freedom 
# Null hypothesis probability =   1.597253e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.27362 ( -0.26541  0.26443 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.86294e-07 ( -2.42324e-08  2.43213e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 92.736 sec.
Hardness ratio (energy fluence ratio) = 1.49427308868

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

S(15-50 keV)  = 1.3900004e-06
S(50-150 keV) = 2.463111e-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 = -5.500314165766547E-01, IMY = 5.561327987189398E-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:
-239.600000 -105.516000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.5361 -40.5661    0.7  22.3  173.4   2.0133  16.6    0.8	Vela X-1                      
170.6190 -60.6993    6.1  32.1  109.1   0.4568   1.9   10.0	Cen X-3                       
186.7087 -62.7416    5.5  37.7   99.4   0.7990   2.1    2.2	GX 301-2                      
183.8097 -33.3999    2.1  21.2   46.4   0.7306   5.5 ------	UNKNOWN                       
168.4946  10.5909    2.6  41.0  -46.7   1.0077   4.4 ------	UNKNOWN                       
135.5652   4.6658    3.8  41.1  -98.2   2.1673   3.0 ------	UNKNOWN                       

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

Time interval of the image:
-105.516000 50.024000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.4364 -40.6276    7.1  22.4  173.3  -0.2874  -1.6    6.1	Vela X-1                      
170.3370 -60.4357    0.0  31.8  109.2   0.2180   0.7   11.3	Cen X-3                       
186.7061 -62.7109   70.8  37.6   99.3   0.0868   0.2    3.8	GX 301-2                      
214.4771 -20.0166    2.2  50.5   32.0   4.6692   5.3 ------	UNKNOWN                       
161.1943   3.4430    2.3  33.0  -57.1   1.2809   4.9 ------	UNKNOWN                       
121.6993 -13.9858    0.6  38.0 -134.7   5.9561  20.7 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
200.500600 962.462500
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
244.9770 -15.6313    0.3  20.3   81.4  25.3777  40.7    0.6	Sco X-1                       
254.4593  35.3413  166.4  54.9    7.9  -0.1567  -0.1    0.1	Her X-1                       
256.0093 -37.8598    2.2  38.4  116.3   8.1920   5.2    1.4	4U 1700-377                   
256.4339 -36.4230    6.6  37.9  114.1   2.6935   1.7    0.1	GX 349+2                      
263.0280 -24.6297    4.9  38.7   92.9   4.3025   2.4    7.0	GX 1+4                        
257.1748 -11.6269    2.7  32.0   71.2   3.8953   4.3 ------	UNKNOWN                       
210.8993 -55.8703    2.7  45.4  168.6   4.8592   4.3 ------	UNKNOWN                       
203.2988  34.8927    3.6  50.7  -44.5  11.9865   3.3 ------	UNKNOWN