GRB070508: 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: Mon Jan 20 09:57:50 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger278854
======================================================================

  Trigger: 00278854      Segment: 000

  BAT Trigger Time: 200290699.776   [s; MET]
      Trigger Stop: 200290700.8   [s; MET]
               UTC: 2007-05-08T04:18:17.835440    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 312.782826014256   Dec: -78.3681172291522  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    19.9
     Image Trigger?:     NO
     Rate S/N Ratio:     51.0392006206994  [ if not an image trigger ]
     Image S/N Ratio:    19.9

  Analysis Position:   [ source = BAT ]
    RA: 312.782826014256   Dec: -78.3681172291522  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 312.813523041667   Dec: -78.3818522566903  [deg; J2000]  
        { 20h 51m 15.2s , -78d 22' 54.7" }
         +/- 0.440186828747394 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.130979377609992 [arcmin] (formal 1-sigma fit error)
    SNR: 98.2218970683203
 
  Angular difference between the analysis and refined position is 0.903818 arcmin
 
  Partial Coding Fraction: 0.625    [ including projection effects ]

  Duration
     T90: 20.9000000059605 +/- 0.73174858089084
        Measured from: -0.412000000476837
                   to: 20.4880000054836     [s; relative to TRIGTIME]
     T50: 7.61600002646446 +/- 0.141534440139191
        Measured from: 5.93999999761581
                   to: 13.5560000240803     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 10.8480000197887     
                   to: 11.8480000197887     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -15.6200000047684     
                   to: 33.1159999966621     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     6.829320  10.468429   9.247947   2.570325
           0.059669   0.065461   0.061655   0.043730 [error]
 Peak      0.540443   1.034408   1.118052   0.334792
           0.013159   0.017115   0.018281   0.011873 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   48.736  -15.620   33.116
T90    20.900   -0.412   20.488
T50     7.616    5.940   13.556
Peak    1.000   10.848   11.848
 
 
====== 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      -1.336    -0.024      0.024       -           -               -         4.20e-02     -5.71e-04          5.70e-04      34.050   57
CPL     -1.220    -0.096      0.098      443.852    -170.782      1549.098      4.65e-02     -3.67e-03          4.05e-03      29.840   56
 
 
=== 1-s peak spectral analysis ===
(Best model with acceptable fit: CPL)
 
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      -1.059     -0.037     0.037       -           -               -         2.14e-01     -4.49e-03          4.49e-03      77.780   57
CPL     -0.679     -0.153     0.158      213.491     -44.398        97.788      3.07e-01     -4.07e-02          4.82e-02      58.940   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   2.24e-06  4.55e-06  7.22e-06  2.54e-05  2.01e-05  3.94e-05   erg/cm2
      90%_error_low -6.75e-08 -8.23e-08 -9.21e-08 -7.59e-07 -2.48e-07 -7.67e-07   erg/cm2
      90%_error_hi   6.85e-08  8.24e-08  9.20e-08  7.75e-07  2.48e-07  7.78e-07   erg/cm2
Peak flux       PL   2.10e-03  2.60e-02  2.18e-01  2.51e+01  9.63e-01  1.72e+01   ph/cm2/s
      90%_error_low     N/A       N/A       N/A       N/A       N/A       N/A     ph/cm2/s
      90%_error_hi      N/A       N/A       N/A       N/A       N/A       N/A     ph/cm2/s
 
Fluence        CPL   2.15e-06  4.55e-06  7.32e-06  2.27e-05  2.00e-05  3.67e-05   erg/cm2
      90%_error_low -9.76e-08 -8.35e-08 -1.23e-07 -2.03e-06 -2.54e-07 -2.03e-06   erg/cm2
      90%_error_hi   9.95e-08  8.33e-08  1.24e-07  2.27e-06  2.55e-07  2.27e-06   erg/cm2
Peak flux      CPL   5.13e+00  7.62e+00  7.62e+00  8.99e+00  2.42e+01  2.94e+01   ph/cm2/s
      90%_error_low -3.41e-01 -2.13e-01 -2.11e-01 -1.04e+00 -5.64e-01 -1.22e+00   ph/cm2/s
      90%_error_hi   3.50e-01  2.13e-01  2.12e-01  1.22e+00  5.66e-01  1.37e+00   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  312.8135   -78.3819   0.0020    28.2572  -126.9372        20.2641644     98.222 TRIG_00278854                 
 
Foreground time interval of the image:
-15.620  12.725 (delta_t =  28.345 [sec])
Background time interval of the image:
-239.776 -15.620 (delta_t = 224.156 [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  -15.620 sec. to   33.116 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.33558     ( -0.0235742   0.0236716 )
Norm@50keV  : 4.19919E-02    ( -0.000571091   0.000569807 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          34.05 using 59 PHA bins.
# Reduced chi-squared =         0.5974 for     57 degrees of freedom 
# Null hypothesis probability =   9.932111e-01
 
Photon flux (15-150 keV)    in 48.74 sec: 5.04410 ( -0.08119  0.0815 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.00574e-05 ( -2.47844e-07  2.47682e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from  -15.620 sec. to   33.116 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.22023     ( -0.0955631   0.0975875 )
Epeak [keV] : 443.852      ( -170.732 1549.15 )
Norm@50keV  : 4.64582E-02    ( -0.00366781   0.00404599 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          29.84 using 59 PHA bins.
# Reduced chi-squared =         0.5329 for     56 degrees of freedom 
# Null hypothesis probability =   9.984080e-01
 
Photon flux (15-150 keV)    in 48.74 sec: 3.07257 (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.99851e-05 ( -2.5422e-07  2.5471e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   10.848 sec. to   11.848 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.05891     ( -0.0365548   0.0366613 )
Norm@50keV  : 0.213810    ( -0.00449256   0.00448763 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          77.78 using 59 PHA bins.
# Reduced chi-squared =          1.365 for     57 degrees of freedom 
# Null hypothesis probability =   3.506968e-02
 
Photon flux (15-150 keV)    in 1 sec: 0.962643 (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.26584e-06 ( -4.91243e-08  4.9208e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   10.848 sec. to   11.848 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.678584     ( -0.152616   0.157576 )
Epeak [keV] : 213.491      ( -44.398 97.7885 )
Norm@50keV  : 0.307298    ( -0.0406574   0.0482327 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          58.94 using 59 PHA bins.
# Reduced chi-squared =          1.053 for     56 degrees of freedom 
# Null hypothesis probability =   3.684315e-01
 
Photon flux (15-150 keV)    in 1 sec: 24.2483 ( -0.5641  0.5662 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.24161e-06 ( -5.07733e-08  5.06823e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 20.9 sec.
Hardness ratio (energy fluence ratio) = 1.58500248819

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

S(15-50 keV)  = 6.794108e-06
S(50-150 keV) = 1.3263416e-05

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 = -3.229942853789712E-01, IMY = 4.296065986230516E-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:
-239.776000 -15.620000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.5723 -40.6710   12.7  52.5  -29.2   0.6469   0.9    7.3	Vela X-1                      
170.5922 -60.5774    9.3  23.3  -26.5   0.2140   1.2    8.6	Cen X-3                       
186.3294 -62.8007    3.3  15.6  -22.5   0.5970   3.5    9.2	GX 301-2                      
255.9836 -37.8398    0.6  33.3  132.3   5.8716  19.9    0.3	4U 1700-377                   
256.6186 -36.4836   10.3  34.7  132.1   0.3620   1.1    9.6	GX 349+2                      
264.6840 -44.5161    6.1  30.9  149.4   0.4583   1.9    4.7	4U 1735-44                    
270.0995 -25.7182    4.3  49.4  140.7   2.2709   2.7   11.1	GRS 1758-258                  
275.9492 -30.3801    3.8  47.6  149.7   1.9779   3.1    1.5	H1820-303                     
263.0936 -33.7801    3.1  39.5  137.9   1.6295   3.7    6.2	GX 354-0                      
100.8568 -72.1306    4.3  37.9  -76.4   1.2753   2.7 ------	UNKNOWN                       

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

Time interval of the image:
-15.620000 12.724600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.5914 -40.6457    6.9  52.5  -29.1  -1.0249  -1.7    6.2	Vela X-1                      
170.0785 -60.5235    9.7  23.5  -26.7   0.2166   1.2    9.2	Cen X-3                       
186.8264 -62.8329   19.0  15.4  -22.3  -0.1002  -0.6    6.0	GX 301-2                      
255.8773 -38.0027    0.0  33.1  132.3  -0.0912  -0.3   10.8	4U 1700-377                   
256.3619 -36.3702    7.9  34.7  131.7  -0.4337  -1.5    4.8	GX 349+2                      
264.5414 -44.4878    7.5  30.9  149.2   0.3119   1.5    8.9	4U 1735-44                    
270.2711 -25.6254    7.0  49.6  140.8  -1.1831  -1.6    7.3	GRS 1758-258                  
275.7591 -30.2970   15.3  47.6  149.4   0.3745   0.8    9.6	H1820-303                     
262.8141 -33.7397   18.1  39.4  137.6  -0.2155  -0.6   10.4	GX 354-0                      
177.3180 -34.1619    2.3  40.3   14.7   1.2938   5.1 ------	UNKNOWN                       
312.8135 -78.3818    0.1  28.3 -126.9  20.2619  98.1 ------	UNKNOWN                       
 25.2160 -84.9394    2.3  30.6 -104.6   1.3437   5.1 ------	UNKNOWN                       
351.3965 -64.4088    2.2  46.1 -129.2   3.9482   5.4 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
64.924600 962.284200
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
170.5075 -60.5390    4.6  39.3   30.0   2.0439   2.5    7.6	Cen X-3                       
186.5919 -62.7351    3.6  35.3   41.4   2.3722   3.2    2.8	GX 301-2                      
264.6533 -44.4970   16.1  38.5  123.1   0.8682   0.7    4.8	4U 1735-44                    
223.7676 -74.4239    2.9  19.2   56.4   1.8542   4.0 ------	UNKNOWN                       
312.7271 -78.3658    2.4   0.0  115.0   2.1635   4.8 ------	UNKNOWN                       
 39.5171 -71.9148    4.1  20.8  -59.0   1.3135   2.8 ------	UNKNOWN                       
 67.6217 -48.7465    5.1  47.1  -53.1   6.6921   2.3 ------	UNKNOWN