GRB090518

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 16:36:33 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger352420
======================================================================

  Trigger: 00352420      Segment: 000

  BAT Trigger Time: 264304489.024   [s; MET]
      Trigger Stop: 264304489.28   [s; MET]
               UTC: 2009-05-18T01:54:44.273640    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 119.933320952001   Dec: 0.767979769129691  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    9.03
     Image Trigger?:     NO
     Rate S/N Ratio:     14.6287388383278  [ if not an image trigger ]
     Image S/N Ratio:    9.03

  Analysis Position:   [ source = BAT ]
    RA: 119.933320952001   Dec: 0.767979769129691  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 119.947725085362   Dec: 0.779777316984645  [deg; J2000]  
        { 07h 59m 47.5s , +00d 46' 47.2" }
         +/- 1.40248311327375 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.626690239514826 [arcmin] (formal 1-sigma fit error)
    SNR: 18.7613725487338
 
  Angular difference between the analysis and refined position is 1.117069 arcmin
 
  Partial Coding Fraction: 0.7578125    [ including projection effects ]

  Duration
     T90: 85.8240000009537 +/- 23.782007304977
        Measured from: -1.19999998807907
                   to: 84.6240000128746     [s; relative to TRIGTIME]
     T50: 39.9360000193119 +/- 26.1148233951774
        Measured from: 0.400000005960464
                   to: 40.3360000252724     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: -0.0679999887943268     
                   to: 0.932000011205673     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -2.47999998927116     
                   to: 93.3280000090599     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.313223   0.404779   0.257267   0.185064
           0.051829   0.052857   0.046489   0.041209 [error]
 Peak      0.073545   0.108577   0.078179   0.022948
           0.007157   0.007813   0.007125   0.005406 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   95.808   -2.480   93.328
T90    85.824   -1.200   84.624
T50    39.936    0.400   40.336
Peak    1.000   -0.068    0.932
 
 
====== 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      -1.531    -0.268      0.263       -           -               -         7.24e-04     -1.11e-04          1.09e-04      61.610   57
CPL     -1.532    -0.266      0.458     9999.360    -9999.360      -9999.360      7.26e-04     -1.11e-04          1.19e-03      61.610   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      -1.501     -0.142     0.140       -           -               -         1.89e-02     -1.61e-03          1.60e-03      62.640   57
CPL     -1.119     -0.450     0.636      112.064     -47.314      -112.064      2.98e-02     -1.33e-02          3.33e-02      61.280   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   9.12e-08  1.64e-07  2.28e-07  6.56e-07  6.55e-07  1.14e-06   erg/cm2
      90%_error_low -2.14e-08 -2.43e-08 -4.67e-08 -2.46e-07 -1.10e-07 -2.91e-07   erg/cm2
      90%_error_hi   2.25e-08  2.41e-08  4.64e-08  3.35e-07  1.12e-07  3.65e-07   erg/cm2
Peak flux       PL   7.78e-01  7.83e-01  5.53e-01  6.20e-01  2.36e+00  2.73e+00   ph/cm2/s
      90%_error_low -1.04e-01 -6.70e-02 -5.99e-02 -1.26e-01 -1.94e-01 -2.29e-01   ph/cm2/s
      90%_error_hi   1.08e-01  6.66e-02  5.95e-02  1.44e-01  1.94e-01  2.30e-01   ph/cm2/s
 
Fluence        CPL   9.21e-08  1.63e-07  2.28e-07  6.53e-07  6.65e-07  1.15e-06   erg/cm2
      90%_error_low    N/A       N/A       N/A       N/A    -1.22e-07 -5.86e-07   erg/cm2
      90%_error_hi     N/A       N/A       N/A       N/A     1.00e-07  1.98e-07   erg/cm2
Peak flux      CPL   7.32e-01  8.14e-01  5.68e-01  3.92e-01  2.32e+00  2.51e+00   ph/cm2/s
      90%_error_low -1.24e-01 -8.09e-02 -6.50e-02 -1.89e-01 -2.01e-01 -2.85e-01   ph/cm2/s
      90%_error_hi   1.26e-01  8.37e-02  6.64e-02  2.75e-01  2.00e-01  3.66e-01   ph/cm2/s
 
======================================================================

Special notes of this burst

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  119.9477     0.7798   0.0103    26.8576   -45.7307         0.7893076     18.761 TRIG_00352420                 
 
Foreground time interval of the image:
 -2.480   9.677 (delta_t =  12.157 [sec])
Background time interval of the image:
-119.024  -2.480 (delta_t = 116.544 [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

Bokeh Plot

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   -2.480 sec. to   93.328 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.53107     ( -0.267698   0.263232 )
Norm@50keV  : 7.24091E-04    ( -0.00011102   0.000109121 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          61.61 using 59 PHA bins.
# Reduced chi-squared =          1.081 for     57 degrees of freedom 
# Null hypothesis probability =   3.147171e-01
 
Photon flux (15-150 keV)    in 95.81 sec: 9.11739E-02 ( -0.0131758  0.0131911 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.55015e-07 ( -1.09657e-07  1.11783e-07 ) ergs/cm2

Cutoff power-law model

Time interval is from   -2.480 sec. to   93.328 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.53157     ( -0.266488   0.458006 )
Epeak [keV] : 9999.36      ( -9999.36 -9999.36 )
Norm@50keV  : 7.25649E-04    ( -0.000111532   0.00118896 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          61.61 using 59 PHA bins.
# Reduced chi-squared =          1.100 for     56 degrees of freedom 
# Null hypothesis probability =   2.822728e-01
 
Photon flux (15-150 keV)    in 95.81 sec: 9.15651E-02 ( -0.0147457  0.0139599 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.648e-07 ( -1.22073e-07  1.00217e-07 ) ergs/cm2

1-s peak spectrum fit

Power-law model

Time interval is from   -0.068 sec. to    0.932 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.50145     ( -0.142382   0.140446 )
Norm@50keV  : 1.88821E-02    ( -0.00161098   0.0016004 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          62.64 using 59 PHA bins.
# Reduced chi-squared =          1.099 for     57 degrees of freedom 
# Null hypothesis probability =   2.830798e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.35820 ( -0.19365  0.19377 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.79106e-07 ( -1.6798e-08  1.6977e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from   -0.068 sec. to    0.932 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.11948     ( -0.450299   0.636022 )
Epeak [keV] : 112.064      ( -47.3178 -112.068 )
Norm@50keV  : 2.98367E-02    ( -0.0133483   0.0333065 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          61.28 using 59 PHA bins.
# Reduced chi-squared =          1.094 for     56 degrees of freedom 
# Null hypothesis probability =   2.924638e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.32277 ( -0.20134  0.20034 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.73516e-07 ( -1.89799e-08  1.88375e-08 ) ergs/cm2

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 85.824 sec.
Hardness ratio (energy fluence ratio) = 1.38410788531

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

S(15-50 keV)  = 2.5564676e-07
S(50-150 keV) = 3.993601e-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 = 3.534827324777359E-01, IMY = 3.626152797423156E-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:
-119.024000 -2.480000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.5337 -40.5600    0.3  16.9  140.3   4.9139  40.5    0.4	Vela X-1                      
108.1407 -71.2747    2.6  48.4  165.0   1.4599   4.4 ------	UNKNOWN                       
148.3491  21.4450    2.2  49.3   -0.7   1.5771   5.2 ------	UNKNOWN

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

Time interval of the image:
-2.480000 9.676600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.5522 -40.5780    1.4  16.9  140.3  -0.3176  -8.5    1.8	Vela X-1                      
119.9477   0.7798    0.6  26.9  -45.7   0.7893  18.8 ------	UNKNOWN

Post-slew image of 15-350 keV band

Time interval of the image:
57.276660 963.022400
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
 83.6085  22.0072    0.8  41.2  -77.3  33.3870  15.2    1.4	Crab                          
135.5380 -40.5569    0.6  43.7  141.9  29.1965  18.3    0.4	Vela X-1                      
133.9082  38.5645    2.9  39.9   -3.8   3.0032   4.1 ------	UNKNOWN

Analysis Summary

Notes:

Image

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

Light Curves

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:

Time averaged spectrum fit using the average DRM

Power-law model

Cutoff power-law model

1-s peak spectrum fit

Power-law model

Cutoff power-law model

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

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

Mask shadow pattern

Spacecraft aspect plot

Bright source in the pre-burst/pre-slew/post-slew images

Pre-burst image of 15-350 keV band

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

Post-slew image of 15-350 keV band

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