GRB090404: 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 18:09:17 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger348428
======================================================================

  Trigger: 00348428      Segment: 000

  BAT Trigger Time: 260553395.072   [s; MET]
      Trigger Stop: 260553397.12   [s; MET]
               UTC: 2009-04-04T15:56:30.440760    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 239.218047211207   Dec: 35.4997092919803  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    8.91
     Image Trigger?:     NO
     Rate S/N Ratio:     16.3401346383682  [ if not an image trigger ]
     Image S/N Ratio:    8.91

  Analysis Position:   [ source = BAT ]
    RA: 239.218047211207   Dec: 35.4997092919803  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 239.233421678625   Dec: 35.5173701981685  [deg; J2000]  
        { 15h 56m 56.0s , +35d 31' 02.5" }
         +/- 0.797735445292206 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.221763035463278 [arcmin] (formal 1-sigma fit error)
    SNR: 42.006835571495
 
  Angular difference between the analysis and refined position is 1.298746 arcmin
 
  Partial Coding Fraction: 0.890625    [ including projection effects ]

  Duration
     T90: 82.0200000107288 +/- 14.4843142781929
        Measured from: -19.472000002861
                   to: 62.5480000078678     [s; relative to TRIGTIME]
     T50: 39.5360000133514 +/- 1.716787695924
        Measured from: 0.956000000238419
                   to: 40.4920000135899     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 17.3199999928474     
                   to: 18.3199999928474     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -35.1719999909401     
                   to: 94.6400000154972     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     2.810544   2.411322   1.082056   0.128240
           0.059469   0.061025   0.053681   0.047541 [error]
 Peak      0.089521   0.082374   0.056105   0.011677
           0.006271   0.006583   0.005590   0.004481 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100  129.812  -35.172   94.640
T90    82.020  -19.472   62.548
T50    39.536    0.956   40.492
Peak    1.000   17.320   18.320
 
 
====== 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      -2.261    -0.081      0.080       -           -               -         2.53e-03     -1.12e-04          1.11e-04      39.840   57
CPL     -1.942    -0.156      0.323        7.982      -7.151        19.303      3.76e-03     -7.17e-04          1.84e-03      37.200   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      -1.805     -0.158     0.154       -           -               -         1.43e-02     -1.35e-03          1.32e-03      47.010   57
CPL     -1.809     -0.154     0.161     9999.340    -9999.330      -9999.340      1.43e-02     -4.68e-03          7.73e-03      47.020   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   8.62e-07  1.00e-06  8.34e-07  1.17e-06  3.12e-06  3.87e-06   erg/cm2
      90%_error_low -5.19e-08 -3.52e-08 -5.33e-08 -1.50e-07 -1.17e-07 -1.99e-07   erg/cm2
      90%_error_hi   5.31e-08  3.52e-08  5.38e-08  1.66e-07  1.18e-07  2.10e-07   erg/cm2
Peak flux       PL   7.89e-01  6.63e-01  3.80e-01  3.23e-01  1.97e+00  2.15e+00   ph/cm2/s
      90%_error_low -1.02e-01 -5.43e-02 -4.74e-02 -7.43e-02 -1.62e-01 -1.75e-01   ph/cm2/s
      90%_error_hi   1.05e-01  5.41e-02  4.74e-02  8.70e-02  1.62e-01  1.76e-01   ph/cm2/s
 
Fluence        CPL   8.23e-07  1.02e-06  8.23e-07  7.34e-07  3.01e-06  3.37e-06   erg/cm2
      90%_error_low -6.38e-08 -3.89e-08 -5.78e-08 -1.40e-07 -1.54e-07 -3.25e-07   erg/cm2
      90%_error_hi   4.82e-08  4.22e-08  5.70e-08  2.13e-07  1.33e-07  2.89e-07   erg/cm2
Peak flux      CPL   7.86e-01  5.89e-01  3.06e-01  2.69e-01  1.79e+00  1.95e+00   ph/cm2/s
      90%_error_low -1.14e-01 -6.37e-02 -4.37e-02 -3.04e-02 -2.13e-01 -2.82e-01   ph/cm2/s
      90%_error_hi   8.72e-02  4.75e-02  3.73e-02  2.45e-02  2.42e-01  2.50e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  239.2334    35.5174   0.0046    19.6844    27.5262         4.2855766     42.007 TRIG_00348428                 
 
Foreground time interval of the image:
-35.172  27.429 (delta_t =  62.601 [sec])
Background time interval of the image:
-239.072 -35.172 (delta_t = 203.900 [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  -35.172 sec. to   94.640 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.26112     ( -0.0809617   0.0795108 )
Norm@50keV  : 2.53084E-03    ( -0.000112364   0.000111374 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          39.84 using 59 PHA bins.
# Reduced chi-squared =         0.6989 for     57 degrees of freedom 
# Null hypothesis probability =   9.591410e-01
 
Photon flux (15-150 keV)    in 129.8 sec: 0.432966 ( -0.016835  0.016936 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.1185e-06 ( -1.16953e-07  1.17549e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from  -35.172 sec. to   94.640 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.94208     ( -0.153435   0.325439 )
Epeak [keV] : 7.98219      ( -6.63265 19.8204 )
Norm@50keV  : 3.76257E-03    ( -0.000691079   0.00186201 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          37.20 using 59 PHA bins.
# Reduced chi-squared =         0.6643 for     56 degrees of freedom 
# Null hypothesis probability =   9.750656e-01
 
Photon flux (15-150 keV)    in 129.8 sec: 0.433002 ( -0.016833  0.016951 ) ph/cm2/s
Energy fluence (15-150 keV)             : 3.01463e-06 ( -1.54245e-07  1.33006e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   17.320 sec. to   18.320 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.80489     ( -0.158289   0.153807 )
Norm@50keV  : 1.42878E-02    ( -0.00134687   0.00132168 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          47.01 using 59 PHA bins.
# Reduced chi-squared =         0.8248 for     57 degrees of freedom 
# Null hypothesis probability =   8.245727e-01
 
Photon flux (15-150 keV)    in 1 sec: 1.97269 ( -0.16165  0.16185 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.31532e-07 ( -1.25284e-08  1.26928e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   17.320 sec. to   18.320 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.80893     ( -0.15478   0.160996 )
Epeak [keV] : 9999.34      ( -9999.35 -9999.36 )
Norm@50keV  : 1.42814E-02    ( -0.00468886   0.00772731 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          47.02 using 59 PHA bins.
# Reduced chi-squared =         0.8396 for     56 degrees of freedom 
# Null hypothesis probability =   7.980705e-01
 
Photon flux (15-150 keV)    in 1 sec: 1.79270 ( -0.21308  0.24157 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.32352e-07 ( -1.25042e-08  1.18463e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 82.02 sec.
Hardness ratio (energy fluence ratio) = 0.834487723505

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

S(15-50 keV)  = 1.8616859e-06
S(50-150 keV) = 1.2568215e-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 = 3.172481208132875E-01, IMY = -1.653331985812935E-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:
-239.072000 -35.172000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
254.5693  35.4392  216.0  27.0    1.5  -0.0090  -0.1    8.0	Her X-1                       
278.3590  14.2679    2.8  56.9   -4.0   3.3071   4.0 ------	UNKNOWN                       
295.3121  56.3331    3.1  39.5  -60.1   1.4305   3.7 ------	UNKNOWN                       
313.8640  72.0748    3.0  40.9  -87.3   2.7546   3.8 ------	UNKNOWN                       

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

Time interval of the image:
-35.172000 27.428600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
254.4516  35.3464   16.9  27.0    1.8  -0.0735  -0.7    0.4	Her X-1                       
239.2334  35.5174    0.3  19.7   27.5   4.2857  42.0 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
76.028590 963.009400
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
254.3081  35.3222    9.1  12.3  -58.8   0.4874   1.3    7.4	Her X-1                       
268.4075  -1.4195    2.8  45.9   -7.9   3.3298   4.1    3.1	SW J1753.5-0127               
288.7681  10.9662    2.8  51.0  -39.1   9.0292   4.1    2.2	GRS 1915+105                  
173.6672  45.8942    3.0  49.4  158.2   5.4547   3.9 ------	UNKNOWN                       
194.6563  46.4026    3.0  34.9  157.0   2.6192   3.8 ------	UNKNOWN