GRB090418A: 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 17:34:51 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger349510
======================================================================

  Trigger: 00349510      Segment: 000

  BAT Trigger Time: 261745664.896   [s; MET]
      Trigger Stop: 261745665.92   [s; MET]
               UTC: 2009-04-18T11:07:40.226940    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 269.33377128532   Dec: 33.4087902749121  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    8.16
     Image Trigger?:     NO
     Rate S/N Ratio:     16.9410743460974  [ if not an image trigger ]
     Image S/N Ratio:    8.16

  Analysis Position:   [ source = BAT ]
    RA: 269.33377128532   Dec: 33.4087902749121  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 269.323254645023   Dec: 33.4019003755011  [deg; J2000]  
        { 17h 57m 17.6s , +33d 24' 06.8" }
         +/- 1.39083934822275 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.48397082612143 [arcmin] (formal 1-sigma fit error)
    SNR: 18.9861538595861
 
  Angular difference between the analysis and refined position is 0.669601 arcmin
 
  Partial Coding Fraction: 0.3164062    [ including projection effects ]

  Duration
     T90: 56.3039999902248 +/- 4.06127123381587
        Measured from: -2.99199998378754
                   to: 53.3120000064373     [s; relative to TRIGTIME]
     T50: 31.7880000174046 +/- 2.77223376513962
        Measured from: 11.1599999964237
                   to: 42.9480000138283     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 0.0640000104904175     
                   to: 1.06400001049042     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -8.27599999308586     
                   to: 61.1319999992847     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     1.603487   2.428561   2.093321   0.763986
           0.071250   0.076223   0.071300   0.063777 [error]
 Peak      0.045605   0.071339   0.076050   0.035811
           0.010886   0.012243   0.011763   0.010154 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   69.408   -8.276   61.132
T90    56.304   -2.992   53.312
T50    31.788   11.160   42.948
Peak    1.000    0.064    1.064
 
 
====== 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    -0.066      0.066       -           -               -         6.85e-03     -2.41e-04          2.41e-04      46.820   57
CPL     -1.334    -0.064      0.069     9999.350    -9999.350      -9999.350      6.87e-03     -2.38e-04          2.45e-04      46.850   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      -1.293     -0.275     0.278       -           -               -         1.60e-02     -2.54e-03          2.54e-03      49.810   57
CPL     -1.159     -2.369     0.985      342.669    -342.669      -342.669      1.85e-02        N/A               N/A         49.840   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   5.20e-07  1.06e-06  1.68e-06  5.90e-06  4.66e-06  9.15e-06   erg/cm2
      90%_error_low -3.72e-08 -4.45e-08 -7.04e-08 -5.56e-07 -1.75e-07 -5.94e-07   erg/cm2
      90%_error_hi   3.82e-08  4.42e-08  7.01e-08  5.96e-07  1.75e-07  6.27e-07   erg/cm2
Peak flux       PL   5.39e-01  6.13e-01  5.01e-01  6.83e-01  1.90e+00  2.34e+00   ph/cm2/s
      90%_error_low -1.55e-01 -1.15e-01 -9.35e-02 -2.34e-01 -3.15e-01 -3.80e-01   ph/cm2/s
      90%_error_hi   1.70e-01  1.13e-01  9.16e-02  2.98e-01  3.16e-01  3.85e-01   ph/cm2/s
 
Fluence        CPL   5.20e-07  1.05e-06  1.66e-06  5.87e-06  4.68e-06  9.16e-06   erg/cm2
      90%_error_low    N/A       N/A       N/A       N/A    -1.96e-07 -1.37e-06   erg/cm2
      90%_error_hi     N/A       N/A       N/A       N/A     1.53e-07  2.67e-07   erg/cm2
Peak flux      CPL   5.34e-01  6.15e-01  5.03e-01  6.80e-01  1.90e+00  2.32e+00   ph/cm2/s
      90%_error_low -1.88e-01 -1.10e-01 -9.52e-02 -6.80e-01 -3.12e-01 -5.75e-01   ph/cm2/s
      90%_error_hi   1.39e-01  1.26e-01  1.12e-01  1.69e-01  3.18e-01  3.86e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  269.3233    33.4019   0.0101    46.3251     1.7944         1.8105231     18.986 TRIG_00349510                 
 
Foreground time interval of the image:
 -8.276  12.405 (delta_t =  20.681 [sec])
Background time interval of the image:
-239.896  -8.276 (delta_t = 231.620 [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   -8.276 sec. to   61.132 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.3356     ( -0.0660167   0.066258 )
Norm@50keV  : 6.84610E-03    ( -0.000241019   0.000240979 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          46.82 using 59 PHA bins.
# Reduced chi-squared =         0.8214 for     57 degrees of freedom 
# Null hypothesis probability =   8.298838e-01
 
Photon flux (15-150 keV)    in 69.41 sec: 0.822365 ( -0.031376  0.031493 ) ph/cm2/s
Energy fluence (15-150 keV)             : 4.65685e-06 ( -1.75053e-07  1.75431e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -8.276 sec. to   61.132 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.33413     ( -0.0648361   0.0684078 )
Epeak [keV] : 9999.35      ( -9999.36 -9999.36 )
Norm@50keV  : 6.86968E-03    ( -0.000241629   0.000241675 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          46.85 using 59 PHA bins.
# Reduced chi-squared =         0.8366 for     56 degrees of freedom 
# Null hypothesis probability =   8.030484e-01
 
Photon flux (15-150 keV)    in 69.41 sec: 0.825583 ( -0.034792  0.028174 ) ph/cm2/s
Energy fluence (15-150 keV)             : 4.67587e-06 ( -1.96135e-07  1.53409e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from    0.064 sec. to    1.064 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.29276     ( -0.274986   0.278403 )
Norm@50keV  : 1.59595E-02    ( -0.00253942   0.00253922 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          49.81 using 59 PHA bins.
# Reduced chi-squared =         0.8739 for     57 degrees of freedom 
# Null hypothesis probability =   7.390478e-01
 
Photon flux (15-150 keV)    in 1 sec: 1.90152 ( -0.31491  0.31617 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.58008e-07 ( -2.73458e-08  2.75117e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from    0.064 sec. to    1.064 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.28879     ( -2.35948   0.995255 )
Epeak [keV] : 9993.03      ( -9988.11 -9988.11 )
Norm@50keV  : 1.60288E-02    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          49.81 using 59 PHA bins.
# Reduced chi-squared =         0.8895 for     56 degrees of freedom 
# Null hypothesis probability =   7.067784e-01
 
Photon flux (15-150 keV)    in 1 sec: 1.89891 ( -0.31212  0.31789 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.57747e-07 ( -2.82499e-08  2.7636e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 56.304 sec.
Hardness ratio (energy fluence ratio) = 1.58492994942

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

S(15-50 keV)  = 1.577462e-06
S(50-150 keV) = 3.07937e-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 = 1.046845803546415E+00, IMY = -3.279586319138547E-02

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:
-239.896000 -8.276000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
254.4233  35.2468    2.9  35.1   10.2   0.9612   4.0    6.0	Her X-1                       

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

Time interval of the image:
-8.276000 12.404600
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
254.3512  35.2436    5.6  35.1   10.2   0.1304   2.1    7.9	Her X-1                       
269.3232  33.4019    0.6  46.3    1.8   1.8104  19.0 ------	UNKNOWN                       
133.1965  71.2880    2.6  41.9 -110.8   0.8039   4.5 ------	UNKNOWN                       
172.9180  87.0764    2.6  40.7  -85.6   0.8177   4.6 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
82.204600 962.191300
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
254.4535  35.3185    1.2  12.4  128.2   5.2389   9.9    1.5	Her X-1                       
268.2951  -1.4152    3.5  34.8   26.9   2.3607   3.3    4.9	SW J1753.5-0127               
273.9679 -14.0384    3.4  47.6   19.0   4.5316   3.4    2.2	GX 17+2                       
288.8005  10.9412    0.7  28.7  -17.9   9.1199  17.3    0.3	GRS 1915+105                  
299.5890  35.2031    0.3  25.0  -77.6  31.1693  44.6    0.1	Cyg X-1                       
308.1387  40.9668    1.7  31.6  -90.2   5.8738   6.8    1.5	Cyg X-3                       
255.8585   2.7537    3.1  33.1   50.3   3.4058   3.7 ------	UNKNOWN                       
182.5413  74.0939    4.2  57.2 -173.9   7.9952   2.8 ------	UNKNOWN                       
167.7609  80.1701    3.2  59.1 -166.1  13.8498   3.6 ------	UNKNOWN                       
304.1841  13.8823    3.1  37.1  -41.6   2.6620   3.7 ------	UNKNOWN                       
317.5470  19.8270    2.6  44.8  -59.8  11.9337   4.4 ------	UNKNOWN