batgrbproduct analysis for trigger=429868

batgrbproduct Analysis for Trigger=429868

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 (local time): Fri Jan 17 17:26:09 EST 2014
             Host Name: batevent1
   Current Working Dir: /local/data/batevent/batevent_reproc/trigger429868
======================================================================

  Trigger: 00429868      Segment: 000

  BAT Trigger Time: 301624945.216   [s; MET]
      Trigger Stop: 301624946.24   [s; MET]
               UTC: 2010-07-24T00:42:19.202780    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 194.566197960917   Dec: -11.1213088935374  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    10.55
     Image Trigger?:     NO
     Rate S/N Ratio:     19.157244060668  [ if not an image trigger ]
     Image S/N Ratio:    10.55

  Flight Position:   [ source = BAT ]
    RA: 194.566197960917   Dec: -11.1213088935374  [deg; J2000]

  Ground Position:   [ source = BAT pre-slew burst ]
    RA: 194.568537601933   Dec: -11.0943885705126  [deg; J2000]  
        { 12h 58m 16.4s , -11d 05' 39.8" }
         +/- 1.70400275741798 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.652239998894621 [arcmin] (formal 1-sigma fit error)
    SNR: 14.2051731743885
 
  Angular difference between Flight and Ground position is 1.621082 arcmin
 
  Partial Coding Fraction: 0.4335938    [ including projection effects ]

  Duration
     T90: 1.38799995183945 +/- 0.15579471580594
        Measured from: 0.148000001907349
                   to: 1.5359999537468     [s; relative to TRIGTIME]
     T50: 0.675999999046326 +/- 0.202385728029818
        Measured from: 0.387999951839447
                   to: 1.06399995088577     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 0.0879999995231628     
                   to: 1.08799999952316     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: 0.0839999914169312     
                   to: 1.64800000190735     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.089869   0.124246   0.055702   0.010843
           0.010600   0.011411   0.010617   0.009438 [error]
 Peak      0.060697   0.097649   0.049617   0.005354
           0.008619   0.009437   0.008718   0.007336 [error]

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

======================================================================
 
=== 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   Power-law 3.34e-08 4.74e-08 5.00e-08 9.74e-08 1.61e-07 2.28e-07   erg/cm2
              Error 5.26e-09 5.50e-09 9.78e-09 3.71e-08 2.28e-08 4.82e-08   erg/cm2
Peak flux Power-law 7.74e-01 6.35e-01 3.53e-01 2.90e-01 1.89e+00 2.05e+00   ph/cm2/s
              Error 1.35e-01 7.95e-02 6.82e-02 1.04e-01 2.37e-01 2.63e-01   ph/cm2/s
 
Fluence   Cutoff-PL 3.00e-08 5.58e-08 4.51e-08 1.28e-08 1.41e-07 1.44e-07   erg/cm2
              Error 6.05e-09 8.15e-09 1.27e-08 -------- 2.41e-08 3.41e-08   erg/cm2
Peak flux Cutoff-PL 6.43e-01 7.79e-01 3.42e-01 4.09e-02 1.80e+00 1.80e+00   ph/cm2/s
              Error 1.59e-01 1.16e-01 8.92e-02 6.15e-02 2.39e-01 2.44e-01   ph/cm2/s
 
Fluence        Band 2.97e-08 5.56e-08 4.47e-08 2.55e-08 1.44e-07 1.56e-07   erg/cm2
              Error -------- -------- -------- 4.63e-08 -------- --------   erg/cm2
Peak flux      Band -------- -------- -------- -------- -------- --------   ph/cm2/s
              Error -------- -------- -------- -------- -------- --------   ph/cm2/s

 
=== Time-averaged spectral analysis ===
 
Model Ph_index Ph_90err Epeak  Epeak_90err Norm     Nomr_90err chi2   dof
PL    1.923    0.208    -      -           1.12e-02 1.62e-03   55.030 57
CPL   0.505    1.161      42.5   11.7      7.65e-02 2.18e-01   49.420 56
 
 
=== 1-s peak spectral analysis ===
 
Model Ph_index Ph_90err Epeak  Epeak_90err Norm     Nomr_90err chi2   dof
PL    1.846    0.212    -      -           1.35e-02 2.01e-03   52.420 57
CPL  -0.035    1.267      45.2    9.4      1.62e-01 5.30e-01   43.250 56
 
Model      : spectral model: simple power-law (PL) and cutoff power-law (CPL)
Ph_index   : photon index: E^-{Ph_index} (minus sign is not included in the 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 PL model and at 1 keV in CPL model
Nomr_90err : 90% error of the normalization
chi2       : Chi-Squared
dof        : degree of freedom

 
=== T90/T50 calculation in the 50-300 keV band (BATSE band) using 64 ms lc ===
 
T90 in the 50-300 keV band: 0.000000 sec.
T50 in the 50-300 keV band: 0.000000 sec.

 
=== Table of the duration information ==
 
        Value   tstart    tstop
T100    1.564    0.084    1.648
T90     1.388    0.148    1.536
T50     0.676    0.388    1.064
Peak    1.000    0.088    1.088

Click here for the BAT GCN circular template

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
  194.5685   -11.0944   0.0136    33.6283    38.4928         0.3046063     14.205 TRIG_00429868                 
 
Foreground time interval of the image:
  0.084   1.648 (delta_t =   1.564 [sec])
Background time interval of the image:
-239.216   0.084 (delta_t = 239.300 [sec])

Lightcurves

Notes:

1) The mask-weighted light curves are using the flight position.
2) Multiple plots of different time binning/intervals are shown to cover all scenarios of short/long GRBs, rate/image triggers, and real/false positives.
3) For all the mask-weighted lightcurves, the y-axis units are counts/sec/det where a det is 0.4 x 0.4 = 0.16 sq cm.
4) The verticle lines correspond to following: green dotted lines are T50 interval, black dotted lines are T90 interval, blue solid line(s) is a spacecraft slew start time, and orange solid line(s) is a spacecraft slew end time.
5) Time of each bin is in the middle of the bin.

1 s binning

From T0-310 s to T0+310 s

From T100_start - 20 s to T100_end + 30 s

Full time interval

64 ms binning

Full time interval

From T100_start to T100_end

From T0-5 sec to T0+5 sec

16 ms binning

From T100_start-5 s to T100_start+5 s

Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000

8 ms binning

From T100_start-3 s to T100_start+3 s

Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000

2 ms binning

From T100_start-1 s to T100_start+1 s

Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000

SN=5 or 10 sec. binning (whichever binning is satisfied first)

SN=5 or 10 sec. binning (T < 200 sec)

Quad-rate summed light curves (from T0-300s to T0+1000s)

The mask-weighted light curves based on cleaned DPHs

Spectral Evolution

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    0.084 sec. to    1.648 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.92336     ( -0.201199   0.21394 )
Norm@50keV  : 1.12170E-02    ( -0.00163388   0.00159966 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          55.03 using 59 PHA bins.
# Reduced chi-squared =         0.9655 for     57 degrees of freedom 
# Null hypothesis probability =   5.492685e-01
 
Photon flux (15-150 keV)    in 1.564 sec: 1.62596 ( -0.186788  0.186793 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.61341e-07 ( -2.25537e-08  2.31363e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from    0.084 sec. to    1.648 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.505062     ( -1.2754   1.04667 )
Epeak [keV] : 42.4999      ( -8.19851 15.1766 )
Norm@50keV  : 7.65264E-02    ( -0.0765289   0.359076 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          49.42 using 59 PHA bins.
# Reduced chi-squared =         0.8825 for     56 degrees of freedom 
# Null hypothesis probability =   7.204400e-01
 
Photon flux (15-150 keV)    in 1.564 sec: 1.55357 ( -0.19073  0.1923 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.41043e-07 ( -2.24572e-08  2.57433e-08 ) ergs/cm2

Band function

Time interval is from    0.084 sec. to    1.648 sec.
 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       : -0.880142   ( -0.791255   0.792613 )
beta        : -3.02986    ( 3.04609   1.04086 )
Epeak [keV] : 44.1280      ( -17.3801 10.421 )
Norm@50keV   : 4.54382E-02    ( -0.039685   408.015 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          49.52 using 59 PHA bins.
# Reduced chi-squared =         0.9003 for     55 degrees of freedom 
# Null hypothesis probability =   6.833625e-01
 
Photon flux (15-150 keV)    in 1.564 sec:  (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.43583e-07 ( 0  0 ) ergs/cm2

Single BB

 
Spectral model blackbody:
------------------------------------------------------------
Parameters  : value    Lower 90%  Upper 90%
kT [keV]    : 10.3155  (-1.25261  1.40827)
R^2/D10^2   : 0.700912  (-0.268336   0.440318)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared =          55.80 using 59 PHA bins.
# Reduced chi-squared =         0.9790 for     57 degrees of freedom 
# Null hypothesis probability =   5.201587e-01
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  2.399e-08   4.911e-09
25- 50  6.229e-08   8.766e-09
50-150  3.554e-08   1.125e-08
15-150  1.218e-07   1.939e-08

Thermal bremsstrahlung (OTTB)

 
 
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT [keV]    : 69.9010       (-20.7752      36.3557)
Norm        : 8.08823       (-1.33035     1.57438)
------------------------------------------------------------
#Fit statistic : Chi-Squared =          50.93 using 59 PHA bins.
# Reduced chi-squared =         0.8935 for     57 degrees of freedom 
# Null hypothesis probability =   7.009993e-01
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  3.245e-08   4.919e-09
25- 50  5.161e-08   7.445e-09
50-150  6.622e-08   2.278e-08
15-150  1.503e-07   2.976e-08

Double BB

 
 
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT1 [keV]   : 5.04451        (-2.4568      3.28685)
R1^2/D10^2  : 4.77748        (-3.64442      79.7806)
kT2 [keV]   : 13.6957        (-2.90961      10.0699)
R2^2/D10^2  : 0.187726    (-0.174367   0.352546)
------------------------------------------------------------
#Fit statistic : Chi-Squared =          48.88 using 59 PHA bins.
# Reduced chi-squared =         0.8887 for     55 degrees of freedom 
# Null hypothesis probability =   7.062104e-01
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  3.048e-08   1.612e-08
25- 50  5.496e-08   2.830e-08
50-150  5.230e-08   3.129e-08
15-150  1.377e-07   7.239e-08

Peak spectrum fit

Power-law model

Time interval is from    0.088 sec. to    1.088 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.84621     ( -0.205874   0.218292 )
Norm@50keV  : 1.34781E-02    ( -0.00203382   0.00199546 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          52.42 using 59 PHA bins.
# Reduced chi-squared =         0.9197 for     57 degrees of freedom 
# Null hypothesis probability =   6.473129e-01
 
Photon flux (15-150 keV)    in 1 sec: 1.89158 ( -0.236622  0.236634 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.23933e-07 ( -1.84907e-08  1.89246e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from    0.088 sec. to    1.088 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -3.47588E-02     ( -1.40932   1.12455 )
Epeak [keV] : 45.1597      ( -7.09231 11.7968 )
Norm@50keV  : 0.162291    ( -0.162788   0.898189 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          43.25 using 59 PHA bins.
# Reduced chi-squared =         0.7724 for     56 degrees of freedom 
# Null hypothesis probability =   8.935840e-01
 
Photon flux (15-150 keV)    in 1 sec: 1.80043 ( -0.23833  0.24001 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.07461e-07 ( -1.74671e-08  1.9539e-08 ) ergs/cm2

Band function

Time interval is from    0.088 sec. to    1.088 sec.
 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       : 6.81310E-02   ( -1.22044   -0.180078 )
beta        : -3.93588    ( 4.09854   1.92266 )
Epeak [keV] : 44.9205      ( -14.372 10.5814 )
Norm@50keV   : 0.170331    ( -0.0972485   256.98 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          43.16 using 59 PHA bins.
# Reduced chi-squared =         0.7847 for     55 degrees of freedom 
# Null hypothesis probability =   8.763498e-01
 
Photon flux (15-150 keV)    in 1 sec:  (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.08741e-07 ( 0  0 ) ergs/cm2

Single BB

 
Spectral model blackbody:
------------------------------------------------------------
Parameters  : value    Lower 90%  Upper 90%
kT [keV]    : 11.0505  (-1.36193  1.53121)
R^2/D10^2   : 0.656050  (-0.252038   0.410243)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared =          46.35 using 59 PHA bins.
# Reduced chi-squared =         0.8132 for     57 degrees of freedom 
# Null hypothesis probability =   8.421529e-01
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  1.675e-08   3.640e-09
25- 50  4.765e-08   8.620e-09
50-150  3.299e-08   9.735e-09
15-150  9.740e-08   1.592e-08

Thermal bremsstrahlung (OTTB)

 
 
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT [keV]    : 80.1019       (-25.0859      47.5277)
Norm        : 9.05208       (-1.46456     1.81116)
------------------------------------------------------------
#Fit statistic : Chi-Squared =          47.21 using 59 PHA bins.
# Reduced chi-squared =         0.8283 for     57 degrees of freedom 
# Null hypothesis probability =   8.189956e-01
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  2.349e-08   3.870e-09
25- 50  3.868e-08   5.565e-09
50-150  5.465e-08   2.850e-08
15-150  1.168e-07   2.937e-08

Double BB

 
 
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT1 [keV]   : 5.34913        (-5.14377      194.564)
R1^2/D10^2  : 3.41615        (-3.05152      -3.37138)
kT2 [keV]   : 13.5541        (-2.90221      -13.5894)
R2^2/D10^2  : 0.250257    (-0.24704   0.469819)
------------------------------------------------------------
#Fit statistic : Chi-Squared =          42.89 using 59 PHA bins.
# Reduced chi-squared =         0.7798 for     55 degrees of freedom 
# Null hypothesis probability =   8.825008e-01
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  2.054e-08   1.143e-08
25- 50  4.335e-08   2.225e-08
50-150  4.213e-08   2.438e-08
15-150  1.060e-07   5.545e-08

Pre-slew spectrum (Pre-slew PHA with pre-slew DRM)

Power-law model

 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.92336     ( -0.201199   0.21394 )
Norm@50keV  : 1.12170E-02    ( -0.00163388   0.00159966 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          55.03 using 59 PHA bins.
# Reduced chi-squared =         0.9655 for     57 degrees of freedom 
# Null hypothesis probability =   5.492685e-01
 
Photon flux (15-150 keV)    in 1.564 sec: 1.62596 ( -0.186788  0.186793 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.61341e-07 ( -2.25537e-08  2.31363e-08 ) ergs/cm2

Cutoff power-law model

Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.505062     ( -1.2754   1.04667 )
Epeak [keV] : 42.4999      ( -8.19851 15.1766 )
Norm@50keV  : 7.65264E-02    ( -0.0765289   0.359076 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          49.42 using 59 PHA bins.
# Reduced chi-squared =         0.8825 for     56 degrees of freedom 
# Null hypothesis probability =   7.204400e-01
 
Photon flux (15-150 keV)    in 1.564 sec: 1.55357 ( -0.19073  0.1923 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.41043e-07 ( -2.24572e-08  2.57433e-08 ) ergs/cm2

Band function

 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       : -0.880142   ( -0.791255   0.792613 )
beta        : -3.02986    ( 3.04609   1.04086 )
Epeak [keV] : 44.1280      ( -17.3683 10.1942 )
Norm@50keV   : 4.54382E-02    ( -0.039685   408.128 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          49.52 using 59 PHA bins.
# Reduced chi-squared =         0.9003 for     55 degrees of freedom 
# Null hypothesis probability =   6.833625e-01
 
Photon flux (15-150 keV)    in 1.564 sec:  (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.43583e-07 ( 0  0 ) ergs/cm2

S(25-50 keV) vs. S(50-100 keV) plot

S(25-50 keV)  = 4.74e-08
S(50-100 keV) = 5.00e-08

T90 vs. Hardness ratio plot

T90                                   = 1.38799995183945 sec.
Hardness ratio (energy fluence ratio) = 1.05485

Color vs. Color plot

Count Ratio  (25-50 keV) / (15-25 keV) = 1.38252
Count Ratio (50-100 keV) / (15-25 keV) = 0.619813

Mask shadow pattern

IMX = 5.205738703707901E-01, IMY = -4.139757957473527E-01

TIME vs. PHA plot around the trigger time

Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000

TIME vs. DetID plot around the trigger time

Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000

100 us light curve (15-350 keV)

Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 1.024000

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:
-239.216000 0.084000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.5235 -40.5409    1.0  35.8  159.4   3.2150  11.4    0.9	Vela X-1                      
169.0540  38.0047    2.6  50.8  -44.5   4.4616   4.4 ------	UNKNOWN

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

Time interval of the image:
0.084000 1.648000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
135.4532 -40.4422    3.6  35.8  159.6  -0.0604  -3.2    7.6	Vela X-1                      
194.5685 -11.0944    0.8  33.6   38.5   0.3046  14.2 ------	UNKNOWN                       
131.3703  17.4768    1.8  41.1  -98.0   0.3157   6.4 ------	UNKNOWN

Post-slew image of 15-350 keV band

Time interval of the image:
72.684600 962.871900
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
170.0839 -60.6054   10.5  52.7  171.2   1.8575   1.1    6.9	Cen X-3                       
186.7007 -62.7725    1.9  52.0  160.9  11.9088   6.2    1.2	GX 301-2                      
167.0346 -10.0337    2.9  27.1 -114.0   2.2940   4.0 ------	UNKNOWN                       
170.0470  29.5436    4.3  47.0  -53.2   7.3766   2.7 ------	UNKNOWN                       
160.2018  11.7926    2.4  41.1  -80.8  10.0543   4.9 ------	UNKNOWN

Plot creation:
Sun May 31 00:51:16 EDT 2015