batgrbproduct analysis for trigger=1211212

batgrbproduct Analysis for Trigger=1211212

WARNING: Good number of pixels are GAIN:49243 and OFFSET:49243 (should be 49478 for both) in the gain/offset file. Check for the gain/offset file.

Analysis Summary

Notes:

1) No attempt has been made to eliminate the non-significant decimal places.
2) This batgrbproduct analysis is done of the amount of data for this trigger downloaded to date.
3) This batgrbproduct analysis is using the flight position for the mask-weighting calculation.
4) This page will be updated for up to 15 downlinks after the trigger.

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.48
    Process Start Time (local time): Sat Jan 27 18:36:07 EST 2024
             Host Name: batproc1
   Current Working Dir: /local/data/bat1/prebascript/trigger1211212/GCN5_download_cron
======================================================================

  Trigger: 01211212      Segment: 000

  BAT Trigger Time: 727992144   [s; MET]
      Trigger Stop: 727992208   [s; MET]
               UTC: 2024-01-26T20:01:51.197640    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 245.626904531816   Dec: -15.6719955460571  [deg; J2000]

     Catalogged Source?: YES
     Point Source?:      YES
     GRB Indicated?:     NO    [ by BAT flight software ]
     Image S/N Ratio:    16.44
     Image Trigger?:     YES
     Rate S/N Ratio:     0  [ if not an image trigger ]
     Image S/N Ratio:    16.44

  Flight Position:   [ source = BAT ]
    RA: 245.626904531816   Dec: -15.6719955460571  [deg; J2000]

  Ground Position:   [ source = BAT pre-slew burst ]
    RA: 245.634520910765   Dec: -15.6814511256148  [deg; J2000]  
        { 16h 22m 32.3s , -15d 40' 53.2" }
         +/- 1.54736642759627 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.672280899898858 [arcmin] (formal 1-sigma fit error)
    SNR: 16.3031301024749
 
  Angular difference between Flight and Ground position is 0.717952 arcmin
 
  Partial Coding Fraction: 1    [ including projection effects ]

  Duration
     T90: 64 +/- 
        Measured from: 0
                   to: 64     [s; relative to TRIGTIME]
     T50: 64 +/- 
        Measured from: 0
                   to: 64     [s; relative to TRIGTIME]

    WARNING: battblocks failed.  Used TDRSS fore/background intervals

  Fluence
     Peak Flux  (peak 64 second)
        Measured from: 0     
                   to: 64     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: 0     
                   to: 64     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     2.086843   0.114493  -0.047735  -0.040666
           0.051770   0.045375   0.037620   0.032583 [error]
 Peak      2.086843   0.114493  -0.047735  -0.040666
           0.051770   0.045375   0.037620   0.032583 [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 5.98e-07 6.40e-08 2.84e-09 1.31e-10 6.65e-07 6.65e-07   erg/cm2
              Error 6.29e-08 1.56e-08 1.68e-09 1.36e-10 6.54e-08 6.54e-08   erg/cm2
Peak flux Power-law 4.31e-01 2.71e-02 6.02e-04 1.37e-05 4.59e-01 4.59e-01   ph/cm2/s
              Error 4.67e-02 6.31e-03 3.48e-04 1.37e-05 4.70e-02 4.70e-02   ph/cm2/s
 
Fluence   Cutoff-PL 6.13e-07 3.92e-08 2.31e-11 4.64e-18 6.52e-07 6.52e-07   erg/cm2
              Error 6.79e-08 2.04e-08 5.37e-10 1.80e-12 6.77e-08 6.77e-08   erg/cm2
Peak flux Cutoff-PL 4.39e-01 1.77e-02 5.50e-06 5.70e-13 4.57e-01 4.57e-01   ph/cm2/s
              Error 5.07e-02 8.46e-03 1.20e-04 2.08e-07 5.00e-02 5.01e-02   ph/cm2/s
 
Fluence        Band -------- -------- -------- -------- -------- --------   erg/cm2
              Error -------- -------- -------- -------- -------- --------   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    6.493    0.489    -      -           6.77e-05 3.31e-05   69.870 57
CPL   1.000    0.000      50.0    0.0      1.85e-03 0.00e+00  316.210 56
 
 
=== 1-s peak spectral analysis ===
 
Model Ph_index Ph_90err Epeak  Epeak_90err Norm     Nomr_90err chi2   dof
PL    6.493    0.489    -      -           6.77e-05 3.31e-05   69.870 57
CPL   1.000    0.000      50.0    0.0      1.85e-03 0.00e+00  316.210 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   64.000    0.000   64.000
T90    64.000    0.000   64.000
T50    64.000    0.000   64.000
Peak   64.000    0.000   64.000

Click here for the BAT GCN circular template

Estimated redshift from machine learning (Ukwatta et al. 2016) - may take a few minutes to calcaulte

Image

Pre-slew 15-350 keV image (Event data; bkg subtracted)

#   RAcent  DECcent POSerr  Theta    Phi     Peak Cts     SNR  Name
  245.6345 -15.6815 0.0118    0.2  -98.1       2.0823    16.3  TRIG_01211212       
------------------------------------------
 
Foreground time interval of the image:
  0.000   3.040 (delta_t =   3.040 [sec])
  6.000  10.240 (delta_t =   4.240 [sec])
 22.000  64.000 (delta_t =  42.000 [sec])
Background time interval of the image:

Lightcurves

Notes:

1) All plots contain as much data as has been downloaded to date.
2) The mask-weighted light curves are using the flight position.
3) Multiple plots of different time binning/intervals are shown to cover all scenarios of short/long GRBs, rate/image triggers, and real/false positives.
4) 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.
5) 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.
6) 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 64.000000

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 64.000000

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 64.000000

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

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

Spectra

Notes:

1) The fitting includes the systematic errors.
2) For long bursts, a spectral fit of 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.
4) For short bursts (T90<1sec), the specrtum is also fit with Blackbody, OTTB, and Double Blackbody.

Time averaged spectrum fit using the pre-slew DRM

Power-law model

Multiple GTIs in the spectrum
tstart tstop
0.000000 3.040000
6.000000 10.240000
22.000000 64.000000
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 6.49327     ( -0.480862   0.497763 )
Norm@50keV  : 6.76903E-05    ( -2.6644e-05   3.94638e-05 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          69.87 using 59 PHA bins.
# Reduced chi-squared =          1.226 for     57 degrees of freedom 
# Null hypothesis probability =   1.177092e-01
 
Photon flux (15-150 keV)    in 49.28 sec: 0.459184 ( -0.046993  0.0470624 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.64758e-07 ( -6.53763e-08  6.54098e-08 ) ergs/cm2

Cutoff power-law model

Multiple GTIs in the spectrum
tstart tstop
0.000000 3.040000
6.000000 10.240000
22.000000 64.000000
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.00000     (     )
Epeak [keV] : 50.0000      (   )
Norm@50keV  : 1.84722E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =         316.21 using 59 PHA bins.
# Reduced chi-squared =         5.6466 for     56 degrees of freedom 
# Null hypothesis probability =   5.633697e-38
 
Photon flux (15-150 keV)    in 49.28 sec: 0.456660 ( -0.050165  0.049908 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.51866e-07 ( -6.80458e-08  6.73263e-08 ) ergs/cm2

Band function

Multiple GTIs in the spectrum
tstart tstop
0.000000 3.040000
6.000000 10.240000
22.000000 64.000000
 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       : 9.59828E-02   ( -1.11809   1.11809 )
beta        : -10.0000    ( 10   10 )
Epeak [keV] : 6.33856      ( -0.641475 3.78503 )
Norm@50keV   : 23.7555    ( -23.7559   190696 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          65.08 using 59 PHA bins.
# Reduced chi-squared =          1.183 for     55 degrees of freedom 
# Null hypothesis probability =   1.658359e-01
 
Photon flux (15-150 keV)    in 49.28 sec:  (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

Single BB

 
Spectral model blackbody:
------------------------------------------------------------
Parameters  : value    Lower 90%  Upper 90%
kT [keV]    : 2.34041  (-0.186206  0.212116)
R^2/D10^2   : 371.907  (-190.936   388.141)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
#Fit statistic : Chi-Squared =          65.33 using 59 PHA bins.
# Reduced chi-squared =          1.146 for     57 degrees of freedom 
# Null hypothesis probability =   2.097932e-01
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  6.140e-07   1.504e-07
25- 50  3.431e-08   1.201e-08
50-150  5.554e-12   5.032e-12
15-150  6.483e-07   1.801e-07

Thermal bremsstrahlung (OTTB)

XSPEC12>exit
 XSPEC: quit
 
 
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT [keV]    : 3.94766       (-0.44851      0.54525)
Norm        : 273.427       (-124.255     229.628)
------------------------------------------------------------
 Reduced chi-squared = 
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  6.126e-07   1.244e-07
25- 50  4.306e-08   1.300e-08
50-150  5.839e-11   4.684e-11
15-150  6.557e-07   1.673e-07

Double BB

XSPEC12>exit
 XSPEC: quit
 
 
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT1 [keV]   : 1.17301        (-0.990843      3.84588)
R1^2/D10^2  : 3.63430E+04        (-228150      -228150)
kT2 [keV]   : 2.44285        (-0.256987      -2.42168)
R2^2/D10^2  : 248.013    (-247.044   479.359)
------------------------------------------------------------
 Reduced chi-squared = 
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  6.135e-07   4.598e-07
25- 50  3.745e-08   4.258e-08
50-150  5.499e-11   2.972e-11
15-150  6.510e-07   5.569e-07

Peak spectrum fit

Power-law model

Time interval is from   22.000 sec. to   64.000 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 6.49327     ( -0.480862   0.497763 )
Norm@50keV  : 6.76903E-05    ( -2.6644e-05   3.94638e-05 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          69.87 using 59 PHA bins.
# Reduced chi-squared =          1.226 for     57 degrees of freedom 
# Null hypothesis probability =   1.177092e-01
 
Photon flux (15-150 keV)    in 49.28 sec: 0.459184 ( -0.046993  0.0470624 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.64758e-07 ( -6.53763e-08  6.54098e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from   22.000 sec. to   64.000 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.00000     (     )
Epeak [keV] : 50.0000      (   )
Norm@50keV  : 1.84722E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =         316.21 using 59 PHA bins.
# Reduced chi-squared =         5.6466 for     56 degrees of freedom 
# Null hypothesis probability =   5.633697e-38
 
Photon flux (15-150 keV)    in 49.28 sec: 0.456660 ( -0.050165  0.049908 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.51866e-07 ( -6.80458e-08  6.73263e-08 ) ergs/cm2

Band function

Time interval is from   22.000 sec. to   64.000 sec.
 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       : 9.59828E-02   ( -1.11809   1.11809 )
beta        : -10.0000    ( 10   10 )
Epeak [keV] : 6.33856      ( -0.375279 8.90804 )
Norm@50keV   : 23.7555    ( -23.7559   190696 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          65.08 using 59 PHA bins.
# Reduced chi-squared =          1.183 for     55 degrees of freedom 
# Null hypothesis probability =   1.658359e-01
 
Photon flux (15-150 keV)    in 49.28 sec:  (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

Single BB

 XSPEC: quit
 
 
Spectral model blackbody:
------------------------------------------------------------
Parameters  : value    Lower 90%  Upper 90%
kT [keV]    : 2.34041  (-0.186206  0.212116)
R^2/D10^2   : 371.907  (-190.936   388.141)
(R is the radius in km and D10 is the distance to the source in units of 10 kpc)
------------------------------------------------------------
 Reduced chi-squared = 
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  6.140e-07   1.414e-07
25- 50  3.431e-08   1.079e-08
50-150  5.554e-12   4.668e-12
15-150  6.483e-07   1.583e-07

Thermal bremsstrahlung (OTTB)

XSPEC12>exit
 XSPEC: quit
 
 
Spectral model: thermal bremsstrahlung
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT [keV]    : 3.94766       (-0.44851      0.54525)
Norm        : 273.427       (-124.255     229.628)
------------------------------------------------------------
 Reduced chi-squared = 
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  6.126e-07   1.456e-07
25- 50  4.306e-08   1.349e-08
50-150  5.839e-11   4.619e-11
15-150  6.557e-07   1.551e-07

Double BB

XSPEC12>exit
 XSPEC: quit
 
 
Spectral model: bbodyrad<1> + bbodyrad<2>
------------------------------------------------------------
Parameters  : value         Lower 90%    Upper 90%
kT1 [keV]   : 1.17301        (-0.990843      3.8435)
R1^2/D10^2  : 3.63430E+04        (-228150      -228150)
kT2 [keV]   : 2.44285        (-0.256987      -2.42168)
R2^2/D10^2  : 248.013    (-247.044   479.359)
------------------------------------------------------------
 Reduced chi-squared = 
 
Energy  Fluence     90% Error
[keV]   [erg/cm2]   [erg/cm2]
15- 25  6.135e-07   4.696e-07
25- 50  3.745e-08   3.780e-08
50-150  5.499e-11   2.710e-11
15-150  6.510e-07   5.002e-07

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: 6.49327     ( -0.480862   0.497763 )
Norm@50keV  : 6.76903E-05    ( -2.6644e-05   3.94638e-05 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          69.87 using 59 PHA bins.
# Reduced chi-squared =          1.226 for     57 degrees of freedom 
# Null hypothesis probability =   1.177092e-01
 
Photon flux (15-150 keV)    in 49.28 sec: 0.459184 ( -0.046993  0.0470624 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.64758e-07 ( -6.53763e-08  6.54098e-08 ) ergs/cm2

Cutoff power-law model

Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 1.00000     (     )
Epeak [keV] : 50.0000      (   )
Norm@50keV  : 1.84722E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =         316.21 using 59 PHA bins.
# Reduced chi-squared =         5.6466 for     56 degrees of freedom 
# Null hypothesis probability =   5.633697e-38
 
Photon flux (15-150 keV)    in 49.28 sec: 0.456660 ( -0.050165  0.049908 ) ph/cm2/s
Energy fluence (15-150 keV)             : 6.51866e-07 ( -6.80458e-08  6.73263e-08 ) ergs/cm2

Band function

 
Spectral model in the Band function:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
alpha       : 9.59828E-02   ( -1.11809   1.11809 )
beta        : -10.0000    ( 10   10 )
Epeak [keV] : 6.33856      ( -0.128887 5.65419 )
Norm@50keV   : 23.7555    ( -23.7559   190696 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          65.08 using 59 PHA bins.
# Reduced chi-squared =          1.183 for     55 degrees of freedom 
# Null hypothesis probability =   1.658359e-01
 
Photon flux (15-150 keV)    in 49.28 sec:  (    ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2

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

S(25-50 keV)  = 6.40e-08
S(50-100 keV) = 2.84e-09

T90 vs. Hardness ratio plot

T90                                   = 64 sec.
Hardness ratio (energy fluence ratio) = 0.044375

Color vs. Color plot

Count Ratio  (25-50 keV) / (15-25 keV) = 0.0548642
Count Ratio (50-100 keV) / (15-25 keV) = -0.0228743

Mask shadow pattern

IMX = -4.371419881288540E-04, IMY = 3.067906363718854E-03

TIME vs. PHA plot around the trigger time

Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 64.000000

TIME vs. DetID plot around the trigger time

Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 64.000000

100 us light curve (15-350 keV)

Blue+Cyan dotted lines: Time interval of the scaled map
From 0.000000 to 64.000000

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:

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

Time interval of the image:
0.000000 3.040000
6.000000 10.240000
22.000000 64.000000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
245.0541 -15.5028    7.3   0.4  100.6  -0.2023  -1.6    9.3	Sco X-1                       
254.5007  35.3983    6.7  51.8  176.7   0.5501   1.7    4.0	Her X-1                       
255.9302 -37.6930   19.1  23.9  -33.5  -0.0803  -0.6    9.5	4U 1700-377                   
256.3867 -36.3765  270.8  22.9  -35.8  -0.0053  -0.0    3.7	GX 349+2                      
262.9182 -24.5939    8.0  18.6  -71.3   0.1865   1.5   10.4	GX 1+4                        
264.7297 -44.4491   36.2  33.1  -38.3   0.0451   0.3    0.6	4U 1735-44                    
268.5067  -1.5012    7.4  26.8 -132.4   0.2194   1.6    8.8	SW J1753.5-0127               
270.1604 -24.9372   10.1  24.9  -76.9  -0.1721  -1.1   10.9	GX 5-1                        
270.4709 -25.7210    6.5  25.4  -75.3  -0.2720  -1.8    9.2	GRS 1758-258                  
273.9056 -14.0859    7.6  27.5 -102.2  -0.2376  -1.5    6.5	GX 17+2                       
276.0845 -30.4692    8.8  31.7  -69.4  -0.2345  -1.3   10.3	H1820-303                     
285.0766 -25.0370    5.0  38.2  -81.9  -0.7421  -2.3    7.3	HT1900.1-2455                 
262.9047 -33.8807   23.5  24.1  -50.3   0.0671   0.5    5.0	GX 354-0                      
217.7028  20.2974    3.0  45.1  129.3   2.0657   3.9 ------	UNKNOWN                       
215.6129 -40.2109    2.8  35.7   28.0   0.9510   4.1 ------	UNKNOWN                       
241.3699  30.4473    2.5  46.3  162.4   1.3339   4.6 ------	UNKNOWN                       
245.6293 -15.6796    0.7   0.2  -98.6   2.0894  16.3 ------	UNKNOWN                       
255.9068 -52.9616    3.6  38.2  -22.9   0.6021   3.2 ------	UNKNOWN                       
286.2237  20.7948    2.1  54.1 -143.8   3.1953   5.4 ------	UNKNOWN

Post-slew image of 15-350 keV band

Time interval of the image:

Plot creation:
Sat Jan 27 18:38:25 EST 2024