GRB180331B: 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: Wed May 30 15:52:41 EDT 2018
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger820513
======================================================================

  Trigger: 00820513      Segment: 000

  BAT Trigger Time: 544203540.032   [s; MET]
      Trigger Stop: 544203542.08   [s; MET]
               UTC: 2018-03-31T15:38:39.320160    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 196.819900496289   Dec: 61.7250399854159  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    9.48
     Image Trigger?:     NO
     Rate S/N Ratio:     21.6794833886788  [ if not an image trigger ]
     Image S/N Ratio:    9.48

  Analysis Position:   [ source = BAT ]
    RA: 196.819900496289   Dec: 61.7250399854159  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 196.799942170466   Dec: 61.7253167959102  [deg; J2000]  
        { 13h 07m 12.0s , +61d 43' 31.1" }
         +/- 1.68461575624069 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.532222162632814 [arcmin] (formal 1-sigma fit error)
    SNR: 14.4392862205162
 
  Angular difference between the analysis and refined position is 0.567500 arcmin
 
  Partial Coding Fraction: 0.3046875    [ including projection effects ]

  Duration
     T90: 78.0320000648499 +/- 4.7389450045999
        Measured from: -20.1679999828339
                   to: 57.864000082016     [s; relative to TRIGTIME]
     T50: 20.432000041008 +/- 7.35756471371748
        Measured from: -13.3679999113083
                   to: 7.06400012969971     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 0.98800003528595     
                   to: 1.98800003528595     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -21.3839999437332     
                   to: 62.4240000247955     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     1.361262   1.236563   0.520607   0.070868
           0.089865   0.092563   0.079495   0.068487 [error]
 Peak      0.121067   0.128716   0.065386   0.003289
           0.012308   0.012621   0.010284   0.007660 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   83.808  -21.384   62.424
T90    78.032  -20.168   57.864
T50    20.432  -13.368    7.064
Peak    1.000    0.988    1.988
 
 
====== 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      -2.265    -0.185      0.174       -           -               -         2.07e-03     -2.57e-04          2.52e-04      41.560   57
CPL     -1.916    -0.086      0.816        9.531      -7.961        30.885      3.34e-03        N/A               N/A         40.860   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      -2.058     -0.203     0.190       -           -               -         1.84e-02     -2.57e-03          2.52e-03      67.840   57
CPL     -0.969     -0.894     1.192       38.850     -18.437        13.386      7.99e-02     -7.99e-02          3.35e-01      63.520   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   4.58e-07  5.30e-07  4.41e-07  6.18e-07  1.65e-06  2.05e-06   erg/cm2
      90%_error_low -5.41e-08 -4.72e-08 -7.40e-08 -1.81e-07 -1.68e-07 -2.78e-07   erg/cm2
      90%_error_hi   5.52e-08  4.69e-08  7.63e-08  2.27e-07  1.72e-07  3.11e-07   erg/cm2
Peak flux       PL   1.30e+00  9.39e-01  4.51e-01  3.06e-01  2.83e+00  2.99e+00   ph/cm2/s
      90%_error_low -1.98e-01 -1.05e-01 -8.06e-02 -9.19e-02 -3.19e-01 -3.36e-01   ph/cm2/s
      90%_error_hi   2.04e-01  1.05e-01  8.14e-02  1.12e-01  3.19e-01  3.36e-01   ph/cm2/s
 
Fluence        CPL    N/A      N/A      N/A      N/A      N/A      N/A      erg/cm2
      90%_error_low -5.41e-08 -4.72e-08 -7.40e-08 -1.81e-07 -1.68e-07 -2.78e-07   erg/cm2
      90%_error_hi   5.52e-08  4.69e-08  7.63e-08  2.27e-07  1.72e-07  3.11e-07   erg/cm2
Peak flux      CPL   1.18e+00  1.07e+00  4.41e-01  8.37e-02  2.76e+00  2.77e+00   ph/cm2/s
      90%_error_low -2.27e-01 -1.51e-01 -1.06e-01 -8.37e-02 -3.25e-01 -3.34e-01   ph/cm2/s
      90%_error_hi   2.28e-01  1.58e-01  9.73e-02  1.62e-01  3.25e-01  3.43e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  196.7999    61.7253   0.0133    34.3464   -67.5790         3.2061141     14.439 TRIG_00820513                 
 
Foreground time interval of the image:
-21.384  62.424 (delta_t =  83.808 [sec])
Background time interval of the image:
-169.731 -21.384 (delta_t = 148.347 [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  -21.384 sec. to   62.424 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.26531     ( -0.184784   0.174355 )
Norm@50keV  : 2.07414E-03    ( -0.000256724   0.000251502 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          41.56 using 59 PHA bins.
# Reduced chi-squared =         0.7291 for     57 degrees of freedom 
# Null hypothesis probability =   9.380130e-01
 
Photon flux (15-150 keV)    in 83.81 sec: 0.355650 ( -0.030641  0.030655 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.65138e-06 ( -1.68189e-07  1.71663e-07 ) ergs/cm2
 

Cutoff power-law model

Time interval is from  -21.384 sec. to   62.424 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.91626     ( -0.0836657   0.818365 )
Epeak [keV] : 9.53149      ( -7.58427 31.2619 )
Norm@50keV  : 3.34389E-03    (     )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          40.86 using 59 PHA bins.
# Reduced chi-squared =         0.7296 for     56 degrees of freedom 
# Null hypothesis probability =   9.357758e-01
 
Photon flux (15-150 keV)    in 83.81 sec: 0.355296 ( -0.030507  0.016061 ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from    0.988 sec. to    1.988 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -2.05842     ( -0.202656   0.190234 )
Norm@50keV  : 1.83529E-02    ( -0.00257374   0.00251763 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          67.84 using 59 PHA bins.
# Reduced chi-squared =          1.190 for     57 degrees of freedom 
# Null hypothesis probability =   1.542529e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.82977 ( -0.31871  0.31881 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.6993e-07 ( -2.19544e-08  2.22464e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from    0.988 sec. to    1.988 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.968682     ( -0.894361   1.19233 )
Epeak [keV] : 38.8503      ( -18.4369 13.3863 )
Norm@50keV  : 7.98876E-02    ( -0.079896   0.335271 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          63.52 using 59 PHA bins.
# Reduced chi-squared =          1.134 for     56 degrees of freedom 
# Null hypothesis probability =   2.286706e-01
 
Photon flux (15-150 keV)    in 1 sec: 2.75883 ( -0.32484  0.32492 ) ph/cm2/s
Energy fluence (15-150 keV)             : 0 ( 0  0 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 78.032 sec.
Hardness ratio (energy fluence ratio) = 0.832051212129

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

S(15-50 keV)  = 9.877745e-07
S(50-150 keV) = 6.63614e-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 = 2.606323414161451E-01, IMY = 6.316842637770844E-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:
-169.731400 -21.384000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
120.2998  35.7109    2.8  49.9 -148.0   1.8475   4.2 ------	UNKNOWN                       
132.0041  51.5873    2.7  41.7 -125.6   1.4333   4.3 ------	UNKNOWN                       

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

Time interval of the image:
-21.384000 62.424000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
141.4936  -2.3870    2.3  48.5  154.2   1.7816   4.9 ------	UNKNOWN                       
207.3811  58.1850    2.2  34.6  -56.3   1.0002   5.3 ------	UNKNOWN                       
196.7999  61.7253    0.8  34.3  -67.6   3.2060  14.4 ------	UNKNOWN                       
207.6000  68.9213    2.1  42.8  -67.5   2.5563   5.6 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image:
647.768590 963.032000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
254.3056  35.3271    3.9  44.2    2.0   1.2648   3.0    7.5	Her X-1                       
212.1788  50.8815    3.9  13.7   37.9   0.7515   2.9 ------	UNKNOWN                       
141.4465  45.2632    3.2  35.4  171.3   1.2845   3.6 ------	UNKNOWN                       
261.6202  36.4052    2.3  46.8   -5.6   2.4015   5.0 ------	UNKNOWN                       
279.2533  49.2096    6.1  45.0  -30.8   0.8610   1.9 ------	UNKNOWN                       
 71.2542  85.0536    2.8  31.4 -105.0   1.8934   4.2 ------	UNKNOWN                       
 75.4986  62.6501    2.9  48.0 -129.1   6.1071   4.0 ------	UNKNOWN