GRB180221A

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: Thu Apr  5 17:46:10 EDT 2018
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger811074
======================================================================

  Trigger: 00811074      Segment: 000

  BAT Trigger Time: 540887465.344   [s; MET]
      Trigger Stop: 540887481.728   [s; MET]
               UTC: 2018-02-21T06:30:44.832320    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 326.772376374209   Dec: -72.8682959674159  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.01
     Image Trigger?:     NO
     Rate S/N Ratio:     9.59166304662544  [ if not an image trigger ]
     Image S/N Ratio:    7.01

  Analysis Position:   [ source = BAT ]
    RA: 326.772376374209   Dec: -72.8682959674159  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 326.787015047631   Dec: -72.8909131142513  [deg; J2000]  
        { 21h 47m 08.9s , -72d 53' 27.3" }
         +/- 2.92318713074618 [arcmin] (estimated 90% radius based on SNR)
         +/- 1.74848091475567 [arcmin] (formal 1-sigma fit error)
    SNR: 6.57065894872872
 
  Angular difference between the analysis and refined position is 1.381442 arcmin
 
  Partial Coding Fraction: 0.3125    [ including projection effects ]

  Duration
     T90: 11 +/- 3.16227766016838
        Measured from: 1.65600001811981
                   to: 12.6560000181198     [s; relative to TRIGTIME]
     T50: 7 +/- 3.60555127546399
        Measured from: 2.65600001811981
                   to: 9.65600001811981     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: 2.65600001811981     
                   to: 3.65600001811981     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: 1.65600001811981     
                   to: 14.6560000181198     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.261867   0.365360   0.235548   0.031659
           0.059640   0.066344   0.059783   0.067162 [error]
 Peak      0.045751   0.045230   0.061815  -0.004705
           0.016544   0.019120   0.017315   0.019041 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100   13.000    1.656   14.656
T90    11.000    1.656   12.656
T50     7.000    2.656    9.656
Peak    1.000    2.656    3.656
 
 
====== 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      -1.709    -0.385      0.357       -           -               -         4.74e-03     -1.13e-03          1.09e-03      59.610   57
CPL     -0.905    -1.317      1.943       63.696     -63.696       -63.696      1.27e-02     -1.27e-02          1.20e-01      58.710   56
 
 
=== 1-s peak spectral analysis ===
(Best model with acceptable fit: N/A)
 
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      -1.542     -0.609     0.559       -           -               -         1.17e-02     -4.09e-03          3.93e-03      74.510   57
CPL     -0.510     -1.666     0.510       73.537     -57.446       -73.537      3.81e-02     -3.81e-02          8.04e+02      74.120   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   9.58e-08  1.55e-07  1.90e-07  4.56e-07  5.70e-07  8.97e-07   erg/cm2
      90%_error_low -2.89e-08 -3.22e-08 -5.91e-08 -2.35e-07 -1.38e-07 -3.04e-07   erg/cm2
      90%_error_hi   3.08e-08  3.22e-08  5.97e-08  3.54e-07  1.43e-07  4.00e-07   erg/cm2
Peak flux       PL   5.01e-01  4.92e-01  3.38e-01  3.65e-01  1.48e+00  1.70e+00   ph/cm2/s
      90%_error_low -2.43e-01 -1.67e-01 -1.47e-01 -2.41e-01 -4.79e-01 -5.55e-01   ph/cm2/s
      90%_error_hi   2.79e-01  1.64e-01  1.43e-01  4.04e-01  4.80e-01  5.66e-01   ph/cm2/s
 
Fluence        CPL   8.62e-08  1.70e-07  1.95e-07  1.51e-07  5.38e-07  6.02e-07   erg/cm2
      90%_error_low -3.47e-08 -4.10e-08 -6.69e-08 -1.29e-07 -1.42e-07 -2.00e-07   erg/cm2
      90%_error_hi   3.51e-08  4.43e-08  6.71e-08  3.97e-07  1.53e-07  4.40e-07   erg/cm2
Peak flux      CPL   4.09e-01  5.37e-01  3.70e-01  1.45e-01  1.42e+00  1.46e+00   ph/cm2/s
      90%_error_low     N/A   -1.99e-01     N/A   -1.45e-01 -6.38e-01 -6.82e-01   ph/cm2/s
      90%_error_hi      N/A    2.17e-01     N/A    3.04e-01  5.07e-01  7.38e-01   ph/cm2/s
 
======================================================================

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
  326.7870   -72.8909   0.0292    41.6116   -43.2779         0.9432681      6.571 TRIG_00811074                 
 
Foreground time interval of the image:
  1.656  14.656 (delta_t =  13.000 [sec])
Background time interval of the image:
-239.344   1.656 (delta_t = 241.000 [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

Bokeh Plot

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    1.656 sec. to   14.656 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.70922     ( -0.38459   0.356784 )
Norm@50keV  : 4.74108E-03    ( -0.00112967   0.00109314 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          59.61 using 59 PHA bins.
# Reduced chi-squared =          1.046 for     57 degrees of freedom 
# Null hypothesis probability =   3.807462e-01
 
Photon flux (15-150 keV)    in 13 sec: 0.631737 ( -0.13163  0.131716 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.7034e-07 ( -1.38499e-07  1.42633e-07 ) ergs/cm2

Cutoff power-law model

Time interval is from    1.656 sec. to   14.656 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.904527     ( -1.31673   1.94303 )
Epeak [keV] : 63.6963      ( -63.6999 -63.6999 )
Norm@50keV  : 1.27466E-02    ( -0.0127452   0.120377 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          58.71 using 59 PHA bins.
# Reduced chi-squared =          1.048 for     56 degrees of freedom 
# Null hypothesis probability =   3.765028e-01
 
Photon flux (15-150 keV)    in 13 sec: 0.613728 ( -0.068144  0.135525 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.37568e-07 ( -1.41934e-07  1.53328e-07 ) ergs/cm2

1-s peak spectrum fit

Power-law model

Time interval is from    2.656 sec. to    3.656 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.54194     ( -0.608702   0.558522 )
Norm@50keV  : 1.16937E-02    ( -0.00408941   0.00392862 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          74.51 using 59 PHA bins.
# Reduced chi-squared =          1.307 for     57 degrees of freedom 
# Null hypothesis probability =   5.960393e-02
 
Photon flux (15-150 keV)    in 1 sec: 1.47697 ( -0.479099  0.48024 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.1023e-07 ( -4.03134e-08  4.16043e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from    2.656 sec. to    3.656 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.51022     ( -1.67794   0.49829 )
Epeak [keV] : 73.5370      ( -57.2186 -73.31 )
Norm@50keV  : 3.80555E-02    ( -0.0388716   804.195 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          74.12 using 59 PHA bins.
# Reduced chi-squared =          1.324 for     56 degrees of freedom 
# Null hypothesis probability =   5.287851e-02
 
Photon flux (15-150 keV)    in 1 sec: 1.41704 ( -0.637511  0.50747 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.04179e-07 ( -3.94767e-08  4.44317e-08 ) ergs/cm2

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 11.0 sec.
Hardness ratio (energy fluence ratio) = 1.22334739113

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

S(15-50 keV)  = 2.5078534e-07
S(50-150 keV) = 3.195575e-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.

 IMX = 6.466458539785949E-01,

Spacecraft aspect plot

Bright

Pre-burst

 Time interval of the image: -239.344000 1.656000

# RAcent #  [deg] 170.1712 -60.8243 187.0933 -62.7835 245.0060 -15.6526 256.1696 -37.8446 256.2277 -36.2935 263.0871 -24.7851 264.8762 -44.5643 270.3242 -25.0903 270.1657 -25.7596 275.8251 -30.5058 262.9817 -33.8411 158.2408 -51.6423 64.9943 -76.4510 299.5028 -61.2421

Pre-slew

 Time interval of the image: 1.656000 14.656000

# RAcent #  [deg] 170.4578 -60.4213 186.6438 -62.7304 244.9270 -15.6056 255.8788 -37.9086 256.2278 -36.2937 263.1358 -24.8774 264.5044 -44.3618 270.3630 -25.0180 270.3493 -25.8654 276.1590 -30.4476 263.1126 -33.6894 50.7716 -65.2633 326.7872 -72.8909

Post-slew

 Time interval of the image: 701.956600 954.556600

# RAcent #  [deg] 244.9799 -15.6221 254.4368  35.3377 256.0371 -37.9478 256.5514 -36.5709 262.8720 -24.6614 264.8622 -44.5736 268.4929  -1.6209 270.2866 -25.0381 270.3113 -25.7060 274.0417 -14.0330 275.9767 -30.2949 285.0264 -24.9413 288.7966  10.9562 299.5683  35.1982 308.1570  40.9596 262.8704 -33.6948 249.8304 -49.8198 283.4350  24.8193 314.8915 -19.5266 316.1467 -29.0426 321.9344  -2.7137

Mask shadow pattern

IMY = 6.088966623792679E-01 source in the pre-burst/pre-slew/post-slew images image of 15-350 keV band DECcent POSerr Theta Phi PeakCts SNR AngSep Name [deg] ['] [deg] [deg] ['] 0.0 27.8 39.0 0.3576 0.3 12.8 Cen X-3 0.0 19.7 35.5 -1.3206 -1.3 12.0 GX 301-2 1.6 43.1 -166.4 12.5335 7.3 1.7 Sco X-1 13.8 28.1 -132.5 1.1752 0.8 8.7 4U 1700-377 5.7 29.3 -134.5 2.8968 2.0 12.7 GX 349+2 10.8 42.1 -137.9 -2.3099 -1.1 4.9 GX 1+4 42.9 28.3 -112.6 0.4573 0.3 8.9 4U 1735-44 10.6 45.6 -129.8 -3.6492 -1.1 2.3 GX 5-1 66.6 44.9 -129.4 0.5409 0.2 7.5 GRS 1758-258 0.0 44.3 -119.6 4.8974 1.0 9.8 H1820-303 122.3 34.7 -129.4 -0.1561 -0.1 0.5 GX 354-0 3.8 37.5 50.0 5.5444 3.0 ------ UNKNOWN 3.0 47.4 -11.0 6.5318 3.8 ------ UNKNOWN 3.4 38.1 -66.9 9.2072 3.4 ------ UNKNOWN background subtracted image of 15-350 keV band DECcent POSerr Theta Phi PeakCts SNR AngSep Name [deg] ['] [deg] [deg] ['] 0.0 27.8 39.9 -0.0147 -0.2 12.8 Cen X-3 4.6 19.9 35.7 0.1855 2.5 2.4 GX 301-2 8.5 43.1 -166.5 0.1690 1.4 3.7 Sco X-1 4.4 27.9 -132.8 0.2359 2.6 6.4 4U 1700-377 9.9 29.3 -134.5 0.1075 1.2 12.7 GX 349+2 3.6 42.1 -137.7 -0.5009 -3.2 10.5 GX 1+4 51.4 28.2 -113.3 0.0246 0.2 11.5 4U 1735-44 7.3 45.6 -129.8 -0.3912 -1.6 5.6 GX 5-1 7.8 45.0 -129.1 0.3507 1.5 7.8 GRS 1758-258 0.0 44.5 -119.4 -0.3802 -1.1 13.0 H1820-303 0.0 34.9 -129.4 0.0940 0.8 10.7 GX 354-0 2.3 59.2 -14.1 2.1841 5.0 ------ UNKNOWN 1.8 41.6 -43.3 0.9430 6.6 ------ UNKNOWN image of 15-350 keV band DECcent POSerr Theta Phi PeakCts SNR AngSep Name [deg] ['] [deg] [deg] ['] 0.6 37.2 60.0 12.9786 18.4 1.1 Sco X-1 15.9 46.0 141.3 0.8220 0.7 1.1 Her X-1 73.8 41.2 21.5 0.0814 0.2 6.7 4U 1700-377 6.4 39.9 22.3 0.9303 1.8 10.5 GX 349+2 7.3 27.3 28.9 -0.5467 -1.6 9.0 GX 1+4 6.4 43.4 7.9 0.8828 1.8 9.0 4U 1735-44 0.0 12.4 89.9 0.3957 1.3 12.6 SW J1753.5-0127 3.2 23.8 15.5 1.0773 3.6 2.5 GX 5-1 3.8 24.4 14.7 0.9241 3.1 2.3 GRS 1758-258 1.8 12.4 23.2 2.0439 6.5 2.1 GX 17+2 4.6 27.2 0.5 0.7087 2.5 5.1 H1820-303 524.5 21.8 -19.1 0.0064 0.0 1.4 HT1900.1-2455 0.7 16.5 -159.7 4.8943 16.3 0.6 GRS 1915+105 0.5 42.5 -165.6 11.6835 21.2 1.1 Cyg X-1 4.3 51.0 -162.0 2.1977 2.7 2.2 Cyg X-3 230.0 34.5 18.2 0.0208 0.0 10.3 GX 354-0 2.6 53.2 15.9 4.9463 4.4 ------ UNKNOWN 2.1 28.5 176.5 1.7558 5.6 ------ UNKNOWN 3.9 37.0 -70.2 2.2907 3.0 ------ UNKNOWN 3.3 42.2 -57.5 3.2150 3.5 ------ UNKNOWN 3.6 41.1 -98.5 5.1190 3.2 ------ UNKNOWN

Analysis Summary

Notes:

Image

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

Light Curves

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:

Time averaged spectrum fit using the average DRM

Power-law model

Cutoff power-law model

1-s peak spectrum fit

Power-law model

Cutoff power-law model

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

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

IMX = 6.466458539785949E-01,

Spacecraft aspect plot

Bright

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