GRB150821A

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.

ADD SPECIAL NOTE BY HAND

======================================================================
                  BAT GRB EVENT DATA PROCESSING REPORT
    Process Script Ver: batgrbproduct v2.46
    Process Start Time: Thu Dec 17 11:16:10 EST 2015
             Host Name: bat1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger652847
======================================================================

  Trigger: 00652847      Segment: 000

  BAT Trigger Time: 461843056   [s; MET]
      Trigger Stop: 461843208   [s; MET]
               UTC: 2015-08-21T09:44:00.976460    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 341.905812314366   Dec: -57.8753482469684  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    7.18
     Image Trigger?:     YES
     Rate S/N Ratio:     0  [ if not an image trigger ]
     Image S/N Ratio:    7.18

  Analysis Position:   [ source = BAT ]
    RA: 341.905812314366   Dec: -57.8753482469684  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 341.916214293096   Dec: -57.8723837737101  [deg; J2000]  
        { 22h 47m 39.9s , -57d 52' 20.6" }
         +/- 2.02173716780448 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.967992881613575 [arcmin] (formal 1-sigma fit error)
    SNR: 11.1267624269188
 
  Angular difference between the analysis and refined position is 0.376554 arcmin
 
  Partial Coding Fraction: 0.02124023    [ including projection effects ]

  Duration
     T90: 168.944000005722 +/- 102.337127308651
        Measured from: 27.5120000243187
                   to: 196.456000030041     [s; relative to TRIGTIME]
     T50: 48.5760000348091 +/- 13.8892718285374
        Measured from: 39.8799999952316
                   to: 88.4560000300407     [s; relative to TRIGTIME]

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100  309.648   21.096  330.744
T90   168.944   27.512  196.456
T50    48.576   39.880   88.456
Peak    1.000   34.268   35.268
 
 
====== 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      -1.931    -0.359      0.331       -           -               -         5.86e-04     -1.44e-04          1.41e-04      62.890   57
CPL      0.607    -1.864      2.978       42.105      -8.933        14.180      1.69e-02     -1.69e-02          7.82e-01      56.830   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      N/A         N/A       N/A          -           -               -           N/A           N/A               N/A         N/A        N/A   
CPL     N/A         N/A       N/A          N/A         N/A           N/A           N/A           N/A               N/A         N/A        N/A   
 
 
=== 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   1.76e-07  2.49e-07  2.61e-07  5.04e-07  8.44e-07  1.19e-06   erg/cm2
      90%_error_low -4.78e-08 -5.11e-08 -8.17e-08 -2.52e-07 -1.98e-07 -3.64e-07   erg/cm2
      90%_error_hi   5.01e-08  5.10e-08  8.55e-08  3.80e-07  2.05e-07  4.61e-07   erg/cm2
Peak flux       PL     N/A      N/A      N/A      N/A      N/A      N/A     ph/cm2/s

Special notes of this burst

Image

Pre-slew 15.0-350.0 keV image (Event data with DETECTION mask)

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  341.9162   -57.8724   0.0172    53.9158   147.9355        28.9170864     11.127 TRIG_00652847                 
 
Foreground time interval of the image:
 21.096 161.301 (delta_t = 140.205 [sec])
Background time interval of the image:
-239.000  21.096 (delta_t = 260.096 [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  174.240 sec. to  330.744 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.93097     ( -0.35792   0.331814 )
Norm@50keV  : 5.86132E-04    ( -0.000144105   0.000141046 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          62.89 using 59 PHA bins.
# Reduced chi-squared =          1.103 for     57 degrees of freedom 
# Null hypothesis probability =   2.758257e-01
 
Photon flux (15-150 keV)    in 156.5 sec: 8.52515E-02 ( -0.0175126  0.0175255 ) ph/cm2/s
Energy fluence (15-150 keV)             : 8.43751e-07 ( -1.97763e-07  2.04594e-07 ) ergs/cm2

Cutoff power-law model

Time interval is from  174.240 sec. to  330.744 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: 0.607063     ( -1.89231   2.9492 )
Epeak [keV] : 42.1053      ( -8.95597 14.1571 )
Norm@50keV  : 1.68954E-02    ( -0.0179153   0.780932 )
------------------------------------------------------------
#Fit statistic : Chi-Squared =          56.83 using 59 PHA bins.
# Reduced chi-squared =          1.015 for     56 degrees of freedom 
# Null hypothesis probability =   4.437534e-01
 
Photon flux (15-150 keV)    in 156.5 sec: 7.95172E-02 ( -0.0177062  0.0177957 ) ph/cm2/s
Energy fluence (15-150 keV)             : 7.13025e-07 ( -1.67375e-07  1.98638e-07 ) ergs/cm2

1-s peak spectrum fit

1-s peak spectrum unavailable, likely because there are no event data in the 1-s peak range.

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 168.944 sec.
Hardness ratio (energy fluence ratio) = 1.04869755298

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

S(15-50 keV)  = 4.24553e-07
S(50-150 keV) = 4.191919e-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

 IMX = 0, IMY = 0

Spacecraft aspect plot

Bright

Event

 Time interval of the image: 21.096000 161.300590

# RAcent #  [deg] 170.4440 -60.7362 186.7031 -62.7299 244.8753 -15.6334 256.0084 -37.8082 256.6458 -36.5018 262.9936 -24.7777 264.8795 -44.2624 268.3628  -1.5936 270.4447 -25.0513 270.3172 -25.7591 274.0826 -14.1529 275.9784 -30.4986 284.9511 -25.0459 262.9638 -33.6875 341.9163 -57.8724 275.7159 -68.9716 61.2211 -75.1454 236.7988   7.3264 203.6642 -23.6111

 Webpage updated on: Mon Jan 11 18:19:16 EST 2016

shadow pattern (with DETECTION mask)

source in the event data image data image of 15-350 keV band DECcent POSerr Theta Phi PeakCts SNR AngSep Name [deg] ['] [deg] [deg] ['] 25.5 49.2 -131.2 -0.3134 -0.5 7.8 Cen X-3 1.9 41.2 -131.6 -1.8543 -6.2 2.7 GX 301-2 6.8 28.9 -5.9 0.3267 1.7 6.0 Sco X-1 6.2 6.6 35.3 0.3091 1.9 2.4 4U 1700-377 5.9 8.0 34.8 0.3334 2.0 11.2 GX 349+2 281.2 20.9 37.2 0.0077 0.0 2.1 GX 1+4 0.0 9.0 106.3 0.1671 0.9 12.7 4U 1735-44 8.7 44.6 32.3 0.5358 1.3 8.5 SW J1753.5-0127 63.7 23.9 53.2 0.0400 0.2 8.9 GX 5-1 5.9 23.2 54.0 -0.4208 -2.0 1.2 GRS 1758-258 132.4 35.0 47.9 0.0287 0.1 8.3 GX 17+2 6.2 22.9 71.6 -0.4155 -1.9 8.4 H1820-303 15.2 32.5 74.6 0.2762 0.8 8.8 HT1900.1-2455 6.1 13.1 51.9 -0.3359 -1.9 8.9 GX 354-0 1.0 53.9 147.9 28.9060 11.1 ------ UNKNOWN 1.9 27.9 171.4 1.2468 6.0 ------ UNKNOWN 2.7 60.8 -174.2 9.3411 4.3 ------ UNKNOWN 2.5 53.0 -10.3 1.9269 4.7 ------ UNKNOWN 2.5 44.4 -70.2 4.0111 4.6 ------ UNKNOWN

Analysis Summary

Notes:

Image

Pre-slew 15.0-350.0 keV image (Event data with DETECTION mask)

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

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

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

Mask IMX = 0, IMY = 0

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

Mask
IMX = 0, IMY = 0