GRB250520A

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 v2.48
    Process Start Time: Fri Jun 20 15:34:09 EDT 2025
             Host Name: batproc1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger1315630
======================================================================

  Trigger: 01315630      Segment: 000

  BAT Trigger Time: 769401772.48   [s; MET]
      Trigger Stop: 769401772.608   [s; MET]
               UTC: 2025-05-20T02:42:16.844680    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 282.268181373042   Dec: -11.8468720448437  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    9.73
     Image Trigger?:     NO
     Rate S/N Ratio:     84.2674314311288  [ if not an image trigger ]
     Image S/N Ratio:    9.73

  Analysis Position:   [ source = BAT ]
    RA: 282.268181373042   Dec: -11.8468720448437  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 282.265937969651   Dec: -11.8555292516449  [deg; J2000]  
        { 18h 49m 03.8s , -11d 51' 19.9" }
         +/- 1.60953429455025 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.491145336966139 [arcmin] (formal 1-sigma fit error)
    SNR: 15.4110535822642
 
  Angular difference between the analysis and refined position is 0.535877 arcmin
 
  Partial Coding Fraction: 0.6875    [ including projection effects ]

  Duration
     T90: 0.46399998664856 +/- 0.147512777518617
        Measured from: -0.248000025749207
                   to: 0.215999960899353     [s; relative to TRIGTIME]
     T50: 0.128000020980835 +/- 0.0357770535203468
        Measured from: 0.00800001621246338
                   to: 0.136000037193298     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: -0.539999961853027     
                   to: 0.460000038146973     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -0.328000068664551     
                   to: 0.23199999332428     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.029102   0.061617   0.091990   0.044337
           0.007611   0.008131   0.008287   0.007619 [error]
 Peak      0.033536   0.069917   0.098516   0.039696
           0.009808   0.009962   0.009483   0.008560 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100    0.560   -0.328    0.232
T90     0.464   -0.248    0.216
T50     0.128    0.008    0.136
Peak    1.000   -0.540    0.460
 
 
====== 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: 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      -0.550    -0.218      0.234       -           -               -         2.50e-02     -3.38e-03          3.27e-03      62.110   57
CPL     -0.531    -0.230      0.967     9899.140    -9899.140      -9899.140      2.51e-02     -3.11e-03          2.91e-02      62.110   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      -0.666     -0.225     0.240       -           -               -         1.60e-02     -2.21e-03          2.15e-03      53.860   57
CPL     -0.376     -0.485     1.045      377.540    -377.540      -377.540      2.04e-02     -5.80e-03          2.59e-02      53.540   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   7.39e-09  2.45e-08  6.69e-08  5.43e-07  1.83e-07  6.42e-07   erg/cm2
      90%_error_low -2.08e-09 -4.36e-09 -7.40e-09 -1.37e-07 -2.10e-08 -1.39e-07   erg/cm2
      90%_error_hi   2.37e-09  4.33e-09  7.38e-09  1.74e-07  2.11e-08  1.73e-07   erg/cm2
Peak flux       PL   2.97e-01  4.94e-01  6.22e-01  1.57e+00  1.85e+00  2.98e+00   ph/cm2/s
      90%_error_low -8.58e-02 -9.29e-02 -7.23e-02 -3.80e-01 -2.32e-01 -3.96e-01   ph/cm2/s
      90%_error_hi   9.90e-02  9.29e-02  7.22e-02  4.66e-01  2.34e-01  4.31e-01   ph/cm2/s
 
Fluence        CPL   7.39e-09  2.45e-08  6.69e-08  5.16e-07  1.98e-07  5.38e-07   erg/cm2
      90%_error_low -3.11e-09 -4.54e-09 -7.41e-09 -3.03e-07 -3.66e-08 -2.26e-07   erg/cm2
      90%_error_hi   1.64e-09  4.16e-09  9.95e-09  1.18e-07  6.28e-09  1.92e-07   erg/cm2
Peak flux      CPL   2.66e-01  4.89e-01  6.44e-01  1.24e+00  1.82e+00  2.64e+00   ph/cm2/s
      90%_error_low -1.16e-01 -1.00e-01 -8.83e-02 -6.01e-01 -2.44e-01 -6.79e-01   ph/cm2/s
      90%_error_hi   1.23e-01  9.64e-02  9.78e-02  4.37e-01  2.47e-01  5.35e-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
  282.2659   -11.8555   0.0126    33.2756   174.4184         0.2333453     15.411 TRIG_01315630                 
 
Foreground time interval of the image:
 -0.328   0.232 (delta_t =   0.560 [sec])
Background time interval of the image:
-74.579  -0.328 (delta_t =  74.251 [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   -0.328 sec. to    0.232 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.550099     ( -0.218246   0.233525 )
Norm@50keV  : 2.49533E-02    ( -0.0033762   0.00326604 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   62.11     using 59 bins.
 Reduced chi-squared = 1.08965
# Null hypothesis probability of 2.99e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 0.56 sec: 0.162922 ( -0.006268  0.223274 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.83108e-07 ( -2.104e-08  2.10928e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from   -0.328 sec. to    0.232 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.530727     ( -0.229854   0.966565 )
Epeak [keV] : 9899.14      ( -9744.19 -9744.19 )
Norm@50keV  : 2.50859E-02    ( -0.00311991   0.0291357 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   62.11     using 59 bins.
 Reduced chi-squared = 1.10911
# Null hypothesis probability of 2.68e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 0.56 sec: 2.92979 ( -0.36721  0.32443 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.98038e-07 ( -3.66064e-08  6.27609e-09 ) ergs/cm2

1-s peak spectrum fit

Power-law model

Time interval is from   -0.540 sec. to    0.460 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.665549     ( -0.224616   0.239547 )
Norm@50keV  : 1.59596E-02    ( -0.00221097   0.00214708 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   53.86     using 59 bins.
 Reduced chi-squared = 0.944912
# Null hypothesis probability of 5.94e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 1.85025 ( -0.23222  0.23442 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.97911e-07 ( -2.37865e-08  2.38474e-08 ) ergs/cm2

Cutoff power-law model

Time interval is from   -0.540 sec. to    0.460 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.376117     ( -0.485296   1.04548 )
Epeak [keV] : 377.540      ( -377.538 -377.538 )
Norm@50keV  : 2.03737E-02    ( -0.00580276   0.025942 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   53.54     using 59 bins.
 Reduced chi-squared = 0.956071
# Null hypothesis probability of 5.68e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 1.82371 ( -0.24372  0.24693 ) ph/cm2/s
Energy fluence (15-150 keV)             : 1.96648e-07 ( -2.44849e-08  2.42593e-08 ) ergs/cm2

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = N/A sec.
Hardness ratio (energy fluence ratio) = N/A

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

S(15-50 keV)  = N/A
S(50-150 keV) = N/A

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 = -6.531553594462511E-01,

Spacecraft aspect plot

Bright

Pre-burst

 Time interval of the image: -74.579400 -0.328000

# RAcent #  [deg] 170.2415 -60.6629 186.6576 -62.7686 244.9777 -15.6330 256.0526 -37.8136 256.4592 -36.5152 263.0364 -24.5398 264.4489 -44.4312 268.4864  -1.5320 270.2797 -25.0153 270.0705 -25.7367 274.1081 -14.0021 275.8536 -30.2219 284.9692 -25.0558 262.8369 -33.8763 171.3868 -55.1473 309.2477 -21.4196 281.6783 -80.2959

Pre-slew

 Time interval of the image: -0.328000 0.232000

# RAcent #  [deg] 170.3485 -60.5015 186.6178 -62.6571 245.1546 -15.6552 255.9198 -38.0314 256.3598 -36.5620 262.9816 -24.9515 264.4489 -44.4312 268.4388  -1.5633 270.0534 -25.0727 270.2841 -25.9216 274.1108 -14.1269 276.0581 -30.4558 285.1332 -24.8011 263.0334 -33.6489 271.1998 -17.2136 282.2659 -11.8555 184.1868 -50.7988

Post-slew

 Time interval of the image: 125.020590 962.592900

# RAcent #  [deg] 244.9723 -15.6409 254.4388  35.2010 255.9906 -37.8331 256.3356 -36.3727 263.0387 -24.6536 264.5997 -44.4247 268.3413  -1.4531 270.3317 -25.0068 270.2888 -25.5973 274.0991 -13.9372 276.0405 -30.1926 285.0529 -25.0729 288.9278  11.0100 299.5732  35.2113 262.9138 -33.7011 312.0136 -52.2698 306.4032  33.6954 328.3666 -17.5058 310.3732  27.7579

Mask shadow pattern

IMY = -6.383055738437568E-02 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] ['] 5.8 57.5 -19.0 1.3086 2.0 3.2 Cen X-3 54.9 49.5 -19.9 0.0740 0.2 0.1 GX 301-2 0.4 23.5 94.5 5.8780 26.5 0.4 Sco X-1 2.5 1.7 -20.2 0.7564 4.6 3.6 4U 1700-377 4.7 0.7 24.3 0.3874 2.5 5.6 GX 349+2 0.0 12.8 149.8 0.3573 2.2 12.4 GX 1+4 0.0 9.7 -86.3 0.3329 2.0 12.6 4U 1735-44 3.5 36.4 144.7 1.0012 3.3 8.6 SW J1753.5-0127 4.4 15.9 173.6 0.4002 2.6 3.8 GX 5-1 0.0 15.2 174.8 -0.1569 -1.0 12.5 GRS 1758-258 9.5 27.0 163.8 0.2397 1.2 6.3 GX 17+2 26.7 16.7 -160.8 -0.0668 -0.4 9.5 H1820-303 4.8 26.2 -162.2 0.4059 2.4 8.9 HT1900.1-2455 4.7 5.2 -171.8 0.3597 2.5 8.0 GX 354-0 2.6 58.7 -12.6 3.2066 4.5 ------ UNKNOWN 2.5 47.3 -148.1 1.6864 4.7 ------ UNKNOWN 2.3 44.9 -60.1 3.8198 5.0 ------ UNKNOWN background subtracted image of 15-350 keV band DECcent POSerr Theta Phi PeakCts SNR AngSep Name [deg] ['] [deg] [deg] ['] 9.6 57.5 -18.8 0.0699 1.2 7.4 Cen X-3 13.1 49.5 -19.7 -0.0233 -0.9 6.9 GX 301-2 4.0 23.4 94.9 0.0449 2.9 10.2 Sco X-1 7.6 2.0 -21.3 0.0177 1.5 11.7 4U 1700-377 4.7 0.8 22.1 -0.0276 -2.5 9.1 GX 349+2 0.0 12.4 150.2 0.0131 1.1 12.4 GX 1+4 0.0 9.7 -86.3 0.0309 2.5 12.6 4U 1735-44 6.5 36.3 144.6 -0.0393 -1.8 7.9 SW J1753.5-0127 0.0 15.7 173.1 0.0156 1.3 12.5 GX 5-1 128.2 15.2 175.8 0.0011 0.1 10.8 GRS 1758-258 4.9 26.9 163.9 0.0344 2.4 8.2 GX 17+2 8.0 16.7 -159.8 0.0166 1.4 8.7 H1820-303 6.2 26.5 -162.5 0.0250 1.9 8.9 HT1900.1-2455 30.5 5.4 -173.0 -0.0043 -0.4 11.4 GX 354-0 2.3 22.8 161.9 0.0639 5.0 ------ UNKNOWN 0.8 33.3 174.4 0.2333 15.4 ------ UNKNOWN 2.5 52.6 -4.9 0.1517 4.7 ------ UNKNOWN image of 15-350 keV band DECcent POSerr Theta Phi PeakCts SNR AngSep Name [deg] ['] [deg] [deg] ['] 0.8 36.4 96.5 11.2868 15.1 0.4 Sco X-1 4.6 53.9 168.7 2.8116 2.5 8.5 Her X-1 1.4 35.0 54.4 5.0161 8.3 0.7 4U 1700-377 25.8 33.9 56.0 0.2417 0.4 5.7 GX 349+2 4.2 22.3 69.0 0.9615 2.8 5.8 GX 1+4 5.1 35.9 38.5 1.1833 2.3 6.3 4U 1735-44 41.0 17.3 142.8 -0.0750 -0.3 1.6 SW J1753.5-0127 6.9 17.3 55.8 0.5093 1.7 5.0 GX 5-1 8.6 17.8 54.6 -0.4107 -1.3 8.8 GRS 1758-258 5.5 8.2 91.2 0.6000 2.1 8.1 GX 17+2 0.0 19.2 33.4 -0.2628 -0.9 12.1 H1820-303 7.9 13.5 5.9 0.4400 1.5 9.2 HT1900.1-2455 3.2 23.8 -146.8 1.0487 3.6 8.5 GRS 1915+105 2.2 49.8 -144.6 4.4618 5.2 1.0 Cyg X-1 13.6 28.1 52.7 0.3354 0.9 8.9 GX 354-0 2.6 47.0 -7.7 2.0662 4.4 ------ UNKNOWN 2.8 51.0 -137.2 6.0933 4.1 ------ UNKNOWN 2.9 44.9 -60.2 6.2765 4.0 ------ UNKNOWN 3.2 48.1 -129.1 5.4693 3.7 ------ 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 = -6.531553594462511E-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