GRB241229B: 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 v2.48
    Process Start Time: Thu Jun 19 21:58:26 EDT 2025
             Host Name: batproc1
   Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/trigger1277428
======================================================================

  Trigger: 01277428      Segment: 000

  BAT Trigger Time: 757129010.752   [s; MET]
      Trigger Stop: 757129011.776   [s; MET]
               UTC: 2024-12-29T01:36:15.955240    [includes UTCF correction] 
       Where From?: TDRSS position message

  BAT 
    RA: 274.149125849278   Dec: 74.7138330676705  [deg; J2000]

     Catalogged Source?: NO
     Point Source?:      YES
     GRB Indicated?:     YES    [ by BAT flight software ]
     Image S/N Ratio:    15.88
     Image Trigger?:     NO
     Rate S/N Ratio:     39.7240481320824  [ if not an image trigger ]
     Image S/N Ratio:    15.88

  Analysis Position:   [ source = BAT ]
    RA: 274.149125849278   Dec: 74.7138330676705  [deg; J2000]

  Refined Position:   [ source = BAT pre-slew burst ]
    RA: 274.139639422753   Dec: 74.6943037113503  [deg; J2000]  
        { 18h 16m 33.5s , +74d 41' 39.5" }
         +/- 1.22698191870708 [arcmin] (estimated 90% radius based on SNR)
         +/- 0.376325163076137 [arcmin] (formal 1-sigma fit error)
    SNR: 22.709455365888
 
  Angular difference between the analysis and refined position is 1.181343 arcmin
 
  Partial Coding Fraction: 0.3984375    [ including projection effects ]

  Duration
     T90: 5.0479998588562 +/- 0.648752741372382
        Measured from: -2.10799992084503
                   to: 2.93999993801117     [s; relative to TRIGTIME]
     T50: 1.50399994850159 +/- 0.392448801217247
        Measured from: -0.0799999237060547
                   to: 1.42400002479553     [s; relative to TRIGTIME]



  Fluence
     Peak Flux  (peak 1 second)
        Measured from: -0.0559999942779541     
                   to: 0.944000005722046     [s; relative to TRIGTIME]
     Total Fluence        
        Measured from: -2.6159999370575     
                   to: 3.37999999523163     [s; relative to TRIGTIME]
     
             Band 1     Band 2     Band 3     Band 4
              15-25      25-50     50-100    100-350     keV
 Total     0.339263   0.496197   0.335499   0.036564
           0.027514   0.029626   0.023916   0.017394 [error]
 Peak      0.122288   0.209274   0.145468   0.025050
           0.012772   0.014730   0.012250   0.007646 [error]

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

======================================================================
 
 
====== Table of the duration information =============================
 
        Value   tstart    tstop
T100    5.996   -2.616    3.380
T90     5.048   -2.108    2.940
T50     1.504   -0.080    1.424
Peak    1.000   -0.056    0.944
 
 
====== 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      -1.699    -0.116      0.114       -           -               -         1.31e-02     -9.50e-04          9.45e-04      55.860   57
CPL     -0.929    -0.477      0.533       68.257     -11.700        33.442      3.28e-02     -1.39e-02          2.80e-02      47.780   56
 
 
=== 1-s peak spectral analysis ===
(Best model with acceptable fit: CPL)
 
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      -1.595     -0.127     0.125       -           -               -         3.15e-02     -2.69e-03          2.68e-03      63.520   57
CPL     -0.233     -0.620     0.720       65.659      -8.595        15.712      1.54e-01     -7.78e-02          1.94e-01      47.290   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   1.21e-07  1.98e-07  2.43e-07  5.92e-07  7.30e-07  1.15e-06   erg/cm2
      90%_error_low -1.30e-08 -1.38e-08 -2.28e-08 -1.07e-07 -5.49e-08 -1.29e-07   erg/cm2
      90%_error_hi   1.34e-08  1.38e-08  2.28e-08  1.20e-07  5.52e-08  1.39e-07   erg/cm2
Peak flux       PL   1.42e+00  1.35e+00  8.95e-01  9.21e-01  4.05e+00  4.59e+00   ph/cm2/s
      90%_error_low -1.81e-01 -1.17e-01 -9.24e-02 -1.71e-01 -3.41e-01 -3.81e-01   ph/cm2/s
      90%_error_hi   1.87e-01  1.17e-01  9.18e-02  1.90e-01  3.41e-01  3.81e-01   ph/cm2/s
 
Fluence        CPL   1.22e-07  1.66e-07  1.73e-07  4.06e-07  5.72e-07  8.67e-07   erg/cm2
      90%_error_low -1.59e-08 -1.74e-08 -2.28e-08 -4.44e-08 -7.61e-08 -1.09e-07   erg/cm2
      90%_error_hi   1.39e-08  1.45e-08  2.11e-08  3.63e-08  9.87e-07  9.40e-08   erg/cm2
Peak flux      CPL   1.12e+00  1.55e+00  1.03e+00  3.09e-01  3.93e+00  4.01e+00   ph/cm2/s
      90%_error_low -2.18e-01 -1.51e-01 -1.16e-01 -1.22e-01 -3.47e-01 -3.70e-01   ph/cm2/s
      90%_error_hi   2.24e-01  1.55e-01  1.18e-01  1.83e-01  3.47e-01  3.79e-01   ph/cm2/s
 
======================================================================

Image

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

#   RAcent    DECcent   POSerr    Theta     Phi              Peak Cts       SNR   Name
  274.1396    74.6943   0.0085    29.9937    69.2012         1.2608474     22.709 TRIG_01277428                 
 
Foreground time interval of the image:
 -2.616   3.380 (delta_t =   5.996 [sec])
Background time interval of the image:
-239.752  -2.616 (delta_t = 237.136 [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   -2.616 sec. to    3.380 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.69867     ( -0.11584   0.113979 )
Norm@50keV  : 1.31473E-02    ( -0.000950409   0.000944974 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   55.86     using 59 bins.
 Reduced chi-squared = 0.98
# Null hypothesis probability of 5.18e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 5.996 sec: 1.74537 ( -0.12275  0.1229 ) ph/cm2/s
Energy fluence (15-150 keV)             : 7.30085e-07 ( -5.49018e-08  5.51898e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -2.616 sec. to    3.380 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.928935     ( -0.476879   0.532836 )
Epeak [keV] : 68.2569      ( -11.6996 33.4418 )
Norm@50keV  : 3.27563E-02    ( -0.0138833   0.027953 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   47.78     using 59 bins.
 Reduced chi-squared = 0.853214
# Null hypothesis probability of 7.75e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 5.996 sec: 1.69556 ( -0.12659  0.12663 ) ph/cm2/s
Energy fluence (15-150 keV)             : 5.72073e-07 ( -7.60844e-08  9.87343e-07 ) ergs/cm2
 

1-s peak spectrum fit

Power-law model

Time interval is from   -0.056 sec. to    0.944 sec.
 
Spectral model in power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -1.59516     ( -0.127357   0.12505 )
Norm@50keV  : 3.15245E-02    ( -0.00268839   0.00267801 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   63.52     using 59 bins.
 Reduced chi-squared = 1.11439
# Null hypothesis probability of 2.58e-01 with 57 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 4.04512 ( -0.34118  0.3415 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.95039e-07 ( -2.65107e-08  2.66454e-08 ) ergs/cm2
 

Cutoff power-law model

Time interval is from   -0.056 sec. to    0.944 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters  : value       lower 90%   higher 90%
Photon index: -0.232561     ( -0.619588   0.720352 )
Epeak [keV] : 65.6594      ( -8.59534 15.7125 )
Norm@50keV  : 0.153985    ( -0.0777632   0.193792 )
------------------------------------------------------------
#Fit statistic  : Chi-Squared                   47.29     using 59 bins.
 Reduced chi-squared = 0.844464
# Null hypothesis probability of 7.90e-01 with 56 degrees of freedom
 
Photon flux (15-150 keV)    in 1 sec: 3.93267 ( -0.34682  0.34674 ) ph/cm2/s
Energy fluence (15-150 keV)             : 2.82319e-07 ( -2.7278e-08  2.75299e-08 ) ergs/cm2
 

Time-resolved spectra

Distribution

T90 vs. Hardness ratio plot

T90                                   = 5.048 sec.
Hardness ratio (energy fluence ratio) = 1.23233876839

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

S(15-50 keV)  = 3.188484e-07
S(50-150 keV) = 4.112233e-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 = 2.049574936706344E-01, IMY = -5.395893732863686E-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:
-239.752000 -2.616000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
254.4555  35.3537    3.8  34.1  -11.9   1.2220   3.0    0.7	Her X-1                       
288.9228  10.9640    6.9  36.3  -83.8  -1.3200  -1.7    7.4	GRS 1915+105                  
299.6252  35.2326    2.2  11.3 -106.3   1.6965   5.3    2.5	Cyg X-1                       
308.1204  41.0329    2.3   9.2 -156.1   1.5295   4.9    4.8	Cyg X-3                       
325.9190  38.2689    0.0  22.2 -177.0  -0.7000  -2.1   12.3	Cyg X-2                       
224.1432  31.4854    3.4  57.0    4.2   4.3869   3.4 ------	UNKNOWN                       
329.2456  37.3338    3.0  24.9 -178.4   1.2384   3.8 ------	UNKNOWN                       
271.5645   7.6600    2.8  44.9  -60.2   5.9673   4.1 ------	UNKNOWN                       

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

Time interval of the image:
-2.616000 3.380000
 
# RAcent  DECcent POSerr Theta    Phi  PeakCts   SNR AngSep     Name
#  [deg]    [deg]    ['] [deg]  [deg]                   [']
254.2458  35.3690   25.5  34.2  -11.7   0.0178   0.5   10.5	Her X-1                       
288.6729  10.9011    5.6  36.4  -83.4   0.1417   2.1    7.9	GRS 1915+105                  
299.4442  35.3733    0.0  11.2 -105.6   0.0471   1.4   12.5	Cyg X-1                       
308.2237  40.7749    5.1   9.5 -155.2  -0.0687  -2.2   11.8	Cyg X-3                       
326.1671  38.4805    4.8  22.3 -177.8   0.0774   2.4    9.5	Cyg X-2                       
274.1397  74.6943    0.5  30.0   69.2   1.2608  22.7 ------	UNKNOWN                       
271.6762   7.5986    2.8  44.9  -60.4   0.4510   4.2 ------	UNKNOWN                       

Post-slew image of 15-350 keV band

Time interval of the image: