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Catalogue XRT results for GRB 191221B

Data were analysed using HEASOFT version 6.32

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Summary Information

RA:10h 19m 19.20sLC breaks:5
Dec:-38° 09′ 27.2′′LC type:Canonical.
Err:1.4′′NH,intr.:5.79×1016 cm-2
Gal long:272.731Redshift1.148
Gal lat:15.636Γ1.9
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Jump to: Light curve | Spectra | Compare to other bursts.

If you use any of these data, please cite Evans et al. (2009), which describes how these products were created (see the usage policy for more information).

Light curve

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This light curve comes from the light curve repository (if you use it, please cite Evans et al [2007, 2009]. Flares, marked by cross-hatched regions, are identified automatically, but may have been manually corrected. These are excluded from the fit. Any power-law breaks added to the fit must be required at the 4-σ level (according to an f-test) to be included in the best-fit. Details of all fits attempted are given below the plot. For more information see the light curve fitting documentation.

Fitted light curve of GRB 191221B

Fit Details

Nbreaksχ2dofCommentsImage
02573756Image of this fit
11670754Break required.

(2.01e-69 % probability of chance improvement)
Image of this fit
2935752Break required.

(2.02e-93 % probability of chance improvement)
Image of this fit
3847750Break required.

(8.39e-15 % probability of chance improvement)
Image of this fit
4804748Break required.

(2.85e-07 % probability of chance improvement)
Image of this fit
5762746Break required.

(2.07e-07 % probability of chance improvement).
This is the best fit.
Image of this fit

There are 2 flares excluded from the fit:

  • 74.2—100 s
  • 850—927 s

The best-fitting light curve has 5 breaks.

Click on the number of breaks in the table to the right to change which fit is plotted above and detailed below.

Currently showing the best fit.

α11.35 (+0.04, -0.04)
Tb,1394 (+23, -33) s
α20.67 (+0.10, -0.09)
Tb,2785 (+24, -48) s
α3-0.8 (+0.5, -0.7)
Tb,3953 (+36, -49) s
α41.42 (+0.04, -0.04)
Tb,41.19 (+0.07, -0.52) × 104 s
α5-1.50 (+0.00, +2.52)
Tb,51.77 (+1.40, -0.10) × 104 s
α61.902 (+0.107, -0.096)

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Spectra

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Spectra have been created for each power-law segment in the best fitting light curve (shown above). Times of flaring have not been removed, however this makes little difference to most spectra (see Fig 7/8c of Evans et al. 2009). For more information see the time-resolved spectroscopy documentation.

Jump to: phase1|phase2|phase3|phase4|phase5|phase6

phase1 spectrum (T0 + 90 to 394 s)

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WT mode spectrum of GRB 191221B

WT mode. Mean photon arrival: T0+204 s

NH (Galactic)8.63 × 1020 cm-2
NH (intrinsic)5 (+34, -5) × 1019 cm-2
z of absorber1.148
Photon index2.095 (+0.030, -0.023)
Flux (0.3-10 keV)
(Observed)
2.00 (+0.03, -0.04) × 10-9 erg cm-2 s-1
Flux (0.3-10 keV)
(Unabsorbed)
2.47 (+0.04, -0.03) × 10-9 erg cm-2 s-1
Counts to flux (obs)3.10 × 10-11 erg cm-2 ct-1
Counts to flux (unabs)3.83 × 10-11 erg cm-2 ct-1
W-stat (dof)
What's this?
656.54 (698)
Spectrum exposure304 s

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phase2 spectrum (T0 + 394 to 785 s)

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WT mode spectrum of GRB 191221B

WT mode. Mean photon arrival: T0+574 s

NH (Galactic)8.63 × 1020 cm-2
NH (intrinsic)0 (+1.65 × 1020, -0) cm-2
z of absorber1.148
Photon index2.071 (+0.031, -0.030)
Flux (0.3-10 keV)
(Observed)
6.81 (+0.17, -0.13) × 10-10 erg cm-2 s-1
Flux (0.3-10 keV)
(Unabsorbed)
8.35 (+0.17, -0.16) × 10-10 erg cm-2 s-1
Counts to flux (obs)3.12 × 10-11 erg cm-2 ct-1
Counts to flux (unabs)3.83 × 10-11 erg cm-2 ct-1
W-stat (dof)
What's this?
654.14 (600)
Spectrum exposure390 s

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phase3 spectrum (T0 + 785 to 952 s)

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WT mode spectrum of GRB 191221B

WT mode. Mean photon arrival: T0+871 s

NH (Galactic)8.63 × 1020 cm-2
NH (intrinsic)8 (+10, -8) × 1020 cm-2
z of absorber1.148
Photon index1.98 (+0.07, -0.07)
Flux (0.3-10 keV)
(Observed)
6.60 (+0.31, -0.29) × 10-10 erg cm-2 s-1
Flux (0.3-10 keV)
(Unabsorbed)
8.08 (+0.30, -0.29) × 10-10 erg cm-2 s-1
Counts to flux (obs)3.29 × 10-11 erg cm-2 ct-1
Counts to flux (unabs)4.03 × 10-11 erg cm-2 ct-1
W-stat (dof)
What's this?
446.21 (497)
Spectrum exposure167 s

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phase4 spectrum (T0 + 952 to 6816 s)

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WT and PC mode spectra of GRB 191221B

WT mode. Mean photon arrival: T0+1155 s

NH (Galactic)8.63 × 1020 cm-2
NH (intrinsic)1.0 (+0.6, -0.6) × 1021 cm-2
z of absorber1.148
Photon index2.01 (+0.05, -0.05)
Flux (0.3-10 keV)
(Observed)
5.09 (+0.16, -0.15) × 10-10 erg cm-2 s-1
Flux (0.3-10 keV)
(Unabsorbed)
6.30 (+0.16, -0.16) × 10-10 erg cm-2 s-1
Counts to flux (obs)3.26 × 10-11 erg cm-2 ct-1
Counts to flux (unabs)4.04 × 10-11 erg cm-2 ct-1
W-stat (dof)
What's this?
539.32 (603)
Spectrum exposure447 s

PC mode. Mean photon arrival: T0+5768 s

NH (Galactic)8.63 × 1020 cm-2
NH (intrinsic)1.2 (+1.7, -1.2) × 1021 cm-2
z of absorber1.148
Photon index1.83 (+0.12, -0.12)
Flux (0.3-10 keV)
(Observed)
6.3 (+0.5, -0.5) × 10-11 erg cm-2 s-1
Flux (0.3-10 keV)
(Unabsorbed)
7.4 (+0.5, -0.4) × 10-11 erg cm-2 s-1
Counts to flux (obs)3.67 × 10-11 erg cm-2 ct-1
Counts to flux (unabs)4.35 × 10-11 erg cm-2 ct-1
W-stat (dof)
What's this?
308.05 (352)
Spectrum exposure2.0 ks

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phase5 spectrum (T0 + 12344 to 12861 s)

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PC mode spectrum of GRB 191221B

PC mode. Mean photon arrival: T0+12606 s

NH (Galactic)8.63 × 1020 cm-2
NH (intrinsic)0 (+2.07 × 1021, -0) cm-2
z of absorber1.148
Photon index1.79 (+0.25, -0.11)
Flux (0.3-10 keV)
(Observed)
2.6 (+0.4, -0.4) × 10-11 erg cm-2 s-1
Flux (0.3-10 keV)
(Unabsorbed)
3.0 (+0.3, -0.3) × 10-11 erg cm-2 s-1
Counts to flux (obs)3.65 × 10-11 erg cm-2 ct-1
Counts to flux (unabs)4.21 × 10-11 erg cm-2 ct-1
W-stat (dof)
What's this?
151.63 (163)
Spectrum exposure516 s

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phase6 spectrum (T0 + 9223372036854775807 to -471493102 s)

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Comparison with other bursts

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Parameter distributions

The plots below show the probability density functions of the temporal and time-averaged spectral parameters for all GRBs, with the data for GRB 191221B shown on in colour. Click the images for larger versions.

For all plots, the solid vertical lines mark the values for this GRB, and the dashed lines the 1-σ uncertainties. For α and Tb, the colour changes for each phase. For the spectral parameters, the WT fits are shown in blue and the PC in red. These figures correspond to Figs. 5,6, 7a and 8a of Evans et al. (2009). See the PDF documentation for more information.

Temporal indicesBreak TimesNHSpectral indices
Comparison of decay indices Comparison of light curve break times Comparison of intrinsic column densities Comparison of spectral energy indices

Closure Relationships

The plots below show (α, β) scatter plots for each phase of all Canonical light curves. GRB 191221B is shown in colour; where multiple points appear in a given phase (e.g. WT and PC mode spectra for that phase), the different colours refer to different spectra. α and β are the temporal and spectral energy power-law indices respectively. The shaded regions mark those allowed by the standard closure relationships. These figures correspond to Fig. 10 of Evans et al. (2009). See the closure relationship documentation for more information.

Canonical
Steep phase
Canonical
Plateau
Canonical
'Normal'
Canonical
Post jet-break
Comparison of Canonical, steep phase closuresComparison of Canonical, plateau phase closuresComparison of Canonical, normal phase closuresComparison of Canonical, post jet-break phase closures

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