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Catalogue XRT results for GRB 130408A

Data were analysed using HEASOFT version 6.32

Summary Information

RA:	08h 57m 37.44s	LC breaks:	3
Dec:	-32° 21′ 39.0′′	LC type:	Oddball.
Err:	1.4′′	N_H,intr.:	2.16×10¹⁵ cm^-2
Gal long:	256.212	Redshift	3.758
Gal lat:	8.584	Γ	2.0

Show light curve? | Show spectrum? | Show comparison with other bursts?

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.

Fit Details

N_breaks	χ²	dof	Comments
0	560	58
1	191	56	Break required. (9.25e-12 % probability of chance improvement)
2	161	54	Break significance <4-σ (0.98 % probability of chance improvement)
3	117	52	Break required. (2.91e-03 % probability of chance improvement). This is the best fit.
4	84.5	50	Break significance <4-σ (0.03 % probability of chance improvement)
5	71.8	48	Break significance <4-σ (8.35e-03 % probability of chance improvement)

There are no flares ignored from this fit.

The best-fitting light curve has 3 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.

α₁	0.489 (+0.058, -0.258)
T_b,1	3532 (+370, -1763) s
α₂	1.26 (+0.09, -0.09)
T_b,2	3.43 (+0.17, -0.34) × 10⁴ s
α₃	8.00 (+0.00, -3.63)
T_b,3	4.43 (+0.95, -0.23) × 10⁴ s
α₄	0.30 (+0.33, -0.29)

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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

phase1 spectrum (T0 + 153 to 3531 s)

Download spectral files for phase1 spectrum.

Plots to download

WT mode. Mean photon arrival: T0+157 s

N_H (Galactic)	3.20 × 10²¹ cm^-2
N_H (intrinsic)	0 (+1.56 × 10²³, -0) cm^-2
z of absorber	3.758
Photon index	2.03 (+1.05, -0.48)
Flux (0.3-10 keV) (Observed)	1.3 (+0.7, -0.6) × 10^-10 erg cm^-2 s^-1
Flux (0.3-10 keV) (Unabsorbed)	2.09 (+1.94, -0.63) × 10^-10 erg cm^-2 s^-1
Counts to flux (obs)	3.16 × 10^-11 erg cm^-2 ct^-1
Counts to flux (unabs)	4.91 × 10^-11 erg cm^-2 ct^-1
W-stat (dof) What's this?	14.97 (27)
Spectrum exposure	9 s

PC mode. Mean photon arrival: T0+414 s

N_H (Galactic)	3.20 × 10²¹ cm^-2
N_H (intrinsic)	0 (+1.66 × 10²², -0) cm^-2
z of absorber	3.758
Photon index	1.68 (+0.24, -0.12)
Flux (0.3-10 keV) (Observed)	1.14 (+0.20, -0.11) × 10^-10 erg cm^-2 s^-1
Flux (0.3-10 keV) (Unabsorbed)	1.51 (+0.18, -0.16) × 10^-10 erg cm^-2 s^-1
Counts to flux (obs)	4.45 × 10^-11 erg cm^-2 ct^-1
Counts to flux (unabs)	5.87 × 10^-11 erg cm^-2 ct^-1
W-stat (dof) What's this?	128.16 (163)
Spectrum exposure	210 s

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phase2 spectrum (T0 + 3534 to 34274 s)

Download spectral files for phase2 spectrum.

Plots to download

PC mode. Mean photon arrival: T0+10600 s

N_H (Galactic)	3.20 × 10²¹ cm^-2
N_H (intrinsic)	0 (+5.32 × 10²¹, -0) cm^-2
z of absorber	3.758
Photon index	2.08 (+0.09, -0.07)
Flux (0.3-10 keV) (Observed)	7.57 (+0.55, -0.22) × 10^-12 erg cm^-2 s^-1
Flux (0.3-10 keV) (Unabsorbed)	1.18 (+0.06, -0.06) × 10^-11 erg cm^-2 s^-1
Counts to flux (obs)	3.58 × 10^-11 erg cm^-2 ct^-1
Counts to flux (unabs)	5.57 × 10^-11 erg cm^-2 ct^-1
W-stat (dof) What's this?	326.03 (371)
Spectrum exposure	7.0 ks

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phase3 spectrum (T0 + 34281 to 44258 s)

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PC mode. Mean photon arrival: T0+37861 s

N_H (Galactic)	3.20 × 10²¹ cm^-2
N_H (intrinsic)	6.0 (+25.1, -6.0) × 10²² cm^-2
z of absorber	3.758
Photon index	2.43 (+1.11, -0.74)
Flux (0.3-10 keV) (Observed)	5.2 (+3.1, -1.9) × 10^-13 erg cm^-2 s^-1
Flux (0.3-10 keV) (Unabsorbed)	1.14 (+2.29, -0.42) × 10^-12 erg cm^-2 s^-1
Counts to flux (obs)	3.18 × 10^-11 erg cm^-2 ct^-1
Counts to flux (unabs)	6.92 × 10^-11 erg cm^-2 ct^-1
W-stat (dof) What's this?	31.82 (31)
Spectrum exposure	2.7 ks

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phase4 spectrum (T0 + 44259 to 783069 s)

Download spectral files for phase4 spectrum.

Plots to download

PC mode. Mean photon arrival: T0+155999 s

N_H (Galactic)	3.20 × 10²¹ cm^-2
N_H (intrinsic)	0 (+5.75 × 10²², -0) cm^-2
z of absorber	3.758
Photon index	2.0 (+0.3, -0.3)
Flux (0.3-10 keV) (Observed)	9.8 (+2.0, -2.2) × 10^-14 erg cm^-2 s^-1
Flux (0.3-10 keV) (Unabsorbed)	1.45 (+0.29, -0.24) × 10^-13 erg cm^-2 s^-1
Counts to flux (obs)	3.84 × 10^-11 erg cm^-2 ct^-1
Counts to flux (unabs)	5.65 × 10^-11 erg cm^-2 ct^-1
W-stat (dof) What's this?	60.86 (88)
Spectrum exposure	54.6 ks

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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 130408A 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 T_b, 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 indices	Break Times	N_H	Spectral indices

Closure Relationships

The plots below show (α, β) scatter plots for each of the different types/phases of light curves (see light-curve types), since GRB 130408A is of type, "Oddball," which has no scatter plots of its own. GRB 130408A is shown in colour, with each light curve phase, or XRT mode marked by a different colour. 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.

No break

One-break, steep first Steep phase	One-break, steep first Shallow phase

One-break, shallow first Shallow phase	One-break, shallow first Steep phase

Canonical Steep phase	Canonical Plateau	Canonical 'Normal'	Canonical Post jet-break

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