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Catalogue XRT results for GRB 091127

Data were analysed using HEASOFT version 6.35.2

Summary Information

RA:	02h 26m 19.87s	LC breaks:	3
Dec:	-18° 57′ 09.4′′	LC type:	Canonical.
Err:	1.4′′	N_H,intr.:	1.05×10²¹ cm^-2
Gal long:	197.398	Redshift	0.49
Gal lat:	-66.738	Γ	1.7

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	587	203
1	383	201	Break required. (2.13e-17 % probability of chance improvement)
2	240	199	Break required. (6.43e-19 % probability of chance improvement)
3	179	197	Break required. (2.99e-11 % probability of chance improvement). This is the best fit.
4	177	195	Break significance <4-σ (45.54 % probability of chance improvement)
5	176	193	Break significance <4-σ (48.61 % probability of chance improvement)

There are 1 flares excluded from the fit:

2.06×10⁴—3.81×10⁵ s

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	0.74 (+0.22, -0.20)
T_b,1	5445 (+69, -114) s
α₂	8.00 (+0.00, -3.90)
T_b,2	8241 (+5.08 × 10⁴, -652) s
α₃	0.73 (+0.10, -0.34)
T_b,3	5.7 (+2.2, -1.3) × 10⁵ s
α₄	1.59 (+0.23, -0.13)

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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 + 3218 to 3825 s)

Download spectral files for phase1 spectrum.

Plots to download

WT mode. Mean photon arrival: T0+3514 s

N_H (Galactic)	3.11 × 10²⁰ cm^-2
N_H (intrinsic)	7 (+3, -3) × 10²⁰ cm^-2
z of absorber	0.49
Photon index	1.77 (+0.06, -0.06)
Flux (0.3-10 keV) (Observed)	3.00 (+0.12, -0.11) × 10^-10 erg cm^-2 s^-1
Flux (0.3-10 keV) (Unabsorbed)	3.33 (+0.10, -0.10) × 10^-10 erg cm^-2 s^-1
Counts to flux (obs)	3.63 × 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?	516.32 (592)
Spectrum exposure	607 s

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Plots to download

PC mode. Mean photon arrival: T0+82209 s

N_H (Galactic)	3.11 × 10²⁰ cm^-2
N_H (intrinsic)	1.0 (+0.4, -0.4) × 10²¹ cm^-2
z of absorber	0.49
Photon index	1.66 (+0.06, -0.06)
Flux (0.3-10 keV) (Observed)	5.33 (+0.23, -0.22) × 10^-12 erg cm^-2 s^-1
Flux (0.3-10 keV) (Unabsorbed)	5.89 (+0.21, -0.20) × 10^-12 erg cm^-2 s^-1
Counts to flux (obs)	3.98 × 10^-11 erg cm^-2 ct^-1
Counts to flux (unabs)	4.39 × 10^-11 erg cm^-2 ct^-1
W-stat (dof) What's this?	539.46 (577)
Spectrum exposure	45.8 ks

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phase4 spectrum (T0 + 575729 to 16849147 s)

Download spectral files for phase4 spectrum.

Plots to download

PC mode. Mean photon arrival: T0+1499800 s

N_H (Galactic)	3.11 × 10²⁰ cm^-2
N_H (intrinsic)	1.1 (+1.3, -1.1) × 10²¹ cm^-2
z of absorber	0.49
Photon index	1.62 (+0.19, -0.18)
Flux (0.3-10 keV) (Observed)	6.6 (+0.9, -0.8) × 10^-14 erg cm^-2 s^-1
Flux (0.3-10 keV) (Unabsorbed)	7.3 (+0.8, -0.7) × 10^-14 erg cm^-2 s^-1
Counts to flux (obs)	4.15 × 10^-11 erg cm^-2 ct^-1
Counts to flux (unabs)	4.57 × 10^-11 erg cm^-2 ct^-1
W-stat (dof) What's this?	236.73 (279)
Spectrum exposure	427.3 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 091127 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 phase of all Canonical light curves. GRB 091127 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.