J/MNRAS/397/1177 Swift-XRT observations of GRBs (Evans+, 2009)
Methods and results of an automatic analysis of a complete sample of
Swift-XRT observations of GRBs.
Evans P.A., Beardmore A.P. Page K.L., Osborne J.P., O'Brien, P.T.,
Willingale R., Starling R.L.C, Burrows D.N., Godet O., Vetere L.,
Racusin J., Goad M.R., Wiersema K., Angelini L., Capalbi M., Chincarini G.,
Gehrels N., Kennea J.A., Margutti R., Morris D.C., Mountford C.J.,
Pagani C., Perri M., Romano P., Tanvir N.
<Mon. Not. R. Astron. Soc. 397, 1177 (2009)>
=2009MNRAS.397.1177E 2009MNRAS.397.1177E
ADC_Keywords: X-ray sources ; Gamma rays
Keywords: methods: data analysis - catalogues - gamma rays: bursts
Abstract:
We present a homogeneous X-ray analysis of all 318 Gamma Ray Bursts
detected by the X-ray Telescope on the Swift satellite up to 2008 July
23; this represents the largest sample of X-ray GRB data published to
date. In Sections 2-3 we detail the methods which the Swift-XRT team
has developed to produce the enhanced positions, light curves,
hardness ratios and spectra presented in this paper. Software using
these methods continues to create such products for all new GRBs
observed by the Swift-XRT. We also detail web-based tools allowing
users to create these products for any object observed by the XRT, not
just GRBs. In Sections 4-6 we present the results of our analysis of
GRBs, including probability distribution functions of the temporal and
spectral properties of the sample. We demonstrate evidence for a
consistent underlying behaviour which can produce a range of light
curve morphologies, and attempt to interpret this behaviour in the
framework of external forward shock emission. We find several
difficulties, in particular that reconciliation of our data with the
forward shock model requires energy injection to continue for days to
weeks.
Description:
Position, temporal and spectral parameters for 318 GRBs observed by
the Swift X-ray telescope, up to GRB 080723B. The values were
determined by automated analysis tools.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
enhpos.dat 40 268 Enhanced X-ray positions for 268 GRBs
lcfit.dat 299 295 Temporal decay parameters for 295 XRT GRB
light curves
avespec.dat 113 320 Time-averaged X-ray spectral parameters
for 318 GRBs
resspec.dat 511 211 Time resolved spectral parameters for 211 GRBs
--------------------------------------------------------------------------------
See also:
J/A+AS/129/1 : GRANAT/WATCH catalogue of gamma-ray bursts (Sazonov+ 1998)
J/A+A/473/347 : BeppoSAX complete catalogue of GRBs (Vetere+, 2007)
J/A+A/427/87 : List of GRBs (Gorosabel+, 2004)
Byte-by-byte Description of file: enhpos.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- TargetID Swift Target ID
9- 11 A3 --- --- [GRB]
13- 19 A7 --- GRB GRB Name (YYMMDDA)
20- 28 F9.5 deg RAdeg Right ascension (J2000.0)
29- 37 F9.5 deg DEdeg Declination (J2000.0)
38- 40 F3.1 arcsec e_Pos Position uncertainty (radius, 90% confidence)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: lcfit.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- TargetID Swift Target ID
9- 11 A3 --- --- [GRB]
13- 19 A7 --- GRB GRB Name (YYMMDDA)
20- 27 E8.4 mW/m2 Flux11 ? 0.3-10keV Flux 11 hours after the trigger
28- 35 E8.4 s Tstart When the XRT observations started,
seconds since trigger
36- 43 E8.4 s Tstop When the XRT observations ended,
seconds since trigger
44- 49 F6.1 s T90 ? The duration of the GRB, from the Swift
data table
50- 55 F6.2 --- alpha1 Power-law decay index of the first light
curve segment
57- 62 F6.2 --- E_alpha1 Positive error (90% conf) on alpha1
64- 69 F6.2 --- e_alpha1 Negative error (90% conf) on alpha1
70- 77 E8.4 s tbr1 ? Time of the first break in the decay
79- 86 E8.4 s E_tbr1 ? Positive error (90% conf) on tbr1
88- 95 E8.4 s e_tbr1 ? Negative error (90% conf) on tbr1
96-101 F6.2 --- alpha2 ? Power-law decay index of the second
light curve segment
103-108 F6.2 --- E_alpha2 ? Positive error (90% conf) on alpha2
110-115 F6.2 --- e_alpha2 ? Negative error (90% conf) on alpha2
116-123 E8.4 s tbr2 ? Time of the second br in the decay
125-132 E8.4 s E_tbr2 ? Positive error (90% conf) on tbr2
134-141 E8.4 s e_tbr2 ? Negative error (90% conf) on tbr2
142-147 F6.2 --- alpha3 ? Power-law decay index of the third
light curve segment
149-154 F6.2 --- E_alpha3 ? Positive error (90% conf) on alpha3
156-161 F6.2 --- e_alpha3 ? Negative error (90% conf) on alpha3
162-169 E8.4 s tbr3 ? Time of the third br in the decay
171-178 E8.4 s E_tbr3 ? Positive error (90% conf) on tbr3
180-187 E8.4 s e_tbr3 ? Negative error (90% conf) on tbr3
188-193 F6.2 --- alpha4 ? Power-law decay index of the fourth
light curve segment
195-200 F6.2 --- E_alpha4 ? Positive error (90% conf) on alpha4
202-207 F6.2 --- e_alpha4 ? Negative error (90% conf) on alpha4
208-215 E8.4 s tbr4 ? Time of the fourth br in the decay
217-224 E8.4 s E_tbr4 ? Positive error (90% conf) on tbr4
226-233 E8.4 s e_tbr4 ? Negative error (90% conf) on tbr4
234-239 F6.2 --- alpha5 ? Power-law decay index of the fifth
light curve segment
241-246 F6.2 --- E_alpha5 ? Positive error (90% conf) on alpha5
248-253 F6.2 --- e_alpha5 ? Negative error (90% conf) on alpha5
254-261 E8.4 s tbr5 ? Time of the fifth br in the decay
263-270 E8.4 s E_tbr5 ? Positive error (90% conf) on tbr5
272-279 E8.4 s e_tbr5 ? Negative error (90% conf) on tbr5
280-285 F6.2 --- alpha6 ? Power-law decay index of the sixth
light curve segment
287-292 F6.2 --- E_alpha6 ? Positive error (90% conf) on alpha6
294-299 F6.2 --- e_alpha6 ? Negative error (90% conf) on alpha6
--------------------------------------------------------------------------------
Byte-by-byte Description of file: avespec.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- TargetID Swift Target ID
9- 11 A3 --- --- [GRB]
13- 19 A7 --- GRB GRB Name (YYMMDDA)
20- 27 E8.2 cm-2 NH Galactic column density, from Kalberla et al.
2005
28- 31 F4.2 --- z ? Redshift, from the GCN circulars
32- 39 E8.2 cm-2 WTNH ? Intrinsic column density for the WT mode
spectrum
41- 48 E8.2 cm-2 E_WTNH ? Positive error on WTNH
50- 57 E8.2 cm-2 e_WTNH ? Negative error on WTNH
58- 62 F5.2 --- WTbeta ? Spectral index for the WT mode spectrum
64- 67 F4.2 --- E_WTbeta ? Positive error on WTbeta
69- 72 F4.2 --- e_WTbeta ? Negative error on WTbeta
73- 80 E8.2 cm-2 PCNH ? Intrinsic column density for the PC mode
spectrum
82- 89 E8.2 cm-2 E_PCNH ? Positive error on PCNH
91- 98 E8.2 cm-2 e_PCNH ? Negative error on PCNH
99-103 F5.2 --- PCbeta ? Spectral index for the PC mode spectrum
105-108 F4.2 --- E_PCbeta ? Positive error on PCbeta
110-113 F4.2 --- e_PCbeta ? Negative error on PCbeta
--------------------------------------------------------------------------------
Byte-by-byte Description of file: resspec.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- TargetID Swift Target ID
9- 11 A3 --- --- [GRB]
13- 19 A7 --- GRB GRB Name (YYMMDDA)
20- 27 E8.2 cm-2 WTNH1 ? Intrinsic column density for the WT mode
spectrum of the first power-law segment of
the light curve
29- 36 E8.2 cm-2 E_WTNH1 ? Positive error on WTNH1
38- 45 E8.2 cm-2 e_WTNH1 ? Negative error on WTNH1
46- 50 F5.2 --- WTbeta1 ? Spectral index for the WT mode spectrum of
the first power-law segment of the light
curve
52- 55 F4.2 --- E_WTbeta1 ? Positive error on WTbeta1
57- 60 F4.2 --- e_WTbeta1 ? Negative error on WTbeta1
61- 68 E8.2 cm-2 PCNH1 ? Intrinsic column density for the PC mode
spectrum of the first power-law segment of
the light curve
70- 77 E8.2 cm-2 E_PCNH1 ? Positive error on PCNH1
79- 86 E8.2 cm-2 e_PCNH1 ? Negative error on PCNH1
87- 91 F5.2 --- PCbeta1 ? Spectral index for the PC mode spectrum of
the first power-law segment of the light
curve
93- 96 F4.2 --- E_PCbeta1 ? Positive error on PCbeta1
98-101 F4.2 --- e_PCbeta1 ? Negative error on PCbeta1
102-109 E8.2 cm-2 WTNH2 ? Intrinsic column density for the WT mode
spectrum of the second power-law segment of
the light curve
111-118 E8.2 cm-2 E_WTNH2 ? Positive error on WTNH2
120-127 E8.2 cm-2 e_WTNH2 ? Negative error on WTNH2
128-132 F5.2 --- WTbeta2 ? Spectral index for the WT mode spectrum of
the second power-law segment of the light
curve
134-137 F4.2 --- E_WTbeta2 ? Positive error on WTbeta2
139-142 F4.2 --- e_WTbeta2 ? Negative error on WTbeta2
143-150 E8.2 cm-2 PCNH2 ? Intrinsic column density for the PC mode
spectrum of the second power-law segment of
the light curve
151 A1 --- --- [±]
152-159 E8.2 cm-2 E_PCNH2 ? Positive error on PCNH2
160 A1 --- --- [±]
161-168 E8.2 cm-2 e_PCNH2 ? Negative error on PCNH2
169-173 F5.2 --- PCbeta2 ? Spectral index for the PC mode spectrum of
the second power-law segment of the light
curve
174 A1 --- --- [±]
175-178 F4.2 --- E_PCbeta2 ? Positive error on PCbeta2
179 A1 --- --- [±]
180-183 F4.2 --- e_PCbeta2 ? Negative error on PCbeta2
184-191 E8.2 cm-2 WTNH3 ? Intrinsic column density for the WT mode
spectrum of the third power-law segment of
the light curve
193-200 E8.2 cm-2 E_WTNH3 ? Positive error on WTNH3
202-209 E8.2 cm-2 e_WTNH3 ? Negative error on WTNH3
210-214 F5.2 --- WTbeta3 ? Spectral index for the WT mode spectrum of
the third power-law segment of the light
curve
216-219 F4.2 --- E_WTbeta3 ? Positive error on WTbeta3
221-224 F4.2 --- e_WTbeta3 ? Negative error on WTbeta3
225-232 E8.2 cm-2 PCNH3 ? Intrinsic column density for the PC mode
spectrum of the third power-law segment of
the light curve
234-241 E8.2 cm-2 E_PCNH3 ? Positive error on PCNH3
243-250 E8.2 cm-2 e_PCNH3 ? Negative error on PCNH3
251-255 F5.2 --- PCbeta3 ? Spectral index for the PC mode spectrum of
the third power-law segment of the light
curve
257-260 F4.2 --- E_PCbeta3 ? Positive error on PCbeta3
262-265 F4.2 --- e_PCbeta3 ? Negative error on PCbeta3
266-273 E8.2 cm-2 WTNH4 ? Intrinsic column density for the WT mode
spectrum of the fourth power-law segment of
the light curve
275-282 E8.2 cm-2 E_WTNH4 ? Positive error on WTNH4
284-291 E8.2 cm-2 e_WTNH4 ? Negative error on WTNH4
292-296 F5.2 --- WTbeta4 ? Spectral index for the WT mode spectrum of
the fourth power-law segment of the light
curve
298-301 F4.2 --- E_WTbeta4 ? Positive error on WTbeta4
303-306 F4.2 --- e_WTbeta4 ? Negative error on WTbeta4
307-314 E8.2 cm-2 PCNH4 ? Intrinsic column density for the PC mode
spectrum of the fourth power-law segment of
the light curve
316-323 E8.2 cm-2 E_PCNH4 ? Positive error on PCNH4
325-332 E8.2 cm-2 e_PCNH4 ? Negative error on PCNH4
333-337 F5.2 --- PCbeta4 ? Spectral index for the PC mode spectrum of
the fourth power-law segment of the light
curve
339-342 F4.2 --- E_PCbeta4 ? Positive error on PCbeta4
344-347 F4.2 --- e_PCbeta4 ? Negative error on PCbeta4
348-355 E8.2 cm-2 WTNH5 ? Intrinsic column density for the WT mode
spectrum of the fifth power-law segment of
the light curve
357-364 E8.2 cm-2 E_WTNH5 ? Positive error on WTNH5
366-373 E8.2 cm-2 e_WTNH5 ? Negative error on WTNH5
374-378 F5.2 --- WTbeta5 ? Spectral index for the WT mode spectrum of
the fifth power-law segment of the light
curve
380-383 F4.2 --- E_WTbeta5 ? Positive error on WTbeta5
385-388 F4.2 --- e_WTbeta5 ? Negative error on WTbeta5
389-396 E8.2 cm-2 PCNH5 ? Intrinsic column density for the PC mode
spectrum of the fifth power-law segment of
the light curve
398-405 E8.2 cm-2 E_PCNH5 ? Positive error on PCNH5
407-414 E8.2 cm-2 e_PCNH5 ? Negative error on PCNH5
415-419 F5.2 --- PCbeta5 ? Spectral index for the PC mode spectrum of
the fifth power-law segment of the light
curve
421-424 F4.2 --- E_PCbeta5 ? Positive error on PCbeta5
426-429 F4.2 --- e_PCbeta5 ? Negative error on PCbeta5
430-437 E8.2 cm-2 WTNH6 ? Intrinsic column density for the WT mode
spectrum of the sixth power-law segment of
the light curve
439-446 E8.2 cm-2 E_WTNH6 ? Positive error on WTNH6
448-455 E8.2 cm-2 e_WTNH6 ? Negative error on WTNH6
456-460 F5.2 --- WTbeta6 ? Spectral index for the WT mode spectrum of
the sixth power-law segment of the light
curve
462-465 F4.2 --- E_WTbeta6 ? Positive error on WTbeta6
467-470 F4.2 --- e_WTbeta6 ? Negative error on WTbeta6
471-478 E8.2 cm-2 PCNH6 ? Intrinsic column density for the PC mode
spectrum of the sixth power-law segment of
the light curve
480-487 E8.2 cm-2 E_PCNH6 ? Positive error on PCNH6
489-496 E8.2 cm-2 e_PCNH6 ? Negative error on PCNH6
497-501 F5.2 --- PCbeta6 ? Spectral index for the PC mode spectrum of
the sixth power-law segment of the light
curve
503-506 F4.2 --- E_PCbeta6 ? Positive error on PCbeta6
508-511 F4.2 --- e_PCbeta6 ? Negative error on PCbeta6
--------------------------------------------------------------------------------
Acknowledgements:
Phil Evans, pae9(at)star.le.ac.uk
(End) Patricia Vannier [CDS] 23-Mar-2009