Pierrick Martin / ctools

Commit 574f9a40a0f2cbe35f4036dbb4f90247d06aadd3

Authored by Jürgen Knödlseder
1 parent b6d6429e

Finish update of first section of How tos

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Showing 1 changed file with 35 additions and 34 deletions
doc/source/users/tutorials/howto/howto_xspec.rst
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... ... @@ -20,14 +20,15 @@ package, you can use that package to fit CTA data that were prepared for an
20 20 On/Off analysis.
21 21  
22 22 To illustrate how you can do this, let's simulate an observation of the Crab
23   -nebula with a pointing direction that is offset by 1 deg:
  23 +nebula with a pointing direction that is offset by 1 deg. We also use energy
  24 +dispersion in the simulation as an On/Off analysis always
24 25  
25 26 .. code-block:: bash
26 27  
27   - $ ctobssim
  28 + $ ctobssim edisp=yes
28 29 RA of pointing (degrees) (0-360) [83.63]
29   - Dec of pointing (degrees) (-90-90) [22.01] 21.01
30   - Radius of FOV (degrees) (0-180) [5]
  30 + Dec of pointing (degrees) (-90-90) [22.51] 21.01
  31 + Radius of FOV (degrees) (0-180) [5.0]
31 32 Start time (UTC string, JD, MJD or MET in seconds) [2020-01-01T00:00:00]
32 33 Stop time (UTC string, JD, MJD or MET in seconds) [2020-01-01T00:30:00]
33 34 Lower energy limit (TeV) [0.1]
... ... @@ -47,18 +48,19 @@ Off counts spectrum:
47 48 Input event list or observation definition XML file [obs.xml] events.fits
48 49 Calibration database [prod2]
49 50 Instrument response function [South_0.5h]
50   - Start value for first energy bin in TeV [0.1]
51   - Stop value for last energy bin in TeV [100]
52   - Radius of source region circle (deg) (0-180) [0.2]
53 51 Input model definition XML file (if NONE, use point source) [NONE]
54 52 Algorithm for defining energy bins (FILE|LIN|LOG) [LOG]
55   - Number of energy bins [20]
  53 + Start value for first energy bin in TeV [0.1]
  54 + Stop value for last energy bin in TeV [100.0]
  55 + Number of energy bins [120] 20
56 56 Stack multiple observations into single PHA, ARF and RMF files? [no]
57 57 Output observation definition XML file [onoff_obs.xml]
  58 + Output model definition XML file [onoff_model.xml]
58 59 Method for background estimation (REFLECTED|CUSTOM) [REFLECTED]
59 60 Coordinate system (CEL - celestial, GAL - galactic) (CEL|GAL) [CEL]
60 61 Right Ascension of source region centre (deg) (0-360) [83.63]
61 62 Declination of source region centre (deg) (-90-90) [22.01]
  63 + Radius of source region circle (deg) (0-180) [0.2]
62 64  
63 65 Now you can start
64 66 `Xspec <https://heasarc.nasa.gov/xanadu/xspec/>`_
... ... @@ -67,10 +69,9 @@ for model fitting.
67 69 .. code-block:: bash
68 70  
69 71 $ xspec
70   - Creating a $HOME/.xspec directory for you
71 72  
72   - XSPEC version: 12.10.0c
73   - Build Date/Time: Tue Jun 12 12:46:58 2018
  73 + XSPEC version: 12.10.1
  74 + Build Date/Time: Mon Jan 7 12:38:07 2019
74 75  
75 76 XSPEC12>
76 77  
... ... @@ -87,10 +88,10 @@ First load the On file ``onoff_pha_on.fits`` using the ``data`` command:
87 88 1 spectrum in use
88 89  
89 90 Spectral Data File: onoff_pha_on.fits Spectrum 1
90   - Net count rate (cts/s) for Spectrum:1 1.585e+00 +/- 3.099e-02 (94.0 % total)
  91 + Net count rate (cts/s) for Spectrum:1 1.619e+00 +/- 3.135e-02 (93.9 % total)
91 92 Assigned to Data Group 1 and Plot Group 1
92 93 Noticed Channels: 1-20
93   - Telescope: unknown Instrument: unknown Channel Type: PI
  94 + Telescope: CTA Instrument: PROD2 Channel Type: PI
94 95 Exposure Time: 1764 sec
95 96 Using fit statistic: chi
96 97 Using test statistic: chi
... ... @@ -135,11 +136,11 @@ model using
135 136 ________________________________________________________________________
136 137  
137 138  
138   - Fit statistic : C-Statistic = 712.82 using 20 PHA bins and 18 degrees of freedom.
  139 + Fit statistic : C-Statistic = 727.46 using 20 PHA bins and 18 degrees of freedom.
139 140  
140   - Test statistic : Chi-Squared = 605.26 using 20 PHA bins.
141   - Reduced chi-squared = 33.625 for 18 degrees of freedom
142   - Null hypothesis probability = 6.662146e-117
  141 + Test statistic : Chi-Squared = 548.66 using 20 PHA bins.
  142 + Reduced chi-squared = 30.481 for 18 degrees of freedom
  143 + Null hypothesis probability = 5.939476e-105
143 144  
144 145 ***Warning: Chi-square may not be valid due to bins with zero variance
145 146 in spectrum number(s): 1
... ... @@ -159,39 +160,39 @@ command:
159 160 XSPEC12>fit
160 161 Parameters
161 162 C-Statistic |beta|/N Lvl 1:PhoIndex 2:norm
162   - 85.7044 11239.1 -3 2.49284 654.424
163   - 25.1265 3951.81 -4 2.48007 578.148
164   - 23.0302 769.247 -5 2.47567 541.654
165   - 22.9323 165.457 -6 2.47509 538.451
166   - 22.9315 13.9094 -7 2.47503 538.072
  163 + 96.8692 11494.2 -3 2.49807 711.693
  164 + 12.0065 4626.2 -4 2.49140 735.585
  165 + 10.9389 553.368 -5 2.48822 701.803
  166 + 10.8978 108.533 -6 2.48774 697.592
  167 + 10.8974 11.7189 -7 2.48768 697.003
167 168 ==============================
168 169 Variances and Principal Axes
169 170 1 2
170   - 8.8843E-07| -1.0000 0.0001
171   - 2.8990E+04| -0.0001 -1.0000
  171 + 8.7349E-07| -1.0000 0.0001
  172 + 4.6499E+04| -0.0001 -1.0000
172 173 ------------------------------
173 174  
174 175 ========================
175 176 Covariance Matrix
176 177 1 2
177   - 2.326e-04 2.592e+00
178   - 2.592e+00 2.899e+04
  178 + 2.228e-04 3.212e+00
  179 + 3.212e+00 4.650e+04
179 180 ------------------------
180 181  
181 182 ========================================================================
182 183 Model powerlaw<1> Source No.: 1 Active/On
183 184 Model Model Component Parameter Unit Value
184 185 par comp
185   - 1 1 powerlaw PhoIndex 2.47503 +/- 1.52504E-02
186   - 2 1 powerlaw norm 538.072 +/- 170.265
  186 + 1 1 powerlaw PhoIndex 2.48768 +/- 1.49258E-02
  187 + 2 1 powerlaw norm 697.003 +/- 215.637
187 188 ________________________________________________________________________
188 189  
189 190  
190   - Fit statistic : C-Statistic = 22.93 using 20 PHA bins and 18 degrees of freedom.
  191 + Fit statistic : C-Statistic = 10.90 using 20 PHA bins and 18 degrees of freedom.
191 192  
192   - Test statistic : Chi-Squared = 437.54 using 20 PHA bins.
193   - Reduced chi-squared = 24.308 for 18 degrees of freedom
194   - Null hypothesis probability = 1.317221e-81
  193 + Test statistic : Chi-Squared = 126.30 using 20 PHA bins.
  194 + Reduced chi-squared = 7.0169 for 18 degrees of freedom
  195 + Null hypothesis probability = 2.683238e-18
195 196  
196 197 ***Warning: Chi-square may not be valid due to bins with zero variance
197 198 in spectrum number(s): 1
... ... @@ -208,7 +209,7 @@ obtained using :ref:`ctlike`.
208 209 +-----------+-------+-----------------+-----------------+
209 210 | Parameter | Truth | Xspec | ctlike |
210 211 +===========+=======+=================+=================+
211   - | Prefactor | 601.4 | 538.0 +/- 170.3 | 536.4 +/- 184.2 |
  212 + | Prefactor | 601.4 | 697.0 +/- 215.6 | 697.5 +/- 234.5 |
212 213 +-----------+-------+-----------------+-----------------+
213   - | Index | 2.48 | 2.475 +/- 0.015 | 2.475 +/- 0.017 |
  214 + | Index | 2.48 | 2.488 +/- 0.015 | 2.488 +/- 0.017 |
214 215 +-----------+-------+-----------------+-----------------+
... ...