Period Search (gtpsearch) Tutorial
The gtpsearch tool searches for pulsations in data which is known or suspected to have a pulsation of a known approximate period or frequency.
Note: It is not useful for a so-called blind period search, in which data are examined for pulsations at any frequency.
Known Issues: When running gtpsearch multiple times using the GUI, plot windows from previous runs reappear after they are closed manually. Thus, there is no way to permanently close plot windows without exiting the GUI.
Prerequisites
- Event data file in FT1 format, also known as a photon data file. (See Extract LAT Data.)
- Orbit file to use for the barycentric correction
- Ephemeris information of suspected pulsation provided in one of the following forms:
- Manually input the source (pulsar) location (for the barycentric correction), pulse frequency or period, and related information
- Automatically extracted from a pulsar ephemerides database, available online.
Sample Files. To try the examples in this section, you can download the following fake data files:
- my_pulsar_events_v3.fits (1.9 MB)
- my_pulsar_spacecraft_data_v3r1.fits (108 kB)
- master_pulsardb_v3.fits (248 kB)
Note: The output of gtpsearch consists of text describing the result of the periodicity search and an optional plot. This tool also creates an output file when requested. The output file contains the result of computation, i.e., the search result in the text output and the data array to plot, for future reference.
Also see:
| Tutorial | SciTools References | |
|---|---|---|
| Pulsar Analysis Tutorial: Calculate Pulse Phase for Each Photon | gtpsearch | Fake Data Gallery |
| Pulse Phase Calculation | gtpphase | |
| Binary Orbital Phase Calculation | gtophase |
How To Perform A Simple Search
Using A Pulsar Ephemerides Database File
Performing a period search is straight forward if the object of interest is listed in a pulsar ephemerides database file. The example below shows how to perform the test under these circumstances using the files described above. The time origin of periodicity test is taken to be the center of the observation. That means, if a pulsation is found, the pulse frequency should be interpreted as measured at the center of the observation (i.e., the time origin).
The command shown below produces the following output message that describes the search criteria and explains the search result.
prompt> gtpsearch
This is gtpsearch version v10r5
Event data file name[] my_pulsar_events_v3.fits
Spacecraft data file name[] my_pulsar_spacecraft_data_v3r1.fits
Pulsar ephemerides database file name[] master_pulsardb_v3.fits
Pulsar name[ANY] PSR B0540-69
Output FITS file name (NONE for no FITS output)[] gtpsearch-example-3.fits
Type of statistical test to perform (CHI2 - Chi squared, RAYLEIGH - Rayleigh testt, Z2N - Z2n test, H - H test) (CHI2|RAYLEIGH|Z2N|H) [CHI2] Chi2
Number of phase bins for Chi2 test[10] 10
Size of steps for trials, in units of the Fourier resolution (0.:) [0.5] 0.5
Number of trials[100] 200
How will the time origin of the periodicity test be specified? (START|STOP|MIDDLEE|USER) [MIDDLE] MIDDLE
How will spin ephemeris be specified? (DB|FREQ|PER) [DB] DB
Search Type: Folding Analysis
Fourier Resolution: 1.32472e-05 Hz
Sampling Frequency: 6.62362e-06 Hz
Type of test: Chi-squared Test, 10 phase bins
Probability distribution: Chi-squared, 9 degrees of freedom
Search Range (Hz): [19.8333552027275, 19.834673303452]
Number of Trial Frequencies: 200
Number of Independent Trials: 100
Maximum Statistic: 593.279468705583 at 19.8340175649006 Hz
Chance Probability Range: (0, 2.03757046903054e-97)
Warning in <TClass::TClass>: no dictionary for class st_graph::IFrame is available
prompt>
A plot will also be produced which is similar to the following plot.
This plot very likely shows a pulsation consistent with the ephemeris found in the file.
Using Estimated Frequency Only
In practice, an ephemerides file which contains the object of interest may not be available. In this case, one may still proceed if one has an estimate for the frequency from some other source. Suppose the best known estimate for the frequency at 54368.11094817 MJD (TDB) were 19.8339 Hz. One could then run gtpsearch as follows.
prompt> gtpsearch
This is gtpsearch version v10r5
Event data file name[] my_pulsar_events_v3.fits
Spacecraft data file name[] my_pulsar_spacecraft_data_v3r1.fits
Pulsar ephemerides database file name[] master_pulsardb_v3.fits
Pulsar name[ANY] PSR B0540-69
Output FITS file name (NONE for no FITS output)[] gtpsearch-example-4.fits
Type of statistical test to perform (CHI2 - Chi squared, RAYLEIGH - Rayleigh testt, Z2N - Z2n test, H - H test) (CHI2|RAYLEIGH|Z2N|H) [CHI2] Chi2
Number of phase bins for Chi2 test[10] 10
Size of steps for trials, in units of the Fourier resolution (0.:) [0.5] 0.5
Number of trials[100] 200
How will the time origin of the periodicity test be specified? (START|STOP|MIDDLEE|USER) [MIDDLE] MIDDLE
How will spin ephemeris be specified? (DB|FREQ|PER) [DB] FREQ
Epoch for the spin ephemeris[0.] 54368.11094817
Time format for spin ephemeris epoch (FILE|MJD|ISO|GLAST) [FILE] MJD
Time system for spin ephemeris epoch (FILE|TAI|TDB|TT|UTC) [FILE] TDB
Right Ascension to be used for barycenter corrections (degrees)[0.] 85.0482
Declination to be used for barycenter corrections (degrees)[0.] -69.3319
Pulse frequency at the epoch of the spin ephemeris (Hz) (0.:) [1.] 19.8339
First time derivative of the pulse frequency at the epoch of the spin ephemeris ((Hz/s)[0.] 0.0
Second time derivative of the pulse frequency at the epoch of the spin ephemeris (Hz/s/s)[0.] 0.0
Search Type: Folding Analysis
Fourier Resolution: 1.32472e-05 Hz
Sampling Frequency: 6.62362e-06 Hz
Type of test: Chi-squared Test, 10 phase bins
Probability distribution: Chi-squared, 9 degrees of freedom
Search Range (Hz): [19.833237637827, 19.8345557385513]
Number of Trial Frequencies: 200
Number of Independent Trials: 100
Maximum Statistic: 477.758221830123 at 19.8340192251911 Hz
Chance Probability Range: (3.2946214815123e-95, 3.3151619212497e-95)
Warning in <TClass::TClass>: no dictionary for class st_graph::IFrame is available
prompt>
The result is similar to the first example, but the main peak in the plot is shifted to the right because the estimated frequency used for the search center was chosen to be noticeably lower than the peak frequency for demonstration purposes. The peak still occurs at the correct frequency, but the value of the statistic is lower because the trial frequencies are coarsely spaced on the natural frequency scale determined intrinsically by the data set.
Correcting For Known Frequency Variations
From the shape of the graph, it appears that there is a strong maximum with mainly symmetric side lobes. Encouraged by this result, one might run the tool again, using the position of the peak from the previous run as the central frequency. (The position of the peak is stated at the beginning of the tool output.) To zoom in on the peak more closely, the number of trials will be reduced to 100. In addition, the process of correcting for variations in the frequency known from other observations will be demonstrated. For this example, the frequency derivatives were taken from full independent analyses of ASCA data.
prompt> gtpsearch
This is gtpsearch version v10r5
Event data file name[] my_pulsar_events_v3.fits
Spacecraft data file name[] my_pulsar_spacecraft_data_v3r1.fits
Pulsar ephemerides database file name[] master_pulsardb_v3.fits
Pulsar name[ANY] PSR B0540-69
Output FITS file name (NONE for no FITS output)[] gtpsearch-example-5.fits
Type of statistical test to perform (CHI2 - Chi squared, RAYLEIGH - Rayleigh testt, Z2N - Z2n test, H - H test) (CHI2|RAYLEIGH|Z2N|H) [CHI2] Chi2
Number of phase bins for Chi2 test[10] 10
Size of steps for trials, in units of the Fourier resolution (0.:) [0.5] 0.5
Number of trials[100] 100
How will the time origin of the periodicity test be specified? (START|STOP|MIDDLEE|USER) [MIDDLE] MIDDLE
How will spin ephemeris be specified? (DB|FREQ|PER) [DB] FREQ
Epoch for the spin ephemeris[0.] 54368.11094817
Time format for spin ephemeris epoch (FILE|MJD|ISO|GLAST) [FILE] MJD
Time system for spin ephemeris epoch (FILE|TAI|TDB|TT|UTC) [FILE] TDB
Right Ascension to be used for barycenter corrections (degrees)[0.] 85.0482
Declination to be used for barycenter corrections (degrees)[0.] -69.3319
Pulse frequency at the epoch of the spin ephemeris (Hz) (0.:) [1.] 19.8340192246 053
First time derivative of the pulse frequency at the epoch of the spin ephemeris ((Hz/s)[0.] -1.8869945816704768775044e-10
Second time derivative of the pulse frequency at the epoch of the spin ephemeris (Hz/s/s)[0.] 0.0
Search Type: Folding Analysis
Fourier Resolution: 1.32472e-05 Hz
Sampling Frequency: 6.62362e-06 Hz
Type of test: Chi-squared Test, 10 phase bins
Probability distribution: Chi-squared, 9 degrees of freedom
Search Range (Hz): [19.8336887247509, 19.8343444633023]
Number of Trial Frequencies: 100
Number of Independent Trials: 50
Maximum Statistic: 485.776650492575 at 19.8340199058375 Hz
Chance Probability Range: (2.17307981976338e-97, 3.19197371027289e-97)
Warning in <TClass::TClass>: no dictionary for class st_graph::IFrame is available
prompt>
The effect of correcting for frequency variation was to increase the value of the maximum statistic, or the height of the main peak. Changing the central frequency brought the main peak back to the center of the graph. With the smaller number of trials, the second lobe on either side was cut off.
Looking For Precise Centroid Of The Peak
By decreasing the steps between subsequent trials, one can see the shape of the peak in a finer resolution.
prompt> gtpsearch
This is gtpsearch version v10r5
Event data file name[] my_pulsar_events_v3.fits
Spacecraft data file name[] my_pulsar_spacecraft_data_v3r1.fits
Pulsar ephemerides database file name[] master_pulsardb_v3.fits
Pulsar name[ANY] PSR B0540-69
Output FITS file name (NONE for no FITS output)[] gtpsearch-example-6.fits
Type of statistical test to perform (CHI2 - Chi squared, RAYLEIGH - Rayleigh testt, Z2N - Z2n test, H - H test) (CHI2|RAYLEIGH|Z2N|H) [CHI2] Chi2
Number of phase bins for Chi2 test[10] 10
Size of steps for trials, in units of the Fourier resolution (0.:) [0.5] 0.05
Number of trials[100] 100
How will the time origin of the periodicity test be specified? (START|STOP|MIDDLEE|USER) [MIDDLE] MIDDLE
How will spin ephemeris be specified? (DB|FREQ|PER) [DB] FREQ
Epoch for the spin ephemeris[0.] 54368.11094817
Time format for spin ephemeris epoch (FILE|MJD|ISO|GLAST) [FILE] MJD
Time system for spin ephemeris epoch (FILE|TAI|TDB|TT|UTC) [FILE] TDB
Right Ascension to be used for barycenter corrections (degrees)[0.] 85.0482
Declination to be used for barycenter corrections (degrees)[0.] -69.3319
Pulse frequency at the epoch of the spin ephemeris (Hz) (0.:) [1.] 19.8340192246 053
First time derivative of the pulse frequency at the epoch of the spin ephemeris ((Hz/s)[0.] -1.8869945816704768775044e-10
Second time derivative of the pulse frequency at the epoch of the spin ephemeris (Hz/s/s)[0.] 0.0
Search Type: Folding Analysis
Fourier Resolution: 1.32472e-05 Hz
Sampling Frequency: 6.62362e-07 Hz
Type of test: Chi-squared Test, 10 phase bins
Probability distribution: Chi-squared, 9 degrees of freedom
Search Range (Hz): [19.8339867877288, 19.834052361584]
Number of Trial Frequencies: 100
Number of Independent Trials: 5
Maximum Statistic: 601.685095329118 at 19.8340172563888 Hz
Chance Probability Range: (0, 1.01878523451527e-98)
Warning in <TClass::TClass>: no dictionary for class st_graph::IFrame is available
prompt>
Getting More Information on Computation
If gtpsearch is invoked with chatter parameter set to 4 or larger, it will display brief summaries of loaded ephemerides, arrival time corrections, and time systems being used, followed by a description of test condition and test result with periodgram data (i.e., a list of all trial frequencies and values of test statistic at the frequencies). This feature shows you additional information on computations being performed, which may help you understand the tool. Also, the extra information printed may contain a clue to diagnose certain types of problem. So, try a high chatter when you are unsure on the tool's behavior.
prompt> gtpsearch chatter=4
This is gtpsearch version v10r5
Event data file name[] my_pulsar_events_v3.fits
Spacecraft data file name[] my_pulsar_spacecraft_data_v3r1.fits
Pulsar ephemerides database file name[] master_pulsardb_v3.fits
Pulsar name[ANY] PSR B0540-69
Output FITS file name (NONE for no FITS output)[] gtpsearch-example-8.fits
Type of statistical test to perform (CHI2 - Chi squared, RAYLEIGH - Rayleigh testt, Z2N - Z2n test, H - H test) (CHI2|RAYLEIGH|Z2N|H) [CHI2] Chi2
Number of phase bins for Chi2 test[10] 10
Size of steps for trials, in units of the Fourier resolution (0.:) [0.5] 0.5
Number of trials[100] 200
How will the time origin of the periodicity test be specified? (START|STOP|MIDDLEE|USER) [MIDDLE] MIDDLE
How will spin ephemeris be specified? (DB|FREQ|PER) [DB] DB
gtpsearch: INFO: ==========================
gtpsearch: INFO: Pulsar ephemerides are loaded and/or filtered as follows:
gtpsearch: INFO: Load FITSDB AUTHOR='Masaharu Hirayama' DATE='2006-03-24T15:40:16'
gtpsearch: INFO: Filter by pulsar name 'PSR B0540-69'
gtpsearch: INFO: Filter by solar system ephemeris 'JPL DE405'
gtpsearch: INFO: ==========================
gtpsearch: INFO: --------------------------
gtpsearch: INFO: Arrival time corrections are applied as follows:
gtpsearch: INFO: Barycentric correction: Applied if necessary
gtpsearch: INFO: Binary demodulation: Not applied
gtpsearch: INFO: Pdot cancellation: Applied
gtpsearch: INFO: Following time system(s) are listed for this task:
gtpsearch: INFO: Spin ephemeri(de)s are defined in: TDB(2)
gtpsearch: INFO: Orbital ephemeri(de)s are defined in: None
gtpsearch: INFO: Pdot cancellation will be performed in: TDB
gtpsearch: INFO: Time series analysis will be performed in: TDB
gtpsearch: INFO: --------------------------
Search Type: Folding Analysis
Fourier Resolution: 1.32472e-05 Hz
Sampling Frequency: 6.62362e-06 Hz
Type of test: Chi-squared Test, 10 phase bins
Probability distribution: Chi-squared, 9 degrees of freedom
Search Range (Hz): [19.8333552027275, 19.834673303452]
Number of Trial Frequencies: 200
Number of Independent Trials: 100
Maximum Statistic: 593.279468705583 at 19.8340175649006 Hz
Chance Probability Range: (0, 2.03757046903054e-97)
FREQUENCY(Hz) STATISTIC
19.8333552027275 5.79625545262951
19.8333618263492 7.01568396804392
19.8333684499709 7.43326961721316
19.8333750735927 14.3940106847032
19.8333816972144 3.98769788756555
19.8333883208361 5.80801842866245
19.8333949444579 8.85462922119296
19.8334015680796 12.7256285840318
19.8334081917013 13.5215899622604
19.8334148153231 8.47331274812528
19.8334214389448 13.5637406263785
19.8334280625665 11.761064549331
19.8334346861882 2.65358035583002
19.83344130981 4.61309611331667
19.8334479334317 15.6585306082439
19.8334545570534 11.2846640199971
19.8334611806752 8.87913542126158
19.8334678042969 10.2671665931481
19.8334744279186 11.5483507327354
19.8334810515404 2.83982747635152
19.8334876751621 12.3737195510464
19.8334942987838 13.5402146743126
19.8335009224056 26.5882958388472
19.8335075460273 5.90310248492869
19.833514169649 8.99676518159094
19.8335207932708 8.35274224378768
19.8335274168925 16.061412537372
19.8335340405142 15.2879968632064
19.8335406641359 7.34994853697986
19.8335472877577 6.82257511150321
19.8335539113794 10.2024702249669
19.8335605350011 7.14213596039798
19.8335671586229 8.17237661128265
19.8335737822446 5.85801107680243
19.8335804058663 3.71028770278881
19.8335870294881 8.65563887663579
19.8335936531098 8.46253002009509
19.8336002767315 14.9752977503308
19.8336069003533 5.99034455717296
19.833613523975 6.20207812576582
19.8336201475967 5.83840611674754
19.8336267712185 6.24226829387835
19.8336333948402 7.76263294613537
19.8336400184619 7.88516394647846
19.8336466420836 17.854286134392
19.8336532657054 14.905700142136
19.8336598893271 25.6021663480861
19.8336665129488 144.118070871931
19.8336731365706 142.820222516297
19.8336797601923 21.0224476792629
19.833686383814 9.03205410968975
19.8336930074358 17.3063275008577
19.8336996310575 7.59599078566877
19.8337062546792 8.40959662794687
19.833712878301 16.4799784345439
19.8337195019227 6.35891780620497
19.8337261255444 7.31662010488654
19.8337327491662 14.537126893104
19.8337393727879 4.32392295250698
19.8337459964096 8.00475420281331
19.8337526200313 7.52933392148213
19.8337592436531 7.65676616183895
19.8337658672748 2.84080772435426
19.8337724908965 13.8029211390482
19.8337791145183 3.50933686222614
19.83378573814 9.05558006175563
19.8337923617617 20.9195216389747
19.8337989853835 31.4483654364554
19.8338056090052 14.2724599323629
19.8338122326269 10.4269470175955
19.8338188562487 32.5119345194334
19.8338254798704 45.7158751164044
19.8338321034921 10.1799245209038
19.8338387271139 75.5134539038377
19.8338453507356 110.960201931089
19.8338519743573 22.9172670685683
19.833858597979 44.2141351761996
19.8338652216008 33.4970837621918
19.8338718452225 12.9736313287262
19.8338784688442 11.8424251335588
19.833885092466 7.34014605695241
19.8338917160877 13.1716414252806
19.8338983397094 10.6318188501691
19.8339049633312 11.891437533696
19.8339115869529 18.1169925991276
19.8339182105746 10.190707248934
19.8339248341964 16.4789981865412
19.8339314578181 25.9178062049699
19.8339380814398 15.266431407146
19.8339447050616 15.7261677204333
19.8339513286833 6.8245356075087
19.833957952305 8.90462186933294
19.8339645759267 10.6004509140813
19.8339711995485 14.0254374356712
19.8339778231702 16.9671616919081
19.8339844467919 13.1098858011077
19.8339910704137 22.1820810665098
19.8339976940354 95.2370239670637
19.8340043176571 9.84271920795961
19.8340109412789 245.568837915993
19.8340175649006 593.279468705583
19.8340241885223 185.125765818752
19.8340308121441 20.0265157084742
19.8340374357658 57.7993922462383
19.8340440593875 4.47586139293241
19.8340506830092 17.6690192618733
19.834057306631 7.322501592903
19.8340639302527 16.0212223692594
19.8340705538744 8.22629025143361
19.8340771774962 5.8178209086899
19.8340838011179 10.6131941381169
19.8340904247396 12.16786747047
19.8340970483614 13.5774640984169
19.8341036719831 16.6162329069255
19.8341102956048 5.74234181247856
19.8341169192266 11.0111748272313
19.8341235428483 7.83027005832476
19.83413016647 9.12027642993677
19.8341367900918 2.62613341175317
19.8341434137135 9.17517031809048
19.8341500373352 9.51825711905112
19.8341566609569 14.441062588835
19.8341632845787 35.3438709993628
19.8341699082004 56.7564083713179
19.8341765318221 41.4694407685144
19.8341831554439 25.3531833553889
19.8341897790656 103.676959270695
19.8341964026873 58.1581630152429
19.8342030263091 17.0730284762045
19.8342096499308 29.7809635837867
19.8342162735525 8.12336421114542
19.8342228971743 20.8469832867716
19.834229520796 12.1688477184728
19.8342361444177 31.945351173847
19.8342427680395 10.4749791697299
19.8342493916612 5.17477821888938
19.8342560152829 7.09312356026075
19.8342626389046 15.8967308729108
19.8342692625264 6.98529627995883
19.8342758861481 20.4637063176984
19.8342825097698 19.0737146498064
19.8342891333916 7.44209184923786
19.8342957570133 11.1817379797089
19.834302380635 7.20879282458462
19.8343090042568 7.38229672107043
19.8343156278785 13.9107484193501
19.8343222515002 10.6249571141499
19.834328875122 4.76013331372837
19.8343354987437 12.3727393030437
19.8343421223654 19.1599764740479
19.8343487459872 9.31142479047199
19.8343553696089 35.5879527520463
19.8343619932306 159.161936970053
19.8343686168523 157.878792334461
19.8343752404741 34.6586776454443
19.8343818640958 10.7739548105671
19.8343884877175 9.8554624319953
19.8343951113393 17.1612507964515
19.834401734961 6.78336519139342
19.8344083585827 8.41057687594962
19.8344149822045 10.5367347939029
19.8344216058262 15.2840758711954
19.8344282294479 14.625349213351
19.8344348530697 16.0241631132677
19.8344414766914 22.7339606920551
19.8344481003131 14.341077292555
19.8344547239349 12.448218399255
19.8344613475566 12.4668431113072
19.8344679711783 9.55452629515267
19.8344745948 7.40974366514728
19.8344812184218 7.48816350536686
19.8344878420435 10.459295201686
19.8344944656652 10.1671812968681
19.834501089287 16.9622604518943
19.8345077129087 10.8298289467235
19.8345143365304 2.45949125128658
19.8345209601522 10.5877076900456
19.8345275837739 8.42037935597706
19.8345342073956 28.5899622604519
19.8345408310174 25.9050629809342
19.8345474546391 7.93809733862667
19.8345540782608 9.96426996029996
19.8345607018825 19.2334950742538
19.8345673255043 10.3593099054061
19.834573949126 5.14929177081802
19.8345805727477 10.4240062735872
19.8345871963695 9.3094642944665
19.8345938199912 6.36381904621869
19.8346004436129 4.27196980836151
19.8346070672347 6.69024163113268
19.8346136908564 15.1576238788413
19.8346203144781 4.60917512130569
19.8346269380999 19.1589962260452
19.8346335617216 20.4529235896682
19.8346401853433 8.478213988139
19.8346468089651 11.8287016615204
19.8346534325868 12.5550654315542
19.8346600562085 5.87761603685732
19.8346666798302 14.5430083811204
19.834673303452 9.50747439102093
Warning in <TClass::TClass>: no dictionary for class st_graph::IFrame is available
prompt>
Going Beyond The Simple Case
How To Use Other Statistical Tests
In the examples above, the Chi-Squared statistic was used for purposes of finding the pulsation. The gtpsearch tool currently also supports the Z2n test, the Rayleigh test, and the H test. A full explanation of the strengths and weaknesses of these approaches is beyond the scope of this document; but in brief, the most effective test depends on the pulse shape. For the sample data used in this test, all the tests return similar results, so specific examples using the other tests will not be shown.
Working In The Period Domain
The examples above all used inputs in the form of frequencies, and derivatives of frequencies. It is also possible to enter the input data as periods and derivatives of periods. These values are immediately converted to the frequency domain, and the search is still performed in the frequency domain. To enter period information instead, select PER for the ephemeris style. For example, the following input should produce the same plot as the example Using Estimated Frequency Only.
prompt> gtpsearch
This is gtpsearch version v10r5
Event data file name[] my_pulsar_events_v3.fits
Spacecraft data file name[] my_pulsar_spacecraft_data_v3r1.fits
Pulsar ephemerides database file name[] master_pulsardb_v3.fits
Pulsar name[ANY] PSR B0540-69
Output FITS file name (NONE for no FITS output)[] gtpsearch-example-7.fits
Type of statistical test to perform (CHI2 - Chi squared, RAYLEIGH - Rayleigh testt, Z2N - Z2n test, H - H test) (CHI2|RAYLEIGH|Z2N|H) [CHI2] Chi2
Number of phase bins for Chi2 test[10] 10
Size of steps for trials, in units of the Fourier resolution (0.:) [0.5] 0.5
Number of trials[100] 200
How will the time origin of the periodicity test be specified? (START|STOP|MIDDLEE|USER) [MIDDLE] MIDDLE
How will spin ephemeris be specified? (DB|FREQ|PER) [DB] PER
Epoch for the spin ephemeris[0.] 54368.11094817
Time format for spin ephemeris epoch (FILE|MJD|ISO|GLAST) [FILE] MJD
Time system for spin ephemeris epoch (FILE|TAI|TDB|TT|UTC) [FILE] TDB
Right Ascension to be used for barycenter corrections (degrees)[0.] 85.0482
Declination to be used for barycenter corrections (degrees)[0.] -69.3319
Pulse period at the epoch of the spin ephemeris (seconds) (0.:) [1.] .0504187275 3215454348
First time derivative of the pulse period at the epoch of the spin ephemeris (dimmension-less)[0.] 0.0
Second time derivative of the pulse period at the epoch of the spin ephemeris (Hzz)[0.] 0.0
Search Type: Folding Analysis
Fourier Resolution: 1.32472e-05 Hz
Sampling Frequency: 6.62362e-06 Hz
Type of test: Chi-squared Test, 10 phase bins
Probability distribution: Chi-squared, 9 degrees of freedom
Search Range (Hz): [19.833237637827, 19.8345557385513]
Number of Trial Frequencies: 200
Number of Independent Trials: 100
Maximum Statistic: 477.758221830123 at 19.8340192251911 Hz
Chance Probability Range: (3.2946214815123e-95, 3.3151619212497e-95)
Warning in <TClass::TClass>: no dictionary for class st_graph::IFrame is available
prompt>
Last updated by: Analia Cillis 02/03/2009