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1、TEMPO2 tutorial,George Hobbs(饺子),Research ScientistCSIRO Australia Telescope National Facility,International Young Scientist of NTSCgeorge.hobbscsiro.au,Content,TEMPO2 is a software package.It implements“pulsar timing”algorithms.Section 1:What TEMPO2 has been used for.Overview of TEMPO2Section 2:How
2、 to use TEMPO2Section 3:How to develop TEMPO2Major TEMPO2 developers(software and algorithms):G.Hobbs,R.Edwards,R.Manchester,W.Coles,X.You,M.Keith,F.Jenet,D.Yardley,J.Verbiest,CSIRO.TEMPO2,What has tempo2 been used for in 2010/2011?,Searching for gravitational wave signals(e.g.,Yardley et al.2011,Ya
3、rdley et al.2010,Abbott et al.2010,van Haasteren et al.2010)Using pulsars as navigational aids(Ruggiero 2011)Statistical analysis of timing residuals(e.g.,Na,X.S.et al.,2011,Hobbs et al.2010)Studying emission geometry(e.g.,Noutsos et al.,2011)Searching for gamma-ray pulsars(Ray et al.,2010)Determini
4、ng pulsar masses(Demorest et al.2010)Studying pulsations from main-sequence stars(Ravi et al.2010)Tests of relativity(Weisberg et al.2010)Measuring Jupiters mass(Champion et al.2010)Observations of glitches(Chukwude et al.2010)Analysis of accreting millisecond X-ray pulsar(Patruno et al.2010)Relativ
5、istic spin precession(Manchester et al.2010),CSIRO.TEMPO2,What does tempo2 do?,USAGE 1:Start with file of pulse arrival timesStart with model of a pulsars spin,astrometric and orbital parameters-pulsar timing residualsUSAGE 2:Start with pulsar timing model-predict the pulse phase and frequency at a
6、given observatory at a given time,CSIRO.TEMPO2,A parameter file(.par),CSIRO.TEMPO2,Pulsar name,astrometric,rotational,dispersion measure and orbital parameters,Realisation of terrestrial time,Solar system ephemeris,Weighted fit?,Fit for this parameter?,An arrival time file(.tim),CSIRO.TEMPO2,States
7、that this is a tempo2 format file,Filename or identifier,Observing frequency(MHz),Site arrival time(MJD),Uncertainty on arrival time(us),Telescope code,User defined flags,How does tempo2 work?,The algorithms are based on those implemented in TEMPO1Details in Hobbs,Edwards&Manchester(2006)and Edwards
8、,Hobbs&Manchester(2006),CSIRO.TEMPO2,Conversion of site-arrival-time to pulse emission time,Clock corrections,Atmospheric delays,Einstein delay,Shapiro delay,Roemer delay,Secular motion(e.g.,radial velocity),Dispersive delay,Orbital motion,Details:clock correction,Must convert from the observatory t
9、ime standard to a realisation of terrestrial time TT.Use set of text files containing the difference between two time standards:pks2gps.clk,gps2utc.clk,utc2tai.clk,tai2tt_bipm2011.,CSIRO.TEMPO2,Youll find these files in$TEMPO2/clockdirectory,Details:Einstein delay,Pulse arrival times(in terrestrial
10、time)must be converted to the frame of the Solar System Barycentre.TEMPO2 uses the tabulated results of Irwin&Fukushima(1999),CSIRO.TEMPO2,Details:Roemer delay,The Roemer delay is the vacuum light travel time between the pulse arriving at the observatory and the equivalent arrival time at the SSB.,C
11、SIRO.TEMPO2,R,k,SSB,Earth,pulsar,K=Unit vector pointing at pulsar.Obtained from RA,DEC,PMRA,PMDEC,R is vector from observatory to SSB.Use JPL ephemeris,observatory coordinates and earth orientation parameters,Use observatory coordinate file to know position of observatory,Roemer delay,CSIRO.Gravitat
12、ional wave detection,Pulsar in ecliptic,Ecliptic latitude=90 deg,Details:Shapiro delay,Time delay caused by the passage of the pulse through large gravitational fields.Tempo2 includes delay caused by Sun(110us),Jupiter(180ns),Saturn(58ns),Neptune(12ns)and Uranus(10ns),CSIRO.TEMPO2,Details:dispersive
13、 delay,D is the dispersion constant.DM(cm-3pc)=2.410 x 10-16 Df is the frequency of the radiation at the Solar System barycentre,CSIRO.TEMPO2,Details:binary system,For pulsars in binary systems,tempo2 includes parameters describing the orbital motion.Various binary models exist.Suggest using“T2”mode
14、l that combines most earlier binary models,CSIRO.TEMPO2,Using the pulsar timing model,Have pulse emission time in the pulsar frame.Predict using the pulsar timing modelCan also include simple model of glitch events,CSIRO.TEMPO2,Phase of pulse sequence,Pulse frequency(and time derivatives),Pulse emis
15、sion time,Time at which df/dt=n,Reference phase,Timing residuals,CSIRO.TEMPO2,Timing residual for ith observation,Pulse phase,Nearest integer to fi,Pulse frequency,Example,CSIRO.TEMPO2,Time,Measured arrival time with observatory clock,Measured arrival time in terrestrial time(Dc),Measured arrival ti
16、me in pulsar frame,1,3,4,2,5,Predicted arrival times in pulsar frame,Timing residual,Pulsar timing residuals,If pulsar model predicts the observations perfectly(and the conversion from the observatory to pulsar frame is perfect)then R=0(within measurement uncertainty).If R!=0 then the pulsar model i
17、s(1)not accurate or(2)does not include a physical process that affects the measured arrival times or(3)the correction from the observatory to pulsar frame is not correct.,CSIRO.TEMPO2,Pulsar timing residuals:incorrect F0,CSIRO.TEMPO2,Pmodel Ptrue,Pulsar timing residuals:incorrect F1,CSIRO.TEMPO2,Pmo
18、del Ptrue,Pmodel Ptrue,Pulsar timing residuals:incorrect position,CSIRO.TEMPO2,Pulsar timing residuals:incorrect proper motion,CSIRO.TEMPO2,Pulsar timing residuals,CSIRO.TEMPO2,Good parameters,Do not have a phase connected solution,Phase wraps,Induced timing residuals from ISM and from gravitational
19、 waves,CSIRO.TEMPO2,50cm(600MHz),20cm(1400MHz),10cm(3000MHz),Induced residuals from gravitational wave background,Incorrect conversion to pulsar frame,CSIRO.TEMPO2,Champion et al.(2010):induced timing residuals from error in mass of Jupiter of 5x10-10 Mo,Predictive mode,TEMPO2 can provide a polynomi
20、al approximation of the phase and pulse frequency at the observatory for a specified time interval.TEMPO1 creates polycos.TEMPO2 can create polycos,but we recommend predictors.Predictors model the phase as a function of time using Chebyshev polynomials.Tempo2 provides a C library to read predictorst
21、empo2 f mypar.par pred sitename mjd1 mjd2 freq1 freq2 ntimecoeff nfreqcoeff seg_length,CSIRO.TEMPO2,Observing frequency range(MHz),Time range,Segment length(s),Part 2,Usage of tempo2 and example of pulsar timingTEMPO2 is written in C/C+(with a little Fortran)and runs on linux and MacOS.Main tempo2 w
22、ebsite:http:/www.atnf.csiro.au/research/pulsar/tempo2(see“tutorials”and“Documentation”)Main tempo2 download site:http:/email distribution list:Sign up at http:/(click on“Mailing Lists”)Contact:george.hobbscsiro.au,use feedback form,CSIRO.TEMPO2,Running tempo2,Need a pulsar model(use the ATNF pulsar
23、catalogue http:/www.atnf.csiro.au/research/pulsar/psrcat-type in pulsar name and click Get Ephemeris)Get some pulse arrival times(use Parkes data archive see Jonathans talk and pat in psrchive see Willems talk)tempo2 f psrname.par psrname.tim,CSIRO.TEMPO2,Using the“plk”graphical interface,tempo2 gr
24、plk f mypar.par mytim.tim,CSIRO.TEMPO2,Which parameters to fit,Re-do the fit,What to plot,The residuals,Press h to get help,Other useful graphical interfaces:spectrum,CSIRO.TEMPO2,Other useful graphical interfaces:plotMany,CSIRO.TEMPO2,tempo2 gr plotMany f par1.par tim1.tim f par2.par tim2.tim f par
25、3.par par3.tim,The glitch plugin,CSIRO.TEMPO2,Yu Meng(in preparation),Glitch events,Pulse frequency,Pulse frequency with mean removed,Pulse frequency derivative,Using“output”interfaces,tempo2 output general s“Hello f0=f0_v f0_en f1=f1_v f1_en”f mypar.par mytim.timtempo2 output general2 s“freq=freq,s
26、at=sat,bat=bat,res=pren”f mypar.par mytim.tim tempo2 output matrix f mypar.par mytim.tim,CSIRO.TEMPO2,Part 3:Developing the software,You should never need to modify the main tempo2 source code.(Please report any bugs to george.hobbscsiro.au)You should create new“plug-in packages”.These can be for te
27、xt output,a graphical interface,methods to select data or new fitting algorithms.,CSIRO.TEMPO2,Creating a new text output format,Print out the pulsar model parameters and the timing residuals in your format,CSIRO.TEMPO2,Must include tempo2.h,Must have this function,Pulsar number,Parameter of interes
28、t,Time derivative,Observation number,Observation parameter,Number of observations,Creating a new graphical interface,CSIRO.TEMPO2,Must include this function,Must process the command line arguments,Read parameter and observation file(s),Form barycentric arrival times,residuals and fit.Repeat with pos
29、t-fit parameters,Do your plotting/analysis etc.,Must define how many pulsars to process,Output format versus graphical interface,Output format:tempo2 runs as usual then gives control to your plugin to display the output(easy,but no control over fitting etc.)Graphical interface:tempo2 provides contro
30、l to your plugin from the beginning(your plugin must call all the functions to read data files,do the fit etc.,but you have more control),CSIRO.TEMPO2,The tempo2 toolkits,To aid development the following toolkits are available:T2toolkit.h:find minimum and maximum values in array,find RMS,mean,range,
31、sort data array,create random numbersTKspectrum.h:routines for spectral estimationTKfit.h:fitting routines(e.g.,SVD,Cholesky decomposition)tempo2Util.h:calculate dot products,turns hh:mm:ss/dd:mm:ss into degrees gwsim.h:gravitational wave simulation routines.(NOTE:Many people use“numerical recipes”r
32、outines in plugins these are copyright and the source code cannot be made publically available use the tempo2 toolkits instead),CSIRO.TEMPO2,Debugging your installation,Sometimes things dont work!If it doesnt compile:check that your version of gfortran,gcc and g+are the same!Check that pgplot has be
33、en correctly installed.It compiles and runs,but doesnt do anything:run your code with tempo2.f mypar.par mytim.tim debug displayVersion outfileand then send your.par,.tim and outfile to george.hobbscsiro.au(or any tempo2 developer)Your plugin does not work.Check that you have installed the plugin in
34、$TEMPO2/plugins/,CSIRO.TEMPO2,Publishing results from tempo2,For general usage,please cite:Hobbs,Edwards&Manchester(2006)For details of the algorithms:Edwards,Hobbs&Manchester(2006)For gravitational wave implementation:Hobbs et al.(2009)To enable complete reproducibility of results should include an
35、 appendix including output of displayVersion.Important:publish the clock reference(e.g.,TT(TAI)and Solar System ephemeris model(e.g.,DE405),CSIRO.TEMPO2,Topics not covered in this presentation,Simulating data(use fake,GWbkgrd plugins)Use of flags(use select,-pass,-filter options)Atmospheric correcti
36、onsXiaopengs Solar Wind modelFERMI gamma-ray pluginUse of fitfunc and splug interfacesUse of region filesMeasuring dispersion measure variationsLook at the tempo2 tutorials on http:/www.atnf.csiro.au/research/pulsar/tempo2,CSIRO.Gravitational wave detection,The future of tempo2,Improved binary model
37、sPlugin to determine irregularities in terrestrial time standards(see Ding Chens talk)In-built algorithms to model gravitational wavesMethods to determine dispersion measure variationsImproved methods for simulating dataAlgorithms to enable pulsar navigationWeb-based access tools(so you do not need
38、to install your own version of tempo2),CSIRO.TEMPO2,Conclusions,Tempo2 is a publically available software package for pulsar timing:http:/www.atnf.csiro.au/research/pulsar/tempo2Plugin-packages can be developed for specific research topicsTempo2 is suitable for all current high-precision pulsar timing applicationsTempo2 can process multiple pulsars simultaneouslyDownload TEMPO2 and try it out!TEMPO2 真的是一个好东西，希望大家都来试试，你会爱上它的！Supported by the Chinese Academy of Sciences#CAS KJCX2-YW-T09 and NSFC 10803006.Australian Research Council QEII Fellowship,CSIRO.TEMPO2,
