Using Tempo to calculate solar barycentric time Dejan

Using Tempo to calculate solar barycentric time Dejan Paradiž University of Ljubljana

Tempo general Autors: J. H. Taylor, R. N. Manchester, D. J. Nice, J. M. Weisberg, A. Irwin, N. Wex and others. Ephemeris routines by E. M. Standish, NASA/JPL. http: //www. atnf. csiro. au/research/pulsar/tempo/ Standard mode allows : Fitting pulse time of arrivals (TOAs) to pulsar timing model including time transformation to solar system barycentre. It includes modeling of pulsar rotation spin down and the possibility of several binary models. Prediction mode : Calculates ephemerides of pulsar phase behavior for specified pulsar model.

Pulsar model parameters Important parameters: Absolute reference for the ephemerides : RA DEC PMRA PMDEC PMRV PX TZRMJD Reference TOA [day] TZRFREQ Frequency of reference TOA [MHz] TZRSITE One-letter observatory code of reference TOA Right Ascension Declination Proper motion in RA [mas/year] Proper motion in Declination [mas/year] Radial 'proper motion [mas/year]' Parallax [mas] PEPOCH Epoch of frequency /period parameters and position F/P F 1/P 1 F 2 Fn DM Pulsar rotation frequency [Hz ] / periodor [s] Pulsar rotation frequency [Hz-2] /period derivative [s 2 10 -15] Pulsar rotation frequency second derivative [Hz-3] Pulsar rotation frequency n'th derivative [Hz-(n+1)] Dispersion measure [pc cm-3]

Prediction mode Input parameters (tz. in): Default settings ASITE a one-character site code MAXHADEF NSPANDEF NCOEFFDEF FREQDEF Pulsar model: Pulsar parameters are stored in files '<psrname>. par' which are located in the 'PARDIR' directory, specified in tempo. cfg file. maximum hour angle [h] time span [min] number of coefficients observing frequency [MHz] Settings for individual pulsar: NAME pulsar name NSPAN time span [min] NCOEFF number of coefficients MAXHA maximum hour angle [h] FREQ observing frequency [MHz] Example of tz. in file. Crab parameters for prediction mode. .

Prediction mode The polynomial ephemerides are written to file 'polyco. dat'. Nspan Date (day-month-year) [min] Observatory Reference Time Pulsar Binary Dispersion Coefficients (hhmmss) name phase measure number (RPHASE) Number Referenc Doppler's Log_10 TMID [MJD] of offrequency shift fit coefficients rms due residual to. F 0 earth [Hz] inmotion periods[10 -4] Example of polyco. dat for Crab pulsar. DT = (T-TMID)*1440 PHASE = RPHASE + DT*60*F 0 + COEFF(1) + DT*COEFF(2) + DT^2*COEFF(3) +. . FREQ(Hz) = F 0 + (1/60)*(COEFF(2) + 2*DT*COEFF(3) + 3*DT^2*COEFF(4) +. . ) Change of Crab frequency over two days. Change of Crab frequency over the year.

Standard mode Header control cards: CLK Terrestrial time standard EPHEM Solar system ephemeris NITS Iterate solution n times, or fewer if it converges. PSR Pulsar name BINARY Binary model to use START Ignore TOAs before this date FINISH Ignore TOAs after this date NTOA Number of TOA lines TRES Time resolution Header control cards and pulsar parameters are stored in file '<pulasr name>. par' or they can be combined whith TOA lines into single file. Example of header file provided with Tempo package.

Standard mode TOAs are entered, one per line, in one of three formats, called 'Princeton', 'Parkes', and 'Interchange TOA (ITOA)' format. TOA commands: DITHER x Add Gaussian noise with rms=x μs. EMIN x Set minimum uncertainty to x JUMP Beginning or end of a jump segment SIGMA x Set uncertainties of following TOAs to x μs (forces MODE=1) SIM Enter simulation mode SKIP Skip all lines until NOSKIP is read TIME x Add x (seconds) to following TOAs Section of TOA lines in 'Parkers' which shows use of JUMP command.

Standard mode Output of standard mode includes files: - resid 2. tmp is binary format in which each record contains eight real*8 values. -matrix. tmp includes covariance matrix. It is in binary format whith variable length records. -itoa. out is ASCII file in ITOA format whit corrected TOAs. (optional) Example number of TOAs verses MJD of TOAs. Diference between input time of TOAs and corrected time.

Tempo 2 Intruduction: Tempo 2 is new version of tempo. Curently only beta version is available on addres below. What is new: - Designed for high precision pulsar timing experiments. - Allows to analyze the pulse arrival times for multiple pulsars simultaneously. - Graphical interface. Tempo 2 graphical interface. (www. atnf. csiro. au/research/pulsar/psrtime/tempo 2/overview. html) http: //www. atnf. csiro. au/research/pulsar/ppta/tempo 2/