Using Tempo to calculate solar barycentric time Dejan Paradiž

University of Ljubljana

Tempo general

AutorsAutors::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/

StandardStandard mode mode allows allows ::FFitting pulse time of arrivals (TOAs) to pulsar timing model including time itting pulse time of arrivals (TOAs) to pulsar timing model including time

transformation to solar system barycentre. It includes modeling of pulsar rotation transformation to solar system barycentre. It includes modeling of pulsar rotation

spin down and the possibility of several binary modelsspin down and the possibility of several binary models..

PredictionPrediction mode mode ::

Calculates ephemerides of pulsar phase behavior for specified pulsar modelCalculates ephemerides of pulsar phase behavior for specified pulsar model..

Pulsar model parameters

Important parameters:RA Right Ascension

DEC Declination

PMRA Proper motion in RA [mas/year]

PMDEC Proper motion in Declination [mas/year]

PMRV Radial 'proper motion [mas/year]'

PX Parallax [mas]

PEPOCH Epoch of frequency /period parameters and position

F / P Pulsar rotation frequency [Hz ] / periodor [s]

F1/P1 Pulsar rotation frequency [Hz-2] /period derivative [s2 10-15]

F2 Pulsar rotation frequency second derivative [Hz-3]

Fn Pulsar rotation frequency n'th derivative [Hz-(n+1)]

DM Dispersion measure [pc cm-3]

Absolute reference for the ephemerephemeriidesdes :

TZRMJD Reference TOA [day]

TZRFREQ Frequency of reference TOA [MHz]

TZRSITE One-letter observatory code of

reference TOA

Prediction modeInput parameters (tz.in):

Default settings

ASITE a one-character site code

MAXHADEF maximum hour angle [h]

NSPANDEF time span [min]

NCOEFFDEF number of coefficients

FREQDEF 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.

Pulsar model:

Pulsar parameters are stored in files

'<psrname>.par' which are located in the 'PARDIR'

directory, specified in tempo.cfg file.

Crab parameters for prediction mode..

The polynomial ephemerides are written to file 'polyco.dat'.

Prediction mode

Example of polyco.dat for Crab pulsar.

Change of Crab frequency over the year.

Pulsar nameDate (day-month-year)Time (hhmmss)TMID [MJD]Dispersion measureDoppler's shift due to earth motion [10-4]Log_10 of fit rms residual in periodsReference phase (RPHASE)Referenc frequency F0 [Hz]Observatory numberNspan [min]Number of coefficientsBinary phaseCoefficients

DT = (T-TMID)*1440 PHASE = RPHASE + DT*60*F0 + COEFF(1) + DT*COEFF(2) + DT^2*COEFF(3) + .... FREQ(Hz) = F0 + (1/60)*(COEFF(2) + 2*DT*COEFF(3) + 3*DT^2*COEFF(4) + ....)

Change of Crab frequency over two days.

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

Standard mode

Example of header file provided with Tempo package.

Header control cards and pulsar

parameters are stored in file '<pulasr

name>.par' or they can be combined whith

TOA lines into single file.

TOAs are entered, one per line, in one of three formats, called 'Princeton', 'Parkes', and 'Interchange TOA

(ITOA)' format.

Standard mode

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)

Section of TOA lines in 'Parkers' which shows use of JUMP command.

SIM Enter simulation mode

SKIP Skip all lines until NOSKIP is read

TIME x Add x (seconds) to following TOAs

TOA commands:

Output of standard mode includes files:- resid2.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)

Standard mode

Example number of TOAs verses MJD of TOAs. Diference between input time of TOAs and

corrected time.

Intruduction:Tempo2 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.

Tempo2

Tempo2 graphical interface. (www.atnf.csiro.au/research/pulsar/psrtime/tempo2/overview.html)

http://www.atnf.csiro.au/research/pulsar/ppta/tempo2/