Using Tempo to calculate solar barycentric time Dejan Paradi

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

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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/tem
  po/
• 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.

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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-(n1) DM Dispersion
measure pc cm-3
Absolute reference for the ephemerides TZRMJD
Reference TOA day
TZRFREQ Frequency of reference TOA
MHz TZRSITE One-letter observatory code of
reference TOA
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Prediction mode
Pulsar model Pulsar parameters are stored in
files 'ltpsrnamegt.par' which are located in the
'PARDIR' directory, specified in tempo.cfg
file.
Input 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
Crab parameters for prediction mode..
Example of tz.in file.
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Prediction mode

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

Pulsar name
Date (day-month-year)
Time (hhmmss)
TMID MJD
Dispersion measure
Doppler's shift due to earth motion 10-4
Log_10 of fit rms residual in periods
Reference phase (RPHASE)
Referenc frequency F0 Hz
Observatory number
Nspan min
Number of coefficients
Binary phase
Coefficients
Example of polyco.dat for Crab pulsar.
DT (T-TMID)1440 PHASE RPHASE DT60F0
COEFF(1) DTCOEFF(2) DT2COEFF(3) ....
FREQ(Hz) F0 (1/60)(COEFF(2) 2DTCOEFF(3)
3DT2COEFF(4) ....)
Change of Crab frequency over the year.
Change of Crab frequency over two days.
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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 'ltpulasr namegt.par' or they can be
combined whith TOA lines into single file.
Example of header file provided with Tempo
package.
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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 rmsx
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 MODE1)?
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.
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Standard mode

• Output of standard mode includes files
• - resid2.tmp is binary format in which each
  record contains eight real8 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.
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Tempo2

• 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 graphical interface. (www.atnf.csiro.au/res
earch/pulsar/psrtime/tempo2/overview.html)
http//www.atnf.csiro.au/research/pulsar/ppta/temp
o2/