Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.atnf.csiro.au/research/pulsar/ppta/tempo2/manual.pdf Äàòà èçìåíåíèÿ: Wed Dec 20 05:16:26 2006 Äàòà èíäåêñèðîâàíèÿ: Tue Dec 25 00:07:06 2007 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: m 31

TEMPO2 user manual
George Hobbs, Russell Edwards
Australia Telescope National Facility, CSIRO, PO Box 76, Epping NSW 1710, Australia

(documentation V2.0)

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Contents
1 INTRODUCTION 2 Obtaining and installing temp o2 3 A simple example of using temp o2 4 Required files 4.1 Clock correction files . . . . . . . 4.1.1 Updating clock corrections 4.2 Earth Orientation Parameters . . 4.3 Time ephemeris . . . . . . . . . . 4.4 Planetary ephemeris . . . . . . . 4.5 Observatory definitions . . . . . . 5 Parameter files 5.0.1 tpo file format . 5.0.2 Changing the mo 5.1 Jumps . . . . . . . . . . 5.2 Removing Timing Noise 5.3 Default values . . . . . . .. del .. .. .. . ep . . . . o . . . . ch . . . .. . .. .. .. .. .. . .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6 6 8 8 9 9 9 10 10 10 14 14 15 15 15 15 17 17 17 17 18 18 19 19 19 19 19 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 21 21 22 22 23 23 23 23 24 24 24 25 25 26 27

6 Observation files 6.1 Setting dispersion measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 Jodrell Bank Observatory binary format . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Atmospheric propagation delays 8 Command-line arguments 8.1 The tempo1 emulation mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3 Aliases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 The b o otstrap fitting algorithm 10 Predictive mo de 10.1 Tempo2 format 10.2 Tempo1 format 11 Global parameters 12 Output form 12.1 general . 12.2 general2 12.3 list . . . 12.4 stats . . a . . . . ts . . . . . . . . . . . . ......................................... .........................................

13 Graphical interfa 13.1 basic . . . . . 13.2 calcDM . . . 13.3 chisq . . . . . 13.4 compare . . . 13.5 compareRes . 13.6 delays . . . . 13.7 errors . . . . 13.8 fake . . . . . 13.9 gorilla . . . . 13.10plk . . . . . .

ces .. .. .. .. .. .. .. .. .. ..


13.11 13.12 13.13 13.14

polytest . splk . . . stridefit . transform

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14 Developing the software 14.1 Creating a plug-in . . . . . 14.1.1 A new output format 14.1.2 A new graphical inter 14.2 The main source code . . .

... .. face ...

15 Temp o2 error and warning messages 15.1 Error messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2 Warning messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Common questions 17 In progress 18 Acknowledgements

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List of Figures
1 2 3 4 5 6 a) pre-fit timing residuals for the test data-set and b) post-fit timing residuals. . . . . . An example of the `basic' graphical interface. A P - P diagram is produced with the pulsar being analysed highlighted. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example of the chisq plug-in for determining the most likely values of the orbital period, PB, and longitude of periastron, OM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . The solar system Shapiro delay for PSR J1810-2005 shown using the delays graphical interface plug-in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Simulating pulsar timing residuals for a pulsar with a proper motion in right ascension of 200 mas/yr using the fake plugin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . An example of the plk graphical interface in use. The post-fit residuals for PSR J0437-4715 are plotted with 20 observations shown in green and 10 cm observations in red. The white circles and black lines indicate arrival times between orbital phases 0.4 and 0.6. . . . . . Example of the splk graphical interface plug-in for showing the pre- and post-fit timing residuals for multiple pulsar simultaneously. . . . . . . . . . . . . . . . . . . . . . . . . . Example of the stridefit graphical interface plug-in which calculates the pulsar's dispersion measure as a function fo time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 23 24 25 27

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28 29 30

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List of Tables
1 2 3 4 5 Observatory details . . . . . . . . . . . Pulsar parameters that can be entered Binary parameters that can be entered Flags in arrival time files . . . . . . . . Commands that may be included in an ........... in a parameter file in a parameter file ........... arrival time file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 12 13 16 17

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1

INTRODUCTION

Tempo2 is a new version of the tempo pulsar timing software. An overview of the software is provided in Hobbs, Edwards & Manchester (2006; MNRAS 369 655). A second paper provides mathematical details of the algorithms used in the software (Edwards, Hobbs & Manchester 2006; currently available from astro-ph). A third paper will describe how tempo2 can be used to simulate the effects of gravitational waves on pulsar timing residuals. A summary of the basic features can also be found in Hobbs, Edwards & Manchester (2006; in press CHJAA). This document provides full usage instructions for tempo2.

2

Obtaining and installing temp o2

The tempo2 software and documentation can be obtained from http://www.atnf.csiro.au/research/ pulsar/ppta/tempo2. Click on the "Download" option to download the software to your local machine. This software requires compilation before it will run. Up-to-date installation instructions are available in a README file with the download. Note: tempo2 makes heavy use of "long double" precision in its calculations. Most compiler/architecture combinations support long doubles of 80 or 128 bits in size, which is sufficient. Tempo2 has been successfully tested under Linux-gcc/x86, Solaris/SPARC and Mac OS 10.4-gcc/PowerPC. Unfortunately, some systems only provide 64-bit long doubles (i.e. identical to a standard "double"); these include Mac OS 10.3.9 and earlier, and many Windows compilers. While parts of the source code make reference to a software quad-precision library, this feature is no longer functional.

3

A simple example of using temp o2

The tempo2 website (http://www.atnf.csiro.au/research/pulsar/tempo2) provides a set of example files for use to test the software. psr1.par contains the catalogued parameters for PSR J0437-4715 in standard tempo2 format (see §5). psr1.tim contains a set of simulated observations of this pulsar over a 10 yr period with an rms residual of 100 ns. See §6 for details of the contents of this file. Running
tempo2 -f psr1.par psr1.tim

should provide some information about clock correction files and also
Results for PSR J0437-4715

RMS pre-fit residual = 0.096 (us), RMS post-fit residual = 0.096 (us) Number of points in fit = 367

PARAMETER Pre-fit Post-fit Uncertainty --------------------------------------------------------------------------------RAJ (rad) 1.20978853473707 1.20978853473707 0 RAJ (hms) 04:37:15.7865145 04:37:15.7865145 0 DECJ (rad) -0.824709094464799 -0.824709094464799 0 DECJ (dms) -47:15:08.46158 -47:15:08.46158 0 F0 (s^-1) 173.687946306032 173.687946306032 0 F1 (s^-2) -1.7283139464043e-15 -1.7283139464043e-15 0 PEPOCH (MJD) 51194.0001248168 51194.0001248168 0 POSEPOCH (MJD) 51194.0001248168 51194.0001248168 0 DMEPOCH (MJD) 51194 51194 0 DM (cm^-3 pc) 2.64690012312213 2.64690012312213 0 PMRA (mas/yr) 121.43799811708 121.43799811708 0 PMDEC (mas/yr) -71.4379988923397 -71.4379988923397 0 PX (mas) 7.19 7.19 0 SINI 0.6788 0.6788 0 PB (d) 5.74104608901605 5.74104608901605 0 T0 (MJD) 51194.6240248265 51194.6240248265 0 A1 (lt-s) 3.36669162220122 3.36669162220122 0 OM (deg) 1.2 1.2 0 ECC 1.9186e-05 1.9186e-05 0

Difference Fit -----------------0 N 0 0 N 0 0 N 0 N 0 N 0 N 0 N 0 N 0 N 0 N 0 N 0 N 0 N 0 N 0 N 0 N 0 N

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PBDOT (10^-12) 3.64 3.64 0 OMDOT (deg/yr) 0.0159999997519168 0.0159999997519168 0 M2 0.236 0.236 0 START (MJD) 50640.9281162413 49350.5129309451 0 FINISH (MJD) 52088.8971386924 53000.5197060478 0 TRACK (MJD) 0 0 0 TZRMJD 51204.6438924841 51204.6438924841 0 TZRFRQ (MHz) 1413.39997808495 1413.39997808495 0 --------------------------------------------------------------------------------Binary model: DD Mass function = 0.001243113190 +- 0.000000000000 solar masses Minimum companion mass = 0.1403 solar masses Median companion mass = 0.1637 solar masses Maximum companion mass = 0.3493 solar masses MTOT derived from sin i and m2 = 1.8186068413766 Inclination angle (deg) = 42.74994182955 (+ 0 - 0)

0 0 0 -1290.4 911.62 0 0 0 ---------------

N N N N N N N N ---

psr1 2.par is similar to psr1.par except that the parameter values have been changed slightly from their true values. As above, running
tempo2 -f psr1_2.par psr1.tim

should produce
Results for PSR J0437-4715

RMS pre-fit residual = 6.895 (us), RMS post-fit residual = 0.096 (us) Number of points in fit = 367

PARAMETER Pre-fit Post-fit Uncertainty --------------------------------------------------------------------------------RAJ (rad) 1.2097885336826 1.20978853474746 2.1206e-11 RAJ (hms) 04:37:15.7865 04:37:15.7865146 2.916e-07 DECJ (rad) -0.824709094076948 -0.824709094473468 1.5157e-11 DECJ (dms) -47:15:08.4615 -47:15:08.46158 3.1264e-06 F0 (s^-1) 173.68794630603 173.687946306032 9.5579e-15 F1 (s^-2) -1.728e-15 -1.72831367406148e-15 2.3325e-22 PEPOCH (MJD) 51194.0001248168 51194.0001248168 0 POSEPOCH (MJD) 51194.0001248168 51194.0001248168 0 DMEPOCH (MJD) 51194 51194 0 DM (cm^-3 pc) 2.64690012312213 2.64690012312213 0 PMRA (mas/yr) 121.43799811708 121.43799811708 0 PMDEC (mas/yr) -71.4379988923397 -71.4379988923397 0 PX (mas) 7.19 7.19 0 SINI 0.6788 0.6788 0 PB (d) 5.741046089 5.74104608900813 1.0437e-11 T0 (MJD) 51194.6240248265 51194.6240248265 0 A1 (lt-s) 3.36669162220122 3.36669162220122 0 OM (deg) 1.2 1.2 0 ECC 1.9186e-05 1.9186e-05 0 PBDOT (10^-12) 3.64 3.64 0 OMDOT (deg/yr) 0.0159999997519168 0.0159999997519168 0 M2 0.236 0.236 0 START (MJD) 50640.9281162413 49350.5129309451 0 FINISH (MJD) 52088.8971386924 53000.5197060478 0 TRACK (MJD) 0 0 0 TZRMJD 51204.6438924841 51204.6438924841 0 TZRFRQ (MHz) 1413.39997808495 1413.39997808495 0 --------------------------------------------------------------------------------Binary model: DD Mass function = 0.001243113190 +- 0.000000047151 solar masses Minimum companion mass = 0.1403 solar masses Median companion mass = 0.1637 solar masses Maximum companion mass = 0.3493 solar masses MTOT derived from sin i and m2 = 1.818606841374 Inclination angle (deg) = 42.74994182955 (+ 0 - 0)

Difference Fit -----------------Y 1.0649e-09 1.4643e-05 -3.9652e-10 Y -8.1788e-05 2.3306e-12 Y -3.1367e-19 Y 0 N 0 N 0 N 0 N 0 N 0 N 0 N 0 N 8.1286e-12 Y 0 N 0 N 0 N 0 N 0 N 0 N 0 N -1290.4 N 911.62 N 0 N 0 N 0 N ------------------

The residuals can be inspected using 7


Figure 1: a) pre-fit timing residuals for the test data-set and b) post-fit timing residuals.
tempo2 -gr plk -f psr1_2.par psr1.tim

which should produce a plot of the pre-fit residuals as shown in Figure 1a. Pressing '2' on the plot will show the post-fit residuals (Figure 1b).

4

Required files

Tempo2 requires certain files in order to run correctly. These files are provided with the download and are discussed in the following sections.

4.1

Clo ck correction files

Times of arrival provided to tempo2 are recorded against local observatory clocks. These times differ from those recorded against a uniform clock, firstly because observatory clocks are typically maintained in approximate synchrony with Coordinated Universal Time (UTC), which itself is not uniform, and secondly because they deviate from ideal UTC owing to deviations in uniformity in the underlying frequency standard (usually a hydrogen maser). The ultimate aim of the clock correction process is to transform all site arrival times to a chosen realisation of TT (Terrestrial Time), which in an ideal realisation is a uniform clock ticking SI seconds on the geoid. By default this is TT(TAI), which (since 1971) differs from UTC by a constant offset plus an integer number of leap seconds. Alternative realisations of TT can be specified using the the CLOCK keyword in the parameter file. The clock correction process proceeds entirely on the basis of linear interpolation of user-supplied tabulations of the difference between named pairs of clocks, as a function of Modified Julian Day (MJD)1 . These files reside in the directory $TEMPO2/clock. Lines beginning with the hash character (#) are treated as comments. The first line must be a comment specifying the name of the clock to convert from, the name of the clock to convert to, and an optional "badness" value (which defaults to 1). For example, the following specifies that the values in the file can be added to times measured against the Parkes clock ("UTC(PKS)") to transform them to the frame of the Global Positioning System (GPS) clock ("UTC(GPS)").
# UTC(PKS) UTC(GPS) 10

Non-comment lines consist of a sequence of pairs of MJDs and offsets (in seconds), specifying the difference between the second and first clocks as a function of date. For example:
50844.72917 -7.49068e-07 50845.77083 -7.47637e-07 50846.81250 -7.46650e-07 ...
1 The frame in which the MJD is measured is not sp ecified: it is assumed that clo ck offsets and drift rates are small enough that if t = t + f (t) then t t - f (t ).

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The spacing of the dates need not be any specific value, or even be regular. For most purposes roughly daily values are suitable. All files ending in .clk in $TEMPO2/clock are read by Tempo2 when it starts executing. Then, given a TOA to transform, it obtains the name of the clock against which it was measured based upon name specified in the observatory database (§4.5), given the observatory code recorded in the TOA file. Given the source and destination clocks, tempo2 must then choose a selection of clock correction tables (from .clk files) to use for the transformation. This is firstly attempted by consulting the list of pre-defined transformation paths, which are defined using CLK CORR CHAIN entries in the parameter file. For example, the following tells tempo2 to convert from UTC(PKS) to TT(TAI) using tables defined in pks2gps.clk, gps2utc.clk,utc2tai.clk and tai2tt tai.clk:
CLK_CORR_CHAIN pks2gps gps2utc utc2tai tai2tt_tai

This parameter may be specified multiple times. Tempo2 will attempt to apply each path in the order in which they were specified (which may fail if the MJD of the TOA is outside the range of component tables). If no applicable pre-defined paths are found, tempo2 find the "best" possible path using all of the available tables. Here "best" means the path for which the sum of badness values is minimized. Tiebreaking is arbitrary. This path is then appended to the global list of pre-defined paths. Since tempo2 always checks this list before attempting automatic path construction, subsequent transformations will always use this path if it is applicable, even if the MJDs of some TOAs would have allowed for a "better" path. Caution is therefore advised in using the automatic path construction feature when multiple paths exist. 4.1.1 Up dating clo ck corrections

The distribution of tempo2 includes several useful files containing corrections based on the BIPM's Circular T (offsets between UTC and its various realisations, as well as the GPS clock) and the IERS Bulletin C (announcing leap seconds). A suite of ancillary software is available on the tempo2 website, which provides among other things a means for parsing Circular T to update the relevant clock correction files (update clkcorr). This program can also parse clock monitoring data from the Parkes Observatory. Interested parties are invited to contribute code for the parsing of clock data from other sources.

4.2

Earth Orientation Parameters

To compute the Roemer delay, the position of the observatory must be known. This depends not only on the Earth's orbit, but on the Earth's orientation and rotation. The necessary parameters are obtained by interpolation of the "C05" series of Earth Orientation Parameters (EOPs) from the IERS. The file $TEMPO2/earth/README specifies the web address for downloading the latest EOPs. The user may optionally select to emulate the algorithm of tempo (which neglects polar motion and uses an out of date precession/nutation model) for transforming the observatory coordinates to the celestial frame, using the T2C METHOD parameter; in this case $TEMPO2/clock/ut1.dat (in the same format as the corresponding file for tempo) is used.

4.3

Time ephemeris

The pulse arrival times at the observatory at transformed to the arrival time at the solar system barycentre (SSB). In this transformation the Einstein delay, which describes the combined effect of gravitiatonal redshift and time dilation due to the motion of the Earth and other bodies, must be taken in to account. This transformation converts the site arrival time from TT to a coordinate time at the SSB, known as Barycentric Coordinate Time (TCB). Optionally, for backward compatibility with tempo the user may also choose to use a scaled version of this frame in which the mean drift relative to TT is divided out: this is nominally (but incorrectly; see Paper II) referred to as TDB. This is accomplished by specifying "UNITS TDB" in the parameter file. The Einstein delay is computed using a polynomial approximation to the numerical evaulation of the time dilation integral as provided by Irwin & Fukushima (1999). It lives in $TEMPO2/ephemeris/TIMEEPH short.te405. For reproducing results obtained with tempo, the user may also chose to use the Fairhead & Bretagnon (1990) version of this integral (stored at $TEMPO2/ephemeris/TDB.1950.2050) by specifying "TIMEEPH FB90" in the pulsar parameter file.

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4.4

Planetary ephemeris

In order to correct the arrival time to the solar system's barycentre, tempo2 requires a solar system ephemeris. By default the JPL ephemeris DE200 is chosen. Different JPL ephemerides may be selected using the EPHEM FILE command in the parameter file. For example,
EPHEM_FILE /pulsar/psr/runtime/tempo//tempo_ephem/DE405.1950.2050

would select the DE405 JPL ephemeris. If the full-path is defined from $TEMPO2/ephemeris then the DE405 ephemeris could be selected from
EPHEM DE405

4.5

Observatory definitions

It is necessary for tempo2 to know the coordinates of the observatory. In the original TEMPO a file, obsys.dat, was used that contained the coordinates of each observatory and a single-character identifying code. This code was used in the arrival time file. Unfortunately, different users used different codes for the same observatory and therefore the arrival time files were not transferable between different installations of TEMPO. To avoid this, tempo2 provides a read-only database of observatories, each identified by a short, non-cryptic mnemonic. This resides in $TEMPO/observatory/observatories.dat. In addition, for backwards compatability or for experimental use, further defintitions can be placed in extra files: tempo2 parses every file in $TEMPO/observatory/. Each line should contain 5­6 whitespace-separated parameters. These are, in order, the x, y and z geocentric coordinates (in metres), a one-word name for the observatory, a few-character mnemonic and optionally the name of the clock associated with the observatory (used to refer to the relevant clock-correction tables). If not supplied, the clock name is constructed as UTC(xxx) where xxx is the observatory mnemonic. For full accuracy, observatory coordinates should be specified in the International Terrestrial Reference System. Geodetic coordinates (as optionally used by tempo, given as latitude and longitude in degrees in the form dddmmss.ss, and height in metres) may be specified, in which case tempo2 will detect this and convert them to the ITRF on the assumption that they refer to the GRS80 geoid. The converted coordinates are displayed and execution is halted for the user to add the converted coordinates to the observatories database (or not! the accuracy of the conversion and the assumption of GRS80 may be dubious). NOTE: The mnemonics in observatories.dat have not been finalised. Please let G. Hobbs or R. Edwards know if you prefer another mnemonic for your observatory. The current observatory file is listed in Table 1.

5

Parameter files

The parameter files have the same design as in the earlier tempo implementations. Each of the pulsar parameters has a label, a value and may have an uncertainty on the value and a flag indicating whether tempo2 should fit for this parameter or whether this parameter should be held constant (0 = default = hold constant; 1 = fit). These labels are described in Table 2. An example of a parameter file for PSR J0437-4715 taken from the catalogue and fitting for various parameters:
PSRJ RAJ DECJ DM PEPOCH F0 F1 PMRA PMDEC BINARY PB ECC A1 T0 J0437-4715 04:37:15.7865145 -47:15:08.461584 2.6469 51194.000 173.6879489990983 -1.728314E-15 121.438 -71.438 DD 5.741046 1.9186E-5 3.36669157 51194.6239 1 1 7.000e-07 8.000e-06 1.000e-04 3.000e-13 1.600e-20 6.000e-03 7.000e-03 3.000e-06 5.000e-09 1.400e-07 8.000e-04

1 1

1 1 1 1

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x 882589.65 -4752329.7000 2390490.0 -228310.702 -4460892.6 -4554231.5 3822252.643 -1601192. 4324165.81 4033949.5 3822252.643 881856.58 882872.57 882315.33 383395.727 3817176.557 3828714.504 3859711.492 3923069.135 0.0 3822473.365 3822294.825 1719555.576

y -4924872.32 2790505.9340 -5564764.0 4631922.905 2682358.9 2816759.1 -153995.683 -5041981.4 165927.11 486989.4 -153995.683 -4925311.86 -4924552.73 -4925191.41 -173759.585 -162921.170 -169458.987 -201995.082 -146804.404 1.0 -153692.318 -153862.275 5327021.651

Table 1: Observatory details z Mnemonic 3943729.348 GBT -3200483.7470 NARRABRI 1994727.0 ARECIBO 4367064.059 NANSHAN -3674756.0 DSS 43 -3454036.3 PARKES 5086051.443 JODRELL 3554871.4 VLA 4670132.83 NANCAY 4900430.8 EFFELSBERG 5086051.443 JODRELLM4 3943459.70 GB300 3944154.92 GB140 3943414.05 GB853 5077751.313 MKIII 5089462.046 TABLEY 5080647.749 DARNHALL 5056134.285 KNOCKIN 5009320.570 DEFFORD 0.0 COE 5085851.303 JB MKII 5085987.071 JB 42ft 3051967.932 LA PALMA

Clock gbt atca ao nanshan tid43 pks jb vla ncy eff jbm4 gb300 gb140 gb853 j k l m n coe jbmk2 jb42 p

OM OMDOT START FINISH CLK EPHEM PBDOT TZRMJD TZRFRQ TZRSITE RM PX SINI M2

1.20 0.016 50640.928 52088.897 UTC(NIST) DE200 3.64E-12 51204.64376750220085 1413.400 7 +1.5 7.19 0.6788 0.236

1

5.000e-02 1.000e-02

2.000e-13

5.000e-01 1.400e-01 1.200e-03 1.700e-02

In more detail, for a pulsar which a spin period of P 0 = 1.23456 s, with no fitting required:
P0 1.23456

To fit to this parameter, use
P0 1.23456 1

or with an uncertainty (which is ignored by tempo2)
P0 1.23456 1 0.00003

Other commands may be given in parameter files that control the algorithms used by tempo2. Tempo2 only requires the following parameters: PSRJ, DM, F0, PEPOCH, RAJ and DECJ. If no period epoch is provided then the position epoch is assumed to be the same as the period epoch. It is also possible to provide the pulsar parameters in the old-style tempo format where the arrival times and the parameters are given in the same file. In this mode tempo2 is called only using one file, e.g.

11


Table 2: Pulsar parameters that can be entered in a parameter file
Label PSRJ, PSRB or PSR FX (e.g F0, F1, F2) P0 or P P1 or Pdot PEPO C H RAJ or RA DECJ or DEC ELONG or LAMBDA ELAT or BETA PO S EPO C H PMLAMBDA or PMELONG PMBETA or PMELAT PMRA PMDEC DMEPOCH DM DMX FDD PX PMRV GLEP X GLPH X GLF0 X GLF1 X GLF0D X GLTD X WAVE OM WAVEX T EM PO 1 U N IT S MODE JUMP CLK TRES NOTRACK NO SS SHAPIRO I PM N IT S DILATEFREQ IBOOT PLANET SHAPIRO CORRECT TROPOSPHERE NE1AU T I M EEPH T2CMETHOD CLK CORR CHAIN EPH EM TZRMJD TZRSITE NSPAN or TSPAN TZRFRQ START F IN IS H EPH V ER TRACK Description Pulsar name The X'th time derivative of the rotational frequency Spin period of pulsar Spin down rate of pulsar Epoch of period determination J2000 right ascension J2000 declination Ecliptic longitude Ecliptic latitude Epoch of position measurement. If not present a warning is given and PEPOCH is used instead Proper motion in ecliptic longitude Proper motion in ecliptic latitude proper motion in right ascension proper motion in declination Epoch of DM measurement Dispersion measure X'th time derivative of the dispersion measure Frequency-dependent delay Parallax Radial velocity Glitch epoch Glitch phase increment Glitch permanent pulse frequency increment Glitch permanent frequency deriv increment Glitch pulse frequency increment Glitch Decay time constant Frequency of fundamental sinusoid for whitening Amplitude of sine and cosine for the X'th harmonic for whitening Run in tempo emulation mode: e.g. TDB units Set units to SI or TDB Fitting with errors MODE 1, or without MODE 0 Add a constant offset between specified TOAs Definition of clock to use Rms timing residual Switch off tracking mode Switch off the calculation of the Solar system Shapiro delay = 0 to switch off calculation of the interplanetary medium Number of iterations for the fitting routines Whether or not to apply gravitational redshift and time dilation to observing frequency (Y/N) Number of iterations used in the bootstrap fitting method Whether or not to apply tropospheric delay corrections The electron density at 1 AU due to the solar wind Which time ephemeris to use (IF99/FB90) Method for transforming from terrestrial to celestial frame (IAU2000B/TEMPO) Clock correction chain(s) to use (Sect. 4.1) Which solar system ephemeris to use Units -- (s-(X -1) ) sec. (â10-15 ) MJD hh:mm:ss.sss dd:mm:ss.sss deg deg MJD mas/yr mas/yr mas/yr mas/yr MJD cm-3 pc cm-3 pcs mas MJD Hz s- 2 Hz Hz

-X

(µs)

12


Table 3: Binary parameters that can be entered in a parameter file
Label BINARY A1 PB ECC or E T0 OM TASC EPS 1 EPS 2 OMDOT PBDOT A1DOT or XDOT S IN I M2 XPBDOT A1DOT EDOT or ECCDOT OMDOT PBDOT PBX GAMMA DR DTH A0 B0 BP BPP DTHETA XOMDOT AFAC A1DOT or XDOT TASC EPS1DOT EPS2DOT KOM KI N S H A PM A X M T OT BPJEP X BPJPH X BPJA1 X BPJEC X BPJOM X BPJPB X Description Binary model (BT/ELL1/DD/MSS) Pro jected semi-ma jor axis of orbit Orbital period Eccentricity of orbit Epoch of periastron Longitude of periastron Epoch of ascending node ECCâ sin(OM) for ELL1 model ECCâ cos(OM) for ELL1 model Rate of advance of periastron 1st time derivative of binary period Rate of change of pro jected semi-ma jor axis Sine of inclination angle Companion mass (solar masses) Rate of change of orbital period minus GR prediction Rate of change of eccentricity Periastron advance 1st time derivative of binary period X'th time derivative of binary period post-Keplerian 'gamma' term Relativistic deformation of the orbit Relativistic deformation of the orbit Aberration parameter A0 Aberration parameter B0 Tensor multi-scalar parameter beta-prime Tensor multi-scalar parameter beta-prime-prime Relativistic deformation of the orbit Rate of periastron advance minus GR prediction Units lt-sec days -- MJD degrees MJD -- -- (deg/yr) (10-12 ) (10-12 )

degrees/yr

s

deg/yr

Epoch of ascending node

MJD

Total system mass

solar masses

tempo2 -gr plk myfile.tempo

where the first line in the file contains flags with '1' to indicate that the parameter should be fit and '0' for not fitting:
Column 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Parameter Phase P0 P1 P2 RAJ DECJ PMRA PMDEC A1 ECC T0 PB OM OMDOT GAMMA DM

13


17 18 19 20 21 22 23 24 25 27

PX PBDOT M1 (not implemented) SINI MTOT M2 DTHETA BP (not implemented) BPP (not implemented) Binary model: 0 = none, 1 = BT, 2 = EH, 3 = DD, 4 = DDGR, 5 = H88, 6 = BT+, 7 = DDT, 8 = DD+, 9 = 2 BT orbits

The actual parameter values are given on three extra lines. The second line in the file gives
Columns 1-12 21-40 41-60 61-70 71-80 Parameter Pulsar name RAJ in the form hhmmss.ss DECJ in the form ddmmss.ss PMRA PMDEC

The third line gives
Columns 2-20 21-40 41-60 61-70 71-80 Parameter P0 P1 PEPOCH as Julian date P2 PX

The fourth line gives
Columns 9-20 Parameter DM

Further lines provide the binary parameters (not implemented yet). 5.0.1 tp o file format

Both the parameters and the arrival times may be provided in a single file. The first line of this file must be
HEAD

followed by the parameters in the same format as above. These are followed by
TOAS

and a list of arrival times. 5.0.2 Changing the mo del ep o ch

It is possible to convert the period epoch from that given in the parameter file using the -epoch command on the command line. For instance -epoch 52000 will update the period epoch, rotational frequency and its first derivative to the new epoch using the inputted values of F0, F1 and F2. Can use -epoch centre (or -epoch center) to set to the centre of the data span. -epoch left will set the epoch to the first observation.

14


5.1

Jumps
the an the all

It is often necessary to fit for a constant offset between two sets of arrival times. For instance, templates used to determine arrival times at different frequencies may not be perfectly aligned or offset may exist between the arrival times provided by different observatories. The command JUMP in parameter file is used to define jumps. JUMP MJD v1 v2 will provide a jump between all TOAs with MJDs between v1 and v2 compared to the other TOAs. JUMP FREQ v1 v2 will section all TOAs with observing frequencies between v1 and v2 MHz. JUMP TEL id will section all TOAs observed with telescope `id'. JUMP NAME str will section all TOAs with observation IDs that contain the string `str'. JUMP flag val will select all TOAs with specified flag (e.g. -o) and value val.

5.2

Removing Timing Noise

Even with accurate spin and positional parameters the residuals for some (particularly the young) pulsars contain remnant structures. Some of these structures are understood: cusps, for instance, signify sudden changes in the pulsar's spin rate during a glitch, sinusoidal oscillations can represent unmodelled companions (such as planets) or the pulsar precessing. However, many of the structures seen in the residuals are still not understood and are known as "timing noise". To obtain the most accurate pulsar's positional and proper motion parameters (and dispersion measure) it is essential to remove this timing noise. This has traditionally been carried out by fitting higher order pulsar rotational derivative terms. More recently, Hobbs et al. (2004) described a method for fitting harmonically related sinusoids.

5.3

Default values

6

Observation files
file must be created that contains all the site-arrival-times2 (i.e. the pulse for each observation3 ). These files can take the form of the old Parkes­ may use a new formatting structure. identified with

For each pulsar an arrival time arrival time at the observatory or Jodrell­style tempo files or The current tempo2 format is
FORMAT 1

at the start of the observation file. Each observation line can be entered in a "free-format" manner (there is no limit on the number of decimal places or characters supplied for each parameter). The file has the following form:
file freq sat satErr siteID

where the flags are listed in Table 4. It is important for the TOAs to be given to high precision. tempo2 reads all parameters with `long double' precision. Other undefined flags may be used in the arrival time files. These flags can provide any information and could be used, for example, in determining colours used for plotting with a personal graphical interface. An example observation file is given below.
FORMAT 1 C ../archives/w040205_062810.cFTp 3072.52800000 53040. ../archives/w040206_070831.cFTp 3092.99900000 53041.3 C ../archives/w040206_084839.cFTp 3068.03800000 53041. ../archives/w040206_111139.cFTp 3105.49900000 53041.4 ../archives/w040207_070619.cFTp 3092.99900000 53042.3 ../archives/w040207_081328.cFTp 1367.99900000 53042.3 ../archives/w040207_084227.cFTp 1415.14600000 53042.3 ../archives/w040207_115804.cFTp 1431.21700000 53042.5 ../archives/w040207_142934.cFTp 1431.43500000 53042.6 ../archives/w040208_081840.cFTp 1563.91900000 53043.3 ../archives/w040208_083501.cFTp 1432.49900000 53043.3 ../archives/n2004-06-27-04:13:58.FTp 685.24900000 531
2 3

27037033597299853 10.07000 7 -i WBC_10 1851839551620031 1.16000 7 -i WBC_10 38807867413299846 9.97000 7 -i WBC_10 7201962440929890 1.15000 7 -i WBC_10 0720476755460169 1.21000 7 -i WBC_10 5109949197099866 1.09000 7 -i WBC_20 6843163794929978 0.98000 7 -i WBC_20 0986685147659827 0.98000 7 -i WBC_20 0951958276880092 0.99000 7 -i WBC_20 4710640092290035 0.82000 7 -i WBC_20 6886551809849877 0.78000 7 -i WBC_20 83.18848980008860039 0.06000 7 -i nCPSR2_50

site-arrival-times can be obtained from pulse profiles and a standard template using software packages such as pat. note: the "pulse" arrival time is measured by the summation of many thousands of individual pulses from the pulsar.

15


Flag dm p t

Parameter DM (cm-3 pc) Phase offset Telescope identifier

Table 4: Flags in arrival time files Type float float string

../archives/n2004-07-15-18:33:23.FTp 685.24900000 53201.79496983790510001 0.08000 7 -i nCPSR2_50 ../archives/n2004-07-15-19:39:47.FTp 685.24900000 53201.81959222764389850 0.22000 7 -i nCPSR2_50 ../archives/n2004-07-15-19:42:31.FTp 685.24800000 53201.84208218378509869 0.19000 7 -i nCPSR2_50

The pat software in the psrchive package has been updated to output arrival time files using this (or earlier) formats. A list of available commands that can be included in an arrival time file are provided in table 5. Note that, when writing out a new arrival time file from tempo2 (using a plugin such as plk, for example - see Section 13.10), most of these commands will not be replicated, but are instead directly executed. (EFLOOR, EMIN, EMAX and EQUAD for example will be absorbed in the TOA uncertainties.) The exception to this is EFAC, which is written to the tim-file without affecting the uncertainties. (GLOBAL EFAC, T2EFAC and EFAC are combined into a single EFAC value, though.) The old Parkes­style structure contains a label indicating the observation (such as a file name containing the folded profile), the observing frequency (MHz), the site­arrival­time (MJD), a phase offset (µs), the uncertainty on the TOA (µs) and an identification flag for the telescope used. These identification flags are defined by the user and differ between users. For example,
f981016_092219.FT 0 0 1374.000 51102.3925603118473 0.00 138.00 7

tempo2 can read arrival times in the "Parkes", "Princeton" and "ITOA" formats. All these formats are "fixed-format" and are defined as:
Princeton Format columns 1-1 2-2 16-24 25-44 45-53 69-78 item Observatory code (1-character) Must be blank Observing frequency (MHz) TOA (decimal point must be in column 30 or 31) TOA uncertainty DM correction (NOT IMPLEMENTED IN TEMPO2)

Parkes Format columns 1-1 26-34 35-55 56-63 64-71 80-80 item Must be blank Observing frequency (MHz) TOA (decimal point must be in column 42) Phase offset (fraction of P0, added to TOA) TOA uncertainty Observatory (1-character)

ITOA Format columns 1-2 10-28 29-34 35-45 46-55 58-59 item ignored, but must not be blank TOA (decimal point must be in column 15) TOA uncertainty Observing frequency (MHz) DM correction (NOT IMPLEMENTED IN TEMPO2) Observatory (2-characters)

16


Table 5: Commands that may be included in an arrival time file Command Meaning EFAC x Multiply uncertainties by x T2EFAC -backend dfb x Multiply TOA uncertainties with flag "-backend dfb" by x GLOBAL EFAC x Multiply all TOA uncertainties by x. If for some or all of the TOAs an "EFAC y" is present as well, then those TOAs will be multiplied by x â y . EMAX x Ignore TOAs with uncertainties greater than x µs EMIN x Ignore TOAs with uncertainties less than x µs EFLOOR x Put uncertainties of less than x µs to x µs END Ignore all remaining lines in the arrival time file EQUAD x Additional uncertainty in us, added in quadrature FMAX x Ignore TOAs at frequencies greater than x F MIN x Ignore TOAs at frequencies less than x INCLUDE x Include the arrival times in file x INFO x Identify all following points with a given highlighting code MODE MODE 0 (default) implies that the TOA error is not taken into account during the fitting procedure. MODE 1 uses the uncertainties (see section on fitting) NOSKIP End of SKIP statement PHASE x Add phase jump SIGMA x Set uncertainties of following TOAs to x µs SKIP Skip all lines until NOSKIP is read TIME x Add x seconds to following TOAs TRACK x Tracks phase wrap-arounds if time step is less than x days

6.1

Setting disp ersion measures

In some situations the dispersion measure is measured accurately for every observation. This information can be provided to tempo2 by adding -dm DMval on the end of each arrival time line in the .tim file. If this is not present then the dispersion measure in the .par file is used instead.

6.2

Jo drell Bank Observatory binary format

It is also possible to provide pulse arrival times in the Jodrell Bank format binary file that containing barycentric arrival times. For instance a typical usage would be:
tempo2 -f psrav.eph psrav.bat -jbo -delete psrav.del

7

Atmospheric propagation delays

(to be written)

8

Command-line arguments
· -debug, provides output useful for identifying problems with the software · -delete fname, delete the observations listed in the file fname by their site-arrival times or observations name. · -clock x, define the clock in conversion to TT as X · -epoch x, set the epoch of the parameter file to be MJD x

tempo2 has a number of options that can be controlled from the command line. Options include:

17


· -f x.par y.tim specifies the parameter (.par) and arrival time (.tim) files to use for subsequent processing. If only a .tim file is present (without -f option) then the parameter file will be assumed to be y.par. · -filter x, filters the set of observations (see below). · -fit x, turn on fitting for parameter 'x' (this command-line option can be repeated for multiple parameters) · -gr x, use the 'x' graphical interface · -h, displays help information · -jbo, expect input in the Jodrell Bank psrav.bat format · -list lists information about the residuals, time delays etc. that have been used by tempo2. · -machine x define the processor being used · -model . . . · -name x define the pulsar name to be 'x' - ignoring what is in the parameter file. · -newpar produces a new .par file from the fitted parameters · -nobs re-defines the maximum number of observations to be stored simultaneously in memory. · -nofit switch off the fitting algorithms · -noWarnings switch off displaying warnings. · -npsr re-defines the maximum number of pulsars to be stored simultaneously in memory. · -output name uses the 'name' plugin instead of displaying the standard tempo2 output. · -polyco runs tempo2 in predictive mode. · -pre only calculates the pre-fit residuals · -residuals outputs the residuals to a file called "residuals.dat". · -set X a, set the parameter X to the value `a' (ignoring the value in the parameter file) · -tempo1 enables tempo1 compatibility mode

8.1

The temp o1 emulation mo de

In the tempo1 compatibility mode the following parameters are automatically set (these can also be set manually in the parameter file): · UNITS TDB · TIMEEPH FB90 TIMEEPH · DILATEFREQ N · PLANET SHAPIRO N · T2CMETHOD TEMPO · CORRECT TROPOSHPHERE N · NE SW 9.961 · ECLIPTIC OBLIQUITY 84381.412

8.2

Filtering

If is often useful to be able to filter the observation file before processing. For instance, an observer may use multiple back-end systems or observatories. These can be defined using "flags":
../archives/n2003-01-10-17:07:45.FTp 1340.749 52649.7 ../archives/w040206_150608.cFTp 3067.999 53041.640421 ../archives/w040206_160503.cFTp 3067.999 53041.681394 ../archives/w040207_133403.cFTp 1421.439 53042.566781 ../archives/w040207_134155.cFTp 1417.998 53042.581972 257990374280 7220093 34.43 0348552 42.73 9871316 6.92 6383262 4.59 0.67 7 -i 7 -i 7 -i 7 -i 7 -i nCPSR2_20 WBC_10 WBC_10 WBC_20 WBC_20

If all the WBC 10 and nCPSR2 20 observations should be ignored then use
tempo2 -f mypar.par mytim.tim -filter "-i nCPSR2_20 -i WBC_10"

18


8.3

Aliases

Occasionally the user must repeatedly run the same tempo2 command which contains multiple arguments. This can be simplified using aliases. Aliases are placed in a file called $TEMPO2/alias.dat as follows:
-jodrell -f psrav.eph psrav.bat -jbo -del psrav.del -quick -newpar -gr plk

The user can then type
tempo2 -jodrell -gr plk

instead of
tempo2 -f psrav.eph psrav.bat -jbo -del psrav.del -gr plk

9

The b o otstrap fitting algorithm

Bootstrapping fitting methods can produce more realistic parameter values and uncertainties when significant correlations between parameters are present. The bootstrapping method implemented in tempo2 estimates the uncertainty on a parameter by 1) randomly selecting observations to produce a new dataset of the same length as the original (the observations are selected with replacement; ie. in the new dataset some of the original observations will be omitted while others will be replicated), 2) recalculating the parameter and 3) repeating as many times as possible.

10

Predictive mo de

For on-line and off-line folding of pulsar data tempo2 can produce a set of polynomial coefficients to predict the pulse phase at any given time. After a standard tempo2 fit has been carried out, the parameters will include the following · tzrmjd: a reference TOA calculated as the first site-arrival-time with an MJD greater than PEPOCH. The residual after fitting is subsequently removed from tzrmjd to produce a site-arrival-time that produces zero residual, · tzrfrq: The frequency of the arrival time corresponding to tzrmjd, · tzrsite: The telescope site code corresponding to tzrmjd. Tempo2 can be used to produce predictions in a new format or in a new format.

10.1

Temp o2 format

(To be written)

10.2

Temp o1 format

Example usage:
tempo2 -f 0437-4715.par -polyco "53000 53001 300 12 8 pks 1400.0" -tempo1

will request that tempo2 makes a prediction for J0437-4715 from MJDs 53000 to 53001 with each divided into segments each of nspan = 300 minutes. The number of coefficients for use in the fitting, ncoeff = 12. The maximum hour angle range for the prediction, maxha = 8. The observatory site for the prediction is site code = pks at an observing frequency of freq = 1400.0. Therefore, the format used in definining the prediction is
-polyco "mjd1 mjd2 nspan ncoeff maxha site_code freq"

19


(note the use of the quote marks around the parameters). Tempo2 should produce a file (polyco new.dat) that takes the form of tempo1. For instance,
0437-4715 27-Dec-03 123000.00 53000.52083333330 2.646966 0.269 -7.575 27109839749.228820 173.687948999098 atca 960 12 600.000 0.5593 0.1742 -5.42287549188530393e-08 1.29656588048219029e-01 -8.73567925939434345e-05 -3.77430102018454689e-08 3.61675384452316159e-11 -5.30580886494090104e-16 -2.11398949708346726e-17 7.50678735870179551e-22 7.17204723641224429e-24 -2.20834139169245321e-28 -1.38834331804078410e-30 6.03780300115982370e-35

Tempo2 also produces a file (newpolyco.dat) which has the same parameters, but listed to more decimal places. Each parameter is listed on an individual line. note: the temp o1 software switches off clo ck corrections in predictive mo de. To emulate this the CLK flag in the parameter file should b e set to CLK UNCORR.

11

Global parameters

(To be written)

12

Output formats

The default output format provides the pre- and post-fit rms residuals, the number of points in the fit and, if a weighted fit has been carried out, the reduced 2 -value of the fit. For each parameter, the values of the pre- and post-fit parameters are listed alongside the uncertainty in the post-fit value and the difference between the pre- and post-fit values. A flag indicates whether the parameter was included in the fit. For binary systems, the default output format also provides details on the binary model and lists, if possible, the mass function, minimum, median and maximum companion masses, the total system mass and the inclination angle. An example is given below,
Results for PSR J0437-4715

RMS pre-fit residual = 6.895 (us), RMS post-fit residual = 0.096 (us) Number of points in fit = 367

PARAMETER Pre-fit Post-fit Uncertainty --------------------------------------------------------------------------------RAJ (rad) 1.2097885336826 1.20978853474746 2.1206e-11 RAJ (hms) 04:37:15.7865 04:37:15.7865146 2.916e-07 DECJ (rad) -0.824709094076948 -0.824709094473468 1.5157e-11 DECJ (dms) -47:15:08.4615 -47:15:08.46158 3.1264e-06 F0 (s^-1) 173.68794630603 173.687946306032 9.5579e-15 F1 (s^-2) -1.728e-15 -1.72831367406148e-15 2.3325e-22 PEPOCH (MJD) 51194.0001248168 51194.0001248168 0 POSEPOCH (MJD) 51194.0001248168 51194.0001248168 0 DMEPOCH (MJD) 51194 51194 0 DM (cm^-3 pc) 2.64690012312213 2.64690012312213 0 PMRA (mas/yr) 121.43799811708 121.43799811708 0 PMDEC (mas/yr) -71.4379988923397 -71.4379988923397 0 PX (mas) 7.19 7.19 0 SINI 0.6788 0.6788 0 PB (d) 5.741046089 5.74104608900813 1.0437e-11 T0 (MJD) 51194.6240248265 51194.6240248265 0 A1 (lt-s) 3.36669162220122 3.36669162220122 0 OM (deg) 1.2 1.2 0 ECC 1.9186e-05 1.9186e-05 0 PBDOT (10^-12) 3.64 3.64 0 OMDOT (deg/yr) 0.0159999997519168 0.0159999997519168 0 M2 0.236 0.236 0 START (MJD) 50640.9281162413 49350.5129309451 0 FINISH (MJD) 52088.8971386924 53000.5197060478 0 TRACK (MJD) 0 0 0 TZRMJD 51204.6438924841 51204.6438924841 0

Difference Fit -----------------1.0649e-09 Y 1.4643e-05 -3.9652e-10 Y -8.1788e-05 2.3306e-12 Y -3.1367e-19 Y 0 N 0 N 0 N 0 N 0 N 0 N 0 N 0 N 8.1286e-12 Y 0 N 0 N 0 N 0 N 0 N 0 N 0 N -1290.4 N 911.62 N 0 N 0 N

20


TZRFRQ (MHz) 1413.39997808495 1413.39997808495 0 0 N --------------------------------------------------------------------------------------------------Binary model: DD Mass function = 0.001243113190 +- 0.000000047151 solar masses Minimum companion mass = 0.1403 solar masses Median companion mass = 0.1637 solar masses Maximum companion mass = 0.3493 solar masses MTOT derived from sin i and m2 = 1.818606841374 Inclination angle (deg) = 42.74994182955 (+ 0 - 0)

Other output formats have been developed and can be used as plug-ins, e.g.
tempo2 -output NAME -f ...

where NAME is the name of the output format. The plug-ins provided with tempo2 are listed below.

12.1

general

The general output format allows the user to detemine, in a general manner, the presentation of the fitted parameters. For instance,
tempo2 -output general -s "\{NORAD\}{ALL\_f}{TAB 20}\& {ALL\_p} {TAB 50}\\\\\\n" -f psr.par psr.tim

A will produce output in a L TEXformat:

RAJ (rad) DECJ (rad) F0 (s^-1) F1 (s^-2) PEPOCH (MJD) POSEPOCH (MJD) DMEPOCH (MJD) DM (cm^-3 pc) PB (d) A1 (lt-s) TASC (MJD) EPS1 EPS2 START (MJD) FINISH (MJD) TRACK (MJD) TZRMJD TZRFRQ (MHz)

& & & & & & & & & & & & & & & & & &

18:02:05.33496(12) -21:24:03.72(6) 79.066424253435(18) -4.574E-16(13) 52855 52855 52855 149.666066 0.69888924320(20) 3.718853847 52595.795078543 1.0412e-06 2.3924e-06 52605.162 53565.334 0 52883.440856822 1390

\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\

Options are also available to increase the uncertainties by a given factor. To change the parameters listed, to change the string displayed if a parameter has not been set and to change the number of decimal places output.

12.2

general2

This output format is similar to the general output described above. However, this output provides access to values calculated for each observation:
{sat} site-arrival-times {bat} barycentric arrival times {clock0 -> clock4} various clock {shapiro} the solar Shapiro delay {shapiroJ} the Shapiro delay due {shapiroS} the Shapiro delay due {shapiroV} the Shapiro delay due {shapiroU} the Shapiro delay due {shapiroN} the Shapiro delay due {tropo} the tropospheric delay {roemer} the solar system Roemer {tt} correction to TT

correction values to to to to to Juptier Saturn Venus Uranus Neptune

delay

21


{tt2tb} correction from TT to TB {earth_ssb} magnitude of vector from Earth to barycentre {earth_ssb1} magnitude of 'x' component from Earth to barycentre {earth_ssb2} magnitude of 'y' component from Earth to barycentre {earth_ssb3} magnitude of 'z' component from Earth to barycentre {sun_earth1} magnitude of 'x' component from Sun to Earth {sun_earth2} magnitude of 'y' component from Sun to Earth {sun_earth3} magnitude of 'z' component from Sun to Earth {ism} interstellar medium dispersion delay {elev} Source elevation {npulse} pulse number {clock} complete clock corrections to TT {ipm} interplanetary medium dispersion delay {freq} observing frequency {pre} prefit timing residual in seconds {pre_phase} prefit timing residual in phase {post} postfit timing residual in seconds {post_phase} postfit timing residual in phase {err} TOA error {binphase} binary phase

For example, to display the barycentric arrival times, the Shapiro delay due to Jupiter and the post-fit residual, use
tempo2 -output general2 -f par.par tim.tim -s "{bat} {shapiroJ} {post}\n"

12.3

list

The list output lists the basic parameters that are being used in the tempo2 calculations. For example: tempo2 -output list -f msp1.par msp1.tim will list 1. the site arrival times 2. pre- and post-fit residuals 3. clock correction to UTC 4. barycentric arrival time 5. other clock corrections 6. the solar system Shapiro delay 7. the dispersion measure time delays due to the interstellar and planetary medium 8. the Roemer delay 9. ephemeris values for the position of the Sun with respect to the solar system barycentre 10. ephemeris values for the earth-moon barycentre with respect to the solar system barycentre 11. ephemeris values for the moon with respect to the Earth 12. the position of the observatory with respect to the centre of the Earth 13. a 3-vector pointing at the pulsar from the observatory

12.4

stats

Provides information on the residuals and observations such as the median TOA uncertainty for different observing frequencies. For example: tempo2 -output stats -f gh.par gh.tim will give
Number of TOAs in fit = 227 Residual = 0.000985 (us) Earliest arrival time at MJD 53041.318518 Most recent arrival time at MJD 53248.801042 Span = 207.5 days Observing frequencies = 1429.29 3099.00

22


Figure 2: An example of the `basic' graphical interface. A P - P diagram is produced with the pulsar being analysed highlighted.
-----------------------------------------------------------------Freq. N Minimum Maximum Mean (MHz) Uncertainty (us) Uncertainty (us) Uncertainty (us) -----------------------------------------------------------------All 226 0.17 2.70 1.23 1429.29 95 0.97 2.70 2.54 3099.00 131 0.17 1.27 0.29 -----------------------------------------------------------------------------------------------Median RMS Uncertainty (us) (us) ------------------------------0.30 9.8452e-12 2.57 0.28 -------------------------------

13
13.1

Graphical interfaces
basic

Plots a P­P diagram and calculates the pulsar's characteristic age (see Figure 2 for an example: tempo2 -gr basic -f myp The plugin also provides information such as the pulsar's spin period, its derivative and the characteristic age = P /(2P ). It is possible to display only pulsars within a certain declination range and to list all the pulsars currently being displayed. This allows the user to obtain a list of pulsars that have similar rotational characteristics to the pulsar currently being analysed by tempo2.

13.2

calcDM

(To be written)

13.3

chisq

This graphical interface is used to create analyse the 2 value of the fit or the post-fit rms residual for a one- or two-dimensional grid of parameter values. The interface repeatedly carries out the fitting routines for specific values of one or two parameters and displays the results as a graph, contour or gray-scale plot.

23


Figure 3: Example of the chisq plug-in for determining the most likely values of the orbital period, PB, and longitude of periastron, OM. This plugin is based on the "parmap" program developed by Swinburne University.

13.4

compare

Graphical interface used to compare the residuals obtained using two different parameter (.par) files. For instance, different solar system ephemeris could be defined in the parameter files and the results compared using this interface.

13.5

compareRes

(To be written)

13.6

delays

This interface allows the user to inspect the clock corrections and propagation time delays that tempo2 has applied in order to obtain barycentric arrival times. See Figure 4 (tempo2 -gr delays -f mypar.par mytim.tim). The following key strokes are possible
q y-1 ('y' followed by '1') y-2 ('y' followed by '2') y-3 y-4 y-5 y-6 y-7 y-8 y-9 y-0 y-a y-b y-c quit plot plot plot plot plot plot plot plot plot plot plot plot plot first clock correction second clock correction third clock correction fourth clock correction fifth clock correction UT1 Shapiro delay due to Sun dispersion delay in solar system dispersion delay in ISM Roemer delay pre-fit residuals post-fit residuals Shapiro delay due to Jupiter

24


Figure 4: The solar system Shapiro delay for PSR J1810-2005 shown using the delays graphical interface plug-in
y-d plot Shapiro delay due to Saturn y-e plot Shapiro delay due to Uranus y-f plot Shapiro delay due to Neptune y-g plot total planetary Shapiro delay y-h plot tropospheric propagation delay 1 plot TOA number on x-axis 2 plot MJD day on x-axis 3 plot observing frequency on x-axis 4 plot day-of-year on x-axis 5 plot binary phase on x-axis 6 plot year on x-axis x redo fit h display this help g change the graphics terminal right mouse button delete TOA left mouse button identify TOA c clear highlights s start zoom region f finish zoom region t simulate new arrival times u unzoom

13.7

errors

(To be written)

13.8

fake

It is often necessary to simulate timing residuals that would be expected to be measured for a particular pulsar. Tempo2 contains a plug-in package to do this. fake automatically generates a set of TOAs between dates specified by the user. The arrival times are defined to be at transit and so only the pulsar's right ascension is used in this calculation. The pre-fit timing residuals are then formed using a parameter file (containing the simulated pulsar's position, spin parameters, binary parameters etc.) and

25


subtracted from the original simulated arrival times. This procedure is iterated until the residuals are zero. These arrival times can subsequently be modified by 1) the addition of Gaussian noise and 2) the addition of simulated timing noise. Upon running the fake plugin, the user is asked to provide · The number of days between observations · The number of observations on a given day · The maximum absolute hour angle allowed · Whether the user required random or regular hour angle coverage · The initial MJD for the simulated TOAs · The final MJD for the simulated TOAs · The rms of Gaussian noise to be added to the TOAs · Whether red noise should be added to simulate timing noise If the red noise option is selected, the user is also requested to provide · The power law index for the red noise · The power law amplitude · A random number seed · Whether the residuals should be smoothed · Whether a cubic should be added to the residuals The red noise is simulated as a shot-noise process obtained by summing many sinusoids with random phase, but with amplitudes given by the requested power-law spectrum. The following example simulates a pulsar with a large proper motion: 1. Produce a parameter file similar to (called testfake.par)
PSRJ RAJ DECJ POSEPOCH PMRA PEPOCH F0 F1 DM CLK UTC(NIST) EPHEM DE200 J1730-2304 17:30:21.6483 -23:04:31.4 51500.0 200 51500.0 123.110289179797 -3.0631E-16 9.611

2. Run tempo2 -gr fake testfake.par 3. Follow on screen instructions 4. The fake plug-in will produce an arrival time file called testfake.simulate 5. In the parameter file change the PMRA back to zero 6. Run tempo2 -gr plk -f testfake.par testfake.simulate The result should be similar to that shown in Figure 5. note: this code was based on the fake software original ly developed by Duncan Lorimer and updated by Simon Johnston

13.9

gorilla

(To be written)

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Figure 5: Simulating pulsar timing residuals for a pulsar with a proper motion in right ascension of 200 mas/yr using the fake plugin.

13.10

plk

plk provides the user with a graphical interface that plots pre-fit and post-fit timing residuals versus parameters such as day, TOA number, binary phase or observing frequency. It is based on the plk standalone package written for the original TEMPO, but has been significantly enhanced. The profiles corresponding to TOAs may be viewed and the TOAs deleted or identified using mouse clicks. Phase jumps can easily be added and the data refit in order to improve the timing model. A simple menu system allows the user to change the fitted parameters and to produce new arrival time and parameter files. This graphical interface only works in single-pulsar mode. An example of the output is shown in Figure 6 (usage: tempo2 -gr plk -f mypar.par mytim.tim). Options available are:
b Bin TOAs within certain time bin c Change fitting parameters C run unix command with filenames for highlighted observations ctrl-c Toggle between period epoch and centre for the reference epoch d (or right mouse) delete point D (or middle mouse) view profile ctrl-D delete highlighted points e multiply all TOA errors by given amount f finish of zoom section F run FITWAVES ctrl-F remove FITWAVES curve from residuals g change graphics device G change gridding on graphics device h this help file H highlight points with specific flag in .tim file i (or left mouse) identify point j draw line between each points l list all data points in zoomed region L add label to plot ctrl-l add line to plot m measure distance between two points M toggle removing mean from the residuals

27


Figure 6: An example of the plk graphical interface in use. The post-fit residuals for PSR J0437-4715 are plotted with 20 observations shown in green and 10 cm observations in red. The white circles and black lines indicate arrival times between orbital phases 0.4 and 0.6.
ctrl-m o p P ctrl-P q r s S ctrl-S u U v V ctrl-V w x ctrl-X y z + ctrl-= < > 1 2 3 4 5 6 7 8 9 a toggle menu bar obtain/highlight all points currently in plot Change model parameter values write new .par file Toggle fitting versus pulse phase quit Reset (reload .par and .tim file) start of zoom section save a new .tim file Overplot Shapiro delay unzoom unhighlight selected points view profiles for highlighted points define the user parameter for pre-fit plotting, decompose the timing model fits toggle fitting using weights redo fit using post-fit parameters place periodic marks on the x-scale Rescale y-axis only Zoom using mouse add positive phase jump add negative phase jump add period to add residuals above cursor in zoom mode include previous observation in zoom mode include next observation plot pre-fit residuals vs date plot post-fit residuals vs date plot pre-fit residuals vs orbital phase plot post-fit residuals vs orbital phase plot pre-fit residuals serially plot post-fit residuals serially plot pre-fit residuals vs day of year plot post-fit residuals vs day of year plot pre-fit residuals vs frequency plot post-fit residuals vs frequency

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Figure 7: Example of the splk graphical interface plug-in for showing the pre- and post-fit timing residuals for multiple pulsar simultaneously.
! @ # $ % ^ plot plot plot plot plot plot pre-fit post-fit pre-fit post-fit pre-fit post-fit residuals residuals residuals residuals residuals residuals vs vs vs vs vs vs TOA TOA user user year year error error values values

13.11

p olytest

(To be written)

13.12

splk

A simple graphical interface that displays pre-fit and post-fit timing residuals for multiple pulsars (Figure 7). Key-strokes enable the user to plot all the pulsars using the same x and y axes (or to scale each axis separately) and the timing residuals can be output in an ASCII format to a file. tempo2 -gr splk -f mypar1.par mytim1.tim -f mypar2.par mytim2.tim -f mypar3.par mytim3.tim

13.13

stridefit

The stridefit plugin is used to fit for a pulsar parameter (commonly DM) using small sections of data and plotting the variation in that parameter versus time. Example usage is: tempo2 -gr stridefit -f psr.par psr.tim The plugin will subsequently ask for the parameter for study (e.g. DM, PMRA, PMDEC . . . ). The stridefit works by running a window with a width entered, from a start time to an end time with a given time step. These can all be entered on the command line: tempo2 -gr stridefit -f psr.par psr.tim -param DM -start 50000 -end 52000 -width 300 -dt 100

29


Figure 8: Example of the stridefit graphical interface plug-in which calculates the pulsar's dispersion measure as a function fo time. The stridefit plugin will produce a graph of the parameter versus time. Clicking on any point will list the points that were used in deriving the parameter. If there is reason to believe that any particular point is in error (for instance trying to obtain a DM value with only one observing frequency) then the point can be deleted using the right mouse button. An example stridefit output is shown in Figure 8. After plotting the following key strokes may be used h provides help 1 zero x-value for first point 2 centre points 3 toggle plotting day/year u rescale the axes q quit f fit a straight line to a region selected by the mouse F fit and remove a straight line r redo the stridefit e re-enter the MJD of the end point s re-enter the MJD of the start point S change the font-size for plotting n enter the minimum number of observations required for a point g set the graphical device w re-enter the width of the fit region t re-enter the time step A (or left mouse) identify closest point X (or right mouse) delete closest point z zoom using the mouse l list all the values L list all the values and ouput to file

13.14

transform

Transforms a tempo1 parameter file into a tempo2-compatable file.
tempo2 -gr transform tempo1.par tempo2.par [back]

30


where the back command is used to convert from tempo2 to tempo1.

14

Developing the software

The plug-in features of tempo2 implies that users can add to the functionality of tempo2 by producing their own plug-in. In this section, we first discuss how such plug-ins can be produced. We also provide a few notes for users who are interested in developing the actual main source code and become part of the tempo2 development team.

14.1

Creating a plug-in

Plug-ins are relatively easy to create in C or C++. These plug-ins may use other libraries such as pgplot, tcl/tk or qt. As described above, plug-ins can be created to change the output format or as a graphical interface. 14.1.1 A new output format

When an "output-format" plug-in is used, the tempo2 software reads in the specified parameter and observation files, carries out the standard techniques to obtain pre- and post-fit timing residuals and their corresponding parameter values and then passes control to the output-format software to display the results. An example output format (in C) is as follows:
#include #include #include #include #include "tempo2.h"

/* Essential for a tempo2 plugin */

extern "C" int tempoOutput(pulsar *psr,int npsr,char timFile[][MAX_FILELEN],char parFile[][MAX_FILELEN]) { int i; printf("Pulsar name = %s\n",psr[0].name); printf("Pulsar spin-frequency = %Lg\n",psr[0].param[param_f].val[0]); for (i=0;i
This plug-in displays the pulsar's name (obtained from the parameter file), its post-fit spin-frequency and the post-fit timing residuals on the screen. The software is built around a structure called pulsar which is defined in tempo2.h. The most important definitions in this structure are
char *name; char *binaryModel; double ne_sw; int fitMode; int nobs; int nits; int ipm; /* /* /* /* /* /* /* The pulsar name */ The binary model (e.g. T2/BT/ELL1 ...) */ The electron density at 1AU due to the solar wind */ = 1 if fitting with errors, 0 = not fitting with errors */ Number of observations */ Number of iterations used for the fit */ = 1 if the interplanetary DM correction is used, 0 otherwise */

An array of pulsars is defined and therefore, in order to display the name of the first three pulsars analysed:
printf("pulsar 1 = %s\n",psr[0].name); printf("pulsar 2 = %s\n",psr[1].name); printf("pulsar 3 = %s\n",psr[2].name);

The structure also includes an array of parameters (param) which are defined as
param_raj,param_decj,param_f,param_pepoch,param_pos param_dmepoch,param_dm,param_pmra,param_pmdec,param param_sini,param_pb,param_t0,param_a1,param_om,para param_ecc,param_edot,param_xpbdot,param_pbdot,param epoch, _px, m_pmrv, _a1dot,

31


param_omdot,param_tasc,param_eps1,param_eps2,param_ param_mtot,param_glep,param_glph,param_glf0,param_g param_glf0d,param_gltd,param_start,param_finish,par param_tzrmjd,param_tzrfrq,param_fdd,param_dr,param_ param_bpjep,param_bpjph,param_bpja1,param_bpjec,par param_wave_om,param_kom,param_kin,param_shapmax,par param_b0,param_xomdot,param_afac,param_eps1dot,para

m2,par lf1, am_tra dtheta am_bpj am_dth m_eps2

am_gamma, ck ,p om ,p do ,p ar ,p ar t, ar am ar am pa am _t am _a ra _b sp _b 0, m_ p,param_bpp, an, pjpb, tres

For each parameter, the user can obtain
char **label; char **shortlabel; longdouble *val; longdouble *err; int *fitFlag; int *paramSet; longdouble *prefit; longdouble *prefitErr; int aSize; /* /* /* /* /* /* /* /* /* Label about this parameter Label about this parameter without units Value of parameter Uncertainty on parameter value = 1 if fitting required = 1 if parameter has been set Pre-fit value of the parameter Pre-fit value of the uncertainty Number of elements in the array for this parameter */ */ */ */ */ */ */ */ */

Each parameter is stored as an array with each element of the array typically storing time derivatives of the parameter. For instance, to obtain the value of the spin-frequency and its first two derivatives:
printf("values = %Lg %Lg %Lg\n",psr[0].param[param_f].val[0], psr[0].param[param_f].val[1],psr[0].param[param_f].val[2]);

(Note: 'C' requires the symbol '%Lg' or '%Lf' to display values in 'long double' precision. The `pulsar' structure also contains the set of observations and corresponding parameters. The observation structure contains (other less-common parameters are defined in the tempo2.h file)
longdouble sat; longdouble bat; int deleted; longdouble prefitResidual; longdouble residual; double freq; double freqSSB; double toaErr; char fname[MAX_FILELEN]; char telID[100]; longdouble correctionTT_TB; double einsteinRate; longdouble correctionTT_Teph; longdouble correctionUT1; double shapiroDelaySun; double shapiroDelayJupiter; double shapiroDelaySaturn; double shapiroDelayUranus; double shapiroDelayNeptune; double troposphericDelay; double tdis1; double tdis2; longdouble roemer; /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* /* Site arrival time Barycentric arrival time = 1 if observation has been deleted Pre-fit residual residual Frequency of observation (in MHz) Frequency of observation in barycentric frame (in Hz) Error on TOA (in us) Name of data file giving TOA Telescope ID Correction to TDB/TCB Derivative of correctionTT_TB Correction to Teph Correction from site TOA to UT1 Shapiro Delay due to the Sun Shapiro Delay due to Jupiter Shapiro Delay due to Saturn Shapiro Delay due to Uranus Shapiro Delay due to Neptune Delay due to neutral refraction in atmosphere Interstellar dispersion measure delay Dispersion measure delay due to solar system Roemer delay */ */ */ */ */ */ */ */ */ */ */ */ */ */ */ */ */ */ */ */ */ */ */

For instance, in order to display the site arrival-time, the barycentric arrival-time, and the Solar Shapiro delay for each observation:
for (i=0;i
14.1.2

A new graphical interface

When a graphical interface is used, tempo2 checks the command-line arguments, initialises the memory and then passes control to the graphical interface. The reading of the parameter and observation files, calculating barycentric arrival times, obtaining residuals, fitting and displaying the output must all be done within the graphical interface. The following tempo2 functions are commonly called: 32


readParfile(...) readTimfile(...) preProcess(...) formBatsAll(...) formResiduals(...) doFit(...) textOutput(...)

/* Read the parameter file /* Read the observation file /* Needs to be called after reading the parameter and observation files /* Forms the barycentric arrival times /* Forms the timing residuals /* Calls the fitting algorithms /* The standard output display

*/ */ */ */ */ */ */

An example of a simple interface would be
#include #include #include #include #include "tempo2.h"

using namespace std; /* The main function called from the TEMPO2 package is 'graphicalInterface' */ /* Therefore this function is required in all plugins */ extern "C" int graphicalInterface(int argc,char *argv[],pulsar *psr,int *npsr) { char parFile[MAX_PSR][MAX_FILELEN]; char timFile[MAX_PSR][MAX_FILELEN]; int i; double globalParameter; *npsr = 1; /* For a graphical interface that only shows results for one pulsar */

printf("Graphical Interface: name\n"); printf("Author: author\n"); printf("Version: version number\n"); /* Obtain the .par and the .tim file from the command line */ if (argc==4) /* Only provided .tim name */ { strcpy(timFile[0],argv[3]); strcpy(parFile[0],argv[3]); parFile[0][strlen(parFile[0])-3] = '\0'; strcat(parFile[0],"par"); } /* Obtain all parameters from the command line */ for (i=2;i
for (i=0;i<2;i++) /* Do two iterations for pre- and post-fit residuals*/ { formBatsAll(psr,*npsr); /* Form the barycentric arrival times */ formResiduals(psr,*npsr,0.0); /* Form the residuals */ if (i==0) doFit(psr,*npsr,&globalParameter,0,0); /* Do the fitting */ else textOutput(psr,*npsr,globalParameter,0,0,0,""); /* Display the output */ } /* Now you have the parameters and residuals */ /* which can be displayed or plotted */

return 0;

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}

14.2

The main source co de

The tempo2 software can be obtained from the ATNF CVS repository soft atnf/tempo2 (please contact members of the ATNF pulsar group for more information). To install type
> make install

The plug-ins provided with the source code are stored in soft atnf/tempo2/plugin and the documentation in soft atnf/tempo2/documentation.

15

Temp o2 error and warning messages

Errors result from serious problems with the pulsar analysis which may not be able to complete at all. Warnings indicate possible problems in the analysis. Generally, the analysis will keep going.

15.1

Error messages

File handling errors · ERROR [FILE1]: No .tim file given on command line · ERROR [FILE2]: No .par file given on command line · ERROR [FILE3]: Unable to open parfile X for pulsar Y · ERROR [FILE4]: Unable to open timefile X · ERROR [FILE5]: Unable to open file OBSERVATORY_CLOCK_2_UTC_NIST · ERROR [FILE6]: Unable to open the leap second file · ERROR [FILE7]: Unable to open OBSYS.DAT Parameter file errors · ERROR [PAR1]: Have not set a period epoch in X Clock errors · ERROR: Too many lines in ut1 file -- increase array size in tai2tdb · ERROR [CLK2] Must increase MAX_CLKCORR · ERROR [CLK3], must increase size of MAX_LEAPSEC · ERROR [CLK4]: Date X out of range of TDB-TDT table Ephemeris errors · ERROR [EPHEM1]: Ephemeris file X not loaded

15.2

Warning messages
Have not set a position epoch in X. The period epoch will be used

Parameter file warnings · WARNING [PAR2]: instead Clock warnings · Warning [CLK1]: will be applied MJD later than last entry in time.dat. Imprecise clock corrections

34


16

Common questions

Our web-page provides a feedback form that allows the user to alert the software developers of any problems in the software. 1. How do I cite temp o2 in my publication? For basic tempo2 usage, please give a reference to Hobbs, Edwards & Manchester (2006; submitted to MNRAS). For details of the timing model please refer to Edwards, Hobbs & Manchester (2006; in preparation). 2. How do I increase the numb er of observations that can b e loaded in temp o2? Use "-nobs X" on the command line where X is the number of observations required (the current default is 10000 observations).

17

In progress

Tempo2 is continually being developed. We are currently developing the following · A set of plug-ins to simulate the effects of gravitational wave sources on pulsar timing residuals and to place limits on the existence of any such gravitational wave sources in real pulsar timing data.

18

Acknowledgements

The tempo2 package is based on the original tempo Fortran code. This software was developed over many years by multiple authors including J. Taylor, R. Manchester, D. Nice, W. Peters, J. Weisberg, A. Irwin and N. Wex. We thank the Australian pulsar community, J. Weisberg, D. Lorimer and M. Kramer for suggestions and comments on tempo2.

35