PSRCHIVE user documentation: psradd

1.0 Purpose

The psradd program combines multiple pulsar archives into one or more output files. It is the primary method of forming a mean pulse profile from many observations, it includes a number of criteria for automatically grouping observations into subsets, and it can perform arbitrarily complex preprocessing tasks using the psrsh command language.

psradd is generally run in two modes:

  1. Single output file: In this mode, all of the input files specified on the command line are combined into a single output file. e.g.
    psradd -f input*.ar
  2. Multiple output files: In this mode, the input files are grouped and integrated into one or more output files based on one or more criteria. These criteria currently include: the maximum time elapsed between archives, the maximum integration length, the minimum signal-to-noise ratio, and/or the maximum difference in the phase of the reference source. The output files will have the same name as the first input file included in the group, plus an additional extension (by default, .it). e.g. to form five-minute integrations from the input files, with the extension .5min,
    psradd -I 300 -e 5min input*.ar

2.0 Usage

psradd uses a polyco, generated by tempo, to align the phases of the sub-integrations of the output archives. The ephemeris used to generate the polyco may be specified using the -p ephemfile command line option. To generate ephemfile, run
psrcat -e Jname > Jname.eph
If psrcat cannot find a new pulsar, try the -all option to load any private catalogues with additional, unpublished data.

2.1 Preprocessing of input archives

Arbitrarily complex preprocessing tasks can be performed on each input archive before it is added to the output file, as described in the psrsh manual. For example, to weight each profile by its signal-to-noise ratio before adding to the total,
psradd -f -j 'w snr' input*.ar
(You can also make psradd produce a tscrunched output archive with the -s option.)

3.0 Algorithms

No information at this time.

4.0 Testing and examples

A simple example:

1. Generate ephem file J1643-1224.eph:

psrcat -e J1643-1224 > J1643-1224.eph

2. Run psradd to phase-align and concatenate the archives listed in 20cm.lis into file called 20cmadd.Ft, using ephemeris file J1643-1224.eph:

psradd -f 20cmadd.Ft -p J1643-1224.eph `cat20cm.lis`

3. Display phase aligned, concatenated archives simultaneously to check for phase alignment:

pav -R or -Y 20cmadd.Ft

5.0 Known bugs and features that require implementation

  • None at this time.