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EVN Data Access

EVN Data Archive

All data correlated at the JIVE correlator are placed in the EVN archive. This archive contains the raw FITS format data, calibration tables, various diagnostic plots, calibrated visibility data, and pipelined images. The images will be preliminary; in many cases further editing, self-calibration, or other refinements may be required to bring out particular features of interest. 

JIVE will ask the Principal Investigator prior to correlation whether to treat each source in the schedule as “public” or “private”. Source-specific pipeline results (calibrated visibilities, images, other plots) for the specified “public sources” will also be available immediately after data distribution, but those for the specified “private sources” will remain protected over the proprietary period. The Principal Investigator is also given the option to avoid generating images of the private sources altogether.
Once the proprietary period expires, the calibrated visibilities, images, and other pipeline plots related to the private sources will become publicly available, as will the raw FITS-format data.

 

EVN Pipeline

The EVN pipeline uses the ParselTongue software to provide access to the AIPS tasks from a Python script.

The main pipeline script is evn.py. It uses three Python modules:

  • evn_aips_tasks.py: Shortcut functions for executing AIPS tasks with most parameters defaulted to sensible values for the EVN. Parameters which must be set are mentioned in the docstring at the beginning, e.g., try: >>> help(evn_aips_tasks.runlwpla)

  • evn_funcs.py: Other functions used by evn.py. Mostly provide simplified interaction with functions in evn_aips_tasks.py.

  • crfuncs.py: Generic functions used by evn.py. At the moment this is a limited number of file handling classes to allow better logging of what the pipeline is doing.

The pipeline is driven by an input file. An example can be found here: template.txt

A folder containing all of the above files can be found here: pypeline-4.7.tar.gz

 

Usage

The pipeline can be run using the following input file: $ ParselTongue EVN.py template.txt

A very brief guide to running the pipeline is available here. Any comments/questions on the pipeline should be directed to JIVE.

 

The pipeline results for all user experiments can be downloaded from the EVN Data Archive. You should first find your experiment, then click on the 'pipeline' link where you will be able to download:

(i) a series of plots produced by the pipeline which will be useful in assessing the antenna performance and data quality in each experiment.

(ii) a set of calibration tables (in FITS format) produced by the pipeline. These can be downloaded and applied to the data provided by the EVN correlator (see the EVN Data Reduction Guide for details).

(iii) A history file associated with the data processed by the pipeline and a summary of what the CL/SN tables contain (typically CL table 2 provides the apriori amplitude calibration and CL table 3 provides phase, phase-rate, delay and amp gain solutions from the calibrators). In addition, the original pipeline script is made available, together with final versions of the ancillary data (ANTAB, UVFLG files etc).