Parkes Pulsar Data Users Guide
Version 1.0: 1 April 2016
- 1.1 About this Guide
- 1.2 Parkes pulsar data
- 1.3 CSIRO's Data Access Portal
- 1.4 Pulsar data and VO Services
- 1.5 The ATNF Pulsar Catalogue
- 1.6 Getting help
- 2.1 Introducing PSRFITS format
- 2.2 Fold-mode observations
- 2.3 Search-mode observations
- 2.4 Calibration files
- 3.1 Login to the DAP using OPAL or NEXUS account
- 3.2 Locate data collections for a specified project ID
- 3.3 Find a persistent link to a specific data collection
- 3.4 Search for data products using the DAP domain search form
- 3.5 Carry out a cone search using the DAP domain search form
- 3.6 Downloading selected data
- 4.1 Install TOPCAT (version 4.3)
- 4.2 Find and download catalogues using the VO Table Access Protocol (TAP)
- 4.3 Run simple queries in Astronomical Data Query Language (ADQL)
- 4.4 Explore TOPCAT Features
- 4.5 Create sky plots
This Guide is intended to help pulsar astronomers find and access Parkes pulsar data from data archives, and query and visualise pulsar parameters.
Three main types of Pulsar data are accessible: fold-mode, search-mode and calibration data.
CSIRO's Data Access Portal (DAP) is the first port of call for searching and retrieving Parkes pulsar data.
The DAP allows querying and download of data by any user, however some data are subject to an embargo period. In this case, members of a science team can login with their OPAL account to access their data during the embargo period.
The DAP supports three types of user authentication as follows:
- OPAL authentication: Using the OPAL proposal applications user account system.
To register with OPAL, go to the OPAL Home Page and click on the link to 'Register'. Enter your email address, name, affiliation and a password. The OPAL application will register you straight away and will then open a screen for you to login.
OPAL user accounts are self managed. Please keep your account details up to date. To change user-registration details, or to request a new OPAL password, use the links to 'Update your details' and 'Change your password'. If you have forgotten your password you may request that a new one be sent my email.
- CSIRO Nexus authentication: Available to individuals who have accounts on the CSIRO NEXUS accounts.
- Australian Access Federation (AAF) authentication: Available to individuals who have accounts through the Australian Access Federation (AAF).
The ATNF Pulsar Catalogue contains parameters of over 2500 known pulsars. These parameters can be queried and visualised.
- Documentation is available online for help with: DAP
- For staff support, please send an email to firstname.lastname@example.org. You will received an automated email to acknowledge that your request has been logged. A CASS staff member will reply soon afterwards. We aim to send an initial reply to user queries within four business hours.
ATNF Pulsar Catalogue
Pulsar data taken by the Parkes Radio Telescope as far back as the early 1990's is archived for long-term storage in the CSIRO's Data Access Portal (DAP), in CSIRO's data centre, Canberra, Australia. This archive of data represents a historic record of the sky as seen from Parkes at radio frequencies ranging from 400MHz to 24GHz.
Parkes Pulsar Data is stored in 'PSRFITS' format, a flexible and extensible standard FITS-based format developed at the ATNF specifically for pulsar data. The format supports mean pulse profile ('fold-mode') and streamed ('search-mode') multi-channel full-polarisation data. A PSRFITS format file consists of a primary header-data unit (HDU) followed by a series of binary extension HDUs, in which are stored specific information about an observation.
Three types of pulsar data products are available for download from the DAP - these are described below.
Fold-mode observations are recorded at the telescope for a particular known pulsar, where the data are stacked or 'folded' at the rotation period of the pulsar, to form a pulse profile averaged over the length of the observation.
Files of this type have the extension '.rf'. All fold-mode files are also processed by averaging over frequency channels, polarisation and time - files of this type have the extension '.FTp'.
Search-mode observations are essentially comprised of a multi-channel full-polarisation data stream for the length of the observation.
Files of this type have the extension '.sf'.
Before and after an observation, a signal from a linear noise diode is injected into the feed. This allows the associated pulsar observation to be polarimetrically calibrated.
Files of this type have the extension '.cf'.
A guide on accessing Parkes pulsar data from CSIRO's DAP is presented below along with some examples.
|3.1 Login to the DAP using OPAL or NEXUS account|
|3.2 Locate specific collections for a specified project ID|
|3.3 Find a persistent link to a specific data collection|
|3.4 Search for data using the DAP domain search form|
|3.5 Carry out a cone search using the DAP domain search form|
In this example, the user wishes to find data files in a defined radius from the centre of the globular cluster 47 Tuc.
Right Ascension: 00:24:05.35
Search window: 2 arcmin
|3.6 Downloading selected data|
|In this example, a user wishes to download specific files from the 47 Tuc listing above.
The notes given in this section provide an introduction to finding and working with VO tables, using TOPCAT. These are intended to be sufficient to get started but do not cover many of the available tools and features.
The information provided is based on using TOPCAT version 4.3.
|4.1 Install TOPCAT|
|4.2 Find and display a catalogue using the VO Table Access Protocol (TAP)|
In this example, you will find and display a pulsar data VO catalogue.
|4.3 Run simple queries in Astronomical Data Query Language (ADQL)|
|Below are two examples of using ADQL.
|4.4 Explore TOPCAT tools|
|4.5 Create sky plots|
In the main TOPCAT window, icons 9 - 12 (counted from the left-hand side) are plotting tools. This example creates a sky plot for a set of source positions.
This section covers finding and querying pulsar attributes in the ATNF Pulsar Catalogue.
|5.1 Basic queries|
|5.2 Advanced queries|
|5.3 Further documentation|