ATNF Pulsar Data Archive: Users Guide
This page is still under construction!
Introduction
The ATNF Pulsar Data Archive exists to allow astronomers access to
observations of pulsars made with the Parkes radio telescope in the
last two decades.
The data comes either from the Parkes Southern Pulsar Survey (the
"70cm Survey", Manchester et al. 1996, MN 279, 1235), or from
observations of known pulsars with one of the Parkes instruments (WBC,
DFB, CPSR2). We hope to make available data from the Multibeam Survey
at some point in the near future.
Using the archive
Overview
The Pulsar Data Archive provides a means for accessing observational
data. Queries are made according to position on the sky and can be
filtered by parameters such as data type and date.
To download data, selections are made from the query results. These
are stored in a "cart" from which they can be downloaded as a tar
file.
How to make queries
The data is queried primarily on positional information. The user
gives either a pulsar name or a RA/Dec position, plus a search
radius. The pulsar name takes precedence over the RA/Dec position
given, so to search by RA/Dec, make sure the pulsar name field is
empty.
Query options
The query can be refined according to a number of parameters:
- Time: A time range for the observations can be specified. The
default values for this are given by the extent of the archive
(ie. the default "from" date is the earliest observation, and the
default "to" date is the latest).
- Obs Mode: The query can be restricted to only survey data (just
the 70cm survey for the moment), or only timing data
(ie. observations of a particular pulsar). The default is both
types.
- Data Type: One of the different instruments (WBC, DFB, CPSR2,
FB_1BIT) can be selected. The default is all of them.
- Frequency range: Multiple frequency bands can be selected from
the list.
The list of options on the left hand side shows the possible
parameters that can be returned with your query. Note that not all
fields will have values for all observations.
The list can be ordered according to a limited range of these
parameters: distance (from the query position - the default), date of
observation, frequency, and filename.
Finally, it is possible to search for calibration observations that
were taken within a given time period of the science observations. To
do so, check the box under "DISPLAY OTHER DATA" and set the time limit
in which to search for Cals (the default is 30 minutes).
Navigating around the archive
The first page returned when you submit your query is the list of the
first (up to) 20 observations. Only 20 observations are displayed at a
time. You can move through the list by clicking on the page numbers
above or below the table.
Note that a limit of 1000 results is returned for the query -- if you
are getting more than this, perhaps you can afford to narrow your
search!
In the top right, you will find information on the number of files and
total size of the cart, as well as a navigation icon. When the Query
Results page is displayed, the icon shown is that of the cart.
Alternatively, when the list of cart items is displayed, the icon
shown is that of the results table.
Clicking on the icon takes you to the page depicted.
Viewing profiles of pulsars
For some types of data, it is possible to view a pre-scrunched pulse
profile. To do so, select the observations using the check boxes in
the table, and select "View selected profiles" from the drop-down
menu. This will display profile plots for all selected observations,
unless they are unable to be pre-scrunched (for instance, survey
observations).
To return to the results table, click the table icon at top right.
Downloading data
Since there can be a large number of query results, spread over many
pages, we have implemented the observation cart to act as a staging
post for downloading data. Desired data is first saved to the cart
using the drop-down menu, by selecting its check box. From the cart
page, the drop-down menu offers the option of downloading either just
the data or the data plus any cals that have been found. The data is
returned in a tar file that can be saved to a local disk.
Caveats
The archive is still in a developmental stage, albeit a fairly
complete one. The main area that needs some work is that many fields
for a lot of the data files are not filled in. This will be rectified
in the near future, but be aware that not all information will be
present. Also note that not all fields can be filled in for
each data file: e.g. survey data cannot have a period defined.
Acknowledgments