ATNF Astronomical Synthesis Imaging Workshop

Workshop Projects

As part of the synthesis workshop, participants will have a chance to have hands-on experience by taking part in practical sessions on the Wednesday and Thursday afternoons. These sessions are both two hours long. Participants can choose to take part in the one project which spans the two sessions.

Below are the descriptions of the projects. Because of fixed resources, the number of participants in each project is limited. Additionally, particpants in each project may be further divided into smaller groups (e.g. for sessions requiring access to computers). You will need to sign up for a project of your choice. Please think through which project you wish to do and sign up early (to avoid disappointment if the project's quota gets filled). Particularly with the data processing projects, you might think about forming a group with your colleague or collaborators.

Mapping the sky at 20 MHz with the Radio Jove receiver

Steven Tingay, David Brodrick

We have built a simple 20 MHz receiver and antenna to demonstrate concepts introduced in the lectures. The simplicity of this instrument allows a straightforward demonstration of an antenna system, frequency conversion, digital sampling, and autocorrelation. We will use this receiver to collect data during the workshop and students will have an opportunity to analyse the data, identifying sources such as the Galaxy, solar bursts, and perhaps bursts from Jupiter. Students will also see the effects of interference.

As an added bonus, we plan to make available a second receiver and antenna, with which to form a 100 m baseline interferometer. This instrument will demonstrate the above plus a distributed local oscillator and cross-correlation. Students should be able to analyse the data and measure the fringes from this interferometer, to extract information on the structure of some astronomical sources. This simple interferometer should demonstrate most things that the ATCA does, but stripped of all the complicated electronics and cryogenics.

This project will be limited to 6 people.

Centimetre observing and data analysis

David McConnell, Robin Wark, Mark Wieringa

This project is intended for those comparatively new to radio interferometery. The Wednesday will be spent using the array to observe. Observing schedules will be created and a variety of sources observed. The on-line tools will be used to get some understanding of the source structure. The Thursday will be spent doing some more detailed analysis of these data. This may include loading the data into reduction packages and performing a number of steps in the reduction process.

This project will be limited to 12 people that may be split into three groups according to experience level.

Using the ATCA antenna as a remote sensing thermometer

Ravi Subrahmanyan, Daron Brooke

This project aims to use the ATCA to measure temperatures and relate this to correlated signals seen from the interferometer.

On the Wednesday, a single antenna equipped with a receiver at 12 mm will be used to measure the temperature of the human body from the mircrowaves it emits. Then the antenna could be used to make a remote sensing measurement of the surface temperature of the Moon. And then on to the surface of Mars. In practice, the 12 mm receiver would be calibrated using a 300K and 77 K black body radiators. This is to establish the temperature scale of the measurement meter. Then the antenna would be used to point at the Moon and Mars to get their surface temperatures.

On the Thursday, the aim is to first measure the radio powers received on two antennas from a source. Then we would let the signals from the two antennas go into the correlator and measure the correlation coefficient. We would look at a source using the 12 mm receivers on two antennas. We would measure the strength of the signals received at the two antennas. Then we would look at the correlation between the two signals. This would be done for a point-like maser, Mars, and the Moon.

This project will be limited to 8 people that may be split into two groups.

Astronomical software and data analysis - aips++ and Miriad

Neil Killeen, David Rayner, Malte Marquarding, Vince McIntyre, Bob Sault

This is intended for people with moderate familiarity with interferometry. This project is composed of two rather different sub-themes, using aips++ and Miriad. Participants will choose one or the other.

The Miriad side of the project will be geared towards practical processing and analysis of ATCA data. Participants will be given a choice from a variety of datasets (e.g. continuum, spectral line, problems involving self-calibration etc), and work through these data. Participants may optionally bring their own data, and work on this with the help of one of the "tutors". CDrom is the best way to bring your data (exabytes are slow and time is limited). Alternatively, those with accounts at Narrabri may be able to ftp their data across beforehand.

For aips++, students will be offered the opportunity to use the aips++ tool kit to create a tool of their own. The tool will use elements from Glish (scripting language), GUI interfaces, event handling, image analysis and visualization. More information is available here.

This project will be limited to 16 people. People will have to form groups of two or three to work at a computer.

Miriad data analysis and single dish techniques

Bob Sault, David Rayner

This project involves both a Miriad data analysis component and a single-dish techniques component. On the Wednesday, as in the above project, the participants will work through some data analysis exercises using Miriad. Again, participants can optionally bring their own data, and work on this with the help of the "tutors".

On the Thursday, two antennas will be used to do some simple single dish experiments. Working at 3cm wavelengths, we will measure the temperature of the human body and the moon. The measurement meter will be calibrated from observations of the sky and an ambient piece of absorber. The contribution from stray radiation from the ground entering the system, and the angular speed ("proper motion") of the Moon can also be measured. A sheet describing this part of the project in more detail is available.

This project will be limited to 8 people that may be split into two to four groups on the Wednesday and two groups on the Thursday.