From KAREN wiki

Contents 1 Summary 2 Project details 3 Project collaborators 4 Publications 5 Contact

Summary

Lead: Dr Slava Kitaev, Auckland University of Technology

This project will support the establishment of Transient Radio Emission Array Detector to explore electromagnetic phenomena in our environment both on Earth and Space. Each sensor element in the array will produce tens of MB of raw data each second, generating several TBytes of data daily. The data will be preprocessed to detect pulse-like signals and then streamed over KAREN for further processing and storing. Sensor networks and sensor arrays are an important emerging field and a key concept of the SKA. This project will build skills in this area.

Project details

Transient radio sky or time-variable radio sources in space have been recognized as one of the key science drivers for the Square Kilometre Array (SKA) what will be reflected in its design and operations. This science area is marked as “Exploration of the Unknown” what includes the likely discovery of new classes of objects and phenomena. Transient Radio Emission or simply transients are characterized by irregular and short (down to nanoseconds) bursts of electromagnetic radiation. Examples of transients that are known range from 0.4 ns to minutes and longer in time scale with apparent brightness temperatures from thermal to 10^42K. However, yet we know very little about the overall constituency of the transient radio sky, what even includes the high-energy transient sky.

Currently used methods and techniques for detecting transients differ depending on the expected nature of the events, their origin, and the types of instruments used for detection. The detection can be severely complicated by the ever growing problem of man-made radio interferences (RFI) which may lead to many false detections. There could be several strategies to attack this problem, such as a) avoid areas which might be contaminated by the RFI (unfortunately such areas are rare nowadays) b)use interferometer technique c) have the ability to discriminate genuine transients from RFI in computing algorithms.

Figure 1 shows the time-luminosity phase space for radio transients. There are many areas there a few or none objects have been fond yet, including the areas where the large sensitivity is not required, but rather the right combination of field of view, sensitivity, time resolution to enable detection. Transient Radio Emission Array Detector (TREAD) is aiming exercizing the ideas to achive detection with a small but optimized array radio telescope.

Figure 1. Time-luminosity phase space for radio transients as a log-log plot of the product of peak flux Spk in Jy and the square of the distance D in kpc vs. the product of frequency ν in GHz and pulse width W in s (adopted from (Cordes, 07/2007 (Revised 04/2009))).

Figure 2 shows one of the concept designs when the antenna-sensors are in compact phased array configuration.

Figure 2. Computer model of TREAD tile station. The approximate dimensions of the station on the ground are 10.5x10.5 m

Figure 3 shows possible deployment of such stations.

Figure 3. Deployment of TREAD in New Zealand.

Figure 4 show an alternative sparse array configuration under investigation which provides imaging capabilities.

Figure 4. Imaging sparse array.

Figure 4 shows TREAD diamond antenna-sensor optimized for 100-200 MHz on a field test at Tekapo area on South Island of NZ.

Figure 5. Antenna-sensor on field test

Project collaborators

TREAD involves NZ-wide collaboration. The participants are:

• Dr Slava Kitaev, School of Engineering, AUT
• Dr Melanie Johnston-Hollitt, Victoria University of Wellington
• Nick Jones, BeSTGRID, University of Auckland
• Dr Tim Molteno, Electronics Research, Department of Physics, University of Otago
• Vladimir Mencl, BlueFern & BeSTGRID, University of Canterbury

KAREN CBF funding has provided Master scholarships.

Publications

Kitaev V., Perera A., Souldenkov G., Digital Receiver for Transient Radio Emission Array Detector Prototype (TREAD-P), 2009, ENZCon, Dunedin

Contact

Dr Slava Kitaev

Email: slava.kitaev at aut.ac.nz

Web: www.ska.ac.nz or crs.aut.ac.nz

Phone: +64-9-9219999x8158