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 a transient radio event sensor network to explore electromagnetic phenomena in our environment both on Earth and Space. Each digital receiver on the network will produce up to 10MB of raw data each second, generating more than 8.6TB of data daily. The data will be continuously streamed over KAREN to a storage facility and processed daily on high performance computing resources at BlueFern and Auckland University of Technology. 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 (TRE) is characterised by irregular and very short (nanoseconds to seconds) bursts of electromagnetic radiation. Examples of TRE that are known range from 0.4 ns, such as giant pulses from the Crab pulsar, 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 TRE differ depending on the expected nature of the events, their origin, and the types of instruments used for detection. The detection of TRE events, especially the short duration ones (<1ms) in radio spectrum can be severely complicated by the ever growing problem of terrestrial radio interferences (RFI) which may even lead to false detections. An effective way to attack this problem is to use interferometers. Multi-antenna/station measurements have a possibility for cross-correlating signals which removes local unresolved RFI.

Figure 1 shows the 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. As one can see there are still 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 and ability to differentiate TRE from RFI. The first stage of the project Transient Radio Emission Array Detector Prototype (TREAD-P) is though to be positioned in the area indicated by yellow fading triangle on Fig 1.

Figure 1. Time-luminosity phase space for radio transients (adopted from (Cordes, 07/2007 (Revised 04/2009))).

It will consist of a few stations deployed in different locations of New Zealand sufficiently distant from each other to have most of RFI at each station uncorrelated with other stations. Each station will consist of a number of cross-polarised low frequency antennas forming a phased array with effective area approximately 100 sq.m in each polarization (see Figure 2).

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

Each station has a single wide beam providing a field of view 15-35° depending on the frequency. A dual-channel direct sampling wide band digital receiver radiometer DRS at each station is equipped with communication interface for real-time data steaming. TREAD-P will exploit already existing infrastructure of Kiwi Advanced Research and Education Network and BeSTGRID to provide real-time 24/7 data streaming and processing. Figure 3 shows planned deployment and operation of TREAD-P.

Figure 3. Deployment and operation of TREAD-P in New Zealand.

Project collaborators

TREAD-P involves NZ-wide collaboration. The participants are:

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

KAREN CBF funding has provided 3 Master scholarships at AUT, UoO and VUW.

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