A Sample IHY 2007 Instrumentation Proposal J. Kasper, B. Thompson, N. Fox.

A Sample IHY 2007 Instrumentation Proposal

J. Kasper, B. Thompson, N. Fox

Overview

• New technology: cheap radio receivers and computers to conduct low-frequency radio observations

• Option (1) low-frequency monitoring of solar radio bursts with single dipoles

• Option (2) 8-16 element arrays for all sky monitoring

Low Frequency Antennae

This discussion borrows from figures developed by MIT,NRL, and ASTRON

for the LOFAR project

PVC pipe and copper wire

For a variety of reasons the designs for low-frequency radio antennae can be very

straightforward

Costing

Let’s get a feel for the costs first, then talk about potential scienceBase cost estimates on LOFAR “compact core”

Antenna + Receiver ~ $1,725 for 32 MHz bandwidth, full StokesComputer + Processing board ~ $2,000Infrastructure? Internet connection?

What Science?

Virgo A seen by VLA at 74 MHz

Ionospheric scintillation and RFI make interferometric imaging very difficult at these low frequencies So we could either produce power spectra of the total power incident on the receiver (dominated by the Sun)

Or we could build imaging arrays with low spatial resolution to act as all-sky monitors

1) Solar Spectra

• Build simple stations consisting of a single antenna, receiver, and computer ( ~ $4,000 )

• The Sun will be the dominant contribution to the daytime signal, so produce

• Produce high-resolution power spectra from 10-100 MHz at each station

• Distribute these receivers across the globe to gain 24-hour coverage of the Sun at low frequencies

• Observations are uploaded to a single data center

Existing President

10

203040 F

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The Bruny Island Radio Spectrometer (BIRS)1

W.C. Erickson

Operational since 1994, observing from 3-30 MHz

1http://fourier.phys.utas.edu.au/birs/descrip.html

1) Proposal

• Propose to the GLOBE program to produce these systems and make them available to classrooms

• The computer would calculate the power spectra and both upload them to the central data center and display the results in real time in the classroom

• Setup and operation is very straightforward• We gain continuous low frequency radio coverage of

the Sun• The students learn about electromagnetism and the

dynamic nature of the Sun

2) An Imaging Array

Combine 8-16 of the individual receivers to construct an imaging array with low spatial resolution that monitors 30ox30o patchAntennae + Receivers $16,000-$32,000Big single time cost is development of software

2) Proposal

• Work with UNBSS to coordinate funding for universities to assemble and operate these arrays

• Students learn about radio interferometers, solar and Jovian emission mechanisms

• Science: Track emission from Jupiter as well as the Sun. Discovery potential, e.g. prompt afterglow from GRBs (HETE,SWIFT)

• Would aim for he construction of several of these arrays