Joe McCauley

The LOw Frequency ARray (LOFAR) is an interferometeric array that operates at 10-240 MHz, with a central hub in the Netherlands and 13 international stations across Europe [1]. LOFAR's Transient Buffer Boards (TBBs) allow upwards of 5 s of data to be recorded at a temporal resolution of ~5.12 ns. Here, we described the development of a data acquisition system to capture TBB observations of solar variability from the Irish LOFAR station (I-LOFAR) at Birr Castle in the Irish Midlands. The system consists of a head node controlling 4 processing nodes offering 64 GB of RAM, as well as an initial 48 TB RAID6 storage node. We present first-light TBB time series data, along with all-sky observations data from a subset of I-LOFAR's Low Band Antennas (LBAs). We also discuss the development of a software based beamformer for TBB data with plans to observe the sun with dynamic spectra using nanosecond time resolution. This could give a new insight into rapidly varying phenomena in the ...

The discovery of the ubiquity of habitable extrasolar planets, combined with revolutionary advances in instrumentation and observational capabilities, have ushered in a renaissance in the millenia-old quest to answer our most profound question about the Universe and our place within it - Are we alone? The Breakthrough Listen Initiative, announced in July 2015 as a 10-year 100M USD program, is the most comprehensive effort in history to quantify the distribution of advanced, technologically capable life in the universe. In this white paper, we outline the status of the on-going observing campaign with our primary observing facilities, as well as planned activities with these instruments over the next few years. We also list collaborative facilities which will conduct searches for technosignatures in either primary observing mode, or commensally. We highlight some of the novel analysis techniques we are bringing to bear on multi-petabyte data sets, including machine learning tools we ...

Poster at European Space Weather Week, November 2018. <br>The Sun is an active star that can launch large eruptions of magnetised plasma into the heliosphere, called coronal mass ejections. These ejections can drive shocks that accelerate particles to high energies, often resulting in radio emission at low frequencies (<200 MHz). To date, the relationship between the expansion of coronal mass ejections, shocks and particle acceleration is not well understood, partially due to difficulties associated with radio imaging at low frequencies. Here, we report unique radio, whitelight and ultraviolet imaging of the second largest flare in the current solar cycle and associated very fast coronal mass ejection (~3000km/s). For the first time, we identify the location of a multitude of radio shock signatures, called herringbones, and find evidence for shock accelerated electron beams at multiple locations along an expanding coronal mass ejection, supporting theories of non-uniform, r...

Geomagnetically induced currents (GICs) are a well-known terrestrial space weather hazard. They occur in power transmission networks and are known to have adverse effects in both high-latitude and midlatitude countries. Here we study GICs in the Irish power transmission network (geomagnetic latitude 54.7–58.5∘N) during five geomagnetic storms (6–7 March 2016, 20–21 December 2015, 17–18 March 2015, 29–31 October 2003, and 13–14 March 1989). We simulate electric fields using a plane wave method together with two ground resistivity models, one of which is derived from magnetotelluric measurements (magnetotelluric (MT) model). We then calculate GICs in the 220, 275, and 400 kV transmission network. During the largest of the storm periods studied, the peak electric field was calculated to be as large as 3.8 V km−1, with associated GICs of up to 23 A using our MT model. Using our homogenous resistivity model, those peak values were 1.46 V km−1 and 25.8 A. We find that three 400 and 275 kV...

Modern radio interferometers such as the LOw Frequency ARray (LOFAR) are capable of producing data at hundreds of gigabits to terabits per second. This high data rate makes the analysis of radio data cumbersome and computationally expensive. While high performance computing facilities exist for large national and international facilities, that may not be the case for instruments operated by a single institution or a small consortium. Data rates for next generation radio telescopes are set to eclipse those currently in operation, hence local processing of data will become all the more important. Here, we introduce the REAL-time Transient Acquisition backend (REALTA), a computing backend at the Irish LOFAR station (I-LOFAR) which facilitates the recording of data in near real-time and post-processing. We also present first searches and scientific results of a number of radio phenomena observed by I-LOFAR and REALTA, including pulsars, fast radio bursts, rotating radio transients, the ...

Due to their ease of fabrication and monodisperse, metallic nature, molybdenum-sulfur-iodine nanowires are an interesting alternative to carbon nanotubes for some applications. However very little is known about the solubility of these materials. In this work we have investigated the solubility of Mo(6)S(4.5)I(4.5) nanowire soot in a range of common solvents by performing sedimentation studies and microscopic and spectroscopic characterization. A sedimentation equation was derived showing that the concentration of any insoluble dispersed phase decreases exponentially with time. We find that in all solvents, Mo(6)S(4.5)I(4.5) nanowire soot contains three phases, two of which are insoluble with one stable phase. Microscopy and spectroscopy show that the first insoluble phase is associated mainly with spherical impurities and sediments rapidly out of solution resulting in purification. The second phase appears to consist of insoluble nanowire bundles and sediments more slowly, eventually leaving a stable dispersion of nanowire bundles. The stably dispersed bundles tend to be smaller than their insoluble counterparts. The best solvents studied were 2-propanol and dimethylformamide. Microscopy studies showed that, in the case of 2-propanol, sonication significantly reduced the bundle size relative to the unsonicated bulk. However, during sedimentation, large quantities of bundles were observed to reaggregate to form larger bundles which subsequently sedimented out of solution. In general, the sedimentation properties of the various phases did not vary significantly with concentration indicating that the insoluble nanowires are intrinsically insoluble. However, the diameter of the stably dispersed bundles decreased with concentration, until very small bundles consisting of only two or three nanowires were observed at concentrations below 0.003 mg/mL. In addition, stable composite dispersions were produced by mixing the nanowires with poly(vinylpyrrolidone) in 2-propanol opening the way for the formation of polymer/inorganic nanowire composites.

In the Celtic Tiger years, Ireland underwent an explosive growth in housing and an increase in light pollution, nationally. We outline work undertaken towards the first ever ground-based survey of light pollution in the island of Ireland and illustrate this with some representative data taken between 2009 and the present. The aim of our work is to establish a database to serve as a reference to monitor future changes, to compare with in-orbit measurements, to study the potential impact on the environment and to permit the calculation of the effects of future changes in lighting usage and patterns. We also report the development of a microcontroller-based data-logging instrument based on a Unihedron Sky Quality Meter-LR detector, which can be used by amateurs or can serve as a stand-alone instrument for night-sky brightness surveys.

The Low Frequency Array (LOFAR) is an international radio telescope array, consisting of 38 stations in the Netherlands and 14 international stations spread over Europe. Here we present an observation method to study the jovian decametric radio emissions from several LOFAR stations (here DE604, FR606 and IE613), at high temporal and spectral resolution. This method is based on prediction tools, such as radio emission simulations and probability maps, and data processing. We report an observation of Io-induced decametric emission from June 2021, and a first case study of the substructures that compose the macroscopic emissions (calledmillisecond bursts). The study of these bursts make it possible to determine the electron populations at the origin of these emissions. We then present several possible future avenues for study based on these observations. The methodology and study perspectives described in this paper can be applied to new observations of jovian radio emissions induced b...

Electrospinning is an old[1] but effective method to continuously produce low diameter polymer fibers from polymer solutions or melts.[2] By the continuous spinning of fibers onto a stationary electrode, it is possible to build a network of fibers into a relatively thick membrane. Such ...