Breakthrough Listen is a 10-yr initiative to search for signatures of technologies created by extraterrestrial civilisations at radio and optical wavelengths. Here, we detail the digital data recording system deployed for Breakthrough Listen observations at the 64-m aperture CSIRO Parkes Telescope in New South Wales, Australia. The recording system currently implements two modes: a dual-polarisation, 1.125-GHz bandwidth mode for single-beam observations, and a 26-input, 308-MHz bandwidth mode for the 21-cm multibeam receiver. The system is also designed to support a 3-GHz single-beam mode for the forthcoming Parkes ultra-wideband feed. In this paper, we present details of the system architecture, provide an overview of hardware and software, and present initial performance results.

Knowledge of the spatial distribution of bed lubrication regimes, i.e. frozen vs wet conditions, is crucial for understanding ice-sheet flow. Radar sounding can probe differing reflectivities between wet and frozen beds, but is limited by uncertainty in attenuation within the ice of bed echoes. Here we present two methods to estimate attenuation: (1) wide-angle radar sounding, in which source and receiver locations are varied so as to vary propagation path length, and thus echo amplitude; and (2) profiling, inwhich similar variations are obtained by sounding through varying ice thicknesses (assuming constant bed reflectivity). Siple Dome, West Antarctica, provides unusually favorable circumstances for application of these methods: the bed beneath Siple Dome is flat and uniform in its radar reflectivity, while ice thickness varies by several hundred meters. Wide-angle data 4 km from the summit yield an estimate for characteristic attenuation length of 124 m (35 dB km–1 loss), whereas profiling yields an estimate of 168 m.The difference between estimates is modest compared to the range of attenuation lengths reported in the literature. It may nonetheless prove informative by bounding effects of two ice properties to which the methods respond differently: (1) wide-angle sounding sampled relatively warm (lossy) ice beneath the summit, whereas the profiling method sampled relatively cold ice beneath the flanks as well; and (2) strain-induced crystal orientation fabrics and resulting dielectric anisotropy in the ice would vary from summit to flank, and may influence wide-angle sounding more strongly than profiling.

Ice-thickness measurements are needed to calculate fluxes through fast-flowing outlet glaciers in Greenland, Alaska, Patagonia and Antarctica. However, relatively high attenuation of radio waves by dielectric absorption and volume scattering from englacial water hampers detection of the bed through warm deep ice. In the past we have had success measuring ice thickness of temperate glaciers using a ground-based monopulse radar system operating at low frequencies (2 MHz). Here we adapt the same system to operate from an airplane. Test flights over Bering Glacier, Alaska, USA, detected the bed through ice up to 1250m thick. Flights across the Seward–Malaspina Glacier system, Alaska, resolved the ice thickness of Malaspina Glacier, but strong hyperbolic-shaped returns obscured the bed echo through the Seward throat. It is likely that this clutter in the signal was caused by off-nadir returns from chaotic surface crevasses that are ubiquitous in the throat region.

Most of our understanding of BPF's is based on observations of the neutral and ionized gas in bright, high luminosity sources. Data on low luminosity (L ≲ 30 L⊙) objects has now become more available (e.g. Frerking and Langer, Astrophys. J. 256, 523, 1982) permitting a test of models at this end of the luminosity range. We have performed a series of multi-wavelength observations, emphasizing low luminosity objects.

Infrared coronal emission lines are providing a new window for observation and analysis of highly ionized gas in Galactic and extragalactic sources such as Seyfert nuclei and classical novae shells. These lines are expected to be primary coolants in colliding galaxies, galaxy cluster cooling flows, cometary-compact HII regions, and supernova remnants. In this poster, we summarize results discussed in detail by Greenhouse et al. 1993, ApJS, 88, 23. We discuss approximately 74 infrared (1 < λ μm < 280) transitions within the ground configurations 2s 22pk and 3s 23pk (k = 1 to 5) or the first excited configurations 2s2p and 3s3p of highly ionized (χ ≥ 100 eV) O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, and Ni. We present results from detailed balance calculations, critical densities for collisional de-excitation, intrinsic photon rates, branching ratios, and excitation temperatures for the transitions. The temperature and density parameter space for dominant cooling via infrared coronal lines is presented, and the relationship of infrared and optical coronal lines is discussed.

We present a snapshot of our ongoing investigation of molecular clouds in Clump 2 located in the Galactic Bar region at a projected distance of ~400pc from the Galactic Center. We show that the analysis of the Clump 2 molecular clouds is complicated because of many fore- and background clouds in the line of sight. Of all clouds, IGGC 22 is the most interesting one, showing very high dust column densities, significant high-J CO emission, and, potentially harbors star formations as eluded to by the detection of [OIII] emission.

Insulating silicon dioxide (SiO2) films can be produced by hydrolysis of metal alkoxide tetraethylorthosilicate (TEOS) in the presence of an acid catalyst in supercritical fluid CO2 (sc-CO2). In this study, SiO2 films are formed on different substrates using TEOS as a source of silicon, and acetic acid (HAc) as a catalyst. Water required for the hydrolysis reaction is from in situ generation of esterification and condensation reactions involving HAc and the alcohol produced. The acid catalyzed deposition reaction actually starts at room temperature but produces decent films in sc-CO2 at moderately high temperatures (e.g. 50 °C). Supercritical fluid CO2 is known to have near zero surface tension and provides an ideal medium for fabrication of SiO2 films. Formation of SiO2 films via hydrolysis reaction in sc-CO2 is more rapid compared to the traditional hydrolysis reaction at room temperature. In general, metal alkoxide hydrolysis reactions carried out in a closed sc-CO2 system is not affected by moisture in air compared with traditional open-air hydrolysis systems. Using sc-CO2 as a reaction medium can eliminate undesirable organic solvents utilized in traditional alkoxide hydrolysis reactions.

X-ray diffraction (XRD) and electron diffraction (ED) measurements demonstrated that the SiO2 films produced are amorphous. Energy dispersive spectroscopy (EDS), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and X-ray photoelectron (XPS) spectroscopy show elemental compositions of the films formed on the substrate surfaces to be SiO2. Film thickness formation by controlling the amount of the catalyst is discussed.

In this paper we describe a new observing system which is currently nearing completation at the Mount Wilson Observatory. This system has been designed to obtain daily measurements of solar photospheric and subphotospheric rotational velocities from the frequency splitting of non-radial solar p-mode oscillations of moderate to high degree (i.e. l > 150). The completed system will combine a 244 x 248 pixel CID camera with a high-speed floating point array processor, a 32-bit minicomputer, and a large-capacity disc storage system. We are integrating these components into the spectrograph of the 60-foot solar tower telescope at Mount Wilson in order to provide a facility which will be dedicated to the acquisition of oscillation data.

All the active regions observed on the Sun with the Mount-Wilson magnetograph between August 1959 and December 1962 have been given magnetic classifications in a system similar to the Mount-Wilson sunspot-classification scheme. The flare productivity of regions classified as unipolar, bipolar, and complex bipolar, as well as regions composed of multiple bipolar components has been studied. It has not been necessary to provide a classification corresponding to the γ class of sunspots. Although the relatively poor angular resolution employed in the magnetograms limits somewhat the accuracy of the data, it is clear that both complex bipolar regions and regions with multiple bipolar components produce more than three times the number of flares than the simple bipolar regions produce. The most flare-productive class of regions is the reversed polarity complex classification.

The statistical relation of the spot magnetic-field classification to the classification of the corresponding plage fields has been studied and found to be poor for these data.

The distribution of the magnetic regions in latitude shows that many of the regions with polarities reversed from the usual orientation are confined to the equatorial zone.

Gaia's Radial Velocity Spectrometer (RVS) has been operating in routine phase for over one year since initial commissioning. RVS continues to work well but the higher than expected levels of straylight reduce the limiting magnitude. The end-of-mission radial-velocity (RV) performance requirement for G2V stars was 15 km s−1 at V = 16.5 mag. Instead, 15 km s−1 precision is achieved at 15 < V < 16 mag, consistent with simulations that predict a loss of 1.4 mag. Simulations also suggest that changes to Gaia's onboard software could recover ~0.14 mag of this loss. Consequently Gaia's onboard software was upgraded in April 2015. The status of this new commissioning period is presented, as well as the latest scientific performance of the on-ground processing of RVS spectra. We illustrate the implications of the RVS limiting magnitude on Gaia's view of the Milky Way's halo in 6D using the Gaia Universe Model Snapshot (GUMS).