Stefan Duchesne

Comparison of NVSS (left; Taylor et al., 2009) and POSSUM (right) Band 1 RMs within the Fornax cluster’s virial radius (grey dashed circle), showcasing POSSUM’s transformative capability to probe magnetised gas in clusters, groups, and many other ∼degree-scale extragalactic objects. The background is a Digitized Sky Survey optical image (greyscale). Solid circles indicate the position, magnitude, and sign of RMs measured by each survey, with diameters proportional to (RM)^2 and colours indicating RM sign (red for positive, blue for negative). While only a few clusters or groups contain >∼ 10 NVSS RMs at sub-virial radii, POSSUM’s RM grid will sample thousands of these systems, including over a dozen with 100 or more RMs.

Recently published in PASA: "The Polarisation Sky Survey of the Universe’s Magnetism (POSSUM): Science Goals and Survey Description", Gaensler, B.M. et al. This is Figure 1. To read the paper visit doi.org/10.1017/pasa...

19.06.2025 07:27 — 👍 6    🔁 3    💬 0    📌 0

The Evolutionary Map of the Universe: A new radio atlas for the southern hemisphere sky We present the Evolutionary Map of the Universe (EMU) survey conducted with the Australian Square Kilometre Array Pathfinder (ASKAP). EMU aims to deliver the touchstone radio atlas of the southern hem...

A day late posting but after a lot of hard work I give you the survey overview papers for the EMU & POSSUM ASKAP surveys #EMU survey arxiv.org/abs/2505.08271 and the #POSSUM survey arxiv.org/abs/2505.08272 🔭

15.05.2025 12:30 — 👍 23    🔁 6    💬 0    📌 2

Close-up view of white bougainvillea with some small flowers poking through the bracts.

Magenta bougainvillea with small white flowers. More bougainvillea leaves and flowers are out of focus in the background.

A close-up of a magenta bougainvillea, with its small white flowers hiding under a green leaf.

Some bougainvillea in the garden. After 13 years of use, I've finally replaced my trusty Canon 1000D - still using the same 60mm and 50mm lenses (for now), but the new camera is a very nice upgrade.

08.03.2025 15:54 — 👍 3    🔁 0    💬 0    📌 0

GitHub - eltos/gradient: Simple web based color gradient designer. Generates code to copy & paste into your project or download as file. Simple web based color gradient designer. Generates code to copy & paste into your project or download as file. - eltos/gradient

I like this tool for making (or modifying) colourmaps for use in e.g. matplotlib: github.com/eltos/gradient.

06.03.2025 07:50 — 👍 2    🔁 0    💬 0    📌 0

The Rapid ASKAP Continuum Survey (RACS) VI: The RACS-high 1655.5 MHz images and catalogue We have conducted a widefield, wideband, snapshot survey using the Australian SKA Pathfinder (ASKAP) referred to as the Rapid ASKAP Continuum Survey (RACS). RACS covers $\approx$ 90% of the sky, with ...

The latest data release for the Rapid ASKAP Continuum Survey (RACS), this time at 1655.5 MHz. Here's the paper describing the RACS-high images and catalogue. You can find links to the data products in the paper: arxiv.org/abs/2501.04978

10.01.2025 08:32 — 👍 17    🔁 2    💬 0    📌 3

Revisiting a flux recovery systematic error arising from common... The point-spread function (PSF) is a fundamental property of any astronomical instrument. In interferometers, differing array configurations combined with their $uv$ coverage, and various...

Technical but important paper for anyone doing work with interferometers arxiv.org/abs/2309.00533

04.09.2023 15:17 — 👍 7    🔁 2    💬 0    📌 1