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Katharine Kelley

Publications and source records attributed to Katharine Kelley.

2 recordsLinked to original sources
arXiv2017

Searching for Axion Dark Matter using Radio Telescopes

We investigate the use of next generation radio telescopes such as the Square Kilometre Array (SKA) to detect axion two-photon coupling in the astrophysical environment. The uncertainty surrounding astrophysical magnetic fields presents new challenges, but with a frequency range corresponding to axions of mass $1.7-57μ$eV and a spectral profile with a number of distinguishing features, SKA-mid offers a tantalising opportunity to constrain axion dark matter properties. To determine the sensitivity of SKA-mid to an axion signal, we consider observations of the Galactic centre and interstellar medium, and find that this new telescope could allow us to probe axion couplings $\gtrsim10^{-16}$GeV$^{-1}$.

astro-ph.CO↗
arXiv2017

A Radio Astronomy Search for Cold Dark Matter Axions

The search for axions has gained ground in recent years, with laboratory searches for cold dark matter (CDM) axions, relativistic solar axions and ultra-light axions the subject of extensive literature. In particular, the interest in axions as a CDM candidate has been motivated by its potential to account for all of the inferred value of $Ω_{DM} \sim 0.26$ in the standard $ΛCDM$ model. Indeed, the value of $Ω_{DM} \sim 0.26$ could be provided by a light axion. We investigate the possibility of complementing existing axion search experiments with radio telescope observations in an attempt to detect axion conversion in astrophysical magnetic fields. Searching for a CDM axion signal from a large-scale astrophysical environment provides new challenges, with the magnetic field structure playing a crucial role in both the rate of interaction and the properties of the observed photon. However, with a predicted frequency in the radio band (200MHz - 200GHz) and a distinguishable spectral profile, next generation radio telescopes may offer new opportunities for detection. The SKA-mid telescope has a planned frequency range of 0.4 - 13.8GHz with optimal sensitivity in the range $\sim$ 2 - 7 GHz. Considering observations at $\sim 500$MHz, the limiting sensitivity is expected to be $\sim 0.04$mK based on a 24 hour integration time. This compares with a predicted CDM axion all-sky signal temperature of $\sim 0.04$mK using SKA Phase 1 telescopes and up to $\sim 1.17$mK using a collecting area of (1km)$^2$ as planned for Phase 2.

astro-ph.CO↗