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IQ Collaboratory III: The Empirical Dust Attenuation Framework — Taking Hydrodynamical Simulations with a Grain of Dust

We present the Empirical Dust Attenuation (EDA) framework — a flexible prescription for assigning realistic dust attenuation to simulated galaxies based on their physical properties. We use the EDA to forward model synthetic observations for three state-of-the-art large-scale cosmological hydrodynamical simulations: SIMBA, IllustrisTNG, and EAGLE. We then compare the optical and UV color-magnitude relations, (g−r)−Mr and (FUV−NUV)−Mr, of …

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Gravitational waves × HI intensity mapping: cosmological and astrophysical applications

Two of the most rapidly growing observables in cosmology and astrophysics are gravitational waves (GW) and the neutral hydrogen (HI) distribution. In this work, we investigate the cross-correlation between resolved gravitational wave detections and HI signal from intensity mapping (IM) experiments. By using a tomographic approach with angular power spectra, including all projection effects, we …

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Deep Extragalactic VIsible Legacy Survey (DEVILS): Consistent Multi-wavelength Photometry for the DEVILS Regions (COSMOS, XMMLSS & ECDFS)

The Deep Extragalactic VIsible Legacy Survey (DEVILS) is an ongoing high-completeness, deep spectroscopic survey of ∼60,000 galaxies to Y<21.2 mag, over ∼6 deg2 in three well-studied deep extragalactic fields: D10 (COSMOS), D02 (XMM- LSS) and D03 (ECDFS). Numerous DEVILS projects all require consistent, uniformly-derived and state-of-the-art photometric data with which to measure galaxy properties. Existing photometric catalogues in …

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Cosmological parameter forecasts by a joint 2D tomographic approach to CMB and galaxy clustering

The cross-correlation between the cosmic microwave background (CMB) fields and matter tracers carries important cosmological information. In this paper, we forecast by a signal-to-noise ratio analysis the information contained in the cross-correlation of the CMB anisotropy fields with source counts for future cosmological observations and its impact on cosmological parameters uncertainties, using a joint tomographic …

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A New Model For Including Galactic Winds in Simulations of Galaxy Formation II: Implementation of PhEW in Cosmological Simulations

Although galactic winds play a critical role in regulating galaxy formation, hydrodynamic cosmological simulations do not resolve the scales that govern the interaction between winds and the ambient circumgalactic medium (CGM). We implement the Physically Evolved Wind (PhEW) model of Huang et al. (2020) in the GIZMO hydrodynamics code and perform test cosmological simulations with …

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The Global Magneto-Ionic Medium Survey: A Faraday Depth Survey of the Northern Sky Covering 1280-1750 MHz

The Galactic interstellar medium hosts a significant magnetic field, which can be probed through the synchrotron emission produced from its interaction with relativistic electrons. Linearly polarized synchrotron emission is generated throughout the Galaxy, and at longer wavelengths, modified along nearly every path by Faraday rotation in the intervening magneto-ionic medium. Full characterization of the polarized …

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Quenching and the UVJ diagram in the SIMBA cosmological simulation

Over the past decade, rest-frame color-color diagrams have become popular tools for selecting quiescent galaxies at high redshift, breaking the color degeneracy between quiescent and dust-reddened star-forming galaxies. In this work, we study one such color-color selection tool — the rest-frame U−V vs. V−J diagram — by employing mock observations of cosmological galaxy formation simulations. In particular, we conduct …

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Gaussian Process Regression for foreground removal in HI intensity mapping experiments

We apply for the first time Gaussian Process Regression (GPR) as a foreground removal technique in the context of single-dish, low redshift HI intensity mapping, and present an open-source python toolkit for doing so. We use MeerKAT and SKA1-MID-like simulations of 21cm foregrounds (including polarisation leakage), HI cosmological signal and instrumental noise. We find that …

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Young scientist has her eyes firmly fixed on the stars

Astrophysics student Nicole Thomas, who is completing her PhD at the University of the Western Cape’s Department of Physics and Astronomy, was selected to attend the 69th Nobel Laureate Meeting in Lindau, Germany, in 2019. Nicole, one of our students, is interviewed in UWC’s latest 360º Perspectives Magazine (p.24-25) – a big issue packed with retrospectives and …

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On the road to percent accuracy V: the non-linear power spectrum beyond ΛCDM with massive neutrinos and baryonic feedback

In the context of forthcoming galaxy surveys, to ensure unbiased constraints on cosmology and gravity when using non-linear structure information, percent-level accuracy is required when modelling the power spectrum. This calls for frameworks that can accurately capture the relevant physical effects, while allowing for deviations from ΛCDM. Massive neutrino and baryonic physics are two of the …

Read moreOn the road to percent accuracy V: the non-linear power spectrum beyond ΛCDM with massive neutrinos and baryonic feedback