codman

Ultra-large-scale approximations and galaxy clustering: debiasing constraints on cosmological parameters

Upcoming galaxy surveys will allow us to probe the growth of the cosmic large-scale structure with improved sensitivity compared to current missions, and will also map larger areas of the sky. This means that in addition to the increased precision in observations, future surveys will also access the ultra-large scale regime, where commonly neglected effects …

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African Science Renaissance at UWC

On 30 June each year, the African Union celebrates the day of Africa’s Science Renaissance, and it is worth celebrating. African science is among the oldest known to man. The university at Timbuktu, founded around 1 800 years ago, served as an intellectual hub of knowledge for the continent until the late 16th century. There are older records …

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An orientation bias in observations of submillimetre galaxies

Recent high-resolution interferometric images of submillimetre galaxies (SMGs) reveal fascinatingly complex morphologies. This raises a number of questions: how does the relative orientation of a galaxy affect its observed submillimetre emission, and does this result in an `orientation bias’ in the selection and analysis of such galaxies in flux-limited cosmological surveys? We investigate these questions …

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NEW X-RAY MAP REVEALS THE GROWING SUPERMASSIVE BLACK HOLES IN NEXT-GENERATION SURVEY FIELDS

One of the largest X-ray surveys using the European Space Agency’s XMM-Newton space observatory has mapped nearly 12,000 X-ray sources across three large, prime regions of the sky. The X-ray sources represent active galactic nuclei and galaxy clusters, and the survey captures the growth of the supermassive black holes at the cores of these galaxies. …

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UWC Astro members elected to IAU committees

The International Astronomical Union recently held its elections for members to lead the various scientific bodies organised as divisions and commissions. UWC Astronomy members Carolina Odman (IDIA) and Lucia Marchetti (former postdoc, now at UCT) were elected to Commission C2 “Communicating Astronomy to the Public” and Division J “Galaxies and Cosmology” respectively. We congratulate them …

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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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