Research

MIGHTEE: the nature of the radio-loud AGN population

We study the nature of the faint radio source population detected in the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) Early Science data in the COSMOS field, focusing on the properties of the radio-loud active galactic nuclei (AGN). Using the extensive multi-wavelength data available in the field, we are able to classify 88 per cent …

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Antenna characterization for the HIRAX experiment

The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) aims to improve constraints on the dark energy equation of state through measurements of large-scale structure at high redshift (0.8<z<2.5), while serving as a state-of-the-art fast radio burst detector. Bright galactic foregrounds contaminate the 400–800~MHz HIRAX frequency band, so meeting the science goals will require precise instrument …

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The total rest-frame UV luminosity function from 3

We present measurements of the rest-frame ultraviolet luminosity function (UV LF) at redshifts z=3, z=4 and z=5, using 96894, 38655 and 7571 sources respectively to map the transition between AGN and galaxy-dominated ultraviolet emission shortly after the epoch of reionization. Sources are selected using a comprehensive photometric redshift approach, using 10\ds\, of deep extragalactic legacy fields covered by both HSC …

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The Physical Nature of Circumgalactic Medium Absorbers in Simba

We study the nature of the low-redshift CGM in the Simba cosmological simulations as traced by ultraviolet absorption lines around galaxies in bins of stellar mass (M⋆>1010M⊙) for star-forming, green valley and quenched galaxies at impact parameters r⊥≤1.25r200. We generate synthetic spectra for HI, MgII, CII, SiIII, CIV, and OVI, fit Voigt profiles to obtain line …

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Emergence of a new HI 21-cm absorption component at z~1.1726 towards the gamma-ray blazar PKS~2355-106

We report the emergence of a new HI 21-cm absorption at z_abs = 1.172635 in the damped Lyman-alpha absorber (DLA) towards the gamma-ray blazar PKS 2355-106 (z_em~1.639) using science verification observations (June 2020) from the MeerKAT Absorption Line Survey (MALS). Since 2006, this DLA is known to show a narrow HI 21-cm absorption at z_abs …

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Quijote PNG: The information content of the halo power spectrum and bispectrum

We investigate how much can be learnt about four types of primordial non-Gaussianity (PNG) from small-scale measurements of the halo field. Using the \textsc{quijote-png} simulations, we quantify the information content accessible with measurements of the halo power spectrum monopole and quadrupole, the matter power spectrum, the halo-matter cross spectrum and the halo bispectrum monopole. This …

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Interferometric HI intensity mapping: perturbation theory predictions and foreground removal effects

We provide perturbation theory predictions for the HI intensity mapping power spectrum multipoles using the Effective Field Theory of Large Scale Structure (EFTofLSS), which should allow us to constrain cosmological parameters exploiting mildly nonlinear scales. Assuming survey specifications typical of proposed interferometric HI intensity mapping experiments like CHORD and PUMA, and realistic ranges of validity …

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Semi-analytic forecasts for JWST — VI. Simulated lightcones and galaxy clustering predictions

In anticipation of the new era of high-redshift exploration marked by the commissioning of the James Webb Space Telescope (JWST), we present two sets of galaxy catalogues that are designed to aid the planning and interpretation of observing programs. We provide a set of 40 wide-field lightcones with footprints spanning approximately ~ 1,000 sq. arcmin, …

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Black Hole Mass Measurements of Early-Type Galaxies NGC 1380 and NGC 6861 Through ALMA and HST Observations and Gas-Dynamical Modeling

We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 2 observations of CO(2-1) emission from the circumnuclear disks in two early-type galaxies, NGC 1380 and NGC 6861. The disk in each galaxy is highly inclined (i∼75∘), and the projected velocities of the molecular gas near the galaxy centers are ∼300kms−1 in NGC 1380 and ∼500kms−1 in NGC 6861. We fit …

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Measuring dark energy with expansion and growth

We combine cosmic chronometer and growth of structure data to derive the redshift evolution of the dark energy equation of state w, using a novel agnostic approach. The background and perturbation equations lead to two expressions for w, one purely background-based and the other relying also on the growth rate of large-scale structure. We compare the features …

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