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HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization

Recently, the Hydrogen Epoch of Reionization Array (HERA) collaboration has produced the experiment’s first upper limits on the power spectrum of 21-cm fluctuations at z~8 and 10. Here, we use several independent theoretical models to infer constraints on the intergalactic medium (IGM) and galaxies during the epoch of reionization (EoR) from these limits. We find …

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Multi-wavelength spectroscopic probes: biases from neglecting light-cone effects

Next-generation cosmological surveys will observe larger cosmic volumes than ever before, enabling us to access information on the primordial Universe, as well as on relativistic effects. In a companion paper, we applied a Fisher analysis to forecast the expected precision on fNL and the detectability of the lensing magnification and Doppler contributions to the power spectrum. Here …

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New analysis of more than 2000 Galaxies with MeerKAT

Using early science data for the MIGHTEE project on the MeerKAT radio telescope, a researcher at the University of the Western Cape – with collaborators from eight countries, including four other South African Institutions – has analysed over 2000 galaxies, growing our understanding of the evolution of galaxies over cosmic time. Dr Fangxia An – …

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Follow-up of 27 radio-quiet gamma-ray pulsars at 110-190 MHz using the international LOFAR station FR606

The Fermi Large Area Telescope has detected over 260 gamma-ray pulsars. About one quarter of these are labeled as radio-quiet. In the population of nonrecycled gamma-ray pulsars, the fraction of radio-quiet pulsars is higher, about one half. Most radio observations of gamma-ray pulsars have been performed at frequencies between 300 MHz and 2 GHz. However, …

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Optimization of the Observing Cadence for the Rubin Observatory Legacy Survey of Space and Time: a pioneering process of community-focused experimental design

Vera C. Rubin Observatory is a ground-based astronomical facility under construction, a joint project of the National Science Foundation and the U.S. Department of Energy, designed to conduct a multi-purpose 10-year optical survey of the southern hemisphere sky: the Legacy Survey of Space and Time. Significant flexibility in survey strategy remains within the constraints imposed …

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Multi-wavelength spectroscopic probes: prospects for primordial non-Gaussianity and relativistic effects

Next-generation cosmological surveys will observe larger cosmic volumes than ever before, enabling us to access information on the primordial Universe, as well as on relativistic effects. We consider forthcoming 21cm intensity mapping surveys (SKAO) and optical galaxy surveys (DESI and Euclid), combining the information via multi-tracer cross-correlations that suppress cosmic variance on ultra-large scales. In …

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Magnification and evolution biases in large-scale structure surveys

Measurements of the galaxy number density in upcoming surveys such as Euclid and the SKA will be sensitive to distortions from lensing magnification and Doppler effects, beyond the standard redshift-space distortions. The amplitude of these contributions depends sensitively on magnification bias and evolution bias in the galaxy number density. Magnification bias quantifies the change in …

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Contributions from primordial non-Gaussianity and General Relativity to the galaxy power spectrum

We compute the real space galaxy power spectrum, including the leading order effects of General Relativity and primordial non-Gaussianity from the fNL and gNL parameters. Such contributions come from the one-loop matter power spectrum terms dominant at large scales, and from the factors of the non-linear bias parameter bNL (akin to the Newtonian bϕ). We use our modelling to assess the ability …

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