Kavli Affiliate: Anthony Lasenby | Summary:We investigate the conditions under which a hypersurface becomes null through the use of coordinate transformations. We demonstrate that, in static spacetimes, the correct criterion for a surface to be null is $g_tt = 0$, rather than $g^rr = 0$, in agreement with the results of Vollick. We further show […]
Kavli Affiliate: Anthony Challinor | Summary:The abundance of galaxy clusters as a function of mass and redshift is a well-established and powerful cosmological probe. Cosmological analyses based on galaxy cluster number counts have traditionally relied on explicitly computed likelihoods, which are often challenging to develop with the required accuracy and expensive to evaluate. In this […]
Kavli Affiliate: George Efstathiou | Summary:Observations of the Epoch of Reionization (EoR) have the potential to answer long-standing questions of astrophysical interest regarding the nature of the first luminous sources and their effects on the intergalactic medium (IGM). We present astrophysical constraints from a Neural Density Estimation-Accelerated Bayesian joint analysis of constraints deriving from Cosmic […]
Kavli Affiliate: R. G. McMahon | First 5 Authors: , , , , | Summary: We present new time delays, the main ingredient of time delay cosmography, for 22 lensed quasars resulting from high-cadence r-band monitoring on the 2.6 m ESO VLT Survey Telescope and Max-Planck-Gesellschaft 2.2 m telescope. Each lensed quasar was typically monitored […]
Kavli Affiliate: R. G. McMahon | Summary:We present new time delays, the main ingredient of time delay cosmography, for 22 lensed quasars resulting from high-cadence r-band monitoring on the 2.6 m ESO VLT Survey Telescope and Max-Planck-Gesellschaft 2.2 m telescope. Each lensed quasar was typically monitored for one to four seasons, often shared between the […]
Kavli Affiliate: George Efstathiou | Summary:The first generation of stars, known as Population III (Pop III), played a crucial role in the early Universe through their unique formation environment and metal-free composition. These stars can undergo chemically homogeneous evolution (CHE) due to fast rotation, becoming more compact and hotter/bluer than their (commonly assumed) non-rotating counterparts. […]
Kavli Affiliate: R. G. McMahon | Summary:Narrow-line Seyfert 1 AGNs (NLS1s) represent a unique stage in the black hole growth history, characterised by low black hole masses of approximately $10^6$-$10^8$ solar masses and around-Eddington accretion rates. X-ray studies of NLS1s have largely been confined to the local Universe ($z < 0.2$), while their broad-line counterparts […]
Kavli Affiliate: George Efstathiou | Summary:In the current era of JWST, we continue to uncover a wealth of information about the Universe deep into the Epoch of Reionization. In this work, we use a suite of simulations with 21cmSPACE, to explore the astrophysical properties of early galaxies and their imprint on high-redshift observables. Our analysis […]
Kavli Affiliate: Roberto Maiolino | Summary:JWST has revealed a population of ‘Little Red Dots’ (LRDs): compact, red objects at redshifts z=2-9 with ‘v’-shaped spectral energy distributions, broad permitted lines, and, often, hydrogen Balmer absorption. We use NIRSpec/IFS data from the BlackTHUNDER survey to study the H$α$ line in the LRD Abell2744-QSO1 at z=7.04, which is […]