21cmVAE: A Very Accurate Emulator of the 21-cm Global Signal

Kavli Affiliate: George Efstathiou | First 5 Authors: Christian H. Bye, Stephen K. N. Portillo, Anastasia Fialkov, , | Summary: Considerable observational efforts are being dedicated to measuring the sky-averaged (global) 21-cm signal of neutral hydrogen from Cosmic Dawn and the Epoch of Reionization. Deriving observational constraints on the astrophysics of this era requires modeling […]


Continue.. 21cmVAE: A Very Accurate Emulator of the 21-cm Global Signal

Shot noise and scatter in the star formation efficiency as a source of 21-cm fluctuations

Kavli Affiliate: George Efstathiou | First 5 Authors: Itamar Reis, Rennan Barkana, Anastasia Fialkov, , | Summary: The 21-cm signal from cosmic dawn and the epoch of reionization (EoR) probes the characteristics of the high redshift galaxy population. Many of the astrophysical properties of galaxies at high redshifts are currently unconstrained due to the lack […]


Continue.. Shot noise and scatter in the star formation efficiency as a source of 21-cm fluctuations

Inference of the optical depth to reionization from low multipole temperature and polarisation Planck data

Kavli Affiliate: George Efstathiou | First 5 Authors: Roger de Belsunce, Steven Gratton, William Coulton, George Efstathiou, | Summary: This paper explores methods for constructing low multipole temperature and polarisation likelihoods from maps of the cosmic microwave background anisotropies that have complex noise properties and partial sky coverage. We use Planck 2018 High Frequency Instrument […]


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Conformal gravity does not predict flat galaxy rotation curves

Kavli Affiliate: Anthony Lasenby | First 5 Authors: Michael Hobson, Anthony Lasenby, , , | Summary: We reconsider the widely held view that the Mannheim–Kazanas (MK) vacuum solution for a static, spherically-symmetric system in conformal gravity (CG) predicts flat rotation curves, such as those observed in galaxies, without the need for dark matter. This prediction […]


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To H0 or not to H0?

Kavli Affiliate: George Efstathiou | First 5 Authors: George Efstathiou, , , , | Summary: This paper investigates whether changes to late time physics can resolve the `Hubble tension’. It is argued that many of the claims in the literature favouring such solutions are caused by a misunderstanding of how distance ladder measurements actually work […]


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A 21-cm power spectrum at 48 MHz, using the Owens Valley Long Wavelength Array

Kavli Affiliate: George Efstathiou | First 5 Authors: Hugh Garsden, Lincoln Greenhill, Gianni Bernardi, Anastasia Fialkov, Daniel C. Price | Summary: The Large-aperture Experiment to detect the Dark Age (LEDA) was designed to measure the 21-cm signal from neutral hydrogen at Cosmic Dawn, $z approx $15-30. Using observations made with the $approx $ 200 m […]


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Delensing the CMB with the cosmic infrared background: the impact of foregrounds

Kavli Affiliate: Anthony Challinor | First 5 Authors: Antón Baleato Lizancos, Anthony Challinor, Blake D. Sherwin, Toshiya Namikawa, | Summary: The most promising avenue for detecting primordial gravitational waves from cosmic inflation is through measurements of degree-scale CMB $B$-mode polarisation. This approach must face the challenge posed by gravitational lensing of the CMB, which obscures […]


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Anomalies in the gravitational recoil of eccentric black-hole mergers with unequal mass ratios

Kavli Affiliate: Ulrich Sperhake | First 5 Authors: Miren Radia, Ulrich Sperhake, Emanuele Berti, Robin Croft, | Summary: The radiation of linear momentum imparts a recoil (or "kick") to the center of mass of a merging black hole binary system. Recent numerical relativity calculations have shown that eccentricity can lead to an approximate 25% increase […]


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The subtlety of Ly-a photons: changing the expected range of the 21-cm signal

Kavli Affiliate: George Efstathiou | First 5 Authors: Itamar Reis, Anastasia Fialkov, Rennan Barkana, , | Summary: We present the evolution of the 21-cm signal from cosmic dawn and the epoch of reionization (EoR) in an upgraded model including three subtle effects of Ly-a radiation: Ly-a heating, CMB heating (mediated by Ly-a photons), and multiple […]


Continue.. The subtlety of Ly-a photons: changing the expected range of the 21-cm signal