Search Publications
Using the full power of the cosmic microwave background to probe axion dark matter
Hložek, Renée; Grin, Daniel; Marsh, David J. E.
The cosmic microwave background (CMB) places stringent constraints on models of dark matter (DM), and on the initial conditions of the Universe. The full Planck data set is used to test the possibility that some fraction of the DM is composed of ultralight axions (ULAs). This represents the first use of CMB lensing to test the ULA model. We find n…
The BAHAMAS project: the CMB-large-scale structure tension and the roles of massive neutrinos and galaxy formation
Schaye, Joop; van Waerbeke, Ludovic; McCarthy, Ian G. +3 more
Recent studies have presented evidence for tension between the constraints on Ωm and σ8 from the cosmic microwave background (CMB) and measurements of large-scale structure (LSS). This tension can potentially be resolved by appealing to extensions of the standard model of cosmology and/or untreated systematic errors in the mo…
Clarifying the Hubble constant tension with a Bayesian hierarchical model of the local distance ladder
Feeney, Stephen M.; Mortlock, Daniel J.; Dalmasso, Niccolò
Estimates of the Hubble constant, H0, from the local distance ladder and from the cosmic microwave background (CMB) are discrepant at the ∼3σ level, indicating a potential issue with the standard Λ cold dark matter (ΛCDM) cosmology. A probabilistic (i.e. Bayesian) interpretation of this tension requires a model comparison calculation, w…
New constraints on time-dependent variations of fundamental constants using Planck data
Chluba, Jens; Hart, Luke
Observations of the cosmic microwave background (CMB) today allow us to answer detailed questions about the properties of our Universe, targeting both standard and non-standard physics. In this paper, we study the effects of varying fundamental constants (i.e. the fine-structure constant, αEM, and electron rest mass, me) arou…
Imprints of cosmic rays in multifrequency observations of the interstellar emission
Orlando, E.
Ever since the discovery of cosmic rays (CRs), significant advancements have been made in modelling their propagation in the Galaxy and in the Heliosphere. However, propagation models suffer from degeneracy of many parameters. To complicate the picture, the precision of recent data have started challenging existing models. To tackle these issues, …
LOFAR discovery of an ultra-steep radio halo and giant head-tail radio galaxy in Abell 1132
Prandoni, I.; Brunetti, G.; Morganti, R. +16 more
Low-Frequency Array (LOFAR) observations at 144 MHz have revealed large-scale radio sources in the unrelaxed galaxy cluster Abell 1132. The cluster hosts diffuse radio emission on scales of ∼650 kpc near the cluster centre and a head-tail (HT) radio galaxy, extending up to 1 Mpc, south of the cluster centre. The central diffuse radio emission is n…
Planck's view on the spectrum of the Sunyaev-Zeldovich effect
Bertoldi, Frank; Chluba, Jens; Basu, Kaustuv +1 more
We present a detailed analysis of the stacked frequency spectrum of a large sample of galaxy clusters using Planck data, together with auxiliary data from the AKARI and IRAS missions. Our primary goal is to search for the imprint of relativistic corrections to the thermal Sunyaev-Zeldovich effect (tSZ) spectrum, which allow to measure the temperat…
An application of an optimal statistic for characterizing relative orientations
Martin, P. G.; Poidevin, F.; Hill, Ryley +5 more
We present the projected Rayleigh statistic (PRS), a modification of the classic Rayleigh statistic, as a test for non-uniform relative orientation between two pseudo-vector fields. In the application here, this gives an effective way of investigating whether polarization pseudo-vectors (spin-2 quantities) are preferentially parallel or perpendicu…
Where does galactic dust come from?
Hunt, L. K.; Valiante, R.; Ginolfi, M. +5 more
Here we investigate the origin of the dust mass (Mdust) observed in the Milky Way (MW) and of dust scaling relations found in a sample of local galaxies from the DGS and KINGFISH surveys. To this aim, we model dust production from Asymptotic Giant Branch (AGB) stars and supernovae (SNe) in simulated galaxies forming along the assembly o…
On the insufficiency of arbitrarily precise covariance matrices: non-Gaussian weak-lensing likelihoods
Sellentin, Elena; Heavens, Alan F.
We investigate whether a Gaussian likelihood, as routinely assumed in the analysis of cosmological data, is supported by simulated survey data. We define test statistics, based on a novel method that first destroys Gaussian correlations in a data set, and then measures the non-Gaussian correlations that remain. This procedure flags pairs of data p…