Search Publications
Indirect dark matter signatures in the cosmic dark ages. I. Generalizing the bound on s -wave dark matter annihilation from Planck results
Slatyer, Tracy R.
Recent measurements of the cosmic microwave background (CMB) anisotropies by Planck provide a sensitive probe of dark matter annihilation during the cosmic dark ages, and specifically constrain the annihilation parameter feff⟨σ v ⟩/mχ. Using new results (paper II) for the ionization produced by particles injected at arbitrary…
Dark energy at early times, the Hubble parameter, and the string axiverse
Kamionkowski, Marc; Karwal, Tanvi
Precise measurements of the cosmic microwave background (CMB) power spectrum are in excellent agreement with the predictions of the standard Λ CDM cosmological model. However, there is some tension between the value of the Hubble parameter H0 inferred from the CMB and that inferred from observations of the Universe at lower redshifts, a…
Improvement of cosmological neutrino mass bounds
Ho, Shirley; Mena, Olga; Gerbino, Martina +3 more
The most recent measurements of the temperature and low-multipole polarization anisotropies of the cosmic microwave background from the Planck satellite, when combined with galaxy clustering data from the Baryon Oscillation Spectroscopic Survey in the form of the full shape of the power spectrum, and with baryon acoustic oscillation measurements, …
Reconciling CMB and structure growth measurements with dark energy interactions
Pourtsidou, Alkistis; Tram, Thomas
We study a coupled quintessence model with pure momentum exchange and present the effects of such an interaction on the cosmic microwave background (CMB) and matter power spectrum. For a wide range of negative values of the coupling parameter β structure growth is suppressed and the model can reconcile the tension between cosmic microwave backgrou…
New constraints on interacting dark energy from cosmic chronometers
Nunes, Rafael C.; Pan, Supriya; Saridakis, Emmanuel N.
We use the latest compilation of observational Hubble parameter measurements estimated with the differential evolution of cosmic chronometers, in combination with the local value of the Hubble constant recently measured with 2.4% precision, to constrain the cosmological scenario where dark energy interacts directly with the dark matter sector. To …
Eliminating the optical depth nuisance from the CMB with 21 cm cosmology
Sherwin, Blake D.; Liu, Adrian; Pritchard, Jonathan R. +3 more
Amongst standard model parameters that are constrained by cosmic microwave background (CMB) observations, the optical depth τ stands out as a nuisance parameter. While τ provides some crude limits on reionization, it also degrades constraints on other cosmological parameters. Here we explore how 21 cm cosmology—as a direct probe of reionization—ca…
CMB constraints on cosmic strings and superstrings
Moss, Adam; Charnock, Tom; Avgoustidis, Anastasios +1 more
We present the first complete Markov chain Monte Carlo analysis of cosmological models with evolving cosmic (super)string networks, using the unconnected segment model in the unequal-time correlator formalism. For ordinary cosmic string networks, we derive joint constraints on Λ cold dark matter (CDM) and string network parameters, namely the stri…
Experimental bounds on collapse models from gravitational wave detectors
Carlesso, Matteo; Bassi, Angelo; Falferi, Paolo +1 more
Wave function collapse models postulate a fundamental breakdown of the quantum superposition principle at the macroscale. Therefore, experimental tests of collapse models are also fundamental tests of quantum mechanics. Here, we compute the upper bounds on the collapse parameters, which can be inferred by the gravitational wave detectors LIGO, LIS…
Search for astrophysical rotating Ellis wormholes with x-ray reflection spectroscopy
Bambi, Cosimo; Zhou, Menglei; Cardenas-Avendano, Alejandro +2 more
Recently, two of us have found numerically rotating Ellis wormholes as solutions of four-dimensional Einstein gravity coupled to a phantom field. In this paper, we investigate possible observational signatures to identify similar objects in the Universe. These symmetric wormholes have a mass and are compact, so they may look like black holes. We s…
Kinematic Sunyaev-Zel'dovich effect with projected fields. II. Prospects, challenges, and comparison with simulations
Spergel, David N.; Ferraro, Simone; Hill, J. Colin +2 more
The kinematic Sunyaev-Zel'dovich (kSZ) signal is a powerful probe of the cosmic baryon distribution. The kSZ signal is proportional to the integrated free electron momentum rather than the electron pressure (which sources the thermal SZ signal). Since velocities should be unbiased on large scales, the kSZ signal is an unbiased tracer of the large-…