POGOSIAN L.

Constraining the dark energy (DE) equation of state, wDE, is one of the primary science goals of ongoing and future cosmological surveys. In practice, with imperfect data and incomplete redshift coverage, this requires making assumptions about the evolution of wDE with redshift z. These assumptions can be manifested in a choice of a specific...

Phenomenological functions Σ and μ, also known as Glight/G and Gmatter/G, are commonly used to parametrize modifications of the growth of large-scale structure in alternative theories of gravity. We study the values these functions can take in Horndeski theories, i.e., the class of scalar-tensor theories with second order equations of motion....

Ongoing and upcoming cosmological surveys will significantly improve our ability to probe the equation of state of dark energy, wDE, and the phenomenology of large scale structure. They will allow us to constrain deviations from the Λ cold dark matter predictions for the relations between the matter density contrast and the weak lensing and the...

Recently, in [1], we presented the first combined non-parametric reconstruction of the three time-dependent functions that capture departures from the standard cosmological model, ΛCDM, in the expansion history and gravitational effects on matter and light from the currently available combination of the background and large scale structure...

There has been substantial interest in modifications of the standard Λ cold dark matter (ΛCDM, where Λ is the cosmological constant) cosmological model prompted by tensions between certain datasets, most notably the Hubble tension. The late-time modifications of the ΛCDM model can be parameterized by three time-dependent functions describing...

A flat Friedmann-Robertson-Walker universe dominated by a cosmological constant (Λ) and cold dark matter (CDM) has been the working model preferred by cosmologists since the discovery of cosmic acceleration 1,2. However, tensions of various degrees of significance are known to be present among existing datasets within the ΛCDM framework 3-11....