English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

One of the outstanding problems in modern physics is the origin is ofaccelerated expansion of the universe. High-precision determinations of theHubble parameter $\mbox{H}_0$ at different redshifts provide direct insightinto the Universe expansion: equation of state of the Dark Energy, geometry andcurvature of space, sum of neutrino masses and isotropy of the Universe. Weinvestigate the effect of chemical composition on the classical distance ladderbased on Cepheids stars and Supernovae type Ia. Cepheids belonging toMagellanic Clouds represent a natural anchor for the ladder, due to theirproximity and the very well known geometric distance. Accordingly, the LACEScollaboration collected the largest spectroscopic sample of MCs Cepheids,containing more than 300 stars and more than 1200 medium-high resolutionspectra. Abundance measurements, performed by equivalent width and curve ofgrowth analysis, have been tested on a wide grid of synthetic spectra toquantify the systematic arising from this procedure. We focus on the errorsarising from temperature measurements, using the Line Depth Ratio method. Wefind that in order to not bias the final results many aspects (e.g. degeneracyof the atmospheric parameters, instrumental set up etc.) should be explicitlytaken into account. In particular, there is a not negligible metallicitydependence.

Towards precise and accurate Cepheid chemical abundances for 1$\%$ $\mbox{H}_0$ measurement: temperature determination