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

Recent attempts to constrain cosmological variation in the fine structureconstant, alpha, using quasar absorption lines have yielded two statisticalsamples which initially appear to be inconsistent. One of these samples wassubsequently demonstrated to not pass consistency tests; it appears that theoptimisation algorithm used to fit the model to the spectra failed.Nevertheless, the results of the other hinge on the robustness of the spectralfitting program VPFIT, which has been tested through simulation but not throughdirect exploration of the likelihood function. We present the application ofMarkov Chain Monte Carlo (MCMC) methods to this problem, and demonstrate thatVPFIT produces similar values and uncertainties for (Delta alpha)/(alpha), thefractional change in the fine structure constant, as our MCMC algorithm, andthus that VPFIT is reliable.

Markov Chain Monte Carlo methods applied to measuring the fine structure constant from quasar spectroscopy