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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Type Ia supernovae (SNe Ia) are powerful tools for measuring the expansionhistory of the universe, but the impact of dust around SNe Ia remains unknownand is a critical systematic uncertainty. One way to improve our empiricaldescription of dust is to analyse highly reddened SNe Ia ($E(B-V)>0.4$, roughlyequivalent to the fitted SALT2 light-curve parameter $c>0.3$). With therecently released Pantheon+ sample, there are 57 SNe Ia that were removedbecause of their high colour alone (with colours up to $c=1.61$), which canprovide enormous leverage on understanding line-of-sight $R_V$. Previousstudies have claimed that $R_V$ decreases with redder colour, though it isunclear if this is due to limited statistics, selection effects, or analternative explanation. To test this claim, we fit two separatecolour-luminosity relationships, one for the main cosmological sample ($c<0.3$)and one for highly reddened ($c>0.3$) SNe Ia. We find the change in thecolour-luminosity coefficient to be consistent with zero. Additionally, wecompare the data to simulations with different colour models, and find that thedata prefers a model with a flat dependence of $R_V$ on colour over a decliningdependence. Finally, our results strongly support that line-of-sight $R_V$ toSNe Ia is not a single value, but forms a distribution.

Constraining R$_V$ Variation Using Highly Reddened Type Ia Supernovae from the Pantheon+ Sample