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 Tools annual

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 monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We analyze existing measurements of [Fe/H] and [$\alpha$/Fe] for individualred giant branch (RGB) stars in the Giant Stellar Stream (GSS) of M31 todetermine whether spatial abundance gradients are present. These measurementswere obtained from low- ($R \sim 3000$) and moderate- ($R \sim 6000$)resolution Keck/DEIMOS spectroscopy using spectral synthesis techniques as partof the Elemental Abundances in M31 survey. From a sample of 62 RGB starsspanning the GSS at 17, 22, and 33 projected kpc, we measure a [Fe/H] gradientof $-$0.018 $\pm$ 0.003 dex kpc$^{-1}$ and negligible [$\alpha$/Fe] gradientwith M31-centric radius. We investigate GSS abundance patterns in the outerhalo using additional [Fe/H] and [$\alpha$/Fe] measurements for 6 RGB starslocated along the stream at 45 and 58 projected kpc. These abundances providetentative evidence that the trends in [Fe/H] and [$\alpha$/Fe] beyond 40 kpc inthe GSS are consistent with those within 33 kpc. We also compare the GSSabundances to 65 RGB stars located along the possibly related Southeast (SE)shelf substructure at 12 and 18 projected kpc. The abundances of the GSS and SEshelf are consistent, supporting a common origin hypothesis, although thisinterpretation may be complicated by the presence of [Fe/H] gradients in theGSS. We discuss the abundance patterns in the context of photometric studiesfrom the literature and explore implications for the properties of the GSSprogenitor, suggesting that the high $\langle$[$\alpha$/Fe]$\rangle$ of the GSS(+0.40 $\pm$ 0.05 dex) favors a major merger scenario for its formation.

Elemental Abundances in M31: Gradients in the Giant Stellar Stream