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

As large-scale stellar surveys have become available over the past decade,the ability to detect and characterize substructures in the Galaxy hasincreased dramatically. These surveys have revealed the Triangulum-Andromeda(TriAnd) region to be rich with substructure in the distance range 20-30 kpc,and the relation of these features to each other -- if any -- remains unclear.This complex situation motivates this re-examination of the TriAnd region witha photometric and spectroscopic survey of M giants. An exploration using 2MASSphotometry reveals not only the faint sequence in M giants detected byRocha-Pinto et al. (2004) spanning the range $100^{\circ}<l<160^{\circ}$ and$-50^{\circ}<b<-15^{\circ}$ but, in addition, a second, brighter and moredensely populated M giant sequence. These two sequences are likely associatedwith the two distinct main-sequences discovered (and labeled TriAnd1 andTriAnd2) by Martin et al. (2007) in an optical survey in the direction of M31,where TriAnd2 is the optical counterpart of the fainter RGB/AGB sequence ofRocha-Pinto et al. (2004). Here, the age, distance, and metallicity ranges forTriAnd1 and TriAnd2 are estimated by simultaneously fitting isochrones to the2MASS RGB tracks and the optical MS/MSTO features. The two populations areclearly distinct in age and distance: the brighter sequence (TriAnd1) isyounger (6-10 Gyr) and closer (distance of $\sim$ 15-21 kpc), while the faintersequence (TriAnd2) is older (10-12 Gyr) and is at an estimated distance of$\sim$ 24-32 kpc. A comparison with simulations demonstrates that thedifferences and similarities between TriAnd1 and TriAnd2 can simultaneously beexplained if they represent debris originating from the disruption of the samedwarf galaxy, but torn off during two distinct pericentric passages. [Abridged]

Exploring Halo Substructure with Giant Stars: The Nature of the Triangulum-Andromeda Stellar Features