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

We present new MMT/Hectochelle spectroscopic measurements for 257 starsobserved along the line of sight to the ultra-faint dwarf galaxy Triangulum II.Combining with results from previous Keck/DEIMOS spectroscopy, we obtain asample that includes 16 likely members of Triangulum II, with up to 10independent redshift measurements per star. To this multi-epoch kinematic dataset we apply methodology that we develop in order to infer binary orbitalparameters from sparsely sampled radial velocity curves with as few as twoepochs. For a previously-identified (spatially unresolved) binary system inTri~II, we infer an orbital solution with period $296.0_{-3.3}^{+3.8} \rm~days$ , semi-major axis $1.12^{+0.41}_{-0.24}\rm~AU$, and a systemic velocity $-380.0 \pm 1.7 \rm~km ~s^{-1}$ that we then use in the analysis of Tri~II'sinternal kinematics. Despite this improvement in the modeling of binary starsystems, the current data remain insufficient to resolve the velocitydispersion of Triangulum II. We instead find a 95% confidence upper limit of$\sigma_{v} \lesssim 3.4 \rm ~km~s^{-1}$.

Stellar kinematics of dwarf galaxies from multi-epoch spectroscopy: application to Triangulum II