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While most moving groups are young and nearby, a small number have beenidentified in the Galactic halo. Understanding the origin and evolution ofthese groups is an important piece of reconstructing the formation history ofthe halo. Here we report on our analysis of three putative halo moving groups:G03-37, G18-39, and G21-22. Based on Gaia EDR3 data, the stars associated witheach group show some scatter in velocity (e.g., Toomre diagram) and integralsof motion (energy, angular momentum) spaces, counter to expectations ofmoving-group stars. We choose the best candidate of the three groups, G21-22,for follow-up chemical analysis based on high-resolution spectroscopy of sixpresumptive members. Using a new Python code that uses a Bayesian method toself-consistently propagate uncertainties from stellar atmosphere solutions incalculating individual abundances and spectral synthesis, we derive theabundances of $\alpha$- (Mg, Si, Ca, Ti), Fe-peak (Cr, Sc, Mn, Fe, Ni), odd-$Z$(Na, Al, V), and neutron-capture (Ba, Eu) elements for each star. We find thatthe G21-22 stars are not chemically homogeneous. Based on the kinematicanalysis for all three groups and the chemical analysis for G21-22, we concludethe three are not genuine moving groups. The case for G21-22 demonstrates thebenefit of combining kinematic and chemical information in identifying conatalpopulations when either alone may be insufficient. Comparing the integrals ofmotion and velocities of the six G21-22 stars with those of known structures inthe halo, we tentatively associate them with the Gaia-Enceladus accretionevent.

Combining Astrometry and Elemental Abundances: The Case of the Candidate Pre-Gaia Halo Moving Groups G03-37, G18-39, and G21-22