Origin of stellar prolate rotation in a cosmologically simulated faint dwarf galaxy

Cardona-Barrero, Salvador; Battaglia, Giuseppina; Di Cintio, Arianna; Revaz, Yves; Jablonka, Pascale
Bibliographical reference

Monthly Notices of the Royal Astronomical Society

Advertised on:
7
2021
Description
Stellar prolate rotation in dwarf galaxies is rather uncommon, with only two known galaxies in the Local Group showing such feature (Phoenix and And II). Cosmological simulations show that in massive early-type galaxies prolate rotation likely arises from major mergers. However, the origin of such kinematics in the dwarf galaxies regime has only been explored using idealized simulations. Here, we made use of hydrodynamical cosmological simulations of dwarfs galaxies with stellar mass between 3 × 105 and 5 × 108 M⊙ to explore the formation of prolate rotators. Out of 27 dwarfs, only one system showed clear rotation around the major axis, whose culprit is a major merger at $z$ = 1.64, which caused the transition from an oblate to a prolate configuration. Interestingly, this galaxy displays a steep metallicity gradient, reminiscent of the one measured in Phoenix and And II: this is the outcome of the merger event that dynamically heats old, metal-poor stars, and of the centrally concentrated residual star formation. Major mergers in dwarf galaxies offer a viable explanation for the formation of such peculiar systems, characterized by steep metallicity gradients and prolate rotation.
Related projects
Project Image
Numerical Astrophysics: Galaxy Formation and Evolution

How galaxies formed and evolved through cosmic time is one of the key questions of modern astronomy and astrophysics. Cosmological time- and length-scales are so large that the evolution of individual galaxies cannot be directly observed. Only through numerical simulations can one follow the emergence of cosmic structures within the current

Claudio
Dalla Vecchia
A view of our Milky Way galaxy with its close neighbors the Magellanic Clouds
Galaxy Evolution in the Local Group

Galaxy formation and evolution is a fundamental Astrophysical problem. Its study requires “travelling back in time”, for which there are two complementary approaches. One is to analyse galaxy properties as a function of red-shift. Our team focuses on the other approach, called “Galactic Archaeology”. It is based on the determination of galaxy

Matteo
Monelli