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 revisit the orbital history of the Triangulum galaxy (M33) around theAndromeda galaxy (M31) in view of the recent Gaia Data Release 2 proper motionmeasurements for both Local Group galaxies. Earlier studies consider highlyidealised dynamical friction, but neglect the effects of dynamical mass loss.We show the latter process to be important using mutually consistent orbitintegration and N-body simulations. Following this approach we find an orbitalsolution that brings these galaxies to within ~50 kpc of each other in thepast, ~6.5 Gyr ago. We explore the implications of their interaction using anN-body/hydrodynamical simulation with a focus on the origin of two prominentfeatures: 1) M31's Giant Stellar Stream; and 2) the M31-M33 HI filament. Wefind that the tidal interaction does not produce a structure reminiscent of thestellar stream that survives up to the present day. In contrast, the M31-M33 HIfilament is likely a fossil structure dating back to the time of the ancientencounter between these galaxies. Similarly, the observed outer disc warp inM33 may well be a relic of this past event. Our model suggests the presence ofa tidally induced gas envelope around these galaxies, and the existence of adiffuse gas stream, the 'Triangulum stream', stretching for tens of kpc fromM33 away from M31. We anticipate upcoming observations with the recentlycommissioned, Five-hundred-meter Aperture Spherical radio Telescope (FAST) thatwill target the putative stream in its first years of operation.

The M31/M33 tidal interaction: A hydrodynamic simulation of the extended gas distribution