Pickles on FIRE: The 3D Shape Evolution of Simulated Milky Way-Mass Galaxies

Clicks: 1
ID: 314689
2026
Free PDF
Article Quality & Performance Metrics
Overall Quality
Not rated
Combines reader engagement with the AI quality analysis. This article has not been analysed, so there is no overall score — reader engagement is measured and shown alongside.
AI Quality Assessment
Not analyzed
Readership in this journal

Ranked #530 of 900 articles by views in monthly notices of the royal astronomical society

Most read Least read

Bar heights use a square-root scale. Only the 120 most-read articles are drawn; the journal has 900 in total.

Mint this article as an NFT
Not yet minted

Create a permanent, verifiable on-chain record of this article on the Scimatic Network. The NFT is held in your Journament account, and you can withdraw it to your own wallet at any time.

5 SUSD one-off · no wallet required
Sign in to mint
Abstract
Abstract We use reduced-mass eigentensors to quantify the 3D ellipsoidal shape evolution of thirteen Milky Way-mass galaxies simulated using zoom simulations with FIRE-2 physics; all but one form disks at z = 0. We find that all of our Milky Way progenitors go through phases when they are elongated. They often oscillate between spheroidal and elongated shapes in the early Universe over billion-year timescales, with ~25 − 45% of the population having elongated luminosity-weighted shapes at any given time at z = 0.5 − 8.5. In contrast, all stellar populations in our z = 0 Milky Way analogs are symmetric about their minor axes at z = 0, even though the old and intermediate-age stellar populations were often arranged in the shape of elongated pickles or triaxial spheroids at the time they formed meaning these populations changed shape significantly over time. During their transient elongated phases, our galaxies have anisotropic velocity dispersion ellipsoids directed along their spatial major axis; however, their shapes do not correlate with their dark matter fraction nor with the shapes and orientations of their underlying dark matter halos. We find that when treated as a population, the fraction of our galaxy progenitors that are elongated at z > 0.5 is roughly consistent with what is observed for systems of the same mass and redshift. Our results suggest that observed elongated galaxies seen in the early Universe with JWST and HST are not stable structures, but rather transitory phases that are nevertheless statistically common. Some of these observed objects may evolve into Milky Way-like galaxies at z = 0.
Reference Key
openalex_W4417256862 Use this key to autocite in the manuscript while using SciMatic Manuscript Manager or Thesis Manager
Authors Luke Y Xia, Courtney Klein, James S. Bullock, Michael Boylan-Kolchin, Vincent Caudillo, Jorge Moreno, Francisco J. Mercado, Robert Feldmann, Robert Feldmann
Journal monthly notices of the royal astronomical society
Year 2026
DOI
10.1093/mnras/stag964
URL
https://doi.org/10.1093/mnras/stag964
Keywords Keywords not found

Citations

No citations found. To add a citation, contact the admin at info@scimatic.org

Comments

No comments yet. Be the first to comment on this article.