text: 32,169,1509849211533201412,584142796,Carl Rodriguez,"Paper day (not an April Fool's joke, pun notwithstanding)! The second in our Great Balls of FIRE series, where we (me, @MikeGrudic, @ZachHafen, Astrid Lambert +) study the formation and evolution of globular clusters in a realistic MHD galaxy simulation <LINK>: <LINK> First paper in the series (<LINK>) identified all the clusters that formed over the history of the MHD m12i FIRE-2 galaxy, and using detailed simulations of collapsing molecular clouds, mapped them to a catalog of young cluster masses, radii, metallicities, etc: This paper (<LINK>) takes the next step: integrating ~1000 of the most massive clusters (10^5 to 10^7 stars) in the catalog forward with a Hénon-style N-body code to the present day, with the initial conditions and tidal fields taken directly from the galaxy sim. This is, to my knowledge, the first study of it's kind using a star-by-star N-body approach that can integrate clusters massive enough to become the old globular clusters we see in the MW and other galaxies. The model predicts about 148 GCs in the m12i galaxy at z=0: <LINK> Because we're using realistic star cluster models, we can extract v-band surface brightness profiles, fit them to King 1966 models like observers do, and directly compare them to the properties of GCs in the MW and M31. Here, we show the masses and radii of our clusters. <LINK> Our clusters are typically smaller (in both core radius and mass) than GCs in the MW and M31. This turns out to be related to the specific formation history of the host galaxy. It turns out that clusters born later tend to lose mass more quickly. At the same time, forming GCs later means they form at higher metallicities, and retain fewer stellar mass black holes due to natal kicks. This means they undergo core collapse FASTER than older, metal pool GCs. There is a LOT more information and analysis in the paper, mapping out how exactly the history of this galaxy shapes its z=0 GC population, so I encourage you to take a look! Damnit, Lamberts, not Lambert! @evbauer_astro @MikeGrudic @ZachHafen Yeah I completely forgot about April fools. Course one could argue that posting a paper with an April Fools-like title but real content is the greatest form of the April fools paper…",https://arxiv.org/abs/2203.16547,"The current generation of galaxy simulations can resolve individual giant molecular clouds, the progenitors of dense star clusters. But the evolutionary fate of these young massive clusters (YMCs), and whether they can become the old globular clusters (GCs) observed in many galaxies, is determined by a complex interplay of internal dynamical processes and external galactic effects. We present the first star-by-star $N$-body models of massive ($N\sim10^5-10^7$) star clusters formed in a FIRE-2 MHD simulation of a Milky Way-mass galaxy, with all of the relevant initial conditions and galactic tidal effects extracted directly from the cosmological simulation. We randomly select 895 ($\sim 30\%$) of the YMCs with $ > 6\times10^4M_{\odot}$ from Grudi\'c et al. 2022 and integrate them to the present day using the Cluster Monte Carlo Code, CMC. This procedure predicts a MW-like system with 148 GCs, most of which were formed during the early, bursty mode of star formation in the galaxy. Our GCs are younger, less massive, and more core collapsed than clusters in the Milky Way or M31. This is a direct result of the assembly history and age-metallicity relationship of the GCs' host galaxy: younger clusters are preferentially born in stronger galactic tidal fields and initially retain fewer stellar-mass black holes, causing them to lose mass faster and reach core collapse sooner than their older counterparts. Our results suggest that the masses and core/half-light radii of GCs are shaped not only by internal dynamical processes, but by the specific evolutionary history of their host galaxies as well. These results emphasize that $N$-body studies with realistic stellar physics are crucial to understanding the evolution and present-day properties of galactic GC systems. ","Great Balls of FIRE II: The evolution and destruction of star clusters