The dynamical evolution of the stellar clumps in the Sparkler galaxy
by
DrEric Giunchi(Università degli Studi di Bologna)
→
Europe/Rome
Sala Jappelli (Osservatorio astronomico di Padova)
Sala Jappelli
Osservatorio astronomico di Padova
Description
The formation and evolution of globular clusters (GCs) is still a key open question of modern astrophysics, strongly linked to the evolution of galaxies. Recent JWST observations detected a system of stellar clumps around the gravitationally lensed Sparkler galaxy at z=1.4, with ages and metallicities compatible with GC-progenitors. However, the masses and effective radii of such clumps are about 10 times those of the Milky Way (MW) GCs. I will present N-body simulations of the clump dynamical evolution to z=0, under the effects of dynamical friction and tidal stripping, aimed at assessing whether these clumps can evolve into GC-like objects. Since the Sparkler morphology is poorly constrained, we explored two scenarios, in which the galaxy is either a spheroid or has a prominent stellar disk. Independently of the galactic morphology, we find that dynamical friction is quite inefficient on clumps with mass <1e7 Msun (the “surviving” clumps), while the massive ones sink to the galaxy central regions, possibly contributing to the bulge growth. Furthermore, the properties of these infalling clumps are compatible with progenitors of bulge fossil fragments. Tidal stripping is important only in presence of the disk, which triggers shocks able to strip considerable mass from low-mass clumps and shifts the peak of the mass distribution of the surviving clumps to 2-3e6 Msun, which is compatible with the high-mass end of the MW GC mass distribution, even though the clump effective radii remain larger than those of GCs even if large fractions of mass are stripped.