Relating galaxies across different redshift to study galaxy evolution

Kai Wang, Houjun Mo, Cheng Li, Yangyao Chen

Submitted on 1 November 2022


We propose a general framework leveraging the halo-galaxy connection to link galaxies observed at different redshift in a statistical way, and use the link to infer the redshift evolution of the galaxy population. Our tests based on hydrodynamic simulations show that our method can accurately recover the stellar mass assembly histories up to z3 for present star-forming and quiescent galaxies down to 1010h1M. Applying the method to observational data shows that the stellar mass evolution of the main progenitors of galaxies depends strongly on the properties of descendants, such as stellar mass, halo mass, and star formation states. Galaxies hosted by low-mass groups/halos at the present time have since z1.8 grown their stellar mass 2.5 times as fast as those hosted by massive clusters. This dependence on host halo mass becomes much weaker for descendant galaxies with similar star formation states. Star-forming galaxies grow about 2-4 times faster than their quiescent counterparts since z1.8. Both TNG and EAGLE simulations over-predict the progenitor stellar mass at z>1, particularly for low-mass descendants.


Comment: 15 pages, 10+3 figures, submitted to MNRAS, comments are welcome

Subjects: Astrophysics - Astrophysics of Galaxies; Astrophysics - Cosmology and Nongalactic Astrophysics


Demonstration of the method that connects galaxies across cosmic time. On the left hand, blue points are the observed galaxies from high redshift (top) to low redshift (bottom). On the right hand, black shades are halos and subhalos on subhalo merger trees from N-body simulations. We first connect galaxies with halos using established halo-galaxy connections, then use links in subhalo merger trees to connect galaxies across cosmic time.