oai:arXiv.org:2409.02233
Wissenschaften: Astrophysik
2024
11.09.2024
The merger timescales of isolated low-mass pairs ($\rm
10^8 It is
common to apply the same separation criteria and expected merger timescales of
high-mass pairs to low-mass systems, however, it is unclear if their merger
timescales are similar, or if they evolve similarly with redshift. We use the
Illustris TNG100 simulation to quantify the merger timescales of isolated
low-mass and high-mass major pairs as a function of cosmic time, and explore
how different selection criteria impact the mass and redshift dependence of
merger timescales. In particular, we present a physically-motivated framework
for selecting pairs via a scaled separation criteria, wherein pair separations
are scaled by the virial radius of the primary's FoF group halo
($r_{\mathrm{sep}}< 1 R_{vir}$). Applying these scaled separation criteria
yields equivalent merger timescales for both mass scales at all redshifts. Alternatively, static physical separation selections applied equivalently to
all galaxy pairs at all redshifts leads to a difference in merger rates of up
to $\rm \sim 1\, Gyr$ between low- and high-mass pairs, particularly for $\rm
r_{sep}<150\, kpc$. As a result, applying the same merger timescales to
physical separation-selected pairs will lead to a bias that systematically
over-predicts low-mass galaxy merger rates. ;Comment: 17 pages, 6 figures
Chamberlain, Katie,Patel, Ekta,Besla, Gurtina,Torrey, Paul,Rodriguez-Gomez, Vicente, 2024, A Physically Motivated Framework to Compare Merger Timescales of Isolated Low- and High-Mass Galaxy Pairs Across Cosmic Time