The fate of the Antennae galaxies

Abstract

We present a high-resolution smoothed particle hydrodynamics simulation of the Antennae galaxies (NGC 4038/4039) and follow the evolution 3 Gyrs beyond the final coalescence. The simulation includes metallicity dependent cooling, star formation, and both stellar feedback and chemical enrichment. The simulated best-match Antennae reproduces well both the observed morphology and the off-nuclear starburst. We also produce for the first time a simulated two-dimensional metallicity map of the Antennae and find good agreement with the observed metallicity of off-nuclear stellar clusters, however the nuclear metallicities are overproduced by ∼ 0.5 dex. Using the radiative transfer code SKIRT we produce multi-wavelength observations of both the Antennae and the merger remnant. The 1 Gyr old remnant is well fitted with a Sérsic profile of n = 7.07, and with an r-band effective radius of r e = 1.6 kpc and velocity dispersion of σ e = 180 km/s the remnant is located on the fundamental plane of early-type galaxies (ETGs). The initially blue Antennae remnant evolves onto the red sequence after ∼ 2.5 Gyr of secular evolution. The remnant would be classified as a fast rotator, as the specific angular momentum evolves from λ Re ≈ 0.11 to λ Re ≈ 0.14 during its evolution. The remnant shows ordered rotation and a double peaked maximum in the mean 2D line-of-sight velocity. These kinematical features are relatively common among local ETGs and we specifically identify three local ETGs (NGC 3226, NGC 3379 and NGC 4494) in the ATLAS 3D sample, whose photometric and kinematic properties most resemble the Antennae remnant.

The GRIFFIN Project—Formation of Star Clusters with Individual Massive Stars in a Simulated Dwarf Galaxy Starburst

“…We chose the same initial orientations as for the Antennae-like simulations studied in Lahén et al (2018). As presented in L19, we have run the simulation for up to 100 Myr after the merger, for a total of ∼ 300 Myr.…”

Galaxy mergers in eagle do not induce a significant amount of black hole growth yet do increase the rate of luminous AGN

“…However observational works must ascertain the merging state of a galaxy from only an instantaneous (often pre-coalescence) snapshot. Thus a truly fair comparison would require us to apply observational techniques to synthetic images to estimate a galaxy's current merging state (similar to Lahén et al 2018;Bottrell et al 2019;Snyder et al 2019, for example), but this is beyond the scope of this study. We can, however, qualitatively compare our results to the observational studies.…”

Structure and Rotation of Young Massive Star Clusters in a Simulated Dwarf Starburst

“…in Cappellari et al (2006) for early-type galaxies and in Bianchini et al (2018) for globular clusters. The same methods can also essentially be used in analysing numerical simulations (Naab et al 2014;Lahén et al 2018;Rantala et al 2018;Frigo et al 2019). As we are modeling individual massive stars rather than massive stellar population particles, we discard seeing effects applied to larger scale simulations (Naab et al 2014), and instead directly fit the LOSVD to the Voronoi-tesselated particle data.…”