Intrinsic alignments of disc and elliptical galaxies in the MassiveBlack-II and Illustris simulations

• DOI: 10.1093/mnras/stw1823
• Publication Date: 2016-07-28T20:53:22Z
• Authors: Ananth Tenneti; Rachel Mandelbaum; Tiziana Di Matteo
• Keywords: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); 0103 physical sciences; FOS: Physical sciences; 20399 Classical Physics not elsewhere classified; Astrophysics - Astrophysics of Galaxies; 01 natural sciences; Astrophysics - Cosmology and Nongalactic Astrophysics

We study the shapes and intrinsic alignments of discs elliptical galaxies in MassiveBlack-II (MBII) Illustris cosmological hydrodynamic simulations, with volumes (100 h−1 Mpc)3 (75 Mpc)3, respectively. find that simulated disc are more oblate shape misaligned their host dark matter subhalo when compared ellipticals. The major axis is found to be oriented towards location nearby galaxies. also thinner MBII misalignments halo orientations smaller both ellipticals Illustris. As a result, alignment correlation functions at fixed mass have higher amplitude than Finally, scales above ∼0.1 Mpc, two-point for simulations consistent null detection, unlike those Despite significant differences treatments hydrodynamics baryonic physics we wδ + function similarly transverse separation. However, less massive show different scale dependence ellipticity-direction correlation. This result indicates that, while promising tool alignments, further needed understand impact implementations feedback.