Tenneti, A;
Kitching, TD;
Joachimi, B;
Di Matteo, T;
(2021)
Group-scale intrinsic galaxy alignments in the Illustris-TNG and MassiveBlack-II simulations.
Monthly Notices of the Royal Astronomical Society
, 501
(4)
pp. 5859-5872.
10.1093/mnras/staa3934.
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Abstract
We study the alignments of satellite galaxies, and their anisotropic distribution, with respect to location and orientation of their host central galaxy in MassiveBlack-II (MB-II) and IllustrisTNG simulations. We find that: the shape of the satellite system in haloes of mass (> 1013 h−1 M) is well aligned with the shape of the central galaxy at z = 0.06 with the mean alignment between the major axes being ∼θ = 12◦ when compared to a uniform random distribution; that satellite galaxies tend to be anisotropically distributed along the major axis of the central galaxy with a stronger alignment in haloes of higher mass or luminosity; and that the satellite distribution is more anisotropic for central galaxies with lower star formation rate, which are spheroidal, and for red central galaxies. Radially, we find that satellites tend to be distributed along the major axis of the shape of the stellar component of central galaxies at smaller scales and the dark matter component on larger scales. We find that the dependence of satellite anisotropy on central galaxy properties and the radial distance is similar in both the simulations with a larger amplitude in MB-II. The orientation of satellite galaxies tends to point toward the location of the central galaxy at small scales and this correlation decreases with increasing distance, and the amplitude of satellite alignment is higher in high-mass haloes. However, the projected ellipticities do not exhibit a scale-dependent radial alignment, as has been seen in some observational measurements.
| Type: | Article |
|---|---|
| Title: | Group-scale intrinsic galaxy alignments in the Illustris-TNG and MassiveBlack-II simulations |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/staa3934 |
| Publisher version: | https://doi.org/10.1093/mnras/staa3934 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | gravitational lensing: weak – hydrodynamics – methods: numerical – galaxies: star formation – cosmology: theory |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10120128 |
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