Mismatch and Misalignment: Dark Haloes and Satellites of Disc Galaxies

Details Mismatch and Misalignment: Dark Haloes and Satellites of Disc Galaxies Mismatch and Misalignment: Dark Haloes and Satellites of Disc Galaxies

2011-01-04

arxiv.org/abs/1101.0816v2

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

19 pages, 17 Figures. Accepted by MNRAS

Scientific paper

(Abridged) We study the phase-space distribution of satellite galaxies associated with late-type galaxies in the GIMIC suite of simulations. GIMIC consists of re-simulations of 5 cosmologically representative regions from the Millennium simulation, which have higher resolution and incorporate baryonic physics. Whilst the disc of the galaxy is well aligned with the inner regions (r ~ 0.1r_200) of the dark matter halo, both in shape and angular momentum, there can be substantial misalignments at larger radii (r ~ r_200). Misalignments of > 45 deg are seen in ~ 30% of our sample. We find that the satellite population aligns with the shape (and angular momentum) of the outer dark matter halo. However, the alignment with the galaxy is weak owing to the mismatch between the disc and dark matter halo. Roughly 20% of the satellite systems with ten bright galaxies within r_200 exhibit a polar spatial alignment with respect to the galaxy --- an orientation reminiscent of the classical satellites of the Milky Way. We find that a small fraction (~10%) of satellite systems show evidence for rotational support which we attribute to group infall. There is a bias towards satellites on prograde orbits relative to the spin of the dark matter halo (and to a lesser extent with the angular momentum of the disc). This preference towards co-rotation is stronger in the inner regions of the halo where the most massive satellites accreted at relatively early times are located. We attribute the anisotropic spatial distribution and angular momentum bias of the satellites at z=0 to their directional accretion along the major axes of the dark matter halo. The satellite galaxies have been accreted relatively recently compared to the dark matter mass and have experienced less phase-mixing and relaxation --- the memory of their accretion history can remain intact to z=0.

Affiliated with

Also associated with

No associations

Rating

Mismatch and Misalignment: Dark Haloes and Satellites of Disc Galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Mismatch and Misalignment: Dark Haloes and Satellites of Disc Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mismatch and Misalignment: Dark Haloes and Satellites of Disc Galaxies will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-265524