Do Halos that Form Early, Have High Concentration, Are Part of a Pair, or Contain a Central Galaxy Potential Host More Pronounced Planes of Satellite Galaxies?

Abstract

The Milky Way, the Andromeda galaxy, and Centaurus A host flattened distributions of satellite galaxies which exhibits coherent velocity trends indicative of rotation. Comparably extreme satellite structures are very rare in cosmological ΛCDM simulations, giving rise to the "satellite plane problem". As a possible explanation it has been suggested that earlier-forming, higher concentration host halos contain more flattened and kinematically coherent satellite planes. We have tested for such a proposed correlation between the satellite plane and host halo properties in the ELVIS suite of simulations. We find evidence neither for a correlation of plane flattening with halo concentration or formation time, nor for a correlation of kinematic coherence with concentration. The height of the thinnest sub-halo planes does correlate with the host virial radius and with the radial extent of the sub-halo system. This can be understood as an effect of not accounting for differences in the radial distribution of sub-halos, and selecting them from different volumes than covered by the actual observations. Being part of a halo pair like the Local Group does not result in more narrow or more correlated satellite planes either. Additionally, using the PhatELVIS simulations we show that the presence of a central galaxy potential does not favor more narrow or more correlated satellite planes, it rather leads to slightly wider planes. Such a central potential is a good approximation of the dominant effect baryonic physics in cosmological simulations has on a sub-halo population. This suggests that, in contrast to other small-scale problems, the planes of satellite galaxies issue is made worse by accounting for baryonic effects. 1 We refer the interested reader to two of our recent contribution on this topic: and Pawlowski et al. (2015b).

The Milky Way’s disc of classical satellite galaxies in light of Gaia DR2

“…9. This confirms the expectation that the satellite galaxy phase space distribution constitutes a robust test of the cosmological model (Kroupa et al 2005;Pawlowski 2018), indicates that previous studies using dark-matter-only simulations to compare to the VPOS remain valid, and confirms earlier indications that the modelling of baryonic processes in cosmological simulations does not alleviate the planes of satellite galaxies problem (Ahmed et al 2017;Pawlowski et al 2015bPawlowski et al , 2017Pawlowski et al , 2019Shao et al 2018).…”

“…Numerous suggested solutions of this Planes of Satellite Galaxies Problem have been investigated, but none are generally agreed upon to satisfactorily address the issue. This includes the infall of satellite galaxies in groups (Li & Helmi 2008;D'Onghia & Lake 2008;Metz et al 2009b;Wang et al 2013;Shao et al 2018), the accretion of satellites along the cosmic web (Lovell et al 2011;Libeskind et al 2011;Pawlowski et al 2012bPawlowski et al , 2014, baryonic effects in cosmological simulations (Pawlowski et al 2015b;Ahmed et al 2017;Müller et al 2018;Pawlowski et al 2019), and special environments or properties of the host halos such as Local-Group-like pair configuration, halo concentration or formation time (Pawlowski & McGaugh 2014b;Libeskind et al 2015;Buck et al 2015;Pawlowski et al 2019). This makes the Planes of Satellite Galaxies problem one of the most long-standing small-scale problems of ΛCDM.…”

Testing gravity with interstellar precursor missions

“…Both problems are rather immune to baryonic physics because they involve length scales of several hundred kpc and relate to the motion of galaxies as a whole. This was recently demonstrated for the satellite plane problem by approximately including the main way in which baryonic physics affects it (Pawlowski et al 2019). A highly anisotropic satellite system also exists around Centaurus A (Müller et al 2018).…”

Tailoring a Dress to Single Protein Molecules: Proteins Can Do It Themselves through Localized Photo‐Polymerization and Molecular Imprinting

“…Starting from the observation that unfavorable to no binding occurs for P* MIP NPs titrated with non‐template proteins (Table 1), we conclude that if the NP polymeric networks are woven around the template, the formed binding sites should possess high template‐fidelity. To investigate whether the imprinted cavities produced by means of the P* approach (mb‐P* MIP NPs) are different from the classical synthesis (mb MIP NPs), we chose fluorescence as an additional method, which provides information on the physical environment surrounding a fluorophore during the course of an interaction, [28, 29] and allows for a deeper inspection of the stamped sites. A fluorescent derivative of the target protein (mb‐655) was prepared by coupling of the Attodye‐655‐isothiocyanate to mb.…”