The distribution of dark matter and gas spanning 6 Mpc around the post-merger galaxy cluster MS 0451−03

Abstract

<jats:title>ABSTRACT</jats:title> <jats:p>Using the largest mosaic of Hubble Space Telescope images around a galaxy cluster, we map the distribution of dark matter throughout an ∼6 × 6 Mpc2 area centred on the cluster MS 0451−03 (z = 0.54, $M_{200}=1.65\times 10^{15}\, {\rm M}_{\odot }$). Our joint strong- and weak-lensing analysis shows three possible filaments extending from the cluster, encompassing six group-scale substructures. The dark matter distribution in the cluster core is elongated, consists of two distinct components, and is characterized by a concentration parameter of c200 = 3.79 ± 0.36. By contrast, XMM–Newton observations show the gas distribution to be more spherical, with excess entropy near the core, and a lower concentration of $c_{200}=2.35^{+0.89}_{-0.70}$ (assuming hydrostatic equilibrium). Such a configuration is predicted in simulations of major mergers 2–7 Gyr after the first core passage, when the two dark matter haloes approach second turnaround, and before their gas has relaxed. This post-merger scenario finds further support in optical spectroscopy of the cluster’s member galaxies, which shows that star formation was abruptly quenched 5 Gyr ago. MS 0451−03 will be an ideal target for future studies of the growth of structure along filaments, star formation processes after a major merger, and the late-stage evolution of cluster collisions.</jats:p>

Cluster–galaxy weak lensing

“…To properly model the weak-lensing signal in such a complex merging system, one needs to directly model the two-dimensional reduced-shear field ðg 1 ðhÞ; g 2 ðhÞÞ with a lens model consisting of multicomponent halos (e.g., Watanabe et al 2011;Okabe et al 2011;Medezinski et al 2013). Alternatively, one may attempt to reconstruct the convergence field jðhÞ in a free-form manner from the observed reduced shear field, with additional constraints or assumptions to break the mass-sheet degeneracy (e.g., Jee et al 2005;Bradač et al 2006;Merten et al 2009;Jauzac et al 2012;Umetsu et al 2015;Tam et al 2020).…”

Imprint of Pressure on Characteristic Dark Matter Profiles: The Case of ESO0140040

“…Recent observations certify that DM amounts for about 26.8% of the total energy budget of the Universe [1], while from theoretical point of view it has been proposed that DM is made of some experimentally as yet undiscovered particles [2,3] coming from extensions of the standard model of particle physics 1 . The number of approaches related to the DM problem is steadily growing, reflecting a noticeable interest in comprehending its nature [4][5][6], which constitutes the 85% of all the matter i.e., DM+baryons, and state function of baryons in the Universe.…”

“…Inferring bounds over free parameters turns out to be essential to investigating galactic dynamics and, in addition, to reconciling DM abundance with the dark energy contribution in the present epoch 4 . Thus, a successfully implemented paradigm can be naturally worked out within the Newtonian approximation [13], for the slow motions of stars as commonly adopted in the literature.…”

Dark Matter Properties in Galaxy U5750

“…Nevertheless, up to date, a huge amount of information has been obtained, which allows one to judge about the distribution of DM and its role in the Universe. The number of scientific works related to the problem of DM is steadily growing from year to year, which reflects a noticeable interest in this intriguing and at the same time fascinating topic [6][7][8].…”