Observational evidence of evolving dark matter profiles atz ≤ 1

Abstract

Context. In the concordance cosmological scenario, the cold collisionless dark matter component dominates the mass budget of galaxies and interacts with baryons only via gravity. However, there is growing evidence that the former, instead, responds to the baryonic (feedback) processes by modifying its density distribution. These processes can be captured by comparing the inner dynamics of galaxies across cosmic time. Aims. We present a pilot study of dynamical mass modeling of high redshift galaxy rotation curves, which is capable of constraining the structure of dark matter halos across cosmic time. Methods. We investigate the dark matter halos of 256 star-forming disk-like galaxies at z ∼ 1 using the KMOS Redshift One Spectroscopic Survey. This sample covers the redshifts 0.6 ≤ z ≤ 1.04, effective radii 0.69 ≤ Re[kpc] ≤ 7.76, and total stellar masses 8.7 ≤ log(Mstar [M⊙]) ≤ 11.32. We present a mass modeling approach to study the rotation curves of these galaxies, which allow us to dynamically calculate the physical properties associated with the baryons and the dark matter halo. For the former we assume a Freeman disk, while for the latter we employ the NFW (cusp) and the Burkert (cored) halo profiles, separately. At the end, we compare the results of both cases with state-of-the-art galaxy simulations (EAGLE, TNG100, and TNG50). Results. We find that the “cored” dark matter halo emerged as the dominant quantity from a radius 1–3 times the effective radius. Its fraction to the total mass is in good agreement with the outcome of hydrodynamical galaxy simulations. Remarkably, we found that the dark matter core of z ∼ 1 star-forming galaxies are smaller and denser than their local counterparts. Conclusions. Dark matter halos have gradually expanded over the past 6.5 Gyrs. That is, observations are capable of capturing the dark matter response to the baryonic processes, thus giving us the first piece of empirical evidence of “gravitational potential fluctuations” in the inner region of galaxies that can be verified with deep surveys and future missions.

Solution of the dark matter riddle within standard model physics: From galaxies and clusters to cosmology

“…For galaxies, such an expansion of z ∼ 1 cores compared to present ones, was reported [77], see the discussion in section 6.3.…”

“…Another piece of evidence is the observational evidence of evolving constant-density dark matter profiles [77]. By subtracting the contributions from normal matter, these authors study the dark matter halos of a set of 256 star-forming disk-like galaxies at redshift z ∼ 1.…”

Dark Matter in Fractional Gravity. I. Astrophysical Tests on Galactic Scales

“…In a future perspective, it will be interesting to investigate the performance of the fractional gravity framework in fitting the outermost RCs of z ∼ 1 spiral galaxies (see Sharma et al 2022) to more robustly check whether the strength and length scale of the fractional dynamics show signs of evolution with redshift. In addition, our analysis of galaxy kinematics suggests that fractional gravity effects tend to fade away when moving to progressively massive systems; to confirm such a trend, a direct inspection of fractional gravity behavior on larger cosmological scales would be welcome.…”

EDGE: the puzzling ellipticity of Eridanus II’s star cluster and its implications for dark matter at the heart of an ultra-faint dwarf

“…Navarro, Eke & Frenk 1996a ;Read & Gilmore 2005 ;Mashchenko, Couchman & Wadsley 2006 ;Mashchenko, Wadsley & Couchman 2008 ;Pontzen & Go v ernato 2012 ;Di Cintio et al 2014 ). Further dynamical evidence for dark matter cusp-core transformations in galaxies at higher redshift has been recently reported by Genzel et al ( 2020 ), Bouch é et al ( 2022 ), and Sharma, Salucci & van de Ven ( 2022 ).…”