The system of stability equations for galactic halos is under-determined in most of the models of dark matter (DM). Conventionally, the issue is resolved by taking the temperature as a constant, and the chemical potential and the mass density as position-dependent variables. In this paper, to close the under-determined set of equations, we remove the mass density using observations and leave the temperature and the chemical potential as position-dependent variables. We analyze observations of the mass profiles of 175 late-type galaxies in the Spitzer Photometry \& Accurate Rotation Curves (SPARC) database as well as 26 late-type dwarfs in the Little Things database, to construct the temperature profile of their DM halos by assuming that (1) DM in the halos obeys either the Fermi-Dirac or the Maxwell-Boltzmann distribution, and (2) the halos are in the virial state. We derive the dispersion velocity of DM at the center of the halos and show that its correlation with the halo's total mass is consistent with the direct observations of visible matter. Taking the latter agreement as a validation of our analysis, we derive the mass to the temperature of DM at the edge of the halos and show that it is galaxy independent and is equal to $m/T_{R_{200}}\simeq 10^{10}$ in natural units. In the thermal models of DM, such universal temperature is inherently assumed. In this paper, we derive the universal temperature from observations without imposing it by assumptions. Therefore, $T_{R_{200}}$ in the above ratio can be expressed in terms of the temperature of the cosmic microwave background (CMB) at the time of DM decoupling. This result is used to study possible cosmological scenarios. We show that observations are at odds with (1) non-thermal DM, (2) hot DM, and (3) collision-less cold DM. If DM is warm, we estimate its mass to be in the range of keV--MeV.
We present atmospheric gas entropy profiles for 40 early type galaxies and 110 clusters spanning several decades of halo mass, atmospheric gas mass, radio jet power, and galaxy type. We show that within $\sim 0.1R_{2500}$ the entropy profiles of low-mass systems, including ellipticals, brightest cluster galaxies, and spiral galaxies, scale approximately as $K\propto R^{2/3}$. Beyond $\sim 0.1R_{2500}$ entropy profiles are slightly shallower than the $K \propto R^{1.1}$ profile expected from gravitational collapse alone, indicating that heating by AGN feedback extends well beyond the central ga…
The NSF AI Institute for Artificial Intelligence and Fundamental Interactions（美国国家科学基金会人工智能与基础交互AI研究所）；Massachusetts Institute of Technology（麻省理工学院）；Harvard University（哈佛大学）；Princeton University（普林斯顿大学）
Dwarf galaxies are small, dark matter-dominated galaxies, some of which are embedded within the Milky Way. Their lack of baryonic matter (e.g., stars and gas) makes them perfect test beds for probing the properties of dark matter -- understanding the spatial dark matter distribution in these systems can be used to constrain microphysical dark matter interactions that influence the formation and evolution of structures in our Universe. We introduce a new method that leverages simulation-based inference and graph-based machine learning in order to infer the dark matter density profiles of dwarf …
The ACS Fornax Cluster Survey. IV. Deprojection of the Surface Brightness Profiles of Early-Type Galaxies in the Virgo and Fornax Clusters: Investigating the "Core/Power-Law Dichotomy"
In this paper, we extend the work of Freundlich et al. 2020 who showed how to obtain a Dekel-Zhao density profile with mass dependent shape parameters in the case of galaxies. In the case of Freundlich et al. 2020, the baryonic dependence was obtained using the NIHAO set of simulations. In our case, we used simulations based on a model of ours. Following Freundlich et al. 2020, we obtained the dependence from baryon physics of the two shape parameters, obtaining in this way a mass dependent Dekel-Zhao profile describing the dark matter profiles from galaxies to clusters of galaxies. The extens…
Dwarf spheroidal galaxies are excellent targets in gamma-ray searches for dark matter. We consider dark matter searches in dwarf spheroidal galaxies (dSphs) with the Cherenkov Telescope Array (CTA). The aim of this work is to reveal a quantitative and precise dependence of the accessible dark matter annihilation cross-sections on the dark matter density profiles of dSphs and on the distance to them. In most data analyses, researchers have assumed point-like signals from dSphs because it is difficult to resolve the expected emission profiles with current gamma-ray observatories. In future howev…
We modify the chemo-dynamical code GEAR to simulate the impact of self-interacting dark matter on the observable quantities of 19 low mass dwarf galaxies with a variety star forming properties. We employ a relatively high, velocity independent cross-section of $σ/m = 10$cm$^2$/g and extract, in addition to integrated quantities, the total mass density profile, the luminosity profile, the line-of-sight velocities, the chemical abundance and the star formation history. We find that despite the creation of large cores at the centre of the dark matter haloes, the impact of SIDM on the observable q…
Polytropes have gained renewed interest because they account for several seemingly-disconnected observational properties of galaxies. Here we study if polytropes are also able to explain the stellar mass distribution within galaxies. We develop a code to fit surface density profiles using polytropes projected in the plane of the sky (propols). Sersic profiles are known to be good proxies for the global shapes of galaxies and we find that, ignoring central cores, propols and Sersic profiles are indistinguishable within observational errors (within 5 % over 5 orders of magnitude in surface densi…
This work uses observed galaxy surface brightness profiles at high redshifts to determine the cosmological model best suited to interpret these observations. Theoretical predictions of galactic surface brightness profiles are compared to observational data in two cosmological models, $Λ$CDM and Einstein-de Sitter, to calculate the evolutionary effects of different spacetime geometries in these profiles in order to try to find out if the available data is capable of indicating the cosmology that best represents actual galactic brightness profiles observations. Starting from the connection betwe…
We present a modified version of the L-GALAXIES 2020 semi-analytic model of galaxy evolution, which includes significantly increased direct metal enrichment of the circumgalactic medium (CGM) by supernovae (SNe). These more metal-rich outflows do not require increased mass-loading factors, in contrast to some other galaxy evolution models. This modified L-GALAXIES 2020 model is able to simultaneously reproduce the gas-phase metallicity $(Z_{\rm g})$ and stellar metallicity $(Z_{*})$ radial profiles observed in nearby disc galaxies by MaNGA and MUSE, as well as the observed mass - metallicity r…
We apply a flexible parametric model, a combination of generalized Plummer profiles, to infer the shapes of the stellar density profiles of the Milky Way's satellite dwarf spheroidal galaxies (dSphs). We apply this model to 40 dSphs using star counts from the Sloan Digital Sky Survey, PanStarrs-1 Survey, Dark Energy Survey, and Dark Energy Camera Legacy Survey. Using mock data, we examine systematic errors associated with modelling assumptions and identify conditions under which our model can identify `non-standard' stellar density profiles that have central cusps and/or steepened outer slopes…
The role played by the large-scale structures in the galaxy evolution is not quite well understood yet. In this study, we investigate properties of galaxy in the range 0.1<z<0.3 from a value-added version of the WISExSCOS catalogue around cosmic filaments detected with DisPerSE. We have fitted a profile of galaxy over-density around cosmic filaments and found a typical radius of r_m = 7.5+-0.2 Mpc. We have measured an excess of passive galaxies near the filament's spine, higher than the excess of transitioning and active galaxies. We have also detected SFR and Mstar gradients pointing towards …
We explore a new realisation of the galactic scale dynamics via gravitational lensing phenomenon in power-law $f(R)$ gravity theory of the type $f(R)\propto R^{1+δ}$ with $δ<<1$ for interpreting the clustered dark matter effects. We utilize the single effective point like potential (Newtonian potential + $f(R)$ background potential) obtained under the weak field limit to study the combined observations of galaxy rotation curve beyond the optical disk size and their lensing profile in $f(R)$ frame work. We calculate the magnitude of light deflection angle with the characteristic length scale (b…
First results on the cluster galaxy population from the Subaru Hyper Suprime-Cam survey. II. Faint end color-magnitude diagrams and radial profiles of red and blue galaxies at $0.1<z<1.1$
