The analysis of the orbits of 47 dwarf satellite galaxies of the Milky Way, built using three models of the Galactic gravitational potential with different masses, is presented. The models of the Galactic potential were chosen based on the analysis of a large number of the Galaxy mass estimates known from the literature. The astrometric data needed for calculation of the initial positions and velocities (6D phase space) of the dwarf galaxies are also taken from the literature, where the average proper motions were determined on the basis of the data from the Gaia DR2 Catalog. We present the orbits and their properties of all 47 dwarf galaxies obtained by integration for 13.5 Gyr backward in all three models of the Galactic potential and give a comparison of the orbital parameters. For each model of the Galactic potential we have identified dwarf galaxies that are not connected gravitationally with the Milky Way.
With Gaia EDR3 data, velocity dispersion of Milky Way field stars around satellite galaxies have been investigated. We have fitted velocity dispersion against distance to satellite galaxy and found the gradient of velocity dispersion is related to the mass of satellite galaxy. With order-of-magnitude approximations, a linear correlation has been fitted between the mass of satellite galaxy and gradient of velocity dispersion caused by its gravitational drag. Though our result is an observational qualitative result, it shows better relation could be obtained with more observations in the future.
Observational work have shown that the two brightest satellite galaxies of the Milky Way (MW), the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC), are rare amongst MW analogues. It is then interesting to know whether the presence of massive satellite has any effect on the whole satellite population in MW analogues. In this article, we investigate this problem using a semi-analytical model combined with the Millennium-II Simulation. MW-analogous galaxies are defined to have similar stellar mass or dark matter halo mass to the MW. We find that, in the first case, the halo mass…
We examine the spatial distribution and orbital pole correlations of satellites in a suite of zoom-in high-resolution dissipationless simulations of Miky Way (MW) sized haloes. We use the measured distribution to estimate the incidence of satellite configurations as flattened and as correlated in their orbital pole distribution as satellite system of the Milky Way. We confirm that this incidence is sensitive to the radial distribution of subhaloes and thereby to the processes that affect it, such as artificial disruption due to numerical effects and disruption due to the central disk. Controll…
Observations of low-mass satellite galaxies in the nearby Universe point towards a strong dichotomy in their star-forming properties relative to systems with similar mass in the field. Specifically, satellite galaxies are preferentially gas poor and no longer forming stars, while their field counterparts are largely gas rich and actively forming stars. Much of the recent work to understand this dichotomy has been statistical in nature, determining not just that environmental processes are most likely responsible for quenching these low-mass systems but also that they must operate very quickly …
We study the distribution of the Milky Way satellites stellar and dark matter debris. For the first time we address the question of the tidal disruption of satellites in simulations by utilising simultaneously a) a realistic set of orbits extracted from cosmological simulations, b) a three component host galaxy with live halo, disc and bulge components, and c) satellites from hydrodynamical simulations. We analyse the statistical properties of the satellite debris of all massive galaxies reaching the inner Milky Way on a timescale of 2 Gyr. Up to 80$\%$ of the dark matter is stripped from the …
We present a new observation of satellite galaxies around seven Milky Way (MW)-like galaxies located outside of the Local Group (LG) using Subaru/Hyper Suprime-Cam imaging data to statistically address the missing satellite problem. We select satellite galaxy candidates using magnitude, surface brightness, Sérsic index, axial ratio, full width half maximum, and surface brightness fluctuation cuts, followed by visual screening of false-positives such as optical ghosts of bright stars. We identify 51 secure dwarf satellite galaxies within the virial radius of nine host galaxies, two of which are…
The tidal features of the classical Milky Way satellites: Expected in MOND but inconsistent with cold dark matter models
Helmholtz Institut für Strahlen und Kernphysik, Universität Bonn（波恩大学赫尔姆霍兹射线与核物理研究所）；Institute of Cosmology & Gravitation, University of Portsmouth（朴茨茅斯大学宇宙学与引力研究所）；Astronomical Institute of Charles University, Faculty of Mathematics and Physics（查理大学数学物理学院天文研究所）
Observations of the low-mass satellites in the Local Group have shown high fractions of gas-poor, quiescent galaxies relative to isolated dwarfs, implying that the host halo environment plays an important role in the quenching of dwarf galaxies. In this work, we present measurements of the quenched fractions and quenching timescales of dwarf satellite galaxies in the DC Justice League suite of 4 high-resolution cosmological zoom-in simulations of Milky Way-mass halos. We show that these simulations accurately reproduce the satellite luminosity functions of observed nearby galaxies, as well as …
On small scales there have been a number of claims of discrepancies between the standard Cold Dark Matter (CDM) model and observations. The 'missing satellites problem' infamously describes the overabundance of subhalos from CDM simulations compared to the number of satellites observed in the Milky Way. A variety of solutions to this discrepancy have been proposed; however, the impact of the specific properties of the Milky Way halo relative to the typical halo of its mass have yet to be explored. Motivated by recent studies that identified ways in which the Milky Way is atypical (e.g., Licqui…
We present results from the "Mint" resolution DC Justice League suite of Milky Way-like zoom-in cosmological simulations, which extend our study of nearby galaxies down into the ultra-faint dwarf (UFD) regime for the first time. The mass resolution of these simulations is the highest ever published for cosmological Milky Way zoom-in simulations run to $z=0$, with initial star (dark matter) particle masses of 994 (17900) M$_\odot$, and a force resolution of 87 pc. We study the surrounding dwarfs and UFDs, and find the simulations match the observed dynamical properties of galaxies with $-3 < M_…
The cuspy central density profiles of cold dark matter (CDM) haloes make them highly resilient to disruption by tides. Self-interactions between dark matter particles, or the cycling of baryons, may result in the formation of a constant-density core which would make haloes more susceptible to tidal disruption. We use N-body simulations to study the evolution of NFW-like "cored" subhaloes in the tidal field of a massive host, and identify the criteria and timescales for full tidal disruption. Our results imply that the survival of Milky Way satellites places constraints on the sizes of dark mat…
In this work we use structural properties of Milky Way's outer halo ($R_G > 25\,\mathrm{kpc}$) satellites (dwarf spheroidal galaxies, ultra-faint dwarf galaxies and globular clusters) derived from deep, wide-field and homogeneous data, to present evidence of a correlation in the Sérsic index v/s effective radius plane followed by a large fraction of outer halo globular clusters and satellite dwarf galaxies. We show that this correlation can be entirely reproduced by fitting empirical relations in the central surface brightness v/s absolute magnitude and Sérsic index v/s absolute magnitude para…
To better understand the formation of large, low surface brightness galaxies, we measure the correlation function between ultra-diffuse galaxy (UDG) candidates and Milky Way analogs (MWAs). We find that (1) the projected radial distribution of UDG satellites (projected surface density $\propto r^{-0.84\pm0.06}$) is consistent with that of normal satellite galaxies, (2) the number of UDG satellites per MWA ($S_{\rm UDG}$) is $\sim 0.5\pm0.1$ over projected radii from 20 to 250 kpc and $-17< M_r < -13.5$, (3) $S_{\rm UDG}$ is consistent with a linear extrapolation of the relationship between the…
The structure of a dwarf galaxy is an important probe into the effects of stellar feedback and environment. Using an unprecedented sample of 223 low-mass satellites from the ongoing Exploration of Local VolumE Satellites (ELVES) Survey, we explore the structures of dwarf satellites in the mass range $10^{5.5}<M_\star<10^{8.5}$M$_\odot$. We survey satellites around $80\%$ of the massive, $M_K<-22.4$ mag, hosts in the Local Volume. Our sample of dwarf satellites is complete to luminosities of $M_V<-9$ mag and surface brightness $μ_{0,V}<26.5$ mag arcsec$^{-2}$ within at least $\sim200$ projected…
We extend the Ultra-Diffuse Galaxy (UDG) abundance relation, $N_{UDG}-M_{200}$, to lower halo mass hosts $(M_{200}\sim10^{11.6-12.2}M_{\odot})$. We select UDG satellites from published catalogs of dwarf satellite galaxies around Milky Way analogs, namely the Exploration of Local Volume Satellites (ELVES) survey, Satellite Around Galactic Analogs (SAGA) survey, and a survey of Milky Way-like systems conducted using the Hyper-Suprime Cam. Of the 516 satellites around a total of 75 Milky Way-like hosts, we find 41 satellites around 33 hosts satisfy the UDG criteria. The distributions of host halo…
Twenty years ago, the mismatch between the observed number of Milky Way satellite galaxies and the predicted number of cold dark matter (CDM) subhalos was dubbed the ``missing satellites problem". Although mostly framed since in terms of satellite counts in luminosity space, the missing satellites problem was originally posed in velocity space. Importantly, the stellar velocity dispersion function encodes information about the density profile of satellites as well as their abundance. In this work, we completeness correct the MW satellite stellar velocity dispersion function down to its ultrafa…
