We present an empirical model for the number of globular clusters (GCs) in galaxies based on recent data showing a tight relationship between dark matter halo virial masses and GC numbers. While a simple base model forming GCs in low-mass haloes reproduces this relation, we show that a second formation pathway for GCs is needed to account for observed younger GC populations. We confirm previous works that reported the observed linear correlation as being a consequence of hierarchical merging and its insensitivity to the exact GC formation processes at higher virial masses, even for a dual formation scenario. We find that the scatter of the linear relation is strongly correlated with the relative amount of smooth accretion: the more dark matter is smoothly accreted, the fewer GCs a halo has compared to other haloes of the same mass. This scatter is smaller than that introduced by halo mass measurements, indicating that the number of GCs in a galaxy is a good tracer for its dark matter mass. Smooth accretion is also the reason for a lower average dark matter mass per GC in low-mass haloes. Finally, we successfully reproduce the observed general trend of GCs being old and the tendency of more massive haloes hosting older GC systems. Including the second GC formation mechanism through gas-rich mergers leads to a more realistic variety of GC age distributions and also introduces an age inversion in the halo virial mass range $\log M_\mathrm{vir}/\mathrm{M}_\odot = 11{-}13$.
We show that hard encounters in the central regions of globular clusters embedded in dark matter (DM) haloes necessarily lead to the formation of gravitationally-bound stellar envelopes that extend far beyond the nominal tidal radius of the system. Using statistical arguments and numerical techniques we derive the equilibrium distribution function of stars ejected from the centre of a non-divergent spherical potential. Independently of the velocity distribution with which stars are ejected, GC envelopes have density profiles that approach asymptotically $ρ\sim r^{-4}$ at large distances and be…
Small distortions in the images of Einstein rings or giant arcs offer the exciting prospect of detecting dark matter haloes or subhaloes of mass below $10^9$M$_{\odot}$, most of which are too small to have made a visible galaxy. A very large number of such haloes are predicted to exist in the cold dark matter model of cosmogony; in contrast other models, such as warm dark matter, predict no haloes below a mass of this order which depends on the properties of the warm dark matter particle. Attempting to detect these small perturbers could therefore discriminate between different kinds of dark m…
The sizes of entire systems of globular clusters (GCs) depend on the formation and destruction histories of the GCs themselves, but also on the assembly, merger and accretion history of the dark matter (DM) haloes that they inhabit. Recent work has shown a linear relation between total mass of globular clusters in the globular cluster system and the mass of its host dark matter halo, calibrated from weak lensing. Here we extend this to GC system sizes, by studying the radial density profiles of GCs around galaxies in nearby galaxy groups. We find that radial density profiles of the GC systems …
The dynamical friction timescale of massive globular clusters (GCs) in the inner regions of cuspy dark haloes in dwarf spheroidal (dSph) galaxies can be much shorter than the Hubble time. This implies that a small fraction of the GCs is expected to be caught close to the centre of these galaxies. We compare the radial distribution of GCs predicted in simple Monte Carlo models with that of a sample of $38$ spectroscopically confirmed GCs plus 17 GC candidates, associated mainly to low-luminosity dSph galaxies. If dark matter haloes follow an NFW profile, the observed number of off-center GCs at…
Recently a theory about the formation of over-densities of stars along tidal tails of globular clusters has been presented, this theory predicts the position and time of formation of such over-densities and was successfully tested with N-body simulations of globular clusters in a point mass galactic potential. In this work we present a comparison between this theory and our simulations using a dwarf galaxy orbiting two differently shaped dark matter halos to study the effects of a cored and a cuspy halo on the formation and evolution of tidal tails. We find no difference using a cuspy or a cor…
We explore how diffuse stellar light and globular clusters (GCs) can be used to trace the matter distribution of their host halo using an observational methodology. For this, we use 117 simulated dark matter (DM) haloes from the $(34.4~\rm cMpc)^3$ periodic volume of the E-MOSAICS project. For each halo, we compare the stellar surface brightness and GC projected number density maps to the surface densities of DM and total mass. We find that the dominant structures identified in the stellar light and in the GCs correspond closely with those from the DM and total mass. Our method is unaffected b…
Lensing flux-ratio anomalies have been frequently observed and taken as evidence for the presence of abundant dark matter substructures in lensing galaxies, as predicted by the cold dark matter (CDM) model of cosmogony. In previous work, we examined the cusp-caustic relations of the multiple images of background quasars lensed by galaxy-scale dark matter haloes, using a suite of high-resolution N-body simulations (the Aquarius simulations). In this work, we extend our previous calculations to incorporate both the baryonic and diffuse dark components in lensing haloes. We include in each lensin…
Globular clusters (GCs) are bright objects that span a wide range of galactocentric distances, and are thus probes of the structure of dark matter (DM) haloes. In this work, we explore whether the projected radial profiles of GCs can be used to infer the structural properties of their host DM haloes. We use the simulated GC populations in a sample of 166 central galaxies from the $(34.4~\rm cMpc)^3$ periodic volume of the E-MOSAICS project. We find that more massive galaxies host stellar and GC populations with shallower density profiles that are more radially extended. In addition, the metal-…
The Aquarius project is the first simulation that can resolve the full mass range of potential globular cluster formation sites. With a particle mass $m_\mathrm{p}=1.4 \times 10^4$\Msun, Aquarius yields more than 100 million particles within the virial radius of the central halo which has a mass of $1.8 \times 10^{12}$\Msun, similar to that of the Milky Way. With this particle mass, dark matter concentrations (haloes) as small as 10$^6$ M$_\odot$ will contain a minimum of 100 particles.Here, we use this simulation to test a model of metal-poor globular cluster formation based on collapse physi…
We use N-body simulations to study the tidal evolution of globular clusters (GCs) in dwarf spheroidal (dSph) galaxies. Our models adopt a cosmologically motivated scenario in which the dSph is approximated by a static NFW halo with a triaxial shape. We apply our models to five GCs spanning three orders of magnitude in stellar density and two in mass, chosen to represent the properties exhibited by the five GCs of the Fornax dSph. We show that only the object representing Fornax's least dense GC (F1) can be fully disrupted by Fornax's internal tidal field--the four denser clusters survive even …
Dynamical friction vs. subhalo heating in Cold Dark Matter haloes
Institute of Corpuscular Physics (IFIC), CSIC–Universitat de València（核物理研究所（IFIC），西班牙科学研究中心-瓦伦西亚大学）；VALER；Institute for Astronomy, University of Edinburgh（爱丁堡大学天文研究所）；Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche（复杂系统研究所，意大利国家研究委员会）；Osservatorio Astrofisico di Arcetri, Istituto Nazionale di Astrofisica（阿切特里天体物理观测台，意大利国家天体物理研究所）；Istituto nazionale di Fisica Nucleare（意大利国家核物理研究所）；McWilliams centre for Cosmology and Astrophysics, Department of Physics, Carnegie Mellon University（卡内基梅隆大学物理学院麦克威廉斯宇宙学与天体物理学中心）
We present an end-to-end, two-phase model for the origin of globular clusters (GCs). In the model, populations of stellar clusters form in the high-pressure discs of high-redshift ($z>2$) galaxies (a rapid-disruption phase due to tidal perturbations from the dense interstellar medium), after which the galaxy mergers associated with hierarchical galaxy formation redistribute the surviving, massive clusters into the galaxy haloes, where they remain until the present day (a slow-disruption phase due to tidal evaporation). The high galaxy merger rates of $z>2$ galaxies allow these clusters to be `…
We study the outer regions of the Milky Way globular cluster NGC 7089 based on new Dark Energy Camera (DECam) observations. The resulting background cleaned stellar density profile reveals the existence of an extended envelope. We confirm previous results that cluster stars are found out to ~ 1deg from the cluster's centre, which is nearly three times the value of the most robust tidal radii estimations. We also used results from direct N-body simulations in order to compare with the observations. We found a fairly good agreement between the observed and numerically generated stellar density p…
Massive galaxies are thought to form in two phases: an initial, early collapse of gas and giant burst of central star formation, followed by the later accretion of material that builds up their stellar and dark matter haloes. The globular cluster systems of such galaxies are believed to form in a similar manner. The initial central burst forms metal-rich (red) clusters, while more metal-poor (blue) clusters are brought in by the later accretion of less massive satellites. This formation process is thought to lead the creation of the multimodal optical colour distributions seen in the globular …
We use N-body simulations to study the tidal evolution of globular clusters (GCs) in dwarf spheroidal (dSph) galaxies. Our models adopt a cosmologically motivated scenario in which the dSph is approximated by a static NFW halo with a triaxial shape. For a large set of orbits and projection angles we examine the spatial and velocity distribution of stellar debris deposited during the complete disruption of stellar clusters. Our simulations show that such debris appears as shells, isolated clumps and elongated over-densities at low surface brightness (>26 mag/arcsec^2), reminiscent of substructu…
We simulate neutralino dark matter ($χ$DM) haloes from their initial collapse, at $\sim$ earth mass, up to a few percent solar. Our results confirm that the density profiles of the first haloes are described by a $\sim r^{-1.5}$ power-law. As haloes grow in mass, their density profiles evolve significantly. In the central regions, they become shallower and reach on average $\sim r^{-1}$, the asymptotic form of an NFW profile. Using non-cosmological controlled simulations, we observe that temporal variations in the gravitational potential caused by major mergers lead to a shallowing of the inne…
One of the primary goals when studying galaxy formation is to understand how the luminous component of the Universe, galaxies, relates to the growth of structure which is dominated by the gravitational collapse of dark matter haloes. The stellar-to-halo mass relation probes how galaxies occupy dark matter haloes and what that entails for their star formation history. We deliver the first self-consistent empirical model that can place constraints on the stellar-to-halo mass relation down to log stellar mass $\log_{10}(m^*/\mathrm{M}_{\odot}) \leq 5.0$ by fitting our model directly to Local Grou…
We investigate galaxy conformity using the Mufasa cosmological hydrodynamical simulation. We show a bimodal distribution in galaxy colour with radius, albeit with too many low-mass quenched satellite galaxies compared to observations. Mufasa produces conformity in observed properties such as colour, sSFR, and HI content; i.e neighbouring galaxies have similar properties. We see analogous trends in other properties such as in environment, stellar age, H$_2$ content, and metallicity. We introduce quantifying conformity using $S(R)$, measuring the relative difference in upper and lower quartile p…
Recent observations of the dwarf elliptical galaxy Scl-dE1 (Sc22) in the Sculptor group of galaxies revealed an extended globular cluster (Scl-dE1 GC1), which exhibits an extremely large core radius of about 21.2 pc. The authors of the discovery paper speculated on whether this object could reside in its own dark matter halo and/or if it might have formed through the merging of two or more star clusters. In this paper, we present N-body simulations to explore thoroughly this particular formation scenario. We follow the merger of two star clusters within dark matter haloes of a range of masses …
We present $N$-body simulations of globular clusters, exploring the effect of different galactic potentials on cluster sizes, $r_h$. For various galactocentric distances, $R_G$, we assess how cluster sizes change when we vary the virial mass and concentration of the host galaxy's dark-matter halo. We show that sizes of GCs are determined by the local galactic mass density rather than the virial mass of the host galaxy. We find that clusters evolving in the inner haloes of less concentrated galaxies are significantly more extended than those evolving in more concentrated ones, while the sizes o…
The concentration parameter is a key characteristic of a dark matter halo that conveniently connects the halo's present-day structure with its assembly history. Using 'Dark Sky', a suite of cosmological $N$-body simulations, we investigate how halo concentration evolves with time and emerges from the mass assembly history. We also explore the origin of the scatter in the relation between concentration and assembly history. We show that the evolution of halo concentration has two primary modes: (1) smooth increase due to pseudo-evolution; and (2) intense responses to physical merger events. Mer…
We model and analyse the secular evolution of stellar bars in spinning dark matter (DM) haloes with the cosmological spin lambda ~ 0 -- 0.09. Using high-resolution stellar and DM numerical simulations, we focus on angular momentum exchange between stellar discs and DM haloes of various axisymmetric shapes --- spherical, oblate and prolate. We find that stellar bars experience a diverse evolution which is guided by the ability of parent haloes to absorb angular momentum lost by the disc through the action of gravitational torques, resonant and non-resonant. We confirm the previous claim that dy…
We summarise some of the recent progress in understanding the formation and evolution of globular clusters (GCs) in the context of galaxy formation and evolution. It is discussed that an end-to-end model for GC formation and evolution should capture four different phases: (1) star and cluster formation in the high-pressure interstellar medium of high-redshift galaxies, (2) cluster disruption by tidal shocks in the gas-rich host galaxy disc, (3) cluster migration into the galaxy halo, and (4) the final evaporation-dominated evolution of GCs until the present day. Previous models have mainly foc…
We investigate whether the galaxy and star formation model used for the Auriga simulations can produce a realistic globular cluster (GC) population. We compare statistics of GC candidate star particles in the Auriga haloes with catalogues of the Milky Way (MW) and Andromeda (M31) GC populations. We find that the Auriga simulations do produce sufficient stellar mass for GC candidates at radii and metallicities that are typical for the MW GC system (GCS). We also find varying mass-ratios of the simulated GC candidates relative to the observed mass in the MW and M31 GC systems for different bins …
Linking globular clusters (GCs) to the assembly of their host galaxies is an overarching goal in GC studies. The inference of tight scaling relations between GC system properties and the mass of both the stellar and dark halo components of their host galaxies are indicative of an intimate physical connection, yet have also raised fundamental questions about how and when GCs form. Specifically, the inferred correlation between the mass of a GC system (Mgc) and the dark matter halo mass (Mhalo) of a galaxy has been posited as a consequence of a causal relation between the formation of dark matte…
We present a detailed comparison of the Milky Way (MW) globular cluster (GC) kinematics with the 25 Milky Way-mass cosmological simulations from the E-MOSAICS project. While the MW falls within the kinematic distribution of GCs spanned by the simulations, the relative kinematics of its metal-rich ($[\rm{Fe/H}]>-1.2$) versus metal-poor ($[\rm{Fe/H}]<-1.2$), and inner ($r<8\rm{kpc}$) versus outer ($r>8\rm{kpc}$) populations are atypical for its mass. To understand the origins of these features, we perform a comprehensive statistical analysis of the simulations, and find 18 correlations describin…
In addition to their low stellar densities, ultra-diffuse galaxies (UDGs) have a broad variety of dynamical mass-to-light ratios, ranging from dark matter (DM) dominated systems to objects nearly devoid of DM. To investigate the origin of this diversity, we develop a simple, semi-empirical model that predicts the structural evolution of galaxies, driven by feedback from massive star clusters, as a function of their departure from the mean SMHM relation. The model predicts that a galaxy located $\gtrsim 0.5$ dex above the mean relation at $M_{\rm halo}=10^{10}M_{\odot}$ will host a factor of $\…
Using adiabatic high-resolution numerical simulations we quantify the effect of the streaming motion of baryons with respect to dark matter at the time of recombination on structure formation and evolution. Formally a second order effect, the baryonic stream velocity has proven to have significant impact on dark matter halo abundance, as well as on the gas content and morphology of small galaxy clusters. In this work, we study the impact of stream velocity on the formation and gas content of haloes with masses up to $10^9 M_{\odot}$, an order of magnitude larger than previous studies. We find …
Globular clusters are prone to lose stars while moving around the Milky Way. These stars escape the clusters and are distributed throughout extended envelopes or tidal tails. However, such extra-tidal structures are not observed in all globular clusters, and yet there is no structural or dynamical parameters that can predict their presence or absence. NGC\,6864 is an outer halo globular cluster with reported no observed tidal tails. We used Dark Energy Camera (DECam) photometry reaching $\sim$ 4 mag underneath its main sequence turnoff to confidently detect an extra-tidal envelope, and stellar…
We apply our recently proposed "quadratic genetic modification" approach to generating and testing the effects of alternative mass accretion histories for a single $Λ$CDM halo. The goal of the technique is to construct different formation histories, varying the overall contribution of mergers to the fixed final mass. This enables targeted studies of galaxy and dark matter halo formation's sensitivity to the smoothness of mass accretion. Here, we focus on two dark matter haloes, each with four different mass accretion histories. We find that the concentration of both haloes systematically decre…
Using a recent homogeneous sample of 40 high quality velocity dispersion profiles for Galactic globular clusters, we study the low gravitational acceleration regime relevant to the outskirts of these systems. We find that a simple empirical profile having a central Gaussian component and a constant large radius asymptote, $σ_{\infty}$, accurately describes the variety of observed velocity dispersion profiles. We use published population synthesis models, carefully tailored to each individual cluster, to estimate mass to light ratios from which total stellar masses, $M$, are inferred. We obtain…
Constraining the shape of dark matter haloes using only starlight II. Tests of the technique with objects of known gravitational potential
Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Universidad Nacional del Noroeste de la Prov. de Buenos Aires, UNNOBA, CONICET（布宜诺斯艾利斯省西北国立大学，UNNOBA，CONICET）；University of Virginia（弗吉尼亚大学）
Formation of globular cluster-rich ultra-diffuse galaxies through mergers
International Centre for Radio Astronomy Research, The University of Western Australia（西澳大利亚大学国际无线电天文研究中心）；National Institute of Technology, Asahikawa College（旭川工业高等专门学校）；ATNF, CSIRO Space and Astronomy（CSIRO空间与天文台射电天文国家设施）；Centre for Astrophysics and Supercomputing, Swinburne University（斯威本科技大学天体物理学与超级计算中心）
We present EMERGE, an Empirical ModEl for the foRmation of GalaxiEs, describing the evolution of individual galaxies in large volumes from $z\sim10$ to the present day. We assign a star formation rate to each dark matter halo based on its growth rate, which specifies how much baryonic material becomes available, and the instantaneous baryon conversion efficiency, which determines how efficiently this material is converted to stars, thereby capturing the baryonic physics. Satellites are quenched following the delayed-then-rapid model, and they are tidally disrupted once their subhalo has lost a…
Apparently similar but multifaceted photometric systems are currently being used to investigate the multiple stellar populations in globular clusters, without the concrete general agreement on the definition of the multiple populations. In recent years, an attractive idea of utilization of the widely used UBI photometry, C_{UBI}, for the populational tagging of the giant stars in globular clusters has been emerged. We perform a critical analysis of the cn_{JWL} and the C_{UBI} indices, finding that the populational tagging from the C_{UBI} index may not be reliable, due to the inherited trait …
Recent spectroscopy on the globular cluster (GC) system of M31 with unprecedented precision witnessed a clear bimodality in absorption-line index distributions of old GCs. Such division of extragalactic GCs, so far asserted mainly by photometric color bimodality, has been viewed as the presence of merely two distinct metallicity subgroups within individual galaxies and forms a critical backbone of various galaxy formation theories. Given that spectroscopy is a more detailed probe into stellar population than photometry, the discovery of index bimodality may point to the very existence of dual …
Stellar haloes encode a fossil record of a galaxy's accretion history, generally in the form of structures of low surface brightness, such as stellar streams. While their low surface brightness makes it challenging to determine their age, metallicity, kinematics and spatial structure, the infalling galaxies also deposit globular clusters (GCs) in the halo, which are bright and therefore easier to observe and characterise. To understand how GCs associated with stellar streams can be used to estimate the stellar mass and the infall time of their parent galaxy, we examine a subset of 15 simulatio…
In this paper, we discuss the origin of the observed correlation between cluster concentration c and present-day mass function (PDMF) slope α reported by De Marchi, Paresce & Pulone. This relation can either be reproduced from universal initial conditions combined with some dynamical mechanism(s) that alter(s) the cluster structure and mass function over time, or it must arise early on in the cluster lifetime, such as during the gas-embedded phase of cluster formation. Using a combination of Monte Carlo and N-body models for globular cluster evolution performed with the MOCCA and NBODY6 codes,…
Using a new method to estimate total galaxy mass (M$_{\rm T}$) and two samples of low luminosity galaxies containing measurements of the number of globular clusters (GCs) per galaxy (N$_{\rm GC}$), we revisit the N$_{\rm GC}-$M$_{\rm T}$ relation using a total of 203 galaxies, 157 of which have M$_{\rm T}$ $\ \le 10^{10}$ M$_\odot$. We find that the relation is nearly linear, N$_{\rm GC} \propto$ M$_{\rm T}^{0.92\pm0.08}$ down to at least M$_{\rm T} \sim 10^{8.75}$ M$_\odot$. Because the relationship extends to galaxies that average less than one GC per galaxy and to a mass range in which merg…
ROLLIN': Rotating globular cluster simulations. I. The kinematic evolution of realistic direct N-body models
Université de Strasbourg, CNRS, Observatoire astronomique de Strasbourg（斯特拉斯堡大学）；School of Mathematics and Maxwell Institute for Mathematical Sciences, University of Edinburgh（爱丁堡大学数学与麦克斯韦数学科学研究所）；Institute for Astronomy, University of Edinburgh, Royal Observatory（爱丁堡大学天文研究所）；Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences（波兰科学院尼古拉·哥白尼天文学中心）；Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università di Padova（帕多瓦大学伽利略·伽利莱物理与天文系）；Dipartimento di Tecnica e Gestione dei Sistemi Industriali, Università di Padova（帕多瓦大学工业系统技术与管理系）；Istituto Nazionale di Astrofisica – Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）
It has long been argued that the radial distribution of globular clusters (GCs) in the Fornax dwarf galaxy requires its dark matter halo to have a core of size $\sim 1$ kpc. We revisit this argument by investigating analogues of Fornax formed in E-MOSAICS, a cosmological hydrodynamical simulation that self-consistently follows the formation and evolution of GCs in the EAGLE galaxy formation model. In EAGLE, Fornax-mass haloes are cuspy and well described by the Navarro-Frenk-White profile. We post-process the E-MOSAICS to account for GC orbital decay by dynamical friction, which is not include…
Recently, both stellar mass-segregation and binary-fractions were uniformly measured on relatively large samples of Galactic Globular Clusters (GCs). Simulations show that both sizeable binary-star populations and Intermediate-Mass Black Holes (IMBHs) quench mass-segregation in relaxed GCs. Thus mass-segregation in GCs with a reliable binary-fraction measurement is a valuable probe to constrain IMBHs. In this paper we combine mass-segregation and binary-fraction measurements from the literature to build a sample of 33 GCs (with measured core-binary fractions), and a sample of 43 GCs (with a bi…
Tracing the relic nature of compact galaxies through their globular cluster systems
Universidade de São Paulo（圣保罗大学）；Universidade Federal do Rio Grande do Sul（南里奥格兰德联邦大学）；University of Michigan（密歇根大学）；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Swinburne University（斯威本科技大学）
Globular cluster (GC) systems around galaxies of a vast mass range show remarkably simple scaling relations. The combined mass of all GCs is a constant fraction of the total galaxy mass and the mean metallicity and metallicity dispersion of the GC system scale up weakly with galaxy mass. The metallicity of massive, metal-poor ("blue") clusters increases with cluster mass, while that of metal-rich ("red") clusters does not. A significant age-metallicity relation emerges from analysis of resolved stellar populations in Galactic GCs and unresolved populations in nearby galaxies. Remarkably, all t…
We study the role of the local tidal environment in determining the assembly bias of dark matter haloes. Previous results suggest that the anisotropy of a halo's environment (i.e, whether it lies in a filament or in a more isotropic region) can play a significant role in determining the eventual mass and age of the halo. We statistically isolate this effect using correlations between the large-scale and small-scale environments of simulated haloes at $z=0$ with masses between $10^{11.6}\lesssim (m/h^{-1}M_{\odot})\lesssim10^{14.9}$. We probe the large-scale environment using a novel halo-by-ha…
We investigate the evolution of the radial distribution of Blue Straggler Stars through a set of Monte Carlo simulations of star clusters under a variety of initial conditions. We used a novel technique based on the "artificial oversampling" of the distribution function of the Blue Stragglers and control population to tear down the effect of statistical fluctuations affecting the determination of the relative distribution of these stellar populations. We find that a bimodal distribution, qualitatively similar but much less pronounced than those observed in many globular clusters, can naturally…
We introduce a simple analytic model of galaxy formation that links the growth of dark matter haloes in a cosmological background to the build-up of stellar mass within them. The model aims to identify the physical processes that drive the galaxy-halo co-evolution through cosmic time. The model restricts the role of baryonic astrophysics to setting the relation between galaxies and their haloes. Using this approach, galaxy properties can be directly predicted from the growth of their host dark matter haloes. We explore models in which the effective star formation efficiency within haloes is a …
The predicted abundance and properties of the low-mass substructures embedded inside larger dark matter haloes differ sharply among alternative dark matter models. Too small to host galaxies themselves, these subhaloes may still be detected via gravitational lensing, or via perturbations of the Milky Way's globular cluster streams and its stellar disk. Here we use the Apostle cosmological simulations to predict the abundance and the spatial and velocity distributions of subhaloes in the range 10^6.5-10^8.5 solar masses inside haloes of mass ~ 10^12 solar masses in LCDM. Although these subhaloe…
