Earth-mass haloes and the emergence of NFW density profiles

Angulo, Raúl E.; Hahn, Oliver; Ludlow, Aaron D.; Bonoli, Silvia

doi:10.1093/mnras/stx1658

Cited by 76 publications

(92 citation statements)

References 56 publications

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“…Using an Einasto profile [65,66] instead amounts to a global increase ∼2 of the number of subhalos per flux decade within the considered integration regions ∆Ω. Please note that micro-halos with m M may show steeper inner slopes [67][68][69]; however, we have found that these micro-halos do not provide new bright, resolved subhalo candidates [1].…”

Section: Fixed Subhalo-related Quantitiesmentioning

confidence: 76%

γ-ray and ν Searches for Dark-Matter Subhalos in the Milky Way with a Baryonic Potential

et al. 2019

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The distribution of dark-matter (DM) subhalos in our galaxy remains disputed, leading to varying γ-ray and ν flux predictions from their annihilation or decay. In this work, we study how, in the inner galaxy, subhalo tidal disruption from the galactic baryonic potential impacts these signals. Based on state-of-the art modeling of this effect from numerical simulations and semi-analytical results, updated subhalo spatial distributions are derived and included in the CLUMPY code. The latter is used to produce a thousand realizations of the γ-ray and ν sky. Compared to predictions based on DM only, we conclude a decrease of the flux of the brightest subhalo by a factor of 2 to 7 for annihilating DM and no impact on decaying DM: the discovery prospects or limits subhalos can set on DM candidates are affected by the same factor. This study also provides probability density functions for the distance, mass, and angular distribution of the brightest subhalo, among which the mass may hint at its nature: it is most likely a dwarf spheroidal galaxy in the case of strong tidal effects from the baryonic potential, whereas it is lighter and possibly a dark halo for DM only or less pronounced tidal effects.

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Section: Fixed Subhalo-related Quantitiesmentioning

confidence: 76%

γ-ray and ν Searches for Dark-Matter Subhalos in the Milky Way with a Baryonic Potential

et al. 2019

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“…The dependence of α and concentration parameter c = r vir /r s on the halo mass is given in I14. The cusp slope gradually becomes shallower with increasing halo mass through major merger processes (see also Ogiya et al 2016;Angulo et al 2017). The concentration parameter slightly depends on the halo mass.…”

Section: Subhalo Density Profilesmentioning

confidence: 98%

The abundance and structure of subhaloes near the free streaming scale and their impact on indirect dark matter searches

Ishiyama

Ando

2020

Monthly Notices of the Royal Astronomical Society

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The free streaming motion of dark matter particles imprints a cutoff in the matter power spectrum and set the scale of the smallest dark matter halo. Recent cosmological N-body simulations have shown that the central density cusp is much steeper in haloes near the free streaming scale than in more massive haloes. Here, we study the abundance and structure of subhaloes near the free streaming scale at very high redshift using a suite of unprecedentedly large cosmological N-body simulations, over a wide range of the host halo mass. The subhalo abundance is suppressed strongly below the free streaming scale, but the ratio between the subhalo mass function in the cutoff and no cutoff simulations is well fitted by a single correction function regardless of the host halo mass and the redshift. In subhaloes, the central slopes are considerably shallower than in field haloes, however, are still steeper than that of the NFW profile. Contrary, the concentrations are significantly larger in subhaloes than haloes and depend on the subhalo mass. We compare two methods to extrapolate the mass-concentration relation of haloes and subhaloes to z=0 and provide a new simple fitting function for subhaloes, based on a suite of large cosmological N-body simulations. Finally, we estimate the annihilation boost factor of a Milky-Way sized halo to be between 1.8 and 6.2.

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“…For masses below M * , haloes form efficiently following a power-law statistics, whereas for masses above M * , the number density falls of exponentially (Schechter 1976). In a scale-free Einstein-de Sitter universe, M * is the only driver of scale-dependence (Smith et al 2003;Angulo et al 2017), apart from the much smaller free-streaming scale (Angulo & White 2010), and hence the evolution of merger tree structures should be explainable by the evolution of M * (z). Explicitly, we expect the evolution of s to depend only upon the so-called peak amplitude ν ≡ δc/σ(M, z).…”

Section: Cosmic Evolution Of Tree Entropiesmentioning

confidence: 99%

Characterizing the structure of halo merger trees using a single parameter: the tree entropy

Obreschkow

Elahi

Lagos

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Linking the properties of galaxies to the assembly history of their dark matter haloes is a central aim of galaxy evolution theory. This paper introduces a dimensionless parameter s ∈ [0, 1], the 'tree entropy', to parametrise the geometry of a halo's entire mass assembly hierarchy, building on a generalisation of Shannon's information entropy. By construction, the minimum entropy (s = 0) corresponds to smoothly assembled haloes without any mergers. In contrast, the highest entropy (s = 1) represents haloes grown purely by equal-mass binary mergers. Using simulated merger trees extracted from the cosmological N -body simulation SURFS, we compute the natural distribution of s, a skewed bell curve peaking near s = 0.4. This distribution exhibits weak dependences on halo mass M and redshift z, which can be reduced to a single dependence on the relative peak height δ c /σ(M, z) in the matter perturbation field. By exploring the correlations between s and global galaxy properties generated by the SHARK semianalytic model, we find that s contains a significant amount of information on the morphology of galaxies -in fact more information than the spin, concentration and assembly time of the halo. Therefore, the tree entropy provides an information-rich link between galaxies and their dark matter haloes.

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Earth-mass haloes and the emergence of NFW density profiles

Cited by 76 publications

References 56 publications

γ-ray and ν Searches for Dark-Matter Subhalos in the Milky Way with a Baryonic Potential

γ-ray and ν Searches for Dark-Matter Subhalos in the Milky Way with a Baryonic Potential

The abundance and structure of subhaloes near the free streaming scale and their impact on indirect dark matter searches

Characterizing the structure of halo merger trees using a single parameter: the tree entropy

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