Impact of substructure on local dark matter searches

Ibarra, Alejandro; Kavanagh, Bradley J.; Rappelt, Andreas

doi:10.1088/1475-7516/2019/12/013

Cited by 21 publications

(16 citation statements)

References 197 publications

(287 reference statements)

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“…For example, it is unclear if small subhaloes survive to the intense tidal forces they are subject to from their accretion times to the present and, if so, under which conditions and orbital configurations (Hayashi et al 2003;Garrison-Kimmel et al 2017;van den Bosch et al 2018;van den Bosch and Ogiya 2018;Errani and Peñarrubia 2019;Grand and White 2020). In addition to representing a cosmological test by themselves, understanding both the statistical and structural properties of subhaloes plays a key role for many other diverse studies, such as gravitational lensing (Vegetti et al 2010), stellar streams (Yoon et al 2011;Erkal et al 2016;Bonaca et al 2019) and indirect or direct DM detection experiments (Sánchez-Conde et al 2011;Fermi LAT Collaboration 2015;Coronado-Blázquez et al 2019;Ibarra et al 2019).…”

Section: Introductionmentioning

confidence: 99%

LCDM halo substructure properties revealed with high resolution and large volume cosmological simulations

Moliné¹,

Aguirre-Santaella²,

Ishiyama³

et al. 2021

Preprint

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In this work, we investigate the structural properties, distribution and abundance of ΛCDM dark matter subhaloes using the Phi-4096 and Uchuu suite of N-body cosmological simulations. Thanks to the combination of their large volume, high mass resolution and superb statistics, we are able to quantify -for the first time consistently over more than seven decades in ratio of subhalo-to-host-halo mass -dependencies of subhalo properties with mass, maximum circular velocity, 𝑉 max , host halo mass and distance to host halo centre. We also dissect the evolution of these dependencies over cosmic time. We provide accurate fits for the subhalo mass and velocity functions, both exhibiting decreasing power-law slopes in the expected range of values and with no significant dependence on redshift. We also find subhalo abundance to depend weakly on host halo mass. More precisely, we find a factor ∼ 2 − 3 more subhaloes in clustersize haloes compared to dwarf-size haloes at the present time, and more subhaloes at higher redshift for the same host halo mass, as expected from a less evolved population of subhaloes. We explore the distribution of subhaloes within their hosts and its evolution over cosmic time for subhaloes located as deep as ∼ 0.1 per cent of the host virial radius. Subhalo structural properties are codified via a concentration parameter, 𝑐 V , that does not depend on any specific, pre-defined density profile and relies only on 𝑉 max . We derive the 𝑐 V − 𝑉 max relation in the range 7 − 1500 km s −1 and find an important dependence on distance of the subhalo to the host halo centre, as already described in Moliné et al. (2017) for subhaloes in Milky-Way-like hosts. The innermost, less massive subhaloes exhibit 𝑐 v values a factor ∼ 3 higher than those located in the outskirts. This difference decreases to a factor ∼ 1.5 for the most massive subhaloes. Interestingly, we also find subhaloes of the same mass to be significantly more concentrated when they reside inside more massive hosts. Finally, we investigate the redshift evolution of 𝑐 v , and provide accurate fits that take into account all mentioned dependencies. Our results offer an unprecedented detailed characterization of the subhalo population, consistent over a wide range of subhalo and host halo masses, as well as cosmic times. Our work enables precision work in any future research involving dark matter halo substructure.

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Section: Introductionmentioning

confidence: 99%

LCDM halo substructure properties revealed with high resolution and large volume cosmological simulations

Moliné¹,

Aguirre-Santaella²,

Ishiyama³

et al. 2021

Preprint

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“…These properties of the MW subhalo population have been inferred from observations of satellite galaxies and stellar streams, both of which are expected to rapidly advance in the coming years (e.g., Drlica-Wagner et al 2019). Furthermore, accurate predictions for the contribution of the LMC system to the MW subhalo population in alternative dark matter models will facilitate the interpretation of future direct (Ibarra et al 2019) and indirect (Ando et al 2019) detection experiments, which also rely on predictions for the abundance and spatial distribution of nearby subhalos.…”

Section: Discussionmentioning

confidence: 98%

The Effects of Dark Matter and Baryonic Physics on the Milky Way Subhalo Population in the Presence of the Large Magellanic Cloud

Nadler,

Banerjee,

Adhikari

et al. 2021

Preprint

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Given recent developments in our understanding of the Large Magellanic Cloud (LMC)'s impact on the Milky Way (MW)'s dark matter subhalo population, we compare the signatures of dark matter and baryonic physics on subhalos in MW systems with realistic LMC analogs. In particular, we study the effects of self-interacting dark matter (SIDM), warm dark matter (WDM), and the Galactic disk on the peak maximum circular velocity (V peak ) function, radial distribution, and spatial distribution of MW and LMC-associated subhalos using cosmological dark matter-only zoom-in simulations of MW-plus-LMC systems. For a fixed abundance of subhalos expected to host dwarf galaxies (V peak 20 km s −1 ), SIDM and WDM can produce a similar mass-dependent suppression of the subhalo V peak function, while disk disruption is mass-independent. Subhalos in the inner regions of the MW are preferentially disrupted by both self-interactions and the disk, while suppression in WDM is radially independent. The relative abundance of LMC-associated subhalos is not strongly affected by disk disruption or WDM, but is significantly suppressed in SIDM due to self-interactions with the LMC at early times and with the MW during LMC infall at late times, erasing spatial anisotropy in the MW subhalo population. These results provide avenues to distinguish dark matter and baryonic physics by combining properties of the MW and LMC subhalo populations probed by upcoming observations of satellite galaxies and stellar streams.

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“…Thus, the pruning of subhalos by stars can have a substantial impact on the prospects for (local) DM searches, especially if the latter are conducted in a stellar-rich environment. For instance, the probability that a subhalo passes through the Earth and enhances the local density by a non-negligible amount changes, which may be important for DM direct detection experiments [37], or for other subhalo searches [89]. Moreover, if DM selfannihilates, the presence of subhalos boosts the local annihilation rate [21,26,27,29,32], and this efficient pruning (if not disruption) expected in regions over which the stellar disk extends, should also modify the amplitude of this boost.…”

Section: Discussionmentioning

confidence: 99%

“…In this respect, having reliable predictions of the properties of subhalo populations in galaxies, especially of those subhalos light enough not to host baryons, is of particular interest. Indeed, subhalos can imprint gravitational signatures [18,19], or boost potential DM annihilation signals [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35], turn into intermittent local DM winds [36,37], hence providing additional ways to test the CDM scenario.…”

Section: Introductionmentioning

confidence: 99%

Tidal stripping of dark matter subhalos by baryons from analytical perspectives: disk shocking and encounters with stars

Facchinetti¹,

Stref²,

Lavalle³

2022

Preprint

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The cold dark matter (CDM) scenario predicts that galactic halos should host a huge amount of subhalos possibly as light as or lighter than planets, depending on the nature of dark matter.Predicting their abundance and distribution on such small scales has important implications for dark matter searches and searches for subhalos themselves, which could provide a decisive test of the CDM paradigm. A major difficulty in subhalo population model building is to account for the gravitational stripping induced by baryons, which strongly impact on the overall dynamics within the scale radii of galaxies. In this paper, we focus on these "baryonic" tides from analytical perspectives, summarizing previous work on galactic disk shocking, and thoroughly revisiting the impact of individual encounters with stars. For the latter, we go beyond the reference calculation of Gerhard and Fall (1983) to deal with penetrative encounters, and provide new analytical results. Based upon a full statistical analysis of subhalo energy change during multiple stellar encounters possibly occurring during disk crossing, we show how subhalos lighter than ∼ 1 M are very efficiently pruned by stellar encounters, and how that modifies their mass function in a stellar environment. If reasonably resilient, surviving subhalos have lost all their mass but the inner cusp, with a tidal mass function strongly departing from the cosmological one; otherwise, their number density can drop by an order of magnitude at the solar position in the Milky Way with respect to disk-shocking effects only. For illustration, we integrate these results into our analytical subhalo population model. They can easily be incorporated to any other analytical or numerical approach. This study complements those using cosmological simulations, which cannot resolve dark matter subhalos on such small scales.

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Impact of substructure on local dark matter searches

Cited by 21 publications

References 197 publications

LCDM halo substructure properties revealed with high resolution and large volume cosmological simulations

LCDM halo substructure properties revealed with high resolution and large volume cosmological simulations

The Effects of Dark Matter and Baryonic Physics on the Milky Way Subhalo Population in the Presence of the Large Magellanic Cloud

Tidal stripping of dark matter subhalos by baryons from analytical perspectives: disk shocking and encounters with stars

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