New constraints on the mass of fermionic dark matter from dwarf spheroidal galaxies

Alvey, James; Tiki, Victoria; Blas, Diego; Bondarenko, Kyrylo; Boyarsky, Alexey; Escudero, Miguel; Fairbairn, Malcolm; Orkney, Matthew D. A.; Read, Justin I.

doi:10.1093/mnras/staa3640

Cited by 37 publications

(29 citation statements)

References 102 publications

(137 reference statements)

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“…The reason for the tighter priors on β(𝑟) is that, theoretically, we expect that dynamical systems in pseudo-equilibrium should be close to isotropic in the centre, with radial anisotropy, or weak tangential anisotropy, at large radii (e.g. Pontzen et al 2015;Genina et al 2019;Alvey et al 2021). For this reason, we allow for only mild tangential anisotropy ( β(𝑟) > −0.1) and demand β(𝑟) → 0 for 𝑟 → 0.…”

Section: Mass Modelling With G Smentioning

confidence: 99%

Andromeda XXI – a dwarf galaxy in a low-density dark matter halo

Collins

Read

Ibata

et al. 2021

Monthly Notices of the Royal Astronomical Society

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Andromeda XXI (And XXI) has been proposed as a dwarf spheroidal galaxy with a central dark matter density that is lower than expected in the Standard Λ Cold Dark Matter (ΛCDM) cosmology. In this work, we present dynamical observations for 77 member stars in this system, more than doubling previous studies to determine whether this galaxy is truly a low density outlier. We measure a systemic velocity of vr = −363.4 ± 1.0 km s−1 and a velocity dispersion of $\sigma _v=6.1^{+1.0}_{-0.9}{\rm \, km\, s^{-1}}$, consistent with previous work and within 1σ of predictions made using the modified Newtonian dynamics framework. We also measure the metallicity of our member stars from their spectra, finding a mean value of [Fe/H] = −1.7 ± 0.1 dex. We model the dark matter density profile of And XXI using an improved version of GravSphere, finding a central density of $\rho _{\rm DM}({\rm 150 pc})=2.6_{-1.5}^{+2.4} \times 10^7 \, {\rm M_\odot \, kpc^{-3}}$ at 68% confidence, and a density at two half light radii of $\rho _{\rm DM}({\rm 1.75 kpc})=0.9_{-0.2}^{+0.3} \times 10^6 \, {\rm M_\odot \, kpc^{-3}}$ at 68% confidence. These are both a factor ∼3 − 5 lower than the densities expected from abundance matching in ΛCDM. We show that this cannot be explained by ‘dark matter heating’ since And XXI had too little star formation to significantly lower its inner dark matter density, while dark matter heating only acts on the profile inside the half light radius. However, And XXI’s low density can be accommodated within ΛCDM if it experienced extreme tidal stripping (losing $>95\%$ of its mass), or if it inhabits a low concentration halo on a plunging orbit that experienced repeated tidal shocks.

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Section: Mass Modelling With G Smentioning

confidence: 99%

Andromeda XXI – a dwarf galaxy in a low-density dark matter halo

Collins

Read

Ibata

et al. 2021

Monthly Notices of the Royal Astronomical Society

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“…The region excluded by X-ray searches [3] is shown in red, while the purple dashed line depicts the potential reach of the proposed Athena mission [88]. In the orange region, sterile neutrinos are too light to be bound in the DM halos of dwarf spheroidal galaxies [89], and in the green-dotted one they are likely to be inconsistent with observations of the Lyman-α forest [90], although a reevaluation of the constraints using the distorted ν s momentum spectrum in our mechanism would be necessary in order to establish a robust limit.…”

Section: Iv2 Numerical Resultsmentioning

confidence: 99%

Sterile neutrino dark matter catalyzed by a very light dark photon

Alonso-Álvarez,

Cline

2021

Preprint

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Sterile neutrinos (νs) that mix with active neutrinos (νa) are interesting dark matter candidates with a rich cosmological and astrophysical phenomenology. In their simplest incarnation, their production is severely constrained by a combination of structure formation observations and X-ray searches. We show that if active neutrinos couple to an oscillating condensate of a very light Lµ −Lτ gauge field, resonant νa-νs oscillations can occur in the early universe, consistent with νs constituting all of the dark matter, while respecting X-ray constraints on νs → νaγ decays. Interesting deviations from standard solar and atmospheric neutrino oscillations can persist to the present.

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“…However, such mass is the thermal relic one (i.e., the mass of the WDM particle if it decouples from the expanding Universe in thermal equilibrium) which may be not the case for the sterile neutrinos. The relation between the physical particle mass of the ∼keV neutrino in galaxy halos and the corresponding thermal mass, which is cosmologically tested, has to be worked out explicitly for every specific WDM particle physics models [93,264,265] many of which, however, have been already discarded [96].…”

Section: Discussionmentioning

confidence: 99%

“…The rotation curves of the whole family of normal spirals are well reproduced by the above scenario with a particle mass of ∼2 keV [94], see Figure 4. Important lower limits for the mass of such fermionic particle are recently obtained by investigating the smallest dwarf spheroidal (dSph) satellites of the Milky Way and of Andromeda [95,96].…”

Section: Sterile Neutrino: Warm Dark Matter Particlementioning

confidence: 99%

Fundamental Properties of the Dark and the Luminous Matter from the Low Surface Brightness Discs

Salucci

Paolo

2021

Universe

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Dark matter (DM) is one of the biggest mystery in the Universe. In this review, we start reporting the evidences for this elusive component and discussing about the proposed particle candidates and scenarios for such phenomenon. Then, we focus on recent results obtained for rotating disc galaxies, in particular for low surface brightness (LSB) galaxies. The main observational properties related to the baryonic matter in LSBs, investigated over the last decades, are briefly recalled. Next, these galaxies are analyzed by means of the mass modelling of their rotation curves both individual and stacked. The latter analysis, via the universal rotation curve (URC) method, results really powerful in giving a global or universal description of the properties of these objects. We report the presence in LSBs of scaling relations among their structural properties that result comparable with those found in galaxies of different morphologies. All this confirms, in disc systems, the existence of a strong entanglement between the luminous matter (LM) and the dark matter (DM). Moreover, we report how in LSBs the tight relationship between their radial gravitational accelerations g and their baryonic components gb results to depend also on the stellar disk length scale and the radius at which the two accelerations have been measured. LSB galaxies strongly challenge the ΛCDM scenario with the relative collisionless dark particle and, alongside with the non-detection of the latter, contribute to guide us towards a new scenario for the DM phenomenon.

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New constraints on the mass of fermionic dark matter from dwarf spheroidal galaxies

Cited by 37 publications

References 102 publications

Andromeda XXI – a dwarf galaxy in a low-density dark matter halo

Andromeda XXI – a dwarf galaxy in a low-density dark matter halo

Sterile neutrino dark matter catalyzed by a very light dark photon

Fundamental Properties of the Dark and the Luminous Matter from the Low Surface Brightness Discs

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