Contribution of ultracompact dark matter minihalos to the isotropic radio background

Yang, Yupeng; Yang, Guilin; Huang, Xiaoyuan; Chen, Xuelei; Liu, Tan; Zong, Hong-Shi

doi:10.1103/physrevd.87.083519

Cited by 21 publications

(19 citation statements)

References 60 publications

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“…It is in any case interesting to ask how the dark matter substructure would change if the initial small scale perturbations were larger than expected. Other papers which constrain the power spectrum on small scales include [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. In particular, we note that CMB spectral distortion constraints provide an upper bound on the primordial power spectrum on about the same scales as UCMHs, which are about an order of magnitude weaker than the currently claimed constraints but independent of the DM model [20].…”

Section: Introductionmentioning

confidence: 68%

3D simulations with boosted primordial power spectra and ultracompact minihalos

et al. 2017

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We perform three-dimensional simulations of structure formation in the early Universe, when boosting the primordial power spectrum on ∼kpc scales. We demonstrate that our simulations are capable of producing power-law profiles close to the steep ρ ∝ r −9=4 halo profiles that are commonly assumed to be a good approximation to ultracompact minihalos (UCMHs). However, we show that for more realistic initial conditions in which halos are neither perfectly symmetric nor isolated the steep power-law profile is disrupted, and we find that the Navarro-Frenk-White profile is a better fit to most halos. In the presence of background fluctuations, even extreme, nearly spherical initial conditions do not remain exceptional. Nonetheless, boosting the amplitude of initial fluctuations causes all structures to form earlier and thus at larger densities. With a sufficiently large amplitude of fluctuations, we find that values for the concentration of typical halos in our simulations can become very large. However, despite the signal coming from dark matter annihilation inside the cores of these halos being enhanced, it is still orders of magnitude smaller compared to the usually assumed UCMH profile. The upper bound on the primordial power spectrum from the nonobservation of UCMHs should therefore be reevaluated.

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Section: Introductionmentioning

confidence: 68%

3D simulations with boosted primordial power spectra and ultracompact minihalos

et al. 2017

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“…In this case we can falsify this assumption. It should be noted that a similar logic can be used to constrain the power of small scale perturbations and in fact intensive investigations have been done in the literature [25][26][27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Testing scenarios of primordial black holes being the seeds of supermassive black holes by ultracompact minihalos and CMBμdistortions

2014

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Supermassive black holes and intermediate mass black holes are believed to exist in the Universe. There is no established astrophysical explanation for their origin and considerations have been made in the literature that those massive black holes (MBHs) may be primordial black holes (PBHs), black holes which are formed in the early universe (well before the matter-radiation equality) due to the direct collapse of primordial overdensities. This paper aims at discussing the possibility of excluding the PBH scenario as the origin of the MBHs. We first revisit the constraints on PBHs obtained from the CMB distortion that the seed density perturbation causes. By adopting a recent computation of the CMB distortion sourced by the seed density perturbation and the stronger constraint on the CMB distortion set by the COBE/FIRAS experiment used in the literature, we find that PBHs in the mass range 6 × 10 4 M ⊙ ∼ 5 × 10 13 M ⊙ are excluded. Since PBHs lighter than 6 × 10 4 M ⊙ are not excluded from the non-observation of the CMB distortion, we propose a new method which can potentially exclude smaller PBHs as well. Based on the observation that large density perturbations required to create PBHs also result in the copious production of ultracompact minihalos (UCMHs), compact dark matter halos formed at around the recombination, we show that weakly interacting massive particles (WIMPs) as dark matter annihilate efficiently inside UCMHs to yield cosmic rays far exceeding the observed flux. Our bound gives severe restriction on the compatibility between the particle physics models for WIMPs and the PBH scenario as the explanation of MBHs.2

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“…These channels are also partly motivated by recent explorations of astroparticle "anomalies", which point to a significant fraction of positrons above the expected background. The annihilation of leptophilic DM has been a candidate explanation for these anomalies, which include the positron fraction excess observed by PAMELA and Fermi above 10 GeV [38][39][40][41][42][43][44][45][46][47][48][49], the strong 511 keV signal from the galactic center seen most recently by the INTEGRAL/SPI experiment [50][51][52][53][54][55][56][57][58][59][60][61][62], and the large isotropic radio signal below 10 GHz observed by ARCADE [63][64][65][66][67][68].…”

Section: Introductionmentioning

confidence: 99%

Constraints on dark matter annihilation from CMB observations before Planck

Lopez-Honorez

Mena

Palomares‐Ruiz

et al. 2013

J. Cosmol. Astropart. Phys.

138

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We compute the bounds on the dark matter (DM) annihilation cross section using the most recent Cosmic Microwave Background measurements from WMAP9, SPT'11 and ACT'10. We consider DM with mass in the MeV-TeV range annihilating 100% into either an e + e − or a µ + µ − pair. We consider a realistic energy deposition model, which includes the dependence on the redshift, DM mass and annihilation channel. We exclude the canonical thermal relic abundance cross section ( σv = 3×10 −26 cm 3 s −1 ) for DM masses below 30 GeV and 15 GeV for the e + e − and µ + µ − channels, respectively. A priori, DM annihilating in halos could also modify the reionization history of the Universe at late times. We implement a realistic halo model taken from results of state-of-the-art N-body simulations and consider a mixed reionization mechanism, consisting on reionization from DM as well as from first stars. We find that the constraints on DM annihilation remain unchanged, even when large uncertainties on the halo model parameters are considered.

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Contribution of ultracompact dark matter minihalos to the isotropic radio background

Cited by 21 publications

References 60 publications

3D simulations with boosted primordial power spectra and ultracompact minihalos

3D simulations with boosted primordial power spectra and ultracompact minihalos

Testing scenarios of primordial black holes being the seeds of supermassive black holes by ultracompact minihalos and CMBμdistortions

Constraints on dark matter annihilation from CMB observations before Planck

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