scholarly journals Machine-learned dark matter subhalo candidates in the 4FGL-DR2: search for the perturber of the GD-1 stream

2021 ◽  
Vol 2021 (11) ◽  
pp. 033
Author(s):  
Nestor Mirabal ◽  
Ana Bonaca
Keyword(s):  
Machine Learning ◽  
Dark Matter ◽  
High Latitude ◽  
Gamma Ray ◽  
Galactic Halo ◽  
Supervised Machine Learning ◽  
Error Ellipse ◽  
Dark Matter Annihilation ◽  
X Ray ◽  
Stellar Component

Abstract The detection of dark matter subhalos without a stellar component in the Galactic halo remains a challenge. We use supervised machine learning to identify high-latitude gamma-ray sources with dark matter-like spectra among unassociated gamma-ray sources in the 4FGL-DR2. Out of 843 4FGL-DR2 unassociated sources at |b| ≥ 10°, we select 73 dark matter subhalo candidates. Of the 69 covered by the Neil Gehrels Swift Observatory (Swift), 17 show at least one X-ray source within the 95% LAT error ellipse and 52 where we identify no new sources. This latest inventory of dark subhalos candidates allows us to investigate the possible dark matter substructure responsible for the perturbation in the GD-1 stellar stream. In particular, we examine the possibility that the alleged GD-1 dark subhalo may appear as a 4FGL-DR2 gamma-ray source from dark matter annihilation into Standard Model particles.

scholarly journals Cosmic X-ray and gamma-ray background from dark matter annihilation

2011 ◽  
Vol 83 (12) ◽  
Author(s):  
Jesús Zavala ◽  
Mark Vogelsberger ◽  
Tracy R. Slatyer ◽  
Abraham Loeb ◽  
Volker Springel
Keyword(s):  
Dark Matter ◽  
Gamma Ray ◽  
Dark Matter Annihilation ◽  
X Ray

scholarly journals The gamma-ray spectral feature from Kaluza–Klein dark matter annihilation and its observability

2017 ◽  
Vol 27 (01) ◽  
pp. 1750187 ◽  
Author(s):  
Satoshi Tsuchida ◽  
Masaki Mori
Keyword(s):  
Dark Matter ◽  
Gamma Ray ◽  
Galactic Halo ◽  
Spectral Feature ◽  
High Energy ◽  
Dark Matter Annihilation ◽  
Peak Structure ◽  
Boost Factor ◽  
Near Future ◽  
Kaluza Klein

The theory of universal extra dimensions involves Kaluza–Klein (KK) particles. The lightest KK particle (LKP) is one of the good candidates for cold dark matter. Annihilation of LKP dark matter in the Galactic halo produces high-energy gamma-rays. The gamma-ray spectrum shows a characteristic peak structure around the LKP mass. This paper investigates the observability of this peak structure by near-future detectors taking account of their energy resolution and calculates the expected energy spectrum of the gamma-ray signal. Then, by using the High-Energy Stereoscopic System (HESS) data, we set some constraints on the boost factor, which is a product of the annihilation cross-section relative to the thermal one and an uncertain factor dependent on the substructure of the LKP distribution in the Galactic halo, for each LKP mass. The resulting upper limit on the boost factor is in the range from 1 to 30. The constraints can be regarded as comparable with the results of previous work for gamma-ray and electron–positron observation. However, the observational data for the TeV or higher energy region are still limited, and the possible LKP signal is not conclusive. Thus, we expect near-future missions with better sensitivity will clarify whether the LKP dark matter should exist or not.

scholarly journals Constraints to Dark Matter Annihilation from High-Latitude HAWC Unidentified Sources

Galaxies ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Javier Coronado-Blázquez ◽  
Miguel A. Sánchez-Conde
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Gamma Rays ◽  
High Latitude ◽  
Gamma Ray ◽  
Detection Threshold ◽  
Dark Matter Annihilation ◽  
Annihilation Channel ◽  
Dark Matter Search ◽  
Spatially Extended

The Λ CDM cosmological framework predicts the existence of thousands of subhalos in our own Galaxy not massive enough to retain baryons and become visible. Yet, some of them may outshine in gamma rays provided that the dark matter is made of weakly interacting massive particles (WIMPs), which would self-annihilate and would appear as unidentified gamma-ray sources (unIDs) in gamma-ray catalogs. Indeed, unIDs have proven to be competitive targets for dark matter searches with gamma rays. In this work, we focus on the three high-latitude ( | b | ≥ 10 ) sources present in the 2HWC catalog of the High Altitude Water Cherenkov (HAWC) observatory with no clear associations at other wavelengths. Indeed, only one of these sources, 2HWC J1040+308, is found to be above the HAWC detection threshold when considering 760 days of data, i.e., a factor 1.5 more exposure time than in the original 2HWC catalog. Other gamma-ray instruments, such as Fermi-LAT or VERITAS at lower energies, do not detect the source. Also, this unID is reported as spatially extended, making it even more interesting in a dark matter search context. While waiting for more data that may shed further light on the nature of this source, we set competitive upper limits on the annihilation cross section by comparing this HAWC unID to expectations based on state-of-the-art N-body cosmological simulations of the Galactic subhalo population. We find these constraints to be particularly competitive for heavy WIMPs, i.e., masses above ∼25 (40) TeV in the case of the b b ¯ ( τ + τ − ) annihilation channel, reaching velocity-averaged cross section values of 2 × 10 − 25 ( 5 × 10 − 25 ) cm 3 ·s − 1 . Although far from testing the thermal relic cross section value, the obtained limits are independent and nicely complementary to those from radically different DM analyses and targets, demonstrating once again the high potential of this DM search approach.

scholarly journals Chapter 5 Dark Matter and New Physics Beyond the Standard Model with LHAASO

2021 ◽  
Author(s):  
Xiaojun Bi
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Gamma Ray ◽  
Galactic Halo ◽  
Effective Area ◽  
High Energy ◽  
New Physics ◽  
Dark Matter Annihilation ◽  
The Standard Model ◽  
Very High Energy

Abstract In order to reveal the nature of dark matter, it is crucial to detect its non-gravitational interactions with the standard model particles. The traditional dark matter searches focused on the so-called weakly interacting massive particles. However, this paradigm is strongly constrained by the null results of current experiments with high precision. Therefore there is a renewed interest of searches for heavy dark matter particles above TeV scale. The Large High Altitude Air Shower Observatory (LHAASO) with large effective area and strong background rejection power is very suitable to investigate the gamma-ray signals induced by dark matter annihilation or decay above TeV scale. In this document, we review the theoretical motivations and background of heavy dark matter. We review the prospects of searching for the gamma-ray signals resulted from dark matter in the dwarf spheroidal satellites and Galactic halo for LHAASO, and present the projected sensitivities. We also review the prospects of searching for the axion-like particles, which are a kind of well motivated light pseudo-scalars, through the LHAASO measurement of the very high energy gamma-ray spectra of astrophysical sources.

scholarly journals The Dark Matter Annihilation Signal from Dwarf Galaxies and Subhalos

2010 ◽  
Vol 2010 ◽  
pp. 1-15 ◽  
Author(s):  
Michael Kuhlen
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Galactic Halo ◽  
Dwarf Galaxies ◽  
Dark Matter Annihilation ◽  
Stellar Component ◽  
Potential Sources ◽  
Ursa Minor ◽  
Galactic Satellites ◽  
Promising Source

Dark Matter annihilation holds great potential for directly probing the clumpiness of the Galactic halo that is one of the key predictions of the Cold Dark Matter paradigm of hierarchical structure formation. Here we review the -ray signal arising from dark matter annihilation in the centers of Galactic subhalos. We consider both known Galactic dwarf satellite galaxies and dark clumps without a stellar component as potential sources. Utilizing theVia Lactea IInumerical simulation, we estimate fluxes for 18 Galactic dwarf spheroidals with published central densities. The most promising source is Segue 1, followed by Ursa Major II, Ursa Minor, Draco, and Carina. We show that if any of the known Galactic satellites can be detected, then at least ten times more subhalos should be visible, with a significant fraction of them being dark clumps.

scholarly journals Formation of massive globular clusters with dark matter and its implication on dark matter annihilation

2020 ◽  
Vol 496 (1) ◽  
pp. L70-L74
Author(s):  
Henriette Wirth ◽  
Kenji Bekki ◽  
Kohei Hayashi
Keyword(s):  
Dark Matter ◽  
Observational Studies ◽  
Globular Clusters ◽  
Galactic Halo ◽  
Dwarf Galaxies ◽  
Large Range ◽  
Dark Matter Annihilation ◽  
Central Regions ◽  
Γ Ray ◽  
The Masses

ABSTRACT Recent observational studies of γ-ray emission from massive globular clusters (GCs) have revealed possible evidence of dark matter (DM) annihilation within GCs. It is, however, still controversial whether the emission comes from DM or from millisecond pulsars. We here present the new results of numerical simulations, which demonstrate that GCs with DM can originate from nucleated dwarfs orbiting the ancient Milky Way. The simulated stripped nuclei (i.e. GCs) have the central DM densities ranging from 0.1 to several M⊙ pc−3, depending on the orbits and the masses of the host dwarf galaxies. However, GCs born outside the central regions of their hosts can have no/little DM after their hosts are destroyed and the GCs become the Galactic halo GCs. These results suggest that only GCs originating from stellar nuclei of dwarfs can possibly have DM. We further calculate the expected γ-ray emission from these simulated GCs and compare them to observations of ω Cen. Given the large range of DM densities in the simulated GCs, we suggest that the recent possible detection of DM annihilation from GCs should be more carefully interpreted.

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