scholarly journals Gamma-Ray Sensitivity to Dark Matter Subhalo Modelling at High Latitudes

Galaxies ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 90 ◽  
Author(s):  
Francesca Calore ◽  
Moritz Hütten ◽  
Martin Stref

Searches for “dark” subhaloes in gamma-ray point-like source catalogues are among promising strategies for indirect dark matter detection. Such a search is nevertheless affected by uncertainties related, on the one hand, to the modelling of the dark matter subhalo distribution in Milky-Way-like galaxies, and, on the other hand, to the sensitivity of gamma-ray instruments to the dark matter subhalo signals. In the present work, we assess the detectability of dark matter subhaloes in Fermi-LAT catalogues, taking into accounts uncertainties associated with the modelling of the galactic subhalo population. We use four different halo models bracketing a large set of uncertainties. For each model, adopting an accurate detection threshold of the LAT to dark matter subhalo signals and comparing model predictions with the number of unassociated point-sources in Fermi-LAT catalogues, we derive upper limits on the annihilation cross section as a function of dark matter mass. Our results show that, even in the best-case scenario (i.e., DMonly subhalo model), which does not include tidal disruption from baryons, the limits on the dark matter parameter space are less stringent than current gamma-ray limits from dwarf spheroidal galaxies. Comparing the results obtained with the different subhalo models, we find that baryonic effects on the subhalo population are significant and lead to dark matter constraints that are less stringent by a factor of ∼2 to ∼5. This uncertainty comes from the unknown resilience of dark matter subhaloes to tidal disruption.

2021 ◽  
Vol 502 (3) ◽  
pp. 4039-4047
Author(s):  
Charles Thorpe-Morgan ◽  
Denys Malyshev ◽  
Christoph-Alexander Stegen ◽  
Andrea Santangelo ◽  
Josef Jochum

ABSTRACT Galaxy clusters are the largest virialized objects in the Universe and, as such, have high dark matter (DM) concentrations. This abundance of dark matter makes them promising targets for indirect DM searches. Here we report the details of a search, utilizing almost 12 yr of Fermi/LAT data, for gamma-ray signatures from the pair annihilation of WIMP dark matter in the GeV energy band. From this, we present the constraints on the annihilation cross-section for the $b\overline{b}$, W+W−, and γγ channels, derived from the non-detection of a characteristic signal from five nearby, high Galactic latitude, galaxy clusters (Centaurus, Coma, Virgo, Perseus, and Fornax). We discuss the potential of a boost to the signal due to the presence of substructures in the DM haloes of selected objects, as well as the impact of uncertainties in DM profiles on the presented results. We assert that the obtained limits are, within a small factor, comparable to the best available limits of those based on Fermi/LAT observations of dwarf spheroidal galaxies.


2020 ◽  
Vol 497 (2) ◽  
pp. 2486-2492
Author(s):  
Ji-Gui Cheng ◽  
Shang Li ◽  
Ying-Ying Gan ◽  
Yun-Feng Liang ◽  
Rui-Jing Lu ◽  
...  

ABSTRACT The tentative 1.4 TeV e+e− excess observed by DAMPE, if not a statistical fluctuation, may be explained by dark matter (DM) annihilation within a nearby subhalo with a distance of <0.3 kpc. The process of DM annihilating to e+e− is accompanied by the production of gamma-ray photons, which could lead to detectable signals of Fermi-LAT. In this work, we focus on the model that the tentative 1.4 TeV signal is from a nearby ultracompact mini halo (UCMH). Due to the small angular extension, the counterpart gamma-ray signal would be hidden among Fermi-LAT unassociated point sources. We examine the point sources in 4FGL systematically by analyzing the Fermi-LAT data, aiming to investigate whether there exist sources with gamma-ray properties consistent with the UCMH model of the 1.4 TeV excess. We find more than 10 sources could be the candidates. Furthermore, we test the possibility that the excess signal is from a DM mini-spike around the nearest BH, but our result does not favour such a scenario.


2017 ◽  
Vol 32 (18) ◽  
pp. 1750108 ◽  
Author(s):  
Douglas Edmonds ◽  
Duncan Farrah ◽  
Chiu Man Ho ◽  
Djordje Minic ◽  
Y. Jack Ng ◽  
...  

We discuss the possibility that the cold dark matter mass profiles contain information on the cosmological constant [Formula: see text], and that such information constrains the nature of cold dark matter (CDM). We call this approach Modified Dark Matter (MDM). In particular, we examine the ability of MDM to explain the observed mass profiles of 13 galaxy clusters. Using general arguments from gravitational thermodynamics, we provide a theoretical justification for our MDM mass profile. In order to properly fit the shape of the mass profiles in galaxy clusters, we find it necessary to generalize the MDM mass profile from the one we used previously to fit galactic rotation curves. We successfully compare it to the NFW mass profiles both on cluster and galactic scales, though differences in form appear with the change in scales. Our results suggest that indeed the CDM mass profiles contain information about the cosmological constant in a nontrivial way.


Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 92
Author(s):  
Man Chan

Recently, many studies indicate that the GeV gamma ray excess signal from the central Milky Way can be best explained by ∼40–50 GeV dark matter annihilating via the b b ¯ channel. However, this model appears to be disfavored by the recent Fermi-LAT data for dwarf spheroidal galaxies and the constraint from synchrotron radiation. In this article, we describe a consistent picture to relieve the tensions between the dark matter annihilation model and the observations. We show that a baryonic feedback process is the key to alleviate the tensions and the ∼40–50 GeV dark matter model is still the best one to account for the GeV gamma ray excess in the Milky Way.


2012 ◽  
Vol 27 (39) ◽  
pp. 1230042 ◽  
Author(s):  
IGNACIO TABOADA

IceCube is a neutrino detector sensitive to energies above 10 GeV. IceCube operates by sensing the Cherenkov light from secondary particles produced in neutrino-matter interactions. One gigaton of highly transparent Antarctic ice is instrumented to achieve this goal. Designed to be modular, IceCube has been collecting data since construction began in 2005. Construction was completed in December 2010. The primary goal of IceCube is to observe astrophysical sources of neutrinos. We present here a summary of IceCube's recent results in atmospheric neutrinos, point sources, diffuse fluxes of neutrinos, cosmogenic neutrinos, a lack of correlation between neutrinos and Gamma Ray Bursts and the search for dark matter.


2016 ◽  
Vol 11 (S322) ◽  
pp. 193-196
Author(s):  
Richard Bartels ◽  
Christoph Weniger

AbstractA clear excess in the Fermi-LAT data is present at energies around a few GeV. The spectrum of this so-called ’GeV excess’ is remarkably similar to the expected annihilation signal of WIMP dark matter. However, a large bulge population of millisecond pulsars living below the Fermi–LAT detection threshold could also explain the excess spectrum. In a recent work we optimized the search for sub-threshold sources, by applying a wavelet transform to the Fermi–LAT gamma-ray data. In the Inner-Galaxy the wavelet signal is significantly enhanced, providing supportive evidence for the point source interpretation of the excess. In these proceedings we will extent our previous work with a spectral analysis and elaborate on the potential contamination from substructures in the gas.


2018 ◽  
Vol 853 (2) ◽  
pp. 154 ◽  
Author(s):  
A. Albert ◽  
R. Alfaro ◽  
C. Alvarez ◽  
J. D. Álvarez ◽  
R. Arceo ◽  
...  

2017 ◽  
Vol 32 (32) ◽  
pp. 1750186 ◽  
Author(s):  
Teruyuki Kitabayashi ◽  
Shinya Ohkawa ◽  
Masaki Yasuè

We discuss the linkage between dark matter mass in the one-loop radiative seesaw model and the effective neutrino mass for the neutrinoless double beta decay. This linkage, which has been already numerically suggested, is confirmed to be a reasonable relationship by deriving analytical expressions for two zero flavor neutrino mass texture.


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