scholarly journals The quest for dark matter in dwarf spheroidal galaxies with the Cherenkov Telescope Array

2019 ◽  
Vol 209 ◽  
pp. 01024 ◽  
Author(s):  
Francesco G. Saturni ◽  
Gonzalo Rodríguez-Fernández ◽  
Aldo Morselli
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Dwarf Galaxy ◽  
Telescope Array ◽  
Kinematic Data ◽  
Dwarf Spheroidal Galaxies ◽  
Cherenkov Telescopes ◽  
Cherenkov Telescope ◽  
Galaxy Halos ◽  
Spheroidal Galaxies

Dwarf spheroidal galaxies are among the best environments that can be studied with Cherenkov telescopes for indirect searches of γ-ray signals coming from dark matter self-interaction (annihilation or decay), due to their proximity and negligible background emission. We present new determinations of the dark-matter amount – i.e. the astrophysical factors J and D – in dwarf-galaxy halos obtained through the MCMC Jeans analysis of their brightness and kinematic data. Such factors are of great importance to test the performances of the next-generation γ-ray instruments such as the Cherenkov Telescope Array in detecting dark-matter signals from astronomical environments, or constraining the limits to dark-matter physics parameters (particle mass and lifetime, annihilation cross section).

scholarly journals Mass Modelling of dwarf Spheroidal Galaxies

2007 ◽  
Vol 3 (S244) ◽  
pp. 321-325
Author(s):  
Jarosław Klimentowski ◽  
Ewa L. Łokas ◽  
Stelios Kazantzidis ◽  
Francisco Prada ◽  
Lucio Mayer ◽  
...  
Keyword(s):  
Milky Way ◽  
Velocity Dispersion ◽  
Dwarf Galaxy ◽  
Data Sets ◽  
Kinematic Data ◽  
Dwarf Spheroidal Galaxies ◽  
Two Component ◽  
Tidal Tails ◽  
Better Than ◽  
Spheroidal Galaxies

AbstractWe study the origin and properties of unbound stars in the kinematic samples of dwarf spheroidal galaxies. For this purpose we have run a high resolution N-body simulation of a two-component dwarf galaxy orbiting in a Milky Way potential. We create mock kinematic data sets by observing the dwarf in different directions. When the dwarf is observed along the tidal tails the kinematic samples are strongly contaminated by unbound stars from the tails. However, most of the unbound stars can be removed by the method of interloper rejection proposed by den Hartog & Katgert. We model the velocity dispersion profiles of the cleaned-up kinematic samples using solutions of the Jeans equation. We show that even for such a strongly stripped dwarf the Jeans analysis, when applied to cleaned samples, allows us to reproduce the mass and mass-to-light ratio of the dwarf with accuracy typically better than 25%.

scholarly journals Constraining Velocity-dependent Self-Interacting Dark Matter with the Milky Way’s dwarf spheroidal galaxies

2021 ◽  
Author(s):  
Camila A Correa
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Cross Sections ◽  
Yukawa Potential ◽  
Analytical Form ◽  
Orbital Evolution ◽  
Particle Model ◽  
Velocity Correlation ◽  
Dwarf Spheroidal Galaxies ◽  
Spheroidal Galaxies

Abstract The observed anti-correlation between the central dark matter (DM) densities of the bright Milky Way (MW) dwarf spheroidal galaxies (dSphs) and their orbital pericenter distances poses a potential signature of self-interacting dark matter (SIDM). In this work we investigate this possibility by analysing the range of SIDM scattering cross section per unit mass, σ/mχ, able to explain such anti-correlation. We simulate the orbital evolution of dSphs subhaloes around the MW assuming an analytical form for the gravitational potential, adopting the proper motions from the Gaia mission and including a consistent characterization of gravitational tidal stripping. The evolution of subhalo density profiles is modelled using the gravothermal fluid formalism, where DM particle collisions induce thermal conduction that depends on σ/mχ. We find that models of dSphs, such as Carina and Fornax, reproduce the observed central DM densities with fixed σ/mχ ranging between 30 and 50 cm2g−1, whereas other dSphs prefer larger values ranging between 70 and 100 cm2g−1. These cross sections correlate with the average collision velocity of DM particles within each subhalo’s core, so that systems modelled with large cross sections have lower collision velocities. We fit the cross section-velocity correlation with a SIDM particle model, where a DM particle of mass mχ = 53.93 ± 9.81 GeV interacts under the exchange of a light mediator of mass mφ = 6.6 ± 0.43 MeV, with the self-interactions being described by a Yukawa potential. The outcome is a cross section-velocity relation that explains the diverse DM profiles of MW dSph satellites and is consistent with observational constraints on larger scales.

scholarly journals The Crab nebula variability at short time-scales with the Cherenkov telescope array

2020 ◽  
Vol 501 (1) ◽  
pp. 337-346
Author(s):  
E Mestre ◽  
E de Oña Wilhelmi ◽  
D Khangulyan ◽  
R Zanin ◽  
F Acero ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Crab Nebula ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Telescope Array ◽  
Cherenkov Telescopes ◽  
Cherenkov Telescope ◽  
Emission Models ◽  
Short Time ◽  
The Crab Nebula

ABSTRACT Since 2009, several rapid and bright flares have been observed at high energies (>100 MeV) from the direction of the Crab nebula. Several hypotheses have been put forward to explain this phenomenon, but the origin is still unclear. The detection of counterparts at higher energies with the next generation of Cherenkov telescopes will be determinant to constrain the underlying emission mechanisms. We aim at studying the capability of the Cherenkov Telescope Array (CTA) to explore the physics behind the flares, by performing simulations of the Crab nebula spectral energy distribution, both in flaring and steady state, for different parameters related to the physical conditions in the nebula. In particular, we explore the data recorded by Fermi during two particular flares that occurred in 2011 and 2013. The expected GeV and TeV gamma-ray emission is derived using different radiation models. The resulting emission is convoluted with the CTA response and tested for detection, obtaining an exclusion region for the space of parameters that rule the different flare emission models. Our simulations show different scenarios that may be favourable for achieving the detection of the flares in Crab with CTA, in different regimes of energy. In particular, we find that observations with low sub-100 GeV energy threshold telescopes could provide the most model-constraining results.

scholarly journals Dark matter and fundamental physics with the Cherenkov Telescope Array

2013 ◽  
Vol 43 ◽  
pp. 189-214 ◽  
Author(s):  
M. Doro ◽  
J. Conrad ◽  
D. Emmanoulopoulos ◽  
M.A. Sànchez-Conde ◽  
J.A. Barrio ◽  
...  
Keyword(s):  
Dark Matter ◽  
Fundamental Physics ◽  
Telescope Array ◽  
Cherenkov Telescope

scholarly journals J-factors for self-interacting dark matter in 20 dwarf spheroidal galaxies

2018 ◽  
Vol 98 (4) ◽  
Author(s):  
Sebastian Bergström ◽  
Riccardo Catena ◽  
Andrea Chiappo ◽  
Jan Conrad ◽  
Björn Eurenius ◽  
...  
Keyword(s):  
Dark Matter ◽  
Dwarf Spheroidal Galaxies ◽  
Spheroidal Galaxies
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