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Related papers: Dark Dwarfs: Dark Matter-Powered Sub-Stellar Objec…

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We present evolutionary calculations for very-low-mass stars and brown dwarfs based on synthetic spectra and non-grey atmosphere models which include dust formation and opacity, i.e. objects with $\te\simle 2800$ K. The interior of the most…

Astrophysics · Physics 2008-11-26 G. Chabrier , I. Baraffe , F. Allard , P. Hauschildt

Ultracool subdwarfs are low luminosity, late-type M and L dwarfs that exhibit spectroscopic indications of subsolar metallicity and halo kinematics. Their recent discovery and ongoing investigation have led to new insights into the role of…

The system of stability equations for galactic halos is under-determined in most of the models of dark matter (DM). Conventionally, the issue is resolved by taking the temperature as a constant, and the chemical potential and the mass…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-13 Ahmad Borzou

We present more results from a fully cosmological LCDM simulation of a group of isolated dwarf galaxies that has been shown to reproduce the observed stellar mass and cold gas content, resolved star formation histories, and metallicities of…

Astrophysics of Galaxies · Physics 2015-06-19 Piero Madau , Sijing Shen , Fabio Governato

Low mass galaxies in the Local Group are dominated by dark matter and comprise the well studied ``dwarf Spheroidal" (dSph) class, with typical masses of $10^{9-10}M_\odot$ and also the equally numerous ``ultra faint dwarfs" (UFD),…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-20 Alvaro Pozo , Tom Broadhurst , George F. Smoot , Tzihong Chiueh , Hoang Nhan Luu , Mark Vogelsberger , Philip Mocz

Motivated by the gamma-ray excess observed from the region surrounding the Galactic Center, we explore particle dark matter models that could potentially account for the spectrum and normalization of this signal. Taking a model-independent…

High Energy Physics - Phenomenology · Physics 2015-06-04 Asher Berlin , Dan Hooper , Samuel D. McDermott

Dwarf spheroidal galaxies are the smallest known stellar systems where under Newtonian interpretations, a significant amount of dark matter is required to explain observed kinematics. In fact, they are in this sense the most heavily dark…

Astrophysics of Galaxies · Physics 2016-08-31 X. Hernandez

We show that dark matter emerging from late decays (z < 1000) produces a linear power spectrum identical to that of Cold Dark Matter (CDM) on all observationally relavant scales (> 0.1 Mpc), and simultaneously generates observable…

Astrophysics · Physics 2008-11-26 Louis E. Strigari , Manoj Kaplinghat , James S. Bullock

Dark matter (DM) halos of Sc-Im galaxies satisfy scaling laws analogous to the fundamental plane relations for elliptical galaxies. Halos in less luminous galaxies have smaller core radii, higher central densities, and smaller central…

Astrophysics of Galaxies · Physics 2015-06-22 John Kormendy , K. C. Freeman

Dwarf galaxies are widely believed to be among the best targets for indirect dark matter searches using high-energy gamma rays; and indeed gamma-ray emission from these objects has long been a subject of detailed study for ground-based…

High Energy Astrophysical Phenomena · Physics 2012-01-27 A. Viana , M. C. Medina , J. Peñarrubia , P. Brun , J. F. Glicenstein , K. Kosack , E. Moulin , M. Naumann-Godo , B. Peyaud

Particle dark matter near the galactic center is accreted by the central black hole into a dense spike, strongly enhancing its annihilation rate. Searching for its annihilation products may give us information on the presence or absence of…

High Energy Physics - Phenomenology · Physics 2009-10-31 Paolo Gondolo , Joseph Silk

The nature of the dark matter in the Universe is one of the outstanding questions in astrophysics. In this talk, I address possible stellar baryonic contributions to the 50-90% of our Galaxy that is made of unknown dark matter. First I show…

Astrophysics · Physics 2007-05-23 Katherine Freese , Brian Fields , David Graff

The gamma-ray excess observed from the Galactic Center can be interpreted as dark matter particles annihilating into Standard Model fermions with a cross section near that expected for a thermal relic. Although many particle physics models…

High Energy Physics - Phenomenology · Physics 2014-08-19 Asher Berlin , Pierre Gratia , Dan Hooper , Samuel D. McDermott

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 gamma-ray…

Astrophysics of Galaxies · Physics 2015-05-13 Michael Kuhlen

Dark matter has been recognized as an essential part of matter for over 70 years now, and many suggestions have been made, what it could be. Most of these ideas have centered on Cold Dark Matter, particles that are expected in extensions of…

Astrophysics · Physics 2009-11-13 Peter L. Biermann , Faustin Munyaneza

We study the imprint of dark matter (DM) annihilation on the global 21 cm signal from the Dark Ages to Cosmic Reionization. Motivated by recent observations, we focus on three DM candidates: (i) a 10 GeV Bino-like neutralino (ii) a 200 GeV…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-16 Marcos Valdés , Carmelo Evoli , Andrei Mesinger , Andrea Ferrara , Naoki Yoshida

The first phase of stellar evolution in the history of the Universe may be Dark Stars, powered by dark matter heating rather than by nuclear fusion. Weakly Interacting Massive Particles, which may be their own antipartners, collect inside…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Katherine Freese , Cosmin Ilie , Douglas Spolyar , Monica Valluri , Peter Bodenheimer

We use the calculations derived in a previous paper (M\'era, Chabrier and Schaeffer, 1997), based on observational constraints arising from star counts, microlensing experiments and kinematic properties, to determine the amount of dark…

Astrophysics · Physics 2007-05-23 D. Méra , G. Chabrier , R. Schaeffer

The large gap between a galactic dark matter subhalo's velocity and its own gravitational binding velocity creates the situation that small subhalos can be evaporated before dark matter thermalize with baryons due to the low binding…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-20 Xiao-jun Bi , Yu Gao , Mingjie Jin , Yugen Lin , Qian-Fei Xiang

Stars form in the Galaxy with a wide range in mass. If the mass is below 7% of the Sun's, then the object does not become hot enough for stable hydrogen burning. These substellar objects are called brown dwarfs. Maps of the sky at infrared…

Earth and Planetary Astrophysics · Physics 2024-09-11 Sandy K. Leggett