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Here we review our current knowledge on diffuse gamma-rays from galactic halos. Estimates of the relative contribution of the various emission processes at low and high latitudes are compared to the data over 6 decades in energy. The…

Astrophysics · Physics 2007-05-23 M. Pohl

Dark-matter-only simulations predict that dark matter halos have cusp-like inner density profiles, while observations of low-mass galaxies have found a range of inner slopes that are typically much shallower. It is still not well…

In a standard cold dark matter (CDM) cosmology, microhalos at the CDM cutoff scale are the first and smallest objects expected to form in the universe. Here we present results of high resolution simulations of three representative roughly…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Donnino Anderhalden , Juerg Diemand

We study the effects of diffuse Galactic, far-infrared extragalactic source, and radio point source emission on the cosmic microwave background (CMB) anisotropy data anticipated from the MAP experiment. We focus on the correlation function…

Astrophysics · Physics 2011-05-10 Chan-Gyung Park , Changbom Park , Bharat Ratra

I consider constraints from observations on a cutoff scale in clustering due to free streaming of the dark matter in a warm dark matter cosmological model with a cosmological constant. The limits are derived in the framework of a sterile…

Astrophysics · Physics 2007-05-23 Kevork Abazajian

We present Atacama Large Millimeter/submillimeter Array (ALMA) [C II] 158 $\mu \rm{m}$ and dust continuum observations of the $z=6.79$ quasar J0109--3047 at a resolution of $0."045$ ($\sim$300 pc). The dust and [C II] emission are enclosed…

Astrophysics of Galaxies · Physics 2024-01-09 Romain A. Meyer , Marcel Neeleman , Fabian Walter , Bram Venemans

The evolution of linear initial conditions present in the early universe into extended halos of dark matter at late times can be computed using cosmological simulations. However, a theoretical understanding of this complex process remains…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-26 Luisa Lucie-Smith , Hiranya V. Peiris , Andrew Pontzen , Brian Nord , Jeyan Thiyagalingam

Dark matter (DM) can form dense condensates around black holes (BHs), such as superradiant clouds and ultracompact mini halos, which can significantly affect the orbital evolution of their companion objects through dynamical friction (DF).…

General Relativity and Quantum Cosmology · Physics 2026-04-22 Qianhang Ding , Minxi He , Hui-Yu Zhu

The scale radius of dark matter halos is a critical parameter for specifying the density distribution of dark matter, and is therefore a fundamental parameter for modeling galaxies. We develop here a novel, observationally motivated probe…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-08 Sukanya Chakrabarti

Low-frequency radio observations are revealing an increasing number of diffuse synchrotron sources from galaxy clusters, dominantly in the form of radio halos or radio relics. The existence of this diffuse synchrotron emission indicates the…

Context. The extreme precision and accuracy of forthcoming observations of CMB temperature and polarization anisotropies, aiming to detect the tiny signatures of primordial gravitational waves or of light relic particles beyond the standard…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-06 Jia-Rui Li , Jacques Delabrouille , Yi-Fu Cai , Dongdong Zhang

A 13x13 degree image of Balmer H-alpha emission at galactic latitude -65 degrees is presented. Sensitivity is limited in part by confusion: the peak-to-valley anisotropy of the H-alpha surface brightness is 0.2 Rayleighs on angular scales…

Astrophysics · Physics 2009-10-30 Peter R. McCullough

An analysis of cosmological models in spatially flat Friedmann Universe with cosmic gravitational wave background and zero $\Lambda$-term is presented. The number of free parameters is equal to 5, they are $\sigma_8$, $n$, $\Omega_\nu$,…

Astrophysics · Physics 2009-10-31 E. V. Mikheeva , V. N. Lukash , N. A. Arkhipova , A. M. Malinovsky

This study explores the impact of cosmic curvature on structure formation through general relativistic first-order perturbation theory. We analyze continuity and Euler equations, incorporating cosmic curvature into Einstein equations.…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-29 Bikash R. Dinda

Based on the Sloan Digital Sky Survey Data Release 16, we have detected the large-scale structure of Ly$\alpha$ emission in the Universe at redshifts $z = 2$--3.5 by cross-correlating quasar positions and Ly$\alpha$ emission imprinted in…

Astrophysics of Galaxies · Physics 2022-09-28 Xiaojing Lin , Zheng Zheng , Zheng Cai

Current cosmological data indicate that our universe contains a substantial component of dark vacuum energy that is driving the cosmos to accelerate. We examine the immediate and longer term consequences of this dark energy (assumed here to…

Astrophysics · Physics 2010-12-09 Michael T. Busha , Fred C. Adams , Risa H. Wechsler , August E. Evrard

We investigate the environment dependence of dark matter halos in the symmetron modified gravity scenario. The symmetron is one of three known mechanisms for screening a fifth-force and thereby recovering General Relativity in dense…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Hans A. Winther , David F. Mota , Baojiu Li

We study the distribution of cold dark matter (CDM) in cosmological simulations from the FIRE (Feedback In Realistic Environments) project, for $M_{\ast}\sim10^{4-11}\,M_{\odot}$ galaxies in $M_{\rm h}\sim10^{9-12}\,M_{\odot}$ halos. FIRE…

Astrophysics of Galaxies · Physics 2015-10-28 T. K. Chan , D. Kereš , J. Oñorbe , P. F. Hopkins , A. L. Muratov , C. -A. Faucher-Giguère , E. Quataert

Recent observations have found the ratio of H-alpha to free-free radio continuum to be surprisingly high in the diffuse ionized ISM (the so-called WIM), corresponding to an electron temperature of only ~3000K. Such low temperatures were…

Astrophysics of Galaxies · Physics 2015-05-19 Ruobing Dong , B. T. Draine

I review the basic theory of the cosmic microwave background anisotropies in adiabatic cold dark matter cosmologies. The latest observational results on the CMB power spectrum are consistent with the simplest inflationary models and…

Astrophysics · Physics 2009-09-25 G. Efstathiou