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Protohalos, primordial regions in the initial cosmic density field that evolve into dark matter halos, are crucial for understanding cosmic structure formation. Motivated by the potential to reconstruct protohalo positions and shapes from…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-12 Farnik Nikakhtar , Daisuke Nagai , Marcello Musso , Ravi K. Sheth

In two previous papers (Salvador-Sol\'e 2012a,b), it was shown that: i) the typical structural and kinematic properties of haloes in (bottom-up) hierarchical cosmologies endowed with random Gaussian density perturbations of dissipationless…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-20 Eduard Salvador-Solé , Sinue Serra , Alberto Manrique

In this work, we investigate the impact of Poisson noise from stellar-mass primordial black holes (PBHs) on the formation of ultradense dark matter halos (UDMHs). Our findings reveal that the discrete spatial distribution of PBHs…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-11 Saeed Fakhry , Javad T. Firouzjaee

In cold dark matter cosmological models, structures form and grow by merging of smaller units. Numerical simulations have shown that such merging is incomplete; the inner cores of halos survive and orbit as "subhalos" within their hosts.…

Astrophysics · Physics 2010-04-06 J. Diemand , M. Kuhlen , P. Madau , M. Zemp , B. Moore , D. Potter , J. Stadel

Ultra-light primordial black holes (PBHs) in the mass range of 10$^{16}$ - 10$^{22}$ g are allowed by current observations to constitute a significant fraction, if not all, of the dark matter in the Universe. In this work, we present limits…

High Energy Astrophysical Phenomena · Physics 2022-12-26 Denys Malyshev , Emmanuel Moulin , Andrea Santangelo

In this work, we use the constrained Gaussian realization technique to study the early growth of supermassive black holes (SMBHs) in cosmological hydrodynamic simulations, exploring its relationship with features of the initial density…

Astrophysics of Galaxies · Physics 2021-11-17 Yueying Ni , Tiziana Di Matteo , Yu Feng

A particular population of galaxies have drawn much interest recently, which are as faint as typical dwarf galaxies but have the sizes as large as $L^*$ galaxies, the so called "ultra-diffuse galaxie" (UDGs). The lack of tidal features of…

Astrophysics of Galaxies · Physics 2017-08-02 Yu Rong , Qi Guo , Liang Gao , Shihong Liao , Lizhi Xie , Thomas H. Puzia , Shuangpeng Sun , Jun Pan

Dark-matter halos are the scaffolding around which galaxies and clusters are built. They form when the gravitational instability of primordial density fluctuations causes regions which are denser than average to slow their cosmic expansion,…

Astrophysics · Physics 2007-05-23 Ilian T. Iliev , Paul R. Shapiro

We analyze circular velocity profiles of seven ultradiffuse galaxies (UDGs) that are isolated and gas-rich. Assuming that the dark matter halos of these UDGs have a Navarro-Frenk-White (NFW) density profile or a Read density profile (which…

Astrophysics of Galaxies · Physics 2022-09-21 Demao Kong , Manoj Kaplinghat , Hai-Bo Yu , Filippo Fraternali , Pavel E. Mancera Piña

We investigate how supermassive black hole (SMBH) seeds form in the early Universe at the centers of ultralight dark matter (ULDM) halos. Focusing on the ULDM Jeans scale, we identify the critical conditions under which high-redshift…

Astrophysics of Galaxies · Physics 2026-03-10 Dongsu Bak , Jae-Weon Lee

Cosmological models in which dark matter consists of cold elementary particles predict that the dark halo population should extend to masses many orders of magnitude below those at which galaxies can form. Here we report a cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-23 Jie Wang , Sownak Bose , Carlos S. Frenk , Liang Gao , Adrian Jenkins , Volker Springel , Simon D. M. White

In the CDM scenario, dark matter halos are assembled hierarchically from smaller subunits. A long-standing problem with this picture is that the number of sub-halos predicted by CDM simulations is orders of magnitudes higher than the known…

Astrophysics · Physics 2014-11-18 T. Riehm , E. Zackrisson , O. Moeller , E. Mortsell , K. Wiik

We present a suite of 15 cosmological zoom-in simulations of isolated dark matter halos, all with masses of $M_{\rm halo} \approx 10^{10}\,{\rm M}_\odot$ at $z=0$, in order to understand the relationship between halo assembly, galaxy…

Some theoretical models for the early Universe predict a spike-type enhancement in the primordial power spectrum on a small scale, which would result in forming early-formed dark matter halos~(EFHs). Some recent studies have claimed to have…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-21 Katsuya T. Abe , Hiroyuki Tashiro

We show that most particle and subhalo orbits in simulated cosmological cold dark matter halos are surprisingly regular and periodic: The phase space structure of the outer halo regions shares some of the properties of the classical…

Astrophysics · Physics 2009-11-13 J. Diemand , M. Kuhlen

We analyzed the statistics of subhalo abundance of galaxy-sized and giant-galaxy-sized halos formed in a high-resolution cosmological simulation of a 46.5Mpc cube with the uniform mass resolution of $10^6 M_{\odot}$. We analyzed all halos…

Astrophysics · Physics 2014-11-18 Tomoaki Ishiyama , Toshiyuki Fukushige , Junichiro Makino

Several observations suggest the existence of super-massive black holes (SMBH) at the centers of giant galaxies. However the mechanism under which these objects form remains non completely understood. In this work we review an alternative…

General Relativity and Quantum Cosmology · Physics 2021-03-04 Ana Avilez-Lopez , Luis Padilla-Albores Luis , Tula Bernal-Marin , Tonatiuh Matos

We use numerical simulations in a Lambda CDM cosmology to model density profiles in a set of 16 dark matter haloes with resolutions of up to 7 million particles within the virial radius. These simulations allow us to follow robustly the…

Cold dark matter subhalos are expected to populate galaxies in numbers. If dark matter self-annihilates, these objects turn into prime targets for indirect searches, in particular with gamma-ray telescopes. Incidentally, the Fermi-LAT…

High Energy Astrophysical Phenomena · Physics 2022-10-31 Gaétan Facchinetti , Julien Lavalle , Martin Stref

We study the mass accretion histories (MAHs) and density profiles of dark matter halos using N-body simulations of self-similar gravitational clustering from scale-free power spectra, $P(k)\propto k^n$. We pay particular attention to the…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-07 Aaron D. Ludlow , Raul E. Angulo