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We investigate the growth of matter fluctuations in holographic dark energy cosmologies. First we use an overall statistical analysis involving the latest observational data in order to place constraints on the cosmological parameters. Then…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-16 Ahmad Mehrabi , Spyros Basilakos , Mohammad Malekjani , Zahra Davari

Perturbations from inflation evolve into large scale structure of the late universe, and encode abundant cosmic structure formation physics. We allow freedom in the primordial power spectrum, rather than assuming a power law scale…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-12 Guilherme Brando , Eric V. Linder

Cosmic microwave background measurements have pushed to higher resolution, lower noise, and more sky coverage. These data enable a unique test of the early universe's expansion rate and constituents such as effective number of relativistic…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-05 Alireza Hojjati , Eric V. Linder , Johan Samsing

Using the global 21-cm signal measurement by the EDGES collaboration, we derive constraints on the fraction of the dark matter that is in the form of primordial black holes (PBHs) with masses in the range $10^{15}$-$10^{17}\,$g. Improving…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-17 Shikhar Mittal , Anupam Ray , Girish Kulkarni , Basudeb Dasgupta

Compared with that of standard dark matter halos, the density profile of the recently proposed new kind of dark matter structure named ultracompact minihalos (UCMHs) is steeper and its formation time is earlier. If the dark matter is…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-27 Yupeng Yang , Guilin Yang , Hongshi Zong

As a candidate bound for the Binary Black Hole (BBH) merger events detected by LIGO/Virgo, Primordial Black Holes (PBHs) provide a useful tool to investigate the primordial curvature perturbations on small scales. Using the GWTC-1 to GWTC-3…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-16 Xinpeng Wang , Ying-li Zhang , Rampei Kimura , Masahide Yamaguchi

The possibility that primordial black holes (PBHs) represent all of the dark matter (DM) in the Universe and explain the coalescences of binary black holes detected by LIGO/Virgo has attracted a lot of attention. PBHs are generated by the…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-28 Chen Yuan , Zu-Cheng Chen , Qing-Guo Huang

We study how the indirect observation of dark matter substructures in the Milky Way, using recent stellar stream studies, translates into constraints for different dark matter models. Particularly, we use the measured number of dark…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-05 María Benito , Juan Carlos Criado , Gert Hütsi , Martti Raidal , Hardi Veermäe

Every dark matter halo and subhalo is expected to have a prompt $\rho\propto r^{-1.5}$ central density cusp, which is a relic of its condensation out of the smooth mass distribution of the early universe. The sizes of these prompt cusps are…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-29 M. Sten Delos

Primordial fluctuations in the relative number densities of particles, or isocurvature perturbations, are generally well constrained by cosmic microwave background (CMB) data. A less probed mode is the compensated isocurvature perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-30 Chen He , Daniel Grin , Wayne Hu

We investigate the non-linear evolution of spherical density and velocity perturbations of dark matter and dark energy in the expanding Universe. For that we have used the conservation and Einstein equations to describe the evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-04 M. Tsizh , B. Novosyadlyj

Supermassive black hole binaries source gravitational waves measured by Pulsar Timing Arrays. The frequency spectrum of this stochastic background is predicted more precisely than its amplitude. We argue that Dark Matter friction can…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-04 Anish Ghoshal , Alessandro Strumia

When using distance measurements to probe spatial curvature, the geometric degeneracy between curvature and dark energy in the distance-redshift relation typically requires either making strong assumptions about the dark energy evolution or…

Cosmology and Nongalactic Astrophysics · Physics 2009-12-14 Michael J. Mortonson

Understanding whether primordial black holes form during strong first-order phase transition (FOPT) is a crucial open question in cosmology. We address this using a fully covariant formalism to study cosmological perturbations, highlighting…

High Energy Physics - Phenomenology · Physics 2026-05-07 Gabriele Franciolini , Yann Gouttenoire , Ryusuke Jinno

The coupling of photons and baryons by Thomson scattering in the early universe imprints features in both the Cosmic Microwave Background (CMB) and matter power spectra. The former have been used to constrain a host of cosmological…

Astrophysics · Physics 2008-11-26 Martin White

Primordial black holes (PBHs) are one of the candidates to explain the gravitational wave (GW) signals observed by the LIGO detectors. Among several phenomena in the early Universe, cosmic inflation is a major example to generate PBHs from…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-14 Keisuke Inomata , Masahiro Kawasaki , Kyohei Mukaida , Yuichiro Tada , Tsutomu T. Yanagida

Tidal disruption of dark matter halos around proto-globular clusters in a halo of a small galaxy is studied in the context of the hierarchical clustering scenario by using semi-cosmological N-body/SPH simulations assuming the standard cold…

Astrophysics · Physics 2009-11-13 Takayuki R. Saitoh , Jin Koda , Takashi Okamoto , Keiichi Wada , Asao Habe

We propose a new method for probing inflationary models of primordial black hole (PBH) production, using only CMB physics at relatively large scales. In PBH scenarios, the primordial power spectrum profile for curvature perturbations is…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-28 Ogan Özsoy , Gianmassimo Tasinato

We present the first attempt to use a combination of CMB, LIGO, and PPTA data to constrain both the tilt and the running of primordial tensor power spectrum through constraints on the gravitational wave energy density generated in the early…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 P. Daniel Meerburg , Renée Hložek , Boryana Hadzhiyska , Joel Meyers

The latest pulsar timing array data reveals evidence of nanohertz gravitational waves (GWs), which have been explained by both cosmological and astrophysical sources. However, current observations lack the precision needed to differentiate…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-10 Jing Liu