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Estimation of density derivatives is a versatile tool in statistical data analysis. A naive approach is to first estimate the density and then compute its derivative. However, such a two-step approach does not work well because a good…

Machine Learning · Statistics 2014-07-01 Hiroaki Sasaki , Yung-Kyun Noh , Masashi Sugiyama

Many dark matter (DM) models that are consistent with current cosmological data show differences in the predicted (sub)halo mass function, especially at sub-galactic scales, where observations are challenging due to the inefficiency of star…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-18 Atınç Çağan Şengül , Cora Dvorkin

We present an analytical and numerical study of the velocity distribution function of self gravitating collisionless particles, which include dark matter and star clusters. We show that the velocity distribution derived through the…

Astrophysics · Physics 2012-06-22 Steen H. Hansen , Daniel Egli , Lukas Hollenstein , Christoph Salzmann

The distortion of images of faint background galaxies by (weak) gravitational lensing can be used to measure the mass distribution of the deflector. The image distortions can be used to define a weighted mean of the mass inside a circular…

Astrophysics · Physics 2015-06-24 Peter Schneider

Numerical simulations indicate that correlations exist between the velocity distributions of stars and dark matter (DM). We study the local DM velocity distribution based on these correlations. We select K giants from LAMOST DR8…

Astrophysics of Galaxies · Physics 2024-10-11 Hai Zhu , Rui Guo , Juntai Shen , Jianglai Liu , Chao Liu , Xiang-Xiang Xue , Lan Zhang , Shude Mao

We consider dark matter velocity distributions with an anisotropic component, and analyze how the velocity structure can be probed in a solid state ionization detector with no directional detection capability using a daily modulation effect…

High Energy Physics - Phenomenology · Physics 2024-04-11 Matti Heikinheimo , Kai Nordlund , Sebastian Sassi , Kimmo Tuominen

We reexamined the framework used to determine the dark matter mass of a subhalo using the gravitational effects of its passage upon the stellar halo of a host. In particular, we aim to include different density distribution functions for…

Astrophysics of Galaxies · Physics 2025-12-01 M. E. Mosquera , K. J. Fushimi , M. J. de L. Domínguez Romero

Using cosmological $N$-body simulations of dark matter haloes, we study the effects of non-sphericity, substructure and streaming motions in reproducing the structure and internal kinematics of clusters of galaxies from kinematical…

Astrophysics · Physics 2009-11-10 Teresa Sanchis , Ewa L. Lokas , Gary A. Mamon

Traditionally, the mass / velocity anisotropy degeneracy (MAD) inherent in the spherical, stationary, non-streaming Jeans equation has been handled by assuming a mass profile and fitting models to the observed kinematical data. Here, the…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-11 Gary A. Mamon , Gwenael Boué

This article introduces a new instrumental variable approach for estimating unknown population parameters with data having nonrandom missing values. With coarse and discrete instruments, Shao and Wang (2016) proposed a semiparametric method…

Methodology · Statistics 2021-11-19 Arkaprabha Ganguli , David Todem

We construct a dynamical model of the Milky Way disk from a data set, which combines Gaia EDR3 and APOGEE data throughout Galactocentric radii between $5.0\leq R\leq19.5$ kpc. We make use of the spherically-aligned Jeans Anisotropic Method…

Astrophysics of Galaxies · Physics 2021-08-05 Maria Selina Nitschai , Anna-Christina Eilers , Nadine Neumayer , Michele Cappellari , Hans-Walter Rix

We explore systematic biases in the identification of dark matter in future direct detection experiments and compare the reconstructed dark matter properties when assuming a self-consistent dark matter distribution function and the standard…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-27 Miguel Pato , Louis E. Strigari , Roberto Trotta , Gianfranco Bertone

A key prediction of the standard cosmological model -- which relies on the assumption that dark matter is cold, i.e. non-relativistic at the epoch of structure formation -- is the existence of a large number of dark matter substructures on…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-31 Nilanjan Banik , Gianfranco Bertone , Jo Bovy , Nassim Bozorgnia

Calculating the abundance of thermally produced dark matter particles has become a standard procedure, with sophisticated methods guaranteeing a precision that matches the percent-level accuracy in the observational determination of the…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-12 Tobias Binder , Torsten Bringmann , Michael Gustafsson , Andrzej Hryczuk

Although the baryons in the intergalactic medium (IGM) trace dark matter on Mpc scales, small-scale (~100 kpc) fluctuations are suppressed by pressure support, analogous to the classical Jeans argument. This Jeans filtering scale has…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-24 Alberto Rorai , Joseph F. Hennawi , Martin White

We present density profiles, that are solutions of the spherical Jeans equation, derived under the following two assumptions: (i) the coarse grained phase-density follows a power-law of radius, rho/(sigma^3) proportional to r^{-alpha}, and…

Astrophysics · Physics 2009-11-07 Nicolaos Hiotelis

Weak lensing provides a direct measure of the distribution of mass in the universe, and is therefore a uniquely powerful probe of dark matter. Weak lensing can also be used to measure the twin phenomenon of dark energy, via its effect upon…

Astrophysics · Physics 2007-05-23 Richard Massey , Alexandre Refregier , Jason Rhodes

Cosmic acceleration is widely believed to require either a source of negative pressure (i.e., dark energy), or a modification of gravity, which necessarily implies new degrees of freedom beyond those of Einstein gravity. In this paper we…

High Energy Physics - Theory · Physics 2017-06-28 Lasha Berezhiani , Justin Khoury , Junpu Wang

Direct searches for dark matter have prompted in recent years a great deal of excitement within the astroparticle physics community, but the compatibility between signal claims and null results of different experiments is far from being a…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-01 Miguel Pato

The nature of the dominant component of galaxies and clusters remains unknown. While the astrophysics community supports the cold dark matter (CDM) paradigm as a clue factor in the current cosmological model, no direct CDM detections have…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Ana Laura Serra , Mariano Javier de León Domínguez Romero