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We introduce a method to infer the vertical distribution of stars in the Milky Way using a Poisson likelihood function, with a view to applying our method to the Gaia catalogue. We show how to account for the sample selection function and…

Astrophysics of Galaxies · Physics 2021-12-08 Andrew Everall , N. Wyn Evans , Vasily Belokurov , Douglas Boubert , Robert J. J. Grand

The predicted size of dark matter substructures in kilo-parsec scales is model-dependent. Therefore, if the correlations between dark matter mass densities as a function of the distances between them are measured via observations, we can…

Astrophysics of Galaxies · Physics 2022-08-02 Ahmad Borzou

For precision cosmological studies it is important to know the local properties of the reference point from which we observe the Universe. Particularly for the determination of the Hubble constant with low-redshift distance indicators, the…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-25 Hans Boehringer , Gayoung Chon , Chris A. Collins

Measurements of the accelerations of stars enabled by time-series extreme-precision spectroscopic observations, from pulsar timing, and from eclipsing binary stars in the Solar Neighborhood offer insights into the mass distribution of the…

High-resolution N-body simulations of dark matter halos indicate that the Milky Way contains numerous subhalos. When a dark matter subhalo passes in front of a star, the light from that star will be deflected by gravitational lensing,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Adrienne L. Erickcek , Nicholas M. Law

The analysis of the vertical velocity dispersion of disc stars is the most direct astronomical means of estimating the local dark matter density, $\rho_{DM}$. Current estimates based on the mid-plane dynamic density use a local baryonic…

Astrophysics of Galaxies · Physics 2015-08-06 Frederic V. Hessman

Ultralight dark matter induces time-dependent perturbations in the spacetime metric, enabling its gravitational direct detection. In this work, we propose using astrometry to detect dark matter. After reviewing the calculation of the metric…

High Energy Physics - Phenomenology · Physics 2025-08-06 Jeff A. Dror , Sarunas Verner

We model vertical breathing mode perturbations in the Milky Way's stellar disc and study their effects on estimates of the local dark matter density, surface density, and vertical force. Evidence for these perturbations, which involve…

Astrophysics of Galaxies · Physics 2016-11-22 Nilanjan Banik , Lawrence M. Widrow , Scott Dodelson

Astrometry -- the precise measurement of positions and motions of celestial objects -- has emerged as a promising avenue for characterizing the dark matter population in our Galaxy. By leveraging recent advances in simulation-based…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-06 Siddharth Mishra-Sharma

We present the recent robust determination of the value of the Dark Matter density at the Sun's location ($\rho_\odot$) with a technique that does not rely on a global mass-modeling of the Galaxy. The method is based on the local equation…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-18 Fabrizio Nesti , Paolo Salucci

Two recently proposed techniques, involving the measurement of the cosmic parallax and redshift drift, provide novel ways of directing probing (over a time-span of several years) the background metric of the universe and therefore shed…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-06 Miguel Quartin , Luca Amendola

Gravitational microlensing is a powerful method for discovering Isolated Stellar-Mass Black Holes(ISMBHs). These objects make long-duration microlensing events. To characterize these lensing objects by fully resolving the microlensing…

Astrophysics of Galaxies · Physics 2023-09-15 Sedighe Sajadian , Arya Mahmoudzadeh , Setareh Moein

The Earth's atmospheric turbulence degrades the precision of ground-based astrometry. Here, we discuss these limitations and propose that, with proper treatment of systematics and by leveraging the many epochs available from the Korean…

In this paper, we investigate the applicability of the astrometric method to the determination of the lens parameters for gravitational microlensing events toward both the LMC and the Galactic bulge. For this analysis, we investigate the…

Astrophysics · Physics 2009-10-30 Cheongho Han , Kyongae Chang

Six challenges for the standard cosmological model $\Lambda$CDM are listed, which arise when comparing theoretical predictions with observational data on scales of ~1 Mpc. Different parameters of luminous and dwarf galaxies in the local…

General Relativity and Quantum Cosmology · Physics 2026-05-29 I. D. Karachentsev

Given the extreme accuracy reached by future global space astrometry, one needs a global relativistic modeling of observations. A relativistic definition of astrometric observables is then essential to find uniquely coordinates, parallax…

General Relativity and Quantum Cosmology · Physics 2013-05-13 Stefano Bertone , Christophe Le Poncin-Lafitte

Reducing theoretical uncertainties in Galactic dark matter (DM) searches is an important challenge as several experiments are now delving into the parameter space relevant to popular (particle or not) candidates. Since many DM signal…

Astrophysics of Galaxies · Physics 2020-10-20 Thomas Lacroix , Arturo Núñez-Castiñeyra , Martin Stref , Julien Lavalle , Emmanuel Nezri

In two recent papers, we developed a powerful technique to link the distribution of galaxies to that of dark matter haloes by considering halo occupation numbers as function of galaxy luminosity and type. In this paper we use these…

Astrophysics · Physics 2009-11-07 Xiaohu Yang , H. J. Mo , Y. P. Jing , Frank C. van den Bosch , YaoQuan Chu

Strong gravitational lensing is a powerful probe of the distribution of matter on sub-kpc scales. It can be used to test the existence of completely dark subhalos surrounding galaxies, as predicted by the standard cold dark matter model, or…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-30 Ioana A. Zelko , Anna M. Nierenberg , Tommaso Treu

In this paper we test the astrometric precision of VLT/FORS2 observations using a serie of CCD frames taken in Galactic bulge area. A special reduction method based on symmetrization of reference fields was used to reduce the atmospheric…

Astrophysics · Physics 2009-11-11 Petro F. Lazorenko