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Stellar streams are sensitive to perturbations from, e.g., giant molecular clouds, bars and spiral arms, infalling dwarf galaxies, or globular clusters which can imprint gaps, clumps, spurs, and asymmetries in tails. In addition to these…

We present a 3D Bayesian method to model the kinematics of strongly lensed galaxies from spatially-resolved emission-line observations. This technique enables us to simultaneously recover the lens-mass distribution and the source kinematics…

星系天体物理 · 物理学 2018-09-21 Francesca Rizzo , Simona Vegetti , Filippo Fraternali , Enrico Di Teodoro

We study potential systematic effects of assembly bias on cosmological parameter constraints from redshift space distortion measurements. We use a semi-analytic galaxy formation model applied to the Millennium N-body WMAP-7 simulation to…

宇宙学与河外天体物理 · 物理学 2019-03-27 Nelson Padilla , Sergio Contreras , Idit Zehavi , Carlton Baugh , Peder Norberg

The kinematics of the stellar halo hold important clues to the assembly history and mass distribution of the Galaxy. In this study, we map the kinematics of stars across the Galactic halo with the H3 Survey. We find a complex distribution…

Precision cosmology requires accurate galaxy redshifts, but next generation optical surveys will observe unprecedented numbers of resolved galaxies, placing strain on the amount of spectroscopic follow-up required. We show how useful…

宇宙学与河外天体物理 · 物理学 2018-11-07 Steven Cunnington , Ian Harrison , Alkistis Pourtsidou , David Bacon

Using neutral hydrogen (HI) rotation curves of 79 galaxies, culled from the literature, as well as measured from HI data, we present a method for classifying disk galaxies by their kinematics. In order to investigate fundamental kinematic…

宇宙学与河外天体物理 · 物理学 2013-05-15 Theresa Wiegert , Jayanne English

We demonstrate that morphological observables (e.g. steepness of the radial light profile, ellipticity, asymmetry) are intertwined and cannot be measured independently of each other. We present strong arguments in favour of model-based…

宇宙学与河外天体物理 · 物理学 2015-05-19 Rene Andrae , Knud Jahnke , Peter Melchior

We have measured the intrinsic disk ellipticity for 7 nearby, nearly face-on spiral galaxies by combining Densepak integral-field spectroscopy with I-band imaging from the WIYN telescope. Initially assuming an axisymmetric model, we…

We use the statistics of strong gravitational lensing from the CLASS survey to impose constraints on the velocity dispersion and density profile of elliptical galaxies. This approach differs from much recent work, where the luminosity…

天体物理学 · 物理学 2009-11-07 Adam N. Davis , Dragan Huterer , Lawrence M. Krauss

Intrinsic alignments of galaxies are a significant astrophysical systematic affecting cosmological constraints from weak gravitational lensing. Obtaining numerical predictions from hydrodynamical simulations of expected survey volumes is…

We use the Galaxy Morphology Posterior Estimation Network (GaMPEN) to estimate morphological parameters and associated uncertainties for $\sim 8$ million galaxies in the Hyper Suprime-Cam (HSC) Wide survey with $z \leq 0.75$ and $m \leq…

Disk galaxies are typically in a stable configuration where matter moves in almost closed circular orbits. However, non-circular motions caused by distortions, warps, lopsidedness, or satellite interactions are common and leave distinct…

星系天体物理 · 物理学 2023-10-25 Francesco Sylos Labini , Matteo Straccamore , Giordano De Marzo , Sébastien Comerón

Systematic effects on HI and Halpha long-slit observations make a measurement of the inner slope of the dark matter density distribution difficult to determine. Halos with constant density cores and ones with r^-1 profiles both appear…

天体物理学 · 物理学 2007-05-23 R. A. Swaters , M. A. W. Verheijen , M. A. Bershady , D. R. Andersen

While it is clear that spiral galaxies can have different handedness, galaxies with clockwise patterns are assumed to be symmetric in all of their other characteristics to galaxies with counterclockwise patterns. Here we use data from SDSS…

星系天体物理 · 物理学 2016-05-25 Lior Shamir

We search for hidden mirror symmetries at large angular scales in the WMAP 7 year Internal Linear Combination map of CMB temperature anisotropies using global pixel based estimators introduced for this aim. Two different axes are found for…

宇宙学与河外天体物理 · 物理学 2015-03-19 F. Finelli , A. Gruppuso , F. Paci , A. A. Starobinsky

Many galaxies display warps, lopsided images, asymmetric rotation curves or other features which suggest that their immediate dynamical environment is neither static nor in equilibrium. In Cold Dark Matter (CDM) theories, such…

天体物理学 · 物理学 2008-11-26 liang Gao , Simon D. M. White

We present combined Halpha+HI rotation curves for a sample of spiral galaxies. Most of the velocity profiles (spectra at single points) in these galaxies are asymmetric, preventing the use of standard methods like the first moment analysis…

天体物理学 · 物理学 2007-05-23 G. Gentile , D. Vergani , P. Salucci , P. Kalberla , U. Klein

Channel simulation is an alternative to quantization and entropy coding for performing lossy source coding. Recently, channel simulation has gained significant traction in both the machine learning and information theory communities, as it…

信息论 · 计算机科学 2026-02-10 Gergely Flamich , Sharang M. Sriramu , Aaron B. Wagner

The problem of finding an appropriate geometrical/physical index for measuring a degree of inhomogeneity for a given space-time manifold is posed. Interrelations with the problem of understanding the gravitational/informational entropy are…

广义相对论与量子宇宙学 · 物理学 2007-05-23 Roustam Zalaletdinov

The local galaxy peculiar velocity field can be reconstructed from the surrounding distribution of large-scale structure and plays an important role in calibrating cosmic growth and expansion measurements. In this paper, we investigate the…

宇宙学与河外天体物理 · 物理学 2023-11-20 Ryan J. Turner , Chris Blake