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The SDSS-IV MaNGA survey has measured two-dimensional maps of emission line velocities for a statistically powerful sample of nearby galaxies. The asymmetric features of these kinematics maps reflect the non-rotational component of a…

星系天体物理 · 物理学 2022-08-24 Shuai Feng , Shi-Yin Shen , Fang-Ting Yuan , Y. Sophia Dai , Karen L. Masters

(Abridged) We study the properties of anisotropic and axisymmetric velocity ellipsoids from maps of the gas velocity dispersion in nearby galaxies. This data allow us to measure the azimuthal-to-radial axis ratio of gas velocity ellipsoids,…

星系天体物理 · 物理学 2020-08-05 Laurent Chemin , Jonathan Braine , Françoise Combes , Zacharie S. Kam , Claude Carignan

We present an analysis of morphological, kinematic and spectral asymmetries in observations of atomic neutral hydrogen (HI) gas from the Local Volume HI Survey (LVHIS), the VLA Imaging of Virgo in Atomic Gas (VIVA) survey and the Hydrogen…

星系天体物理 · 物理学 2020-03-11 T. N. Reynolds , T. Westmeier , L. Staveley-Smith , G. Chauhan , C. D. P. Lagos

Recent observations using several different telescopes and sky surveys showed patterns of asymmetry in the distribution of galaxies by their spin directions as observed from Earth. These studies were done with data imaged from the Northern…

宇宙学与河外天体物理 · 物理学 2021-08-18 Lior Shamir

Observations of intergalactic neutral hydrogen can provide a wealth of information about structure and galaxy formation, potentially tracing accretion and feedback processes on Mpc scales. Below a column density of NHI ~ 10^19 cm-2, the…

宇宙学与河外天体物理 · 物理学 2015-05-13 Attila Popping , Romeel Dave , Robert Braun , Benjamin D. Oppenheimer

We use galaxy-galaxy lensing to study the statistical properties of the dark matter halos of galaxies. Our data is taken from the COMBO-17 survey which has imaged 1 square degree in 17 optical filters giving accurate photometric redshifts…

We introduce a new methodology to robustly determine the mass profile, as well as the overall distribution, of Local Group satellite galaxies. Specifically we employ a statistical multilevel modelling technique, Bayesian hierarchical…

星系天体物理 · 物理学 2015-06-23 Gregory D. Martinez

While galaxy rotation curves provide one of the most powerful methods for measuring dark matter profiles in the inner regions of rotation-supported galaxies, at the dwarf scale there are factors that can complicate this analysis. Given the…

Thanks to recent advances in integral field spectroscopy (IFS), modern surveys of nearby galaxies are capable of resolving metallicity maps of Hii regions down to scales of ~50pc. However, statistical analysis of these metallicity maps has…

星系天体物理 · 物理学 2021-09-22 Benjamin Metha , Michele Trenti , Tingjin Chu

We present simulated observations of gas kinematics in galaxies formed in 10 pc resolution cosmological simulations with the hydrodynamical + N-body code RAMSES, using the new RAMSES2HSIM pipeline with the simulated observing pipeline…

Disc galaxies commonly show asymmetric features in their morphology, such as warps and lopsidedness. These features can provide key information regarding the recent evolution of a given disc galaxy. In the nearby Universe, up to $\sim30$…

Using a generalized self-similar secondary infall model, which accounts for tidal torques acting on the halo, we analyze the velocity profiles of halos in order to gain intuition for N-body simulation results. We analytically calculate the…

宇宙学与河外天体物理 · 物理学 2010-12-23 Phillip Zukin , Edmund Bertschinger

We present a measurement of lopsidedness for the stellar disks of 60 field spiral galaxies in terms of the azimuthal m=1 Fourier amplitude, A_1, of the stellar light. We conjecture that this lopsidedness is caused by tidal interactions and…

天体物理学 · 物理学 2009-10-28 Dennis Zaritsky , Hans-Walter Rix

The classification of galaxy morphologies is an important step in the investigation of theories of hierarchical structure formation. While human expert visual classification remains quite effective and accurate, it cannot keep up with the…

天体物理仪器与方法 · 物理学 2023-10-13 Matthew J. Baumstark , Giuseppe Vinci

We present 21-cm HI line and optical R-band observations for a sample of 26 edge-on galaxies. The HI observations were obtained with the Westerbork Synthesis Radio Telescope, and are part of the WHISP database (Westerbork HI Survey of…

天体物理学 · 物理学 2016-08-30 I. Garcia-Ruiz , R. Sancisi , K. Kuijken

Large-scale asymmetries (i.e. lopsidedness) are a common feature in the stellar density distribution of nearby disk galaxies both in low- and high-density environments. In this work, we characterize the present-day lopsidedness in a sample…

We present a new method of constraining the mass and velocity anisotropy profiles of galaxy clusters from kinematic data. The method is based on a model of the phase space density which allows the anisotropy to vary with radius between two…

宇宙学与河外天体物理 · 物理学 2015-05-13 Radoslaw Wojtak , Ewa L. Lokas , Gary A. Mamon , Stefan Gottloeber

We devise improved photometric parameters for the morphological classification of galaxies using a bright sample from the First Data Release of the Sloan Digital Sky Survey. In addition to using an elliptical aperture concentration index…

We consider the consequences of applying general relativity to the description of the dynamics of a galaxy, given the observed flattened rotation curves. The galaxy is modeled as a stationary axially symmetric pressure-free fluid. In spite…

天体物理学 · 物理学 2010-10-27 F. I. Cooperstock , S. Tieu

We present a Bayesian inference approach to estimating the cumulative mass profile and mean squared velocity profile of a globular cluster given the spatial and kinematic information of its stars. Mock globular clusters with a range of…

星系天体物理 · 物理学 2022-03-09 Gwendolyn M. Eadie , Jeremy J. Webb , Jeffrey S. Rosenthal