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We present Halpha rotation curves for a sample of 15 dwarf and LSB galaxies. From these, we derive limits on the slopes of the central mass distributions. Assuming the density distributions of dark matter halos follow a power-law at small…

天体物理学 · 物理学 2008-11-26 R. A. Swaters , B. F. Madore , F. C. van den Bosch , M. Balcells

We analyze four epochs of HST imaging over 18 years for the Draco dwarf spheroidal galaxy. We measure precise proper motions (PMs) for hundreds of stars and combine these with existing line-of-sight (LOS) velocities. This provides the first…

This survey, once completed, will provide a 3D sample of 200 nearby spiral and irregular galaxies in the Halpha line, using a Fabry-Perot system. The data cubes obtained for each galaxy allow derivation of lines maps, velocity fields and…

天体物理学 · 物理学 2007-05-23 Philippe Amram , Olivia Garrido

The unusually large "dwarf" galaxy Crater II, with its small velocity dispersion, $\simeq 3$ km/s, defies expectations that low mass galaxies should be small and dense. We combine the latest stellar and velocity dispersion profiles finding…

宇宙学与河外天体物理 · 物理学 2022-07-20 A. Pozo , T. Broadhurst , R. Emami , G. Smoot

The condensation of baryons within a dark matter (DM) halo during galaxy formation should result in some contraction of the halo as the combined system settles into equilibrium. We quantify this effect on the cuspy primordial halos…

星系天体物理 · 物理学 2022-09-21 Pengfei Li , Stacy S. McGaugh , Federico Lelli , James M. Schombert , Marcel S. Pawlowski

In spiral galaxies, we explain their non-Keplerian rotation curves (RCs) by means of a non-luminous component embedding their stellar-gaseous disks. Understanding the detailed properties of this component (labelled Dark Matter, DM) is one…

宇宙学与河外天体物理 · 物理学 2012-05-21 Gianluca Castignani , Noemi Frusciante , Daniele Vernieri , Paolo Salucci

A dark matter halo model is developed postulating a new state of matter, entities which have internal spin-like terms. Their motion in an external Schwarzschild metric is discussed. The internal spin motion contributes to the centrifugal…

综合物理 · 物理学 2017-05-25 H. L. Helfer

The Draco dwarf spheroidal galaxy (dSph), with its apparent immense mass to light ratio and compact size, holds many clues to the nature of the enigmatic dark matter. Here we present deep photometric studies of this dwarf galaxy, undertaken…

天体物理学 · 物理学 2008-11-26 Mathieu Segall , Rodrigo Ibata , Michael Irwin , Nicolas Martin , Scott Chapman

We present the HI data for 5 spiral galaxies that, along with their Halpha rotation curves, are used to derive the distribution of dark matter within these objects. A new method for extracting rotation curves from HI data cubes is…

天体物理学 · 物理学 2009-11-10 G. Gentile , P. Salucci , U. Klein , D. Vergani , P. Kalberla

We investigate the structure of the dark matter halo formed in the cold dark matter scenario using $N$-body simulations. We simulated 12 halos with the mass of $6.6\times 10^{11}M_{\odot}$ to $8.0\times 10^{14}M_{\odot}$. In almost all…

天体物理学 · 物理学 2008-11-26 Toshiyuki Fukushige , Junichiro Makino

The shape and diversity of dwarf galaxy rotation curves is at apparent odds with dark matter halos in a $\Lambda$ Cold Dark Matter ($\Lambda$CDM) cosmology. We use mock data from isolated dwarf galaxy simulations to show that this owes to…

星系天体物理 · 物理学 2016-09-07 J. I. Read , G. Iorio , O. Agertz , F. Fraternali

We use the concept of the spiral rotation curves universality to investigate the luminous and dark matter properties of the dwarf disc galaxies in the local volume (size $\sim11$ Mpc). Our sample includes 36 objects with rotation curves…

星系天体物理 · 物理学 2017-01-09 Ekaterina V. Karukes , Paolo Salucci

We show that measuring the proper motion of ${{\sim 2000}}$ stars within a dwarf galaxy, with an uncertainty of 1 km/s at most, can establish whether the Dark Matter (DM) density profile of the dwarf has a central core or cusp. We derive…

星系天体物理 · 物理学 2022-08-31 Ivan de Martino , Antonaldo Diaferio , Luisa Ostorero

We use $\Lambda$CDM cosmological hydrodynamical simulations to explore the kinematics of gaseous discs in late-type dwarf galaxies. We create high-resolution 21-cm 'observations' of simulated dwarfs produced in two variations of the EAGLE…

Dark matter (DM) halo angular momentum is very challenging to determine from observations of galaxies. In this study, we present a new hybrid method of estimating the dimensionless halo angular momentum, halo spin of a gas-rich dwarf barred…

星系天体物理 · 物理学 2026-01-14 Sioree Ansar , Sandeep K Kataria , Mousumi Das

Dark-matter halos grown in cosmological simulations appear to have central NFW-like density cusps with mean values of $d\log\rho/d\log r \approx -1$, and some dispersion, which is generally parametrized by the varying index $\alpha$ in the…

宇宙学与河外天体物理 · 物理学 2015-09-15 Jens Hjorth , Liliya L. R. Williams , Radosław Wojtak , Michael McLaughlin

We present the mass models of 31 spiral and irregular nearby galaxies obtained using hybrid rotation curves (RCs) combining high resolution GHASP Fabry-Perot H$\alpha$ RCs and extended WHISP HI ones together with 3.4 $\mu$m WISE photometry.…

星系天体物理 · 物理学 2019-10-09 M. Korsaga , B. Epinat , P. Amram , C. Carignan , P. Adamczyk , A. Sorgho

The shapes of individual self-gravitating structures of an ensemble of identical, collisionless particles have remained elusive for decades. In particular, a reason why mass density profiles like the Navarro-Frenk-White or the Einasto…

宇宙学与河外天体物理 · 物理学 2020-07-01 Jenny Wagner

We derive rotation curves for four nearby, low-mass spiral galaxies and use them to constrain the shapes of their dark matter density profiles. This analysis is based on high-resolution two-dimensional Halpha velocity fields of NGC 4605,…

天体物理学 · 物理学 2008-11-26 Joshua D. Simon , Alberto D. Bolatto , Adam Leroy , Leo Blitz , Elinor L. Gates

While N-body simulations testify for a cuspy profile of the central region of the dark matter haloes, observations favor a shallow, cored density profile of the central region of, at least, some spiral galaxies and dwarf spheroidals. We…

高能天体物理现象 · 物理学 2014-07-15 Anton N. Baushev