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We present a detailed study of the shape of the innermost part of the rotation curves of a sample of 29 nearby spiral galaxies, based on high angular and spectral resolution kinematic Halpha Fabry-Perot observations. In particular, we…

This is the third paper in a series in which we attempt to put constraints on the flattening of dark halos in disk galaxies. For this purpose we need to analyse the observed XV diagrams in edge-on galaxies to accurately measure the radial…

Astrophysics of Galaxies · Physics 2015-05-18 J. C. O'Brien , K. C. Freeman , P. C. van der Kruit

The proper motions of stars in the outskirts of globular clusters are used to estimate cluster velocity dispersion profiles as far as possible within their tidal radii. We use individual color-magnitude diagrams to select high probability…

Astrophysics of Galaxies · Physics 2021-12-08 Raymond G. Carlberg , Carl J. Grillmair

We recover spiral and barred spiral patterns in disk galaxy simulations with a Wave Dark Matter (WDM) background (also known as Scalar Field Dark Matter (SFDM), Ultra-Light Axion (ULA) dark matter, and Bose-Einstein Condensate (BEC) dark…

Astrophysics of Galaxies · Physics 2015-12-15 L. A. Martinez-Medina , Hubert L. Bray , Tonatiuh Matos

We present a study of the dynamical properties of 125 compact stellar systems (CSSs) in the nearby giant elliptical galaxy NGC5128, using high-resolution spectra (R 26,000) obtained with VLT/FLAMES. Our results provide evidence for a new…

Astrophysics of Galaxies · Physics 2015-05-27 Matthew Taylor , Thomas Puzia , Matias Gomez , Kristin Woodley

In a previous paper (Olling 1995, astro-ph/9505002) a method was developed to determine the shapes of dark matter halos of spiral galaxies from an accurate determination of the rotation curve, the flaring of the gas layer and the velocity…

Astrophysics · Physics 2007-05-23 Rob P. Olling

Detailed neutral hydrogen observations have been obtained of the large barred spiral galaxy NGC 3992 and its three small companion galaxies, UGC 6923, UGC 6940, and UGC 6969. For the main galaxy, the HI distribution is regular with a low…

Astrophysics · Physics 2009-11-07 Roelof Bottema , Marc A. W. Verheijen

Rotation curves of galaxies show a wide range of shapes, which can be paramaterized as scatter in Vrot(1kpc)/Vmax i.e.the ratio of the rotation velocity measured at 1kpc and the maximum measured rotation velocity. We examine whether the…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-19 Chris Brook

Tremaine and Weinberg (TW) proposed a conceptually simple procedure relying on long-slit spectroscopy to measure the pattern speeds of bars ($\Omega_{\rm p}$) in disk galaxies. Using a simulated galaxy, we investigate the potential biases…

Astrophysics of Galaxies · Physics 2019-10-16 Yanfei Zou , Juntai Shen , Martin Bureau , Zhao-Yu Li

The recently discovered Ursa Major dwarf spheroidal (dSph) galaxy candidate is about five to eight times less luminous than the faintest previously known dSphs And IX, Draco, and UMi. In this Letter, we present velocity measurements of…

Astrophysics · Physics 2009-11-13 J. T. Kleyna , M. I. Wilkinson , N. W. Evans , G. Gilmore

We consider seven distant galaxies with clearly evident spiral structure from HST images. Three of these were chosen from Vogt et al. (1996) (VFP) and have measured rotational velocities. Five were chosen from the Medium Deep Survey and are…

Astrophysics · Physics 2009-10-30 A. C. Quillen , V. L. Sarajedini

We investigate pattern speeds in spiral galaxies where the structure is induced by an interaction with a companion galaxy. We perform calculations modeling the response of the stellar and/or gaseous components of a disc. Generally we do not…

Astrophysics of Galaxies · Physics 2010-02-08 C. L. Dobbs

As a first step of a program aimed to the detection of dark matter (or radial variations of M/L) in early-type galaxies, we report deep spectroscopic observations of the bulge-dominated edge-on S0 galaxy NGC 3115, made at ESO, La Silla,…

Astrophysics · Physics 2007-05-23 M. Capaccioli , E. Cappellaro , E. V. Held , M. Vietri

We perform several high resolution N-Body/SPH simulations of low surface brightness galaxies (LSBs) embedded in cold dark matter halos to study how likely is bar formation in such systems. The behavior of various collisionless galaxy models…

Astrophysics · Physics 2009-11-07 Lucio Mayer , James Wadsley

We explore the vertical light distribution as a function of galactocentric radius in the edge-on (i=88) Sd `superthin' galaxy UGC7321. UGC7321 is a low-luminosity spiral (M_B,i=-17.0) with a diffuse, low surface brightness stellar disk and…

Astrophysics · Physics 2009-10-31 L. D. Matthews

This study examines the effect of dark matter halos on the orbital and escape dynamics of stars in the central region of barred galaxies. A three-dimensional gravitational model with a central bulge, bar, disc, and dark matter halo (or…

Astrophysics of Galaxies · Physics 2024-09-20 Debasish Mondal , Tanuka Chattopadhyay

In this paper, we measure the optical-to-virial velocity ratios Vopt/V200c of disk galaxies in the Sloan Digital Sky Survey (SDSS) at a mean redshift of <z> = 0.07 and with stellar masses 10^9 M_sun < M_* < 10^11 M_sun. Vopt/V200c, the…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 Reinabelle Reyes , Rachel Mandelbaum , James E. Gunn , Reiko Nakajima , Uros Seljak , Chris M. Hirata

This is the fourth paper in a series in which we attempt to put constraints on the flattening of dark halos in disk galaxies. We observed for this purpose the HI in edge-on galaxies, where it is in principle possible to measure the force…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 J. C. O'Brien , K. C. Freeman , P. C. van der Kruit

Recent studies of ultra-diffuse galaxies (UDGs) have shown their globular cluster (GC) systems to be central in unveiling their remarkable properties and halo masses. Deep HST imaging revealed 54 GC candidates around the UDG NGC5846_UDG1…

An overwhelming majority of galactic spiral arms trail with respect to the rotation of the galaxy, though a small sample of leading spiral arms has been observed. The formation of these leading spirals is not well understood. Here we show,…

Astrophysics of Galaxies · Physics 2021-10-20 Emma Lieb , Angela Collier , Ann-Marie Madigan
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