Related papers: Outer Galactic Disks and a Quantitative Test of Gr…
We present a method to derive the dynamical mass of face-on galaxy disks using their neutral hydrogen (HI) velocity dispersion. We have applied the method to nearby, gas rich galaxies that have extended HI gas disks and have low…
We present a two-step method to simulate and study non-circular motions in strongly barred galaxies. The first step is to constrain the initial parameters using a Bayesian analysis of each galaxy's azimuthally averaged rotation curve, the…
Extremely wide binary stars represent ideal systems to probe Newtonian dynamics in the low acceleration regimes (<10e-10 m/s/s) typical of the external regions of galaxies. Here we present a study of 60 alleged wide binary stars with…
In this Letter, we demonstrate that short-period stars orbiting around the supermassive black hole in our Galactic Center can successfully be used to probe the gravitational theory in a strong regime. We use 19 years of observations of the…
The young star velocity field is analysed by means of a galactic model which takes into account solar motion, differential galactic rotation and spiral arm kinematics. We use two samples of Hipparcos data, one containing O- and B-type stars…
The observed flaring of HI disk in the outer region of galaxies has been used in the past to determine the shape of the dark matter halo. Previous studies based on this concept suggest a slightly oblate halo (axis ratio ~ 0.8) for our…
Selected from a sample of nine, isolated, dwarf early-type galaxies (ETGs) having the same range of kinematic properties as dwarf ETGs in clusters, we use CG 611 (LEDA 2108986) to address the Nature versus Nurture debate regarding the…
We have studied the properties of giant star forming clumps in five z~2 star-forming disks with deep SINFONI AO spectroscopy at the ESO VLT. The clumps reside in disk regions where the Toomre Q-parameter is below unity, consistent with…
The outer regions of disk galaxies show a drop-off in optical and Halpha emission, suggesting a star formation threshold radius, assumed to owe to a critical surface density below which star formation does not take place. Signs of…
We use deep (~27.5 mag V-band point-source limiting magnitude) V- and U-band LBT imaging to study the outer disk (beyond the optical radius R_25) of the non-interacting, face-on spiral galaxy NGC 3184 (D = 11.1 Mpc; R_25 = 11.1 kpc) and…
The ultra-diffuse dwarf galaxy NGC 1052-DF2 (DF2) has ten (eleven) measured globular clusters (GCs) with a line-of-sight velocity dispersion of $\sigma=7.8^{+5.2}_{-2.2}\,$km/s ($\sigma=10.6^{+3.9}_{-2.3}\,$km/s). Our conventional…
We use the rotation curves of more than 100 disk galaxies to examine whether the structure of their surrounding dark halos is consistent with the universal density profile proposed by Navarro, Frenk & White (NFW profiles). Rotation curve…
Gamma-ray emission produced by interactions between cosmic rays (CRs) and interstellar gas traces the product of their densities throughout the Milky Way. The outer Galaxy is a privileged target of investigation to separate interstellar…
After their initial formation, disk galaxies are observed to be rotationally stable over periods of >6 Gyr, implying that any large velocity disturbances of stars and gas clouds are damped rapidly on the timescale of their rotation.…
Based on sensitive CO measurements from HERACLES and HI data from THINGS, we show that the azimuthally averaged radial distribution of the neutral gas surface density (Sigma_HI + Sigma_H2) in 33 nearby spiral galaxies exhibits a…
Current constraints on gravity are relatively weak on galactic and intergalactic scales. Screened modified gravity models can exhibit complex behaviour there without violating stringent tests of gravity within our Solar System. They might…
(ABRIDGED) Gaseous halos of nine nearby galaxies (with redshifts cz < 6000 km/s) were probed at large galactocentric radii using background quasars observed with HST GHRS and STIS. The projected quasar-galaxy separations range from 55 to…
Using a sample of over 70, 000 red clump (RC) stars with $5$-$10$% distance accuracy selected from the LAMOST Spectroscopic Survey of the Galactic Anti-center (LSS-GAC), we study the radial and vertical gradients of the Galactic disk(s)…
We present sensitive aperture synthesis observations of the nearby, late-type spiral galaxy NGC 6503, and produce HI maps of considerably higher quality than previous observations by van Moorsel & Wells (1985). We find that the velocity…
In a previous paper (Olling 1995, \aj, 110, 591; 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…