相关论文: Simulations of cluster ultra-diffuse galaxies in M…

We report the discovery of ultra-diffuse galaxies (UDGs) in Abell 370 ($z=0.375$). We find 46 UDGs in Abell 370 from the images of the Hubble Frontier Fields (HFF). Most UDGs are low-luminosity red sequence galaxies, while a few of them are…

Recently a population of large, very low surface brightness, spheroidal galaxies was identified in the Coma cluster. The apparent survival of these Ultra Diffuse Galaxies (UDGs) in a rich cluster suggests that they have very high masses.…

We report that the density profiles of globular cluster (GC) systems in a sample of 17 early-type galaxies (ETGs) show breaks at the radii where the gravitational acceleration exerted by the stars equals the galactic acceleration scale…

In MOND (modified Newtonian dynamics)-based theories the strong equivalence principle is generically broken in an idiosyncratic manner, manifested in the action of an "external field effect (EFE)". The internal dynamics in a…

Modified Newtonian Dynamics (MOND) at low acceleration has been astonishingly powerful at explaining the flat rotation curve of galaxies and the relation between the baryonic content of the galaxies and their observed circular velocity,…

We perform a systematic statistical study of ultra-diffuse galaxy analogues (NUDGEs) in a large sample of galaxy clusters to investigate their properties with respect to the host clusters. We used data from the Hyper Suprime-Cam Subaru…

We study the population of ultra-diffuse galaxies (UDGs) in a set of eight nearby ($z <$ 0.035) galaxy clusters, from the Kapteyn IAC WEAVE INT Clusters Survey ($\texttt{KIWICS}$). We report the discovery of 442 UDG candidates in our eight…

We investigate the physical properties of dense cores formed in turbulent, magnetized, parsec-scale clumps of molecular clouds, using three-dimensional numerical simulations that include protostellar outflow feedback. The dense cores are…

Gas-rich ultra-diffuse galaxies (UDGs) are an unusually sharp test for gravity models tied to the baryonic Tully--Fisher relation because several systems appear to rotate too slowly for their baryonic masses. This study revisits the six…

We describe how to estimate the velocity dispersions of ultra diffuse galaxies, UDGs, using a previously defined galaxy scaling relationship. The method is accurate for the two UDGs with spectroscopically measured dispersions, as well as…

Large low surface brightness galaxies have recently been found to be abundant in nearby galaxy clusters. In this paper, we investigate these ultra-diffuse galaxies (UDGs) in the six Hubble Frontier Fields galaxy clusters: Abell 2744,…

We study the kinematics of stars in clusters undergoing gas expulsion in standard Newtonian dynamics and also in Milgromian dynamics (MOND). Gas expulsion can explain the observed line-of-sight (LoS) velocity dispersion profile of NGC 2419…

Globular clusters (GCs) in the Milky Way have characteristic velocity dispersions that are consistent with the predictions of Newtonian gravity, and may be at odds with Modified Newtonian Dynamics (MOND). We discuss a modified gravity (MOG)…

The self-binding energy and stability of a galaxy in MOND-based gravity are curiously decreasing functions of its center of mass acceleration towards neighbouring mass concentrations. A tentative indication of this breaking of the Strong…

A dataset of 23,351 globular clusters (GCs) and ultra-compact dwarfs (UCDs) in the Coma cluster of galaxies was built using Hubble Space Telescope Advanced Camera for Surveys data. Based on the standard magnitude cut of $M_V \leq -11$, a…

The inverse Compton (IC) interpretation of the excess EUV emission, that was recently reported from several clusters of galaxies, suggests that the amount of relativistic electrons in the intracluster medium is highly significant,…

Using a recent homogeneous sample of 40 high quality velocity dispersion profiles for Galactic globular clusters, we study the low gravitational acceleration regime relevant to the outskirts of these systems. We find that a simple empirical…

We point out an interesting theoretical prediction for elliptical galaxies residing inside galaxy clusters in the framework of modified Newtonian dynamics (MOND), that could be used to test this paradigm. Apart from the central brightest…

I pinpoint a previously unrecognized MOND effect that may act in the inner solar system, and is due to the galactic acceleration, g_g=eta*a0: a byproduct of the MOND external-field effect. Predictions of the effect are not generic to the…

In this work, we compare galaxies from the NIHAO and HESTIA simulation suites to ultra-diffuse galaxies (UDGs) with spectroscopically measured dynamical masses. For each observed UDG, we identify the simulated dark matter halo that best…