Related papers: Fitting the radial acceleration relation to indivi…
The Radial Acceleration Relation (RAR) follows from Milgromian gravitation (MoND). Velocity dispersion data of many dwarf spheroidal galaxies (dSphs) and galaxy clusters have been reported to be in tension with it. We consider the…
MOdified Newtonian Dynamics (MOND) is an alternative to the standard Cold Dark Matter (CDM) paradigm which proposes an alteration of Newton's laws of motion at low accelerations, characterized by a universal acceleration scale a_0. It…
The physical background of scaling laws of disk galaxies is reviewed. The match between analytically derived and observed scaling laws is briefly discussed. Accurate modeling of the fraction of baryons that end populating a disk, and the…
[Abridged] We present ground-based MDM V-band and Spitzer/IRAC 3.6um-band photometric observations of the 72 representative galaxies of the SAURON Survey. In combination with the SAURON stellar velocity dispersion measured within an…
Modified Newtonian Dynamics (MOND), postulating a breakdown of Newtonian mechanics at low accelerations, has considerable success at explaining galaxy kinematics. However, the quadrupole of the gravitational field of the Solar System (SS)…
Starting with the spherical Jeans equation, we show that there exists a radius where the mass enclosed depends only on the projected tangential velocity dispersion, assuming that the anisotropy profile slowly varies. This is…
In our recent report, observational evidence supports that the rotational direction of a galaxy tends to be coherent with the average motion of its nearby neighbors within 1 Mpc. We extend the investigation to neighbors at farther…
Near-future surveys promise a dramatic improvement in the number and precision of astrometric, photometric and spectroscopic measurements of stars in the Milky Way's disk. We examine the impact of such surveys on our understanding of the…
It has been suggested recently that the change in cosmological redshift (the Sandage test of expansion) could be observed in the next generation of large telescopes and ultra-stable spectrographs. In a recent paper we estimated the change…
High-precision astrometric and radial-velocity observations require accurate modelling of stellar motions in order to extrapolate measurements over long time intervals, and to detect deviations from uniform motion caused for example by…
The baryonic Faber-Jackson relation (BFJR) links the baryonic mass of pressure-supported systems to their mean velocity dispersion. For elliptical galaxies, the BFJR is thought to be a projection of the fundamental plane (FP), which…
Galaxies accrete their mass by means of both smooth accretion from the cosmic web, and the mergers of smaller entities. We wish to quantify the respective role of these two modes of accretion, which could determine the morphological types…
We used 1627 faint (15.5< R<23) stars in five fields of the Calar Alto Deep Imaging Survey (CADIS) to estimate the structure parameters of the Galaxy. The results were derived by applying two complementary methods: first by fitting the…
Two groups of astronomers used the large telescopes Keck and VLT for decades to observe trajectories of bright stars near the Galactic Centre. Based on results of their observations the astronomers concluded that trajectories of the stars…
We have studied the relationships between the radio continuum (RC) and CO emission for a set of galaxies selected from the BIMA Survey of Nearby Galaxies. We find that the global CO-RC correlation is as tight as the global FIR-RC…
We derive relations between the effective radii $R_{\rm{eff}}$ of galaxies and the virial radii $R_{200c}$ of their dark matter halos over the redshift range $0 < z < 3$. For galaxies, we use the measured sizes from deep images taken with…
Galaxies evolve via a complex interaction of numerous different physical processes, scales and components. In spite of this, overall trends often appear. Simplified models for galaxy histories can be used to search for and capture such…
We propose a random forest (RF) machine learning approach to determine the accreted stellar mass fractions ($f_\mathrm{acc}$) of central galaxies, based on various dark matter halo and galaxy features. The RF is trained and tested using…
We quantify the differences between stellar accelerations in disk galaxies formed in a MONDian universe relative to galaxies with the identical baryonic matter distributions and a fitted cold dark matter halo. In a Milky Way-like galaxy the…
We transformed radial velocities compiled from more than 1400 published sources, including the Geneva--Copenhagen survey of the solar neighborhood (CORAVEL-CfA), into a uniform system based on the radial velocities of 854 standard stars in…