A plane of high-velocity galaxies across the Local Group

  title={A plane of high-velocity galaxies across the Local Group},
  author={Indranil Banik and HongSheng Zhao},
  journal={Monthly Notices of the Royal Astronomical Society},
We recently showed that several Local Group (LG) galaxies have much higher radial velocities (RVs) than predicted by a 3D dynamical model of the standard cosmological paradigm. Here, we show that 6 of these 7 galaxies define a thin plane with root mean square thickness of only 101 kpc despite a widest extent of nearly 3 Mpc, much larger than the conventional virial radius of the Milky Way (MW) or M31. This plane passes within ${\sim 70}$ kpc of the MW-M31 barycentre and is oriented so the MW… 

MOND simulation suggests an origin for some peculiarities in the Local Group

Context. The Milky Way (MW) and Andromeda (M 31) galaxies possess rotating planes of satellites. The formation of these planes has not been explained satisfactorily so far. It has been suggested that

The High Fraction of Thin Disk Galaxies Continues to Challenge ΛCDM Cosmology

Any viable cosmological framework has to match the observed proportion of early- and late-type galaxies. In this contribution, we focus on the distribution of galaxy morphological types in the

Census and classification of low-surface-brightness structures in nearby early-type galaxies from the MATLAS survey

The morphology of galaxies gives essential constraints on the models of galaxy evolution. The morphology of the features in the low-surface-brightness regions of galaxies has not been fully explored

Are Disks of Satellites Comprised of Tidal Dwarf Galaxies?

It was found that satellites of nearby galaxies can form flattened co-rotating structures called disks of satellites or planes of satellites. Their existence is not expected by the current galaxy

Milky Way and Andromeda past-encounters in different gravity models: the impact on the estimated Local Group mass

The Two-body problem of $M31$ and the Milky Way (MW) galaxies with a Cosmological Constant background is studied, with emphasis on the possibility that they experienced Past Encounters. By

The two body problem in the presence of dark energy and modified gravity: application to the Local Group

We explore mass estimation of the Local Group via the use of the simple, dynamical `timing argument' in the context of a variety of theories of dark energy and modified gravity: a cosmological

The KBC void and Hubble tension contradict ΛCDM on a Gpc scale − Milgromian dynamics as a possible solution

The KBC void is a local underdensity with the observed relative density contrast δ ≡ 1 − ρ/ρ0 = 0.46 ± 0.06 between 40 and 300 Mpc around the Local Group. If mass is conserved in the Universe, such

Directly testing gravity with Proxima Centauri

  • I. BanikP. Kroupa
  • Physics, Geology
    Monthly Notices of the Royal Astronomical Society
  • 2019
The wide binary orbit of Proxima Centauri around α Centauri A and B differs significantly between Newtonian and Milgromian dynamics (MOND). By combining previous calculations of this effect with

Testing gravity with interstellar precursor missions

We consider how the trajectory of an interstellar precursor mission would be affected by the gravity of the Sun in Newtonian and Milgromian dynamics (MOND). The Solar gravity is ${\approx 50\%}$



A Dynamical Model of the Local Group

This dynamical model for the 28 galaxies with distances less than 1.5 Mpc, and not apparently tight satellites, is constrained by the initial condition that peculiar velocities at high redshift are

Dynamical history of the Local Group in ΛCDM

The positions and velocities of galaxies in the Local Group (LG) measure the gravitational field within it. This is mostly due to the Milky Way (MW) and Andromeda (M31). We constrain their masses

The formation of Local Group planes of galaxies

The confinement of most satellite galaxies in the Local Group to thin planes presents a challenge to the theory of hierarchical galaxy cl ustering. The PAndAS collaboration has identified a


We demonstrate the presence of an extended and massive circumgalactic medium (CGM) around Messier 31 using archival HST Cosmic Origins Spectrograph ultraviolet spectroscopy of 18 QSOs projected

A vast, thin plane of corotating dwarf galaxies orbiting the Andromeda galaxy

Radial velocity measurements reveal that the satellites in this structure have the same sense of rotation about their host, and shows conclusively that substantial numbers of dwarf satellite galaxies share the same dynamical orbital properties and direction of angular momentum.

Planes of satellite galaxies: when exceptions are the rule

The detection of planar structures within the satellite systems of both the Milky Way (MW) and Andromeda (M31) has been reported as being in stark contradiction to the predictions of the standard


We report on the presence of large amounts of million-degree gas in the Milky Way’s interstellar and circum-galactic medium. This gas (1) permeates both the Galactic plane and the halo, (2) extends

The remnants of galaxy formation from a panoramic survey of the region around M31

A panorama of galaxy structure of the Andromeda galaxy (M31) is reported, which directly confirms the basic tenets of the hierarchical galaxy formation model and reveals the shared history of M31 and M33 in the unceasing build-up of galaxies.

Galaxy Groups Within 3500 km s−1

A study of the group properties of galaxies in our immediate neighborhood provides a singular opportunity to observationally constrain the halo mass function, a fundamental characterization of galaxy

A dynamical model of the local cosmic expansion

We combine the equations of motion that govern the dynamics of galaxies in the local volume with Bayesian techniques in order to fit orbits to published distances and velocities of galaxies within