Related papers: On the Generalized-Faber Jackson relation for NGC …
The significant deviations among observations and the expectations based on self-similar scaling model of galaxy clusters, especially up to redshift $z\lesssim 0.4$, constrain the evolution of the X-ray clusters scaling relations with the…
Recent observations of ultra-dwarf galaxy NGC1052-DF2 started an interesting discussion between dark matter hypothesis and modified gravity theories. Reported low velocity dispersion (< 10.5 km/s at 90% confidence level) derived from the…
The Ultra-Diffuse galaxy NGC1052-DF2 has recently been under intense scrutiny because from its kinematics it has revealed to be "extremely deficient" in dark matter, if not lacking it at all. This claim has raised many questions and…
Recently van Dokkum et al. (2018b) reported that the galaxy NGC 1052-DF2 (DF2) lacks dark matter if located at $20$ Mpc from Earth. In contrast, DF2 is a dark-matter-dominated dwarf galaxy with a normal globular cluster population if it has…
Nearby isolated galaxies ($z\sim 0$), are considered immerse within a thermal bath at 2.73 K. However the dwarf galaxies orbiting these galaxies are also subject to additional radiation from their hosts, so they are within a thermal bath…
The ultra-diffuse galaxy NGC1052-DF2 has a very low velocity dispersion, indicating that it has little or no dark matter. Here we report the discovery of a second galaxy in this class, residing in the same group. NGC1052-DF4 closely…
The discovery of the ultra-diffuse galaxy NGC 1052-DF2 and its peculiar population of star clusters has raised new questions about the connections between galaxies and dark matter halos at the extremes of galaxy formation. In light of…
Recent observations revealed a mysterious ultra diffuse galaxy, NGC1052-DF2, in the group of a large elliptical galaxy, NGC1052. Compared to expectations from abundance matching models, the dark matter mass contained in NGC1052-DF2 is…
The recent observation of the ultra-diffuse galaxy NGC 1052-DF2 shows a galaxy may lack dark matter. Usually dark matter is much more abundant than stellar in galaxy environment. This dark matter to baryon mass ratio is generally larger…
Studies of galaxy surveys in the context of the cold dark matter paradigm have shown that the mass of the dark matter halo and the total stellar mass are coupled through a function that varies smoothly with mass. Their average ratio…
The ultra-diffuse galaxy (UDG) NGC1052-DF2 has captured the interest of astronomers ever since the low velocity dispersion measured from ten globular clusters (GCs) suggested a low dark matter fraction. Also, its GC system was found to be…
It was recently proposed that the globular cluster system of the very low surface-brightness galaxy NGC1052-DF2 is dynamically very cold, leading to the conclusion that this dwarf galaxy has little or no dark matter. Here, we show that a…
The possible existence of two dark matter free galaxies (NGC1052-DF2 and NGC1052-DF4) in the field of the early-type galaxy NGC1052 presents a challenge to theories of dwarf galaxy formation according to the current cosmological paradigm.…
We recently inferred that the galaxy NGC1052-DF2 has little or no dark matter and a rich system of unusual globular clusters. We assumed that the galaxy is a satellite of the luminous elliptical galaxy NGC1052 at ~20 Mpc, on the basis of…
The ultra-diffuse galaxy NGC 1052-DF2 has an overabundance of luminous globular clusters (GCs), and its kinematics is consistent with the presence of little to no dark matter. As the velocity dispersion among the GCs is comparable to the…
NGC1052-DF4 was found to be the second "galaxy lacking dark matter" in the NGC1052 group, based on its velocity dispersion of $\sigma_{\rm gc}=4.2^{+4.4}_{-2.2}$ km/s as measured from the radial velocities of seven of its globular clusters.…
A great challenge in present-day physics is to understand whether the observed internal dynamics of galaxies is due to dark matter matter or due to a modification of the law of gravity. Recently, van Dokkum et al. reported that the…
The recently claimed discovery of an ultra-diffuse galaxy lacking dark matter has important implications for alternate theories to dark matter as well as models of galaxy formation within the $\Lambda$CDM context. In this letter, we present…
Observations have revealed a significant dark matter deficit in the ultra-diffuse galaxy NGC1052-DF2 (DF2). It is widely accepted that the formation of this unique galaxy can be attributed to the tidal stripping of its host galaxy, NGC1052.…
In this study, we use Keck/KCWI spectroscopy to measure the age, metallicity and recessional velocity of NGC~1052-DF9 (DF9), a dwarf galaxy in the NGC~1052 group. We compare these properties to those of two other galaxies in the group,…