Distance astronomers discovered a second galaxy without dark matter, NGC 1052-DF4, which is also a very diffuse galaxy – quite large, widely scattered and faintly observable. ngc 1052-df2 thus falls on the same empirical mass-metallicity relation as other dwarfs for the entire distance range assumed in the literature. NGC 1052-DF2 thus falls on the same empirical mass-metallicity relation as other dwarfs for the entire range of distances assumed in the literature. The distance of the red giant branch tip of 22.1 ± 1.2 Mpc to the galaxy NGC 1052-DF2 with dark matter deficiency from 40 orbits of Hubble Space Telescope images.
A peak of the red giant branch at a distance of 22.1 ± 1.2 Mpc from the galaxy NGC 1052-DF2 with a lack of dark matter from 40 orbits of Hubble Space Telescope images. NASA’s Hubble Space Telescope is an international collaboration project between NASA and ESA. NGC 1052-DF2 is an ultra-diffuse galaxy (UDG) in the constellation Cetus, discovered in a wide-field survey of the NGC 1052 group by the Hubble Space Telescope.
What is special about the galaxy NGC 1052-DF2?
This large, fuzzy-looking galaxy is so diffuse that astronomers call it a “transparent galaxy” because they can see clearly distant galaxies behind it. In the first study, the team confirmed their initial observations of NGC 1052-DF2, or DF2, showing that there is virtually no dark matter in this galaxy. When astronomers first observed this strange galaxy, they could not believe that it lacked the primary source of material that holds it, dark matter. The mystery surrounding the galaxy NGC 1052-DF2 deepens with each new revelation astronomers make with the Hubble Space Telescope.
We see that DF2 has a similar metallicity to the other UDGs previously studied and falls on the empirical relationship for dwarf galaxies of Kirby et al.
What kind of galaxy is NGC 1052?
As mentioned in Section 4.1, the systemic velocity of NGC1052-DF4 is almost identical to the average of the galaxies in the NGC 1052 group. Two of the four lower-priority objects turn out to be compact background galaxies, and the other two are too faint for a redshift measurement. We conclude that the galaxy belongs to the NGC 1052 group and use D = 20 Mpc for distance-dependent magnitudes. Following the adage “one is an exception, but two is a population”, this new object provides an impetus to characterise the properties of diffuse galaxies with a lack of dark matter as a class.
It is located at a projected distance of 285 (165 kpc) from NGC 1052 itself, a factor of two further than NGC1052-DF2, and 26′ (150 kpc) from the spiral galaxy NGC 1042 (which is almost certainly also a group member; see van Dokkum et al.
Are there galaxies without dark matter?
Instead of dark matter, these strange galaxies are mainly filled with normal matter, such as the protons, neutrons and electrons that make up everything we know. Dark energy takes up another 68 per cent, creating a repulsive force that accelerates the expansion of the universe. The find dramatically increases the number of galaxies that appear to lack dark matter, the mysterious, invisible material that exerts a gravitational pull but emits no light. So who was right? One team claimed to have fixed the distance at a high value with a low velocity dispersion, suggesting that there is no dark matter inside.
This is because dark matter, the invisible framework that makes up most of the mass of the universe, is thought to be essential to the formation and shaping of galaxies.
What kind of galaxy is NGC 3115?
Fitting galaxies is tricky because you have to strike a balance between freely varying parameters and placing constraints on some components so that the final model is not unphysical. Indeed, the black hole in NGC 3115 was one of the easiest to find because it is unusually massive compared to the rest of the galaxy. In particular, another step forward would be to more closely link the two-dimensional (gaseous and stellar) kinematics and stellar population information, looking at the multi-dimensional data set across the LOSVDs, ages and metallicity ranges, which should provide an unprecedented view of galaxy formation and mass structure. NGC 3115 is about 32 million light years from Earth and is classified as a so-called lenticular galaxy because it contains a disk and a central bulge of stars, but has no discernible spiral pattern.
