Astronomers using ESO’s VLT Survey Telescope (VST) have examined a small group of five galaxies in the southern hemisphere. The results will be published in the Astrophysical Journal.
This deep image of the area of sky around the elliptical galaxy NGC 5018 offers a spectacular view of its tenuous streams of stars and gas. These delicate features are hallmarks of galactic interactions, and provide vital clues to the structure and dynamics of early-type galaxies. Image credit: Spavone et al / ESO.
The NGC 5018 galaxy group lies in the constellation of Virgo, approximately 130 million light-years from Earth.
It consists of the giant elliptical galaxy NGC 5018, the edge-on spiral galaxy NGC 5022, the spiral galaxy MCG-03-34-013, and two face-on dwarf, gas-rich spirals.
NGC 5018 (the milky-white galaxy near the center of the new VST image) is the dominant member of the group.
It may at first resemble nothing but a diffuse blob. But, on closer inspection, a tenuous stream of stars and gas — a tidal tail — can be seen stretching outwards from this galaxy.
Delicate galactic features such as tidal tails and stellar streams are hallmarks of galactic interactions, and provide vital clues to the structure and dynamics of galaxies.
This annotated view of the surroundings of NGC 5018 shows many of its neighbors. It also reveals a few asteroids that were captured by chance during the deep exposures needed to reveal the delicate streams of stars between the galaxies. Image credit: Spavone et al / ESO.
As well as the many elliptical — and a few spiral — galaxies in the VST image, a colorful variety of bright foreground stars in our own Milky Way Galaxy also pepper the image.
These stellar interlopers, such as the vividly blue HD 114746 near the center of the image, are not the intended subjects of this astronomical portrait, but happen to lie between the Earth and the distant galaxies under study.
Less prominent, but no less fascinating, are the faint tracks left by asteroids in our own Solar System.
Just below NGC 5018, the faint streak left by the asteroid 2001 TJ21 (110423) can be seen stretching across the image.
Further to the right, another asteroid, 2000 WU69 (98603), left its trace in this spectacular image.
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Marilena Spavone et al. 2018. VEGAS: A VST Early-type GAlaxy Survey. III. Mapping the galaxy structure, interactions and intragroup light in the NGC 5018 group. ApJ, in press; arXiv: 1807.11204
