Elliptical and Lenticular galaxies (historically referred to as early-type galaxies) are thought to be no longer giving birth to new stars. Now, a team led by astronomers from the Instituto de Astrofísica e Ciências do Espaço (IA) in Portugal has discovered optical spiral features in the outskirts of three nearby early-type galaxies, which points to a still ongoing inside-out growth.
This new image from the NASA/ESA Hubble Space Telescope shows a cosmic tadpole, with its bright head and elongated tail, wriggling through the inky black pool of space. Tadpole galaxies are rare and difficult to find in the local universe. This striking example, named LEDA 36252, was explored as part of a Hubble study into their mysterious properties — with interesting results.
A new study finds that elliptical galaxies maintain a remarkably constant circular speed out to large distances from their centres, in the same way that spiral galaxies do. In these very different types of galaxies, stars and dark matter somehow conspire to redistribute themselves to produce this effect, or does modified Newtonian dynamics offer an explanation?