Galaxies

Gamma-ray burst map showing a ring 5 billion light years across (Image courtesy Lajos Balazs)

An article published in the journal “Monthly Notices of the Royal Astronomical Society” describes the discovery of what appears to the largest structure of the universe. It’s a ring of nine gamma-ray bursts, which means as many galaxies, for a length of 5 billions light years. This ring, though it’s not really a circle, seems to contradict the current models and in particular the cosmological principle, the idea that the distribution of matter in the universe is uniform at a large enough scale.

Artistic impression of the galaxy CR7 (Image ESO/M. Kornmesser)

An article accepted for publication in “The Astrophysical Journal” describes the discovery of a galaxy called CR7 seen as it was at the time of the early universe in which first-generation stars were found. This research was carried out mainly using ESO’s Very Large Telescope but data collected by the W. M. Keck Observatory, the Subaru Telescope and the Hubble Space Telescope were also used.

Galaxies containing quasars observed using the Hubble Space Telescope: in the top row the quasars are visible, in the bottom row the quasars' light is subtracted (Image NASA/ESA)

An article in the journal “Astrophysical Journal” describes a research conducted on quasars using the Hubble Space Telescope. These objects that are incredibly bright were observed in their formation phase, when they were in a sense teen-agers. The observations confirm the hypothesis that quasars are generated by galactic collisions that feed the supermassive black hole at their center.

The galaxy group NGC 5813 observed with the Chandra X-Ray Observatory (Image X-ray: NASA/CXC/SAO/S.Randall et al., Optical: SDSS)

An article in “The Astrophysical Journal” describes a research group of NGC 5813 made using the NASA’s Chandra X-ray Observatory. In this galaxy group, multiple eruptions originate from the supermassive black hole at the galactic center that gives its name to the group were discovered. This activity took place over about 50 million years and has changed the appearance of the group, creating various cavities, huge bubbles within the cloud of hot gas that surrounds it.

Pictures of the galaxy SDP.81. On the left a picture taken by the Hubble Space Telescope. In the middle, the galaxy as an Einsetin ring and on the left as it's seen after being processed to eliminate the gravitational lensing distorsion (Image ALMA (NRAO/ESO/NAOJ)/Y. Tamura (The University of Tokyo)/Mark Swinbank (Durham University))

ESO’s telescope ALMA (Atacama Large Millimeter / submillimeter Array) in Chile allowed to take the most detailed images ever obtained of a galaxy called HATLAS J090311.6+003906 or SDP.81. It’s about 11.4 billion light years from Earth and its light is distorted by the phenomenon called gravitational lensing. A galaxy between it and the Earth distorts its light with its huge gravity and the result is that we see an almost perfect ring, called an Einstein ring.