The loneliest of galaxies: Only three local stars appear in this image, quartered by right-angled diffraction spikes. Everything besides them is a galaxy; floating like a swarm of microbes in a drop of water, and brought into view here not by a microscope, but by the Advanced Camera for Surveys on the Hubble Space Telescope. In the foreground, the spiral arms of MCG+01-02-015 seem to wrap around one another, cocooning the galaxy. The scene suggests an abundance of galactic companionship for MCG+01-02-015, but this is a cruel trick of perspective. Instead, MCG+01-02-015’s unsentimental naming befits its position within the cosmos: It is a void galaxy, the loneliest of galaxies. The vast majority of galaxies are strung out along galaxy filaments — thread-like formations that make up the large-scale structure of the Universe — drawn together by the influence of gravity into sinuous threads weaving through space. Between these filaments stretch shallow but immense voids; the Universe’s wastelands, where, outside of the extremely rare presence of a galaxy, there is very little matter — about one atom per cubic metre. One such desolate stretch of space is what MCG+01-02-015 reluctantly calls home. The galaxy is so isolated that if our galaxy, the Milky Way, were to be situated in the same way, we would not have known of the existence of other galaxies until the 1960s.

Name: MCG+01-02-015
Type: Unspecified : Galaxy
Category: Galaxies
Constellation: Pisces
Distance: z=0.024 (redshift)
Release date: 9 November 2015, 10:00
Credit: ESA/Hubble & NASA and N. Gorin (STScI) Acknowledgement: Judy Schmidt

A young elliptical: At the centre of this amazing image is the elliptical galaxy NGC 3610. Surrounding the galaxy are a wealth of other galaxies of all shapes. There are spiral galaxies, galaxies with a bar in their central regions, distorted galaxies and elliptical galaxies, all visible in the background. In fact, almost every bright dot in this image is a galaxy — the few foreground stars are clearly distinguishable due to the diffraction spikes that overlay their images. NGC 3610 is of course the most prominent object in this image — and a very interesting one at that! Discovered in 1793 by William Herschel, it was later found that this elliptical galaxy contains a disc. This is very unusual, as discs are one of the main distinguishing features of a spiral galaxy. And NGC 3610 even hosts a memarkable bright disc. The reason for the peculiar shape of NGC 3610 stems from its formation history. When galaxies form, they usually resemble our galaxy, the Milky Way, with flat discs and spiral arms where star formation rates are high and which are therefore very bright. An elliptical galaxy is a much more disordered object which results from the merging of two or more disc galaxies. During these violent mergers most of the internal structure of the original galaxies is destroyed. The fact that NGC 3610 still shows some structure in the form of a bright disc implies that it formed only a short time ago. The galaxy’s age has been put at around four billion years and it is an important object for studying the early stages of evolution in elliptical galaxies.

Name: NGC 3610
Type: Local Universe : Galaxy : Type : EllipticalLocal Universe : Galaxy : Component : Disk
Category: Galaxies
Constellation: Ursa Major
Distance: 70 million light years
Release date: 16 November 2015, 06:00
Credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt (Geckzilla)

The last waltz: This curious galaxy — only known by the seemingly random jumble of letters and numbers 2MASX J16270254+4328340 — has been captured by the NASA/ESA Hubble Space Telescope dancing the crazed dance of a galactic merger. The galaxy has merged with another galaxy leaving a fine mist, made of millions of stars, spewing from it in long trails. Despite the apparent chaos, this snapshot of the gravitational tango was captured towards the event’s conclusion. This transforming galaxy is heading into old age with its star-forming days coming to an end. The true drama occurred earlier in the process, when the various clouds of gas within the two galaxies were so disturbed by the event that they collapsed, triggering an eruption of star formation. This flurry of activity exhausted the vast majority of the galactic gas, leaving the galaxy sterile and unable to produce new stars. As the violence continues to subside, the newly formed galaxy’s population of stars will redden with age and eventually begin drop off one by one. With no future generations of stars to take their place, the galaxy thus begins a steady descent towards death.

Name: 2MASX J16270254+4328340
Type: Local Universe : Galaxy : Type : Interacting
Category: Galaxies
Constellation: Hercules
Release date: 23 November 2015, 06:00
Credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt (Geckzilla)

Through the elliptical haze: Like a lighthouse in the fog the luminous core of NGC 2768 slowly fades outwards to a dull white haze in this image taken by the NASA/ESA Hubble Space Telescope. NGC 2768 is an elliptical galaxy in the constellation of Ursa Major (The Great Bear). It is a huge bundle of stars, dominated by a bright central region, where a supermassive black hole feasts on a constant stream of gas and dust being fed to it by its galactic host. The galaxy is also marked by a prominent plume of dust reaching out from the centre and lying perpendicular to the galaxy’s plane. This dust conceals a symmetrical, s-shaped pair of jets that are being produced by the supermassive black hole as it feeds.

Name: NGC 2768
Type: Local Universe : Galaxy : Activity : AGN : Seyfert
Category: Galaxies
Constellation: Ursa Major
Distance: 60 million light years
Release date: 30 November 2015, 06:00

Galactic politics: Only rarely does an astronomical object have a political association. However, the spiral galaxy NGC 7252 acquired exactly that when it was given an unusual nickname. In December 1953, the US President Dwight D. Eisenhower gave a speech advocating the use of nuclear power for peaceful purposes. This  “Atoms for Peace” speech was significant for the scientific community, as it brought nuclear research into the public domain, and NGC 7252, which has a superficial resemblance to an atomic nucleus surrounded by the loops of electronic orbits, was dubbed the Atoms for Peace galaxy in honour of this. These loops are well visible in a wider field of view image. This nickname is quite ironic, as the galaxy’s past was anything but peaceful. Its peculiar appearance is the result of a collision between two galaxies that took place about a billion years ago, which ripped both galaxies apart. The loop-like outer structures, likely made up of dust and stars flung outwards by the crash, but recalling orbiting electrons in an atom, are partly responsible for the galaxy’s nickname. This NASA/ESA Hubble Space Telescope image shows the inner parts of the galaxy, revealing a pinwheel-shaped disc that is rotating in a direction opposite to the rest of the galaxy. This disc resembles a spiral galaxy like our own galaxy, the Milky Way, but is only about 10 000 light-years across — about a tenth of the size of the Milky Way. It is believed that this whirling structure is a remnant of the galactic collision. It will most likely have vanished in a few billion years’ time, when NGC 7252 will have completed its merging process.

Name: NGC 7252
Type: Local Universe : Galaxy : Type : Interacting
Category: Galaxies
Constellation: Aquarius
Release date: 7 December 2015, 06:00
Credit: NASA & ESA, Acknowledgements: Judy Schmidt (Geckzilla)