Pockets of star formation in DDO 68: The dwarf galaxy DDO 68, also known as UGC 5340, lies about 40 million light-years away from Earth. Due to its proximity it became one of the 50 targets of LEGUS. In UGC 5340, a pocket of rapid star birth appears in the lower right corner. This region of star formation was probably triggered by a gravitational interaction with an unseen companion galaxy. But star formation is present across the entire body of UGC 5340, and the relatively young stars are responsible for the galaxy’s blue-white colour. An image of this galaxy was already released back in 2014 (heic1421). This newly-processed image now also shows ultraviolet radiation Hubble captured from the galaxy.

Name: DDO 68
Type: Local Universe : Galaxy : Size : Dwarf
Category: Galaxies
Constellation: Leo
Distance: 40 million light years
Release date: 17 May 2018, 19:00
Credit: NASA, ESA, and the LEGUS team

Wave of star formation in Messier 96: Messier 96, also known as NGC 3368, is a spiral galaxy about 35 million light-years away in the constellation of Leo (The Lion). It is of about the same mass and size as the Milky Way. It was first discovered by astronomer Pierre Méchain in 1781, and added to Charles Messier’s famous catalogue of astronomical objects just four days later. A wave of star formation is occurring along the dark filaments that make up the spiral arms. The fledgling stars illuminate the surrounding hydrogen gas, making the stars appear pink. Star birth begins at the inner spiral arms and moves outward. The milky white regions in the centre of these galaxies represent the glow of countless stars. An image of this galaxy was already released back in 2015 (potw1535a). This newly-processed image now also shows ultraviolet radiation Hubble captured from the galaxy.

Name: Messier 96
Type: Local Universe : Galaxy : Type : Spiral
Category: Galaxies
Constellation: Leo
Distance: 35 million light years
Release date: 17 May 2018, 19:00
Credit: NASA, ESA, and the LEGUS team

Parts of Messier 106: Messier 106, also known as NGC 4258, is a relatively nearby spiral galaxy, a little over 20 million light-years away. This makes it one of the nearest spiral galaxies. Despite carrying his name, Messier 106 was neither discovered nor catalogued by the renowned 18th-century astronomer Charles Messier. Discovered by his assistant, Pierre Méchain, the galaxy was never added to the Messier catalogue in his lifetime. Along with six other objects discovered but not logged by the pair, Messier 106 was posthumously added to the catalogue in the 20th century. An image of this galaxy was already released back in 2013 (heic1302). This newly-processed image now also shows ultraviolet radiation Hubble captured from the galaxy.

Name: Messier 106
Type: Local Universe : Galaxy : Type : Spiral
Category: Galaxies
Constellation: Canes Venatici
Distance: 20 million light years
Release date: 17 May 2018, 19:00
Credit: NASA, ESA, and the LEGUS team

Peculiar galaxy NGC 3256: This image, taken with the Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS), both installed on the NASA/ESA Hubble Space Telescope, shows the peculiar galaxy NGC 3256. The galaxy is about 100 million light-years from Earth and is the result of a past galactic merger, which created its distorted appearance. As such, NGC 3256 provides an ideal target to investigate starbursts that have been triggered by galaxy mergers. Another image of NGC 3256 was already released in 2008, as part of a collection of interacting galaxies, created for Hubble’s 18th birthday.

Name: NGC 3256
Type: Local Universe : Galaxy : Type : Interacting
Category: Galaxies
Constellation: Vela
Distance: 100 million light years
Release date: 31 May 2018, 16:00
Credit: ESA/Hubble, NASA

Wide-field image of NGC 3256 (ground-based image): This ground-based image shows the spiral galaxy NGC 3256 and its surroundings.

Name: NGC 3256
Type: Local Universe : Galaxy : Type : Interacting
Category: Galaxies
Constellation: Vela
Distance: 100 million light years
Release date: 31 May 2018, 16:00
Credit: NASA, ESA, Digitized Sky Survey 2; Acknowledgement: Davide De Martin

Image of ESO 325-G004: An image of the nearby galaxy ESO 325-G004, created using data collected by the NASA/ESA Hubble Space Telescope and the MUSE instrument on the ESO’ Very Large Telescope. MUSE measured the velocity of stars in ESO 325-G004 to produce the velocity dispersion map that is overlaid on top of the Hubble Space Telescope image. Knowledge of the velocities of the stars allowed the astronomers to infer the mass of ESO 325-G004. The inset shows the Einstein ring resulting from the distortion of light from a more distant source by intervening lens ESO 325-004, which becomes visible after subtraction of the foreground lens light.

Name: ESO 325-G004
Type: Early Universe : GalaxyEarly Universe : Cosmology : Phenomenon : Lensing
Category: Galaxies
Distance: 450 million light years
Release date: 21 June 2018, 20:00
Credit: ESO, ESA/Hubble, NASA

Two methods of measuring the mass of a galaxy: This infographic compares the two methods used to measure the mass of the galaxy ESO 325-G004. The first method used ESO’s Very Large Telescope to measure the velocities of stars in ESO 325-G004. The second method used the NASA/ESA Hubble Space Telescope to observe an Einstein ring caused by light from a background galaxy being bent and distorted by ESO 325-G004. By comparing these two methods of measuring the strength of the gravity of ESO 325-G004, it was determined that Einstein’s general theory of relativity works on extragalactic scales — something that had not been previously tested.

Name: ESO 325-G004
Type: Early Universe : Galaxy
Category: Galaxies
Release date: 21 June 2018, 20:00
Credit: ESA/Hubble, ESO, NASA

BUFFALO’s view on Abell 370: The galaxy cluster Abell 370 was the first target of the BUFFALO survey, which aims to search for some of the first galaxies in the Universe. This remarkable cluster in the constellation of Cetus is located approximately four billion light-years away. Its mass, consisting of both hundreds of galaxies and dark matter, bends and distorts the light coming from even more distant objects behind it. This effect is known as strong gravitational lensing. The most stunning demonstration of gravitational lensing can be seen just below the centre of the image. Nicknamed “the Dragon”, this extended feature is made up of a multitude of duplicated images of a spiral galaxy in the background of Abell 370 — all lying five billion light-years away.

Name: Abell 370
Type: Early Universe : Galaxy : Grouping : Cluster
Category: Galaxies
Constellation: Cetus
Distance: 4 billion light years
Release date: 13 September 2018, 17:00
Credit: NASA, ESA, A. Koekemoer, M. Jauzac, C. Steinhardt, and the BUFFALO team

Comparison between Frontier Fields and BUFFALO: This image composite shows the new observations of Abell 370 made for the BUFFALO project, as well as the old observation made for the Frontier Fields programme. The composition clearly shows the extended field of view in the new observations.

Name: Abell 370
Type: Early Universe : Galaxy : Grouping : Cluster
Category: Galaxies
Distance: 4 billion light years
Release date: 13 September 2018, 17:00
Credit: NASA, ESA, A. Koekemoer, M. Jauzac, C. Steinhardt, the BUFFALO team and HST Frontier Fields.