Artist’s impression of two neutron stars merging: This artist’s impression shows two tiny but very dense neutron stars at the point at which they merge and explode as a kilonova. Such a very rare event is expected to produce both gravitational waves and a short gamma-ray burst, both of which were observed on 17 August 2017 by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo Interferometer, and ESA’s INTEGRAL telescope and NASA’s Fermi Gamma-ray Space Telescope respectively. Subsequent detailed observations with telescopes all over the world, including the NASA/ESA Hubble Space Telescope, confirmed that this object, seen in the galaxy NGC 4993 about 130 million light-years from the Earth, is indeed a kilonova. Such objects are the main source of very heavy chemical elements, such as gold and platinum, in the Universe.

Type: Local Universe : Star : Evolutionary Stage : Neutron Star
Category: Illustrations
Release date: 16 October 2017, 16:00
Credit: ESO/L. Calçada/M. Kornmesser

NGC 4993 seen with Hubble: The lenticular galaxy NGC 4993 is located about 130 million light-years from Earth. On 17 August 2017 the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo Interferometer both detected gravitational waves from the collision of two neutron stars within this galaxy. The event also resulted in a flare of light, called a kilonova, which is visible to the upper left of the galactic centre in this image from the NASA/ESA Hubble Space Telescope.

Name: NGC 4993
Type: Local Universe : Galaxy : Type : Elliptical
Category: Galaxies
Constellation: Hydra
Distance: 130 million light years
Release date: 16 October 2017, 16:00
Credit: NASA and ESA

Wide-field view of NGC 4993 (ground-based view): This image shows the sky around the lenticular galaxy NGC 4993. Within this galaxy Hubble discovered the first visual counterpart of a gravitational wave event — the merger of two neutron stars.

Name: NGC 4993
Type: Local Universe : Galaxy : Type : Elliptical
Category: Galaxies
Constellation: Hydra
Release date: 16 October 2017, 16:00
Credit: NASA, ESA, Digitized Sky Survey 2. Acknowledgement: Davide De Martin

The changing brightness and colour of the kilonova seen in NGC 4993: This plot shows how the spectrum and brightness of the kilonova seen in the galaxy NGC 4993 changed over 12 days following the detection of gravitational waves on 17 August 2017. In blue light the object faded rapidly, but at longer wavelengths, in the near infrared part of the spectrum, it brightened a little and then faded much more slowly. As a result this object changed colour from very blue to very red during this period. Each line is labeled with the number of days since the explosion and the horizontal axis is the colour of the light, from ultraviolet to near-infrared. The colours of the lines indicate the overall colour of the object at the different times.

Name: NGC 4993
Type: Unspecified
Category: Stars
Release date: 16 October 2017, 16:00
Credit: N. Tanvir et al.

Hubble’s view of the Sculptor Dwarf Galaxy (pointing 1): This image shows a small part of the Sculptor Dwarf Galaxy, a satellite galaxy of the Milky Way, situated only about 300 000 light-years away from Earth. This is one of two different pointings of the telescope that were used in a study combining data from the NASA/ESA Hubble Space Telescope and ESA’s Gaia satellite to measure the 3D motion of stars in this galaxy.

Name: Sculptor Dwarf Galaxy
Type: Local Universe : Galaxy : Size : Dwarf
Category: Galaxies
Constellation: Sculptor
Distance: 300000 light years
Release date: 27 November 2017, 17:00
Credit: ESA/Hubble & NASA

Hubble’s view of the Sculptor Dwarf Galaxy (pointing 2): This image shows a small part of the Sculptor Dwarf Galaxy, a satellite galaxy of the Milky Way, situated only about 300 000 light-years away from Earth. This is one of two different pointings of the telescope that were used in a study combining data from the NASA/ESA Hubble Space Telescope and ESA’s Gaia satellite to measure the 3D motion of stars in this galaxy.

Name: Sculptor Dwarf Galaxy
Type: Local Universe : Galaxy : Size : Dwarf
Category: Galaxies
Constellation: Sculptor
Distance: 300000 light years
Release date: 27 November 2017, 17:00
Credit: ESA/Hubble & NASA

Sculptor Dwarf Galaxy (ground-based view): The Sculptor Dwarf Galaxy is one of the Milky Way’s neighbouring dwarf galaxies. Like all large galaxies, the Milky Way is thought to have formed from smaller galaxies in the early Universe. This image is composed from data from the Digitized Sky Survey 2.

Name: Sculptor Dwarf Galaxy
Type: Local Universe : Galaxy : Size : Dwarf
Category: Galaxies
Constellation: Sculptor
Distance: 300000 light years
Release date: 27 November 2017, 17:00
Credit: ESA/Hubble, Digitized Sky Survey 2

Wide-field image of the sky around the Sculptor Dwarf Galaxy: This image of the sky around the Sculptor Dwarf Galaxy was created from images from the Digitized Sky Survey 2. The galaxy appears as a small faint cloud, close to the centre of the image.

Name: Sculptor Dwarf Galaxy
Type: Local Universe : Galaxy : Size : Dwarf
Category: Galaxies
Constellation: Sculptor
Distance: 300000 light years
Release date: 27 November 2017, 17:00
Credit: ESA/Hubble, Digitized Sky Survey 2

Wide-field image of the sky around the Sculptor Dwarf Galaxy: This image of the sky around the Sculptor Dwarf Galaxy was created from images from the Digitized Sky Survey 2. The galaxy appears as a small faint cloud, close to the centre of the image.

Name: Sculptor Dwarf Galaxy
Type: Local Universe : Galaxy : Size : Dwarf
Category: Galaxies
Constellation: Sculptor
Distance: 300000 light years
Release date: 27 November 2017, 17:00
Credit: ESA/Hubble, Digitized Sky Survey 2

Wide-field image of the sky around the Sculptor Dwarf Galaxy: This image of the sky around the Sculptor Dwarf Galaxy was created from images from the Digitized Sky Survey 2. The galaxy appears as a small faint cloud, close to the centre of the image.

Name: Sculptor Dwarf Galaxy
Type: Local Universe : Galaxy : Size : Dwarf
Category: Galaxies
Constellation: Sculptor
Distance: 300000 light years
Release date: 27 November 2017, 17:00
Credit: ESA/Hubble, Digitized Sky Survey 2

Wide-field image of the sky around the Sculptor Dwarf Galaxy: This image of the sky around the Sculptor Dwarf Galaxy was created from images from the Digitized Sky Survey 2. The galaxy appears as a small faint cloud, close to the centre of the image.

Name: Sculptor Dwarf Galaxy
Type: Local Universe : Galaxy : Size : Dwarf
Category: Galaxies
Constellation: Sculptor
Distance: 300000 light years
Release date: 27 November 2017, 17:00
Credit: ESA/Hubble, Digitized Sky Survey 2

Hubble observing the Sculptor Dwarf Galaxy: This image shows the Sculptor Dwarf Galaxy as it is seen from the ground with the Digitized Sky Survey 2. The two insets show the two pointings of Hubble that were used in the latest discovery, using data from both the NASA/ESA Hubble Space Telescope and ESA’s Gaia satellite.

Name: Sculptor Dwarf Galaxy
Type: Local Universe : Galaxy : Size : Dwarf
Category: Galaxies
Distance: 300000 light years
Release date: 27 November 2017, 17:00
Credit: ESA/Hubble, Digitized Sky Survey 2

ESA’s Gaia satellite: ESA’s Gaia satellite is a space telescope designed to measure the positions of billions of stars with unprecedented precision. Gaia was launched on 19 December 2013 and is located at the L2 Lagrange point — the same location that the upcoming NASA/ESA/CSA James Webb Space Telescope will have.

Name: Gaia
Type: Unspecified : Technology : Spacecraft
Category: Spacecraft
Release date: 27 November 2017, 17:00
Credit: ESA/ATG medialab