Some 45 light years from Earth, the galaxy NGC 4051 was discovered in the constellation Ursa Major by John Herschel in 1788. It is part of a spiral-rich subset of the Virgo supercluster of galaxies that includes the Milky Way. Classified as a Seyfert galaxy, NGC 4051 hosts a supermassive black hole in its core with 1.7 million times the mass of the Sun. Multiple supernovae blasts have been observed in the galaxy over the past several decades, the first in 1983 and the most recent in 2010 when the core of a massive star that had already lost its outer layers of hydrogen and helium exploded in a type 1c supernova. Such explosions are sometimes referred to as stripped core-collapse supernovae. This beautifully rendered view of NGC 4051 was captured by the Hubble Space Telescope.
Galaxy clusters are often described by superlatives. After all, they are huge conglomerations of galaxies, hot gas, and dark matter, representing the largest structures in the universe held together by gravity. New observations of the galaxy cluster SPT-CLJ2344-4243 (or Phoenix Cluster) at X-ray, ultraviolet, and optical wavelengths are helping astronomers better understand this extraordinary system.
Surrounded by an envelope of dust, the subject of this NASA/ESA Hubble Space Telescope image is a young pre-main-sequence star known as HBC 1. The star is in an immature and adolescent phase of life, hence its classification — most of a Sun-like star’s life is spent in a stage comparable to human adulthood dubbed the main sequence.
Due for launch in 2020, ESA’s Euclid satellite will set astronomers a huge challenge: to analyse 100,000 strong gravitational lenses. The gravitational deflection of light from distant astronomical sources by interposing massive galaxies can create multiple images of the source that are not just visually stunning, but are also valuable tools for probing our universe.