NGC 1579: The Trifid of the North: Unlike the venomous fictional plants that share its name, the Trifid of the North, otherwise known as the  Northern Trifid or NGC 1579, poses no threat to your vision. The  nebula’s moniker is inspired by the better-known Messier 20, the Trifid  Nebula, which lies very much further south in the sky and displays  strikingly similar swirling clouds of gas and dust. The  Trifid of the North is a large, dusty region that is currently forming  new stars. These stars are very hot and therefore appear to be very  blue. During their short lives they radiate strongly into the gas  surrounding them, causing it to glow brightly. Many regions like the  Trifid of the North — named H II regions — are clumpy and strangely  shaped due to the powerful winds emanating from the stars within them. H  II regions also have relatively short lives, furiously forming baby  stars until the immense winds from these bodies blow the gas and dust  away, leaving just stars behind. The image above, captured by the NASA/ESA Hubble Space Telescope, shows the bright body of the nebula, with dark dust lanes snaking across the frame. The Trifid of the North glows strongly due to the many stars within it, like young binary EM* LkHA 101. Visible to the bottom right of the image, this binary is thought to be surrounded by a hundred or so fainter and less massive stars, making up a recently formed cluster. It lies behind a cloud of dust so thick that it is almost invisible to astronomers at optical wavelengths. Infrared imaging has now penetrated this dusty veil and is uncovering the secrets of this binary star, which is about five thousand times brighter than our own Sun. A version of this image by Bruno Conti was entered into the Hubble’s Hidden Treasures competition.

Name: EM* LkHA 101, NGC 1579
Type: Milky Way : Nebula : Type : Star Formation
Category: Nebulae
Constellation: Perseus
Distance: 2000 light years
Release date: 3 June 2013, 10:00
Credit: ESA/Hubble & NASAAcknowledgement: Bruno Conti

A very bright contortionist: The  contorted object captured by Hubble in this picture is IRAS 22491-1808,  also known as the South America Galaxy. It is an ultraluminous infrared  galaxy (ULIRG) that emits a huge amount of light at infrared  wavelengths. The reason for this intense infrared emission lies in an  episode of strong star formation activity, which was set off by a  collision between two interacting galaxies. In  this image the twisted shape hides a number of features. In the central  region, which is very complex and disturbed, scientists have been able  to distinguish two nuclei, remains of the two different galaxies that  are currently colliding to form a new one. IRAS 22491-1808 is amongst  the most luminous of these types of galaxies, and is considered to be  mid-way through its merging stage. The  centre of this appealing object also shows several intense star-forming  knots which, as seen in the picture, actually  outshine the nuclei in optical wavelengths. To pick out the two merging  nuclei in IRAS 22491-1808, scientists have had to observe it in infrared  wavelengths, where they are more distinct. Other  traces of the galactic collision are the three very noticeable tails in  the image — two linear and one circular.  The tail extending towards the bottom of the image from the main body exhibits a red clump of star formation at its base.

Name: IRAS 22491-1808
Type: Early Universe : Galaxy : Type : Interacting
Category: Galaxies
Constellation: Aquarius
Distance: z=0.076 (redshift)
Release date: 10 June 2013, 10:00
Credit: ESA/Hubble & NASA

Messier 61 looks straight into the camera: The  NASA/ESA Hubble Space Telescope has captured this image of nearby spiral galaxy Messier 61, also known as NGC 4303. The galaxy,  located only 55 million light-years away from Earth, is roughly the size  of the Milky Way, with a diameter of around 100 000 light-years. The  galaxy is notable for one particular reason — six supernovae have been  observed within Messier 61, a total that places it in the top handful of  galaxies alongside Messier 83, also with six, and NGC 6946, with a  grand total of nine observed supernovae. In  this Hubble image the galaxy is seen face-on as if posing for a  photograph, allowing us to study its structure closely. The spiral arms  can be seen in stunning detail, swirling inwards to the very centre of  the galaxy, where they form a smaller, intensely bright spiral. In the  outer regions, these vast arms are sprinkled with bright blue regions  where new stars are being formed from hot, dense clouds of gas. Messier  61 is part of the Virgo Galaxy Cluster, a massive group of galaxies in  the constellation of Virgo (the Virgin). Galaxy clusters, or groups of  galaxies, are among the biggest structures in the Universe to be held  together by gravity alone. The Virgo Cluster contains more than 1300  galaxies and forms the central region of the Local Supercluster, an even  bigger gathering of galaxies. The image was taken using data from Hubble’s Wide Field Camera 2. Different versions of this image were submitted to the Hubble’s Hidden Treasures image processing competition by contestants Gilles Chapdelaine, Luca Limatola, and Robert Gendler.

Name: M 61, Messier 61
Type: Local Universe : Galaxy : Type : Spiral
Category: Galaxies
Constellation: Virgo
Distance: 55 million light years
Release date: 17 June 2013, 10:00
Credit: ESA/Hubble & NASAAcknowledgements: G. Chapdelaine, L. Limatola, and R. Gendler.

Inseparable galactic twins: Looking  towards the constellation of Triangulum (The Triangle), in the northern  sky, lies the galaxy pair MRK 1034. The two very similar galaxies,  named PGC 9074 and PGC 9071, are close enough to one another to be bound  together by gravity, although no gravitational disturbance can yet be  seen in the image. These objects are probably only just beginning to  interact gravitationally. Both  are spiral galaxies, and are presented to our eyes face-on, so we are  able to appreciate their distinctive shapes. On the left of the image,  spiral galaxy PGC 9074 shows a bright bulge and two spiral arms tightly  wound around the nucleus, features which have led scientists to classify  it as a type Sa galaxy. Close by, PGC 9071 — a type Sb galaxy —  although very similar and almost the same size as its neighbour, has a  fainter bulge and a slightly different structure to its arms: their  coils are further apart. The  spiral arms of both objects clearly show dark patches of dust  obscuring the light of the stars lying behind, mixed with bright blue clusters of hot, recently-formed stars. Older, cooler  stars can be found in the glowing, compact yellowish bulge towards the  centre of the galaxy. The whole structure of each galaxy is surrounded  by a much fainter round halo of old stars, some residing in globular  clusters. Gradually,  these two neighbours will attract each other, the process of star  formation will be increased and tidal forces will throw out long tails  of stars and gas. Eventually, after maybe hundreds of millions of years,  the structures of the interacting galaxies will merge together into a  new, larger galaxy. The  images combined to create this picture were captured by Hubble's Advanced  Camera for Surveys (ACS). A version of this image was  submitted to the Hubble’s Hidden Treasures image processing competition by Judy Schmidt.

Name: MRK 1034
Type: Early Universe : Galaxy : Type : Interacting
Category: Galaxies
Constellation: Triangulum
Distance: z=0.033 (redshift)
Release date: 24 June 2013, 10:00
Credit: ESA/Hubble & NASAAcknowledgement: Judy Schmidt