Studying How Galaxy Collisions Affect Star Production

The International Centre for Radio Astronomy Research (ICRAR) is studying the relationship between colliding galaxies and star formation.

Looking beyond the common belief, that star production is faster when two galaxies collide, scientists at ICRAR believe that this is only true if the two galaxies are of similar mass. They theorize that if one galaxy is more massive than the other, the smaller of the galaxies generate less stars while the other has an increase production of it.

They explain that the reason for the unequal production of stars from two galaxies of different mass is because the bigger galaxy strips away its smaller galaxy's gas from its gas clouds which is a primary component for star production.

Spheroid Galaxies Shut Down Star Formation From Inside Out

Astronomers have shown for the first time how star formation in “dead” galaxies sputtered out billions of years ago. ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope have revealed that three billion years after the Big Bang, these galaxies still made stars on their outskirts, but no longer in their interiors. The quenching of star formation seems to have started in the cores of the galaxies and then spread to the outer parts. The results will be published in the 17 April 2015 issue of the journal Science.

Spheroid galaxies are elliptical shaped galaxies and are common in the Universe. The center of these galaxies are densely packed with stars; about then times more than in the Milky Way.

Observing 22 galaxies , spanning a range of masses, from an era about three billion years after the Big Bang, the researchers noted that the galaxies were still producing stars at the outskirts but not in the center. The Star formation in the bulging center slowed down and stopped starting at the center of the galaxies and spread outwards towards the edges.

Sharpest Image of Prawn Nebula (IC 4628) and Star Cluster Collinder 316 Imaged by the ESO

The European Southern Observatory just released the sharpest image of the Prawn Nebula (IC 4628) and the star cluster star, Collinder 316. The Prawn Nebula is 6,000 light years away in the constellation of Scorpius (The Scorpion)

A nebula is a cloud of dust and gas where stars are made. Ionized gasses such as helium and hydrogen combine with interstellar dust and start to gain mass. Over milions of years, the mass gets more dense and starts to generate heat. Once thermonuclear fusion starts a star starts to form.

The image of the Prawn Nebula was taken by the largest telescope in the world, the VLT Survey Telescope (VST). It is a 2.6-metre telescope built around the OmegaCAM camera that contains 32 CCD detectors that can create 268-megapixel images. This new 24 000-pixel-broad image is a mosaic of two such images and is one of the largest single images released by ESO so far.

This is the 1000th press release by the ESO. A milestone that started in 1985 when it featured an image of Halley's comet by the ESO 1 metre Schmidt telescope at La Silla on December 9, 1985 .

Unique Pairing of Star Forming Regions in Large Magellanic Cloud Imaged

By attaching the FOcal Reducer and low dispersion Spectrograph (FORS2) instrument to the ESO's Very Large Telescope, scientists were able to capture a sharp image of NGC 2020 and NGC 2014 side by side. NGC 2020 is the blue cloud in the image while the red colored cloud is NGC 2014.

The two star forming regions contain gas and dust that is essential to forming stars. NGC 2014 is surrounded by hydrogen gas which when exposed to radiation from hot young stars, ionizes the gas and produces a red glow. The bluish color of NGC 2020 is caused also by radiation from hot stars but instead of ionizing hydrogen, NGC 2020 is using oxygen which produces a blue glow.

The Large Magellanic Cloud is an irregular shaped galaxy containing around 35 million stars. It is believed to be a spiral shaped galaxy once but has become misshapen because of the gravitational pull of the Milky Way galaxy. The LMC is 163,000 light years away and is around 14,000 light years wide. By comparison, the Milky Way Galaxy is around 100,000 light years wide.

The distance between the Large Magellanic Cloud and the Milky Way Galaxy was accurately measured using light pulses from a binary star system within the LMC.

Gas Outflow From Sculptor Galaxy (NGC 253) Hints At Scarcity Of High Mass Galaxies

This comparison picture of the nearby bright spiral galaxy NGC 253, also known as the Sculptor Galaxy, shows the infrared view from ESO’s VISTA Telescope (left) and a detailed new view of the cool gas outflows at millimetre wavelengths from ALMA (right).
Credit:ESO/ALMA (ESO/NAOJ/NRAO)/J. Emerson/VISTA

The Atacama Large Millimeter/submillimeter Array (ALMA) have observed massive molecular gas outflows ejected by the Sculptor Galaxy (NGC 253). This may explain how starburst galaxies behave and why there is a scarcity of very massive galaxies in the Universe.

Starburst galaxies are galaxies that have a very high rate of star formation compared to regular galaxies. They produce stars so fast that their available gas content is depleted in a shorter time span. Starburst galaxies like the Sculptor Galaxy are defined by the rate at which they convert gas into stars, the available quantity of gas available, and the timescale on which SFR (star formation rate) will consume the available gas with the age or rotation period of the galaxy.

With the available data supplied by ALMA, scientist can study and explain why there are so few massive galaxies around. And if the ejected gas theory holds true for most of these galaxies, they also want to find out what ultimately happens to to these gas outflows.

New Image of the Orion Molecular Cloud Reveals Fiery Ribbon Like Orange Glow

This dramatic new image of cosmic clouds in the constellation of Orion reveals what seems to be a fiery ribbon in the sky. This orange glow represents faint light coming from grains of cold interstellar dust, at wavelengths too long for human eyes to see. It was observed by the ESO-operated Atacama Pathfinder Experiment (APEX) in Chile.

The Large Apex Bolometer Camera (LABOCA) operated at the ESO-operated Atacama Pathfinder Experiment (APEX) in Chile has imaged the invisible band of gas and dust at the Orion Molecular Cloud in the constellation Orion the Hunter.

The constellation Orion is a well known formation of stars that can be seen throughout the world. The name Orion is derived from Greek mythology (Orion the Hunter). Zeus elevates him to the stars upon his death and is also mentioned in Homer's Odyssey where Odysseus sees his shade in the underworld.

The two brightest stars in Orion are the blue-white Beta (Rigel) and the red supergiant Alpha (Betelgeuse)

Combination Reflection Nebula and Emission Nebula in NGC 6559 Imaged

The Danish 1.54-metre telescope located at ESO’s La Silla Observatory in Chile has captured a striking image of NGC 6559, an object that showcases the anarchy that reigns when stars form inside an interstellar cloud.

An interstellar cloud of dust, hydrogen, helium and other ionized gases is called a nebula. This region of space is where stars are formed. The materials needed to form stars such as hydrogen and other gases are abundant in a nebula. Stars are formed when dust and gas start to clump together and gain mass. As the mass gets more dense and generates heat, thermonuclear fusion starts and a star starts to form.

NGC 6559 is a nebula that was imaged by the Danish Faint Object Spectrograph and Camera (DFOSC) in La Silla Observatory. The colors radiated of the object are from the light given off by the newly formed stars and because of the gasses present in the center gives the nebula a reddish glow and the dust cloud beside it blocks light which gives the nebula a dark and bluish tinge in that area. It is this combination of gas and dust that makes NGC 6559 both an emission nebula in the red part, and a diffusion nebula in the darker area.

Starburst Galaxies Effect Far Into The Universe Than Initially Believed

Astronomers using the NASA/ESA Hubble Space Telescope have shown for the first time that bursts of star formation have a major impact far beyond the boundaries of their host galaxy. These energetic events can affect galactic gas at distances of up to twenty times greater than the visible size of the galaxy — altering how the galaxy evolves, and how matter and energy is spread throughout the Universe.

Scientists observing 20 galaxies undergoing a starburst noted that they have an ionizing effect on gases as far as 650,000 light years from its center. Ionized gas is a gas that have lost one or more electrons. In a starburst, the electrons are lost when energetic winds from the starburst excites the galactic gas and knocks the electrons out of the atoms within.

A galaxy that is experiencing a very high rate of stars being formed within it is known as a starburst galaxy. Within a starburst galaxy, the rate of star formation is so high that the galaxy consumes all of its gas. They are known as starbursts because of the frantic episodes of activity when stars are formed.

The burst is triggered by certain events such as being in close proximity with another galaxy, colliding with another galaxy, or by a process where interstellar material is forced into the center of the galaxy. Most stars formed in a starburst burn very bright and very fast. They are likely candidates to explode into a supernova at the end of its life cycle.