ESO VLT: Two different gas clouds in the Large Magellanic Cloud

ESO's Very Large Telescope has captured a detailed view of a star-forming region in the Large Magellanic Cloud -- one of the Milky Way's satellite galaxies.

This sharp image reveals two glowing clouds of gas. NGC 2014 (right) is irregularly shaped and red and its neighbour, NGC 2020, is round and blue.

These odd and very different forms were both sculpted by powerful stellar winds from extremely hot newborn stars that also radiate into the gas, causing it to glow brightly. Credit: ESO

ESO's Very Large Telescope has captured an intriguing star-forming region in the Large Magellanic Cloud—one of the Milky Way's satellite galaxies.

This sharp image reveals two distinctive glowing clouds of gas: Red-hued NGC 2014, and its blue neighbour NGC 2020.

While they are very different, they were both sculpted by powerful stellar winds from extremely hot newborn stars that also radiate into the gas, causing it to glow brightly.

This image was taken by the Very Large Telescope (VLT) at ESO's Paranal Observatory in Chile—the best place in the southern hemisphere for astronomical observing.

But even without the help of telescopes like the VLT, a glance towards the southern constellation of Dorado (The Swordfish or Dolphinfish) on a clear, dark night reveals a blurry patch which, at first sight, appears to be just like a cloud in the Earth's atmosphere.

At least, this may have been explorer Ferdinand Magellan's first impression during his famous voyage to the southern hemisphere in 1519.

Although Magellan himself was killed in the Philippines before his return, his surviving crew announced the presence of this cloud and its smaller sibling when they returned to Europe, and these two small galaxies were later named in Magellan's honour.

However, they were undoubtedly seen by both earlier European explorers and observers in the southern hemisphere, although they were never reported.

The Large Magellanic Cloud (LMC) is actively producing new stars. Some of its star-forming regions can even be seen with the naked eye, for example, the famous Tarantula Nebula.

However, there are other smaller—but no less intriguing—regions that telescopes can reveal in intricate detail. This new VLT image explores an oddly mismatched pair: NGC 2014 and NGC 2020.

The pink-tinged cloud on the right, NGC 2014, is a glowing cloud of mostly hydrogen gas.

It contains a cluster of hot young stars. The energetic radiation from these new stars strips electrons from the atoms within the surrounding hydrogen gas, ionising it and producing a characteristic red glow.

This zoom video starts with a wide view of the Milky Way and ends with a close-up look at a pair of mysterious glowing gas clouds in the nearby Large Magellanic Cloud — NGC 2014, and NGC 2020, both in the southern constellation of Dorado (The Swordfish).

The final view of these clouds was captured by ESO's Very Large Telescope at the Paranal Observatory in Chile. 

Credit: ESO/Nick Risinger (skysurvey.org)/Digitized Sky Survey 2. Music: John Dyson

In addition to this strong radiation, massive young stars also produce powerful stellar winds that eventually cause the gas around them to disperse and stream away.

To the left of the main cluster, a single brilliant and very hot star seems to have started this process, creating a cavity that appears encircled by a bubble-like structure called NGC 2020.

The distinctive blueish colour of this rather mysterious object is again created by radiation from the hot star—this time by ionising oxygen instead of hydrogen.

The Milky Way is surrounded by a massive halo of hot gas

An international team of astronomers has combined data from NASA's Chandra X-ray observatory, ESA's XMM-Newton space observatory and Japan's Suzaku satellite to suggest that our galaxy may be surrounded by a halo of hot gas extending in all directions for hundreds of thousands of light-years. 

The finding also offers clues as to why more than half of the ordinary matter in early galaxies has seemingly disappeared without leaving a trace.

Protons and neutrons are classified as "baryons," a type of subatomic particle that interacts strongly to form the nuclei of atoms. Taken together, baryons make up nearly all of the ordinary matter in our universe.

But if you were to tally the number of atoms in the universe, you'd find that something doesn't quite add up.

Astronomers have observed that entire galaxies seem to lose over half of their atoms compared to when they first formed.

All of this matter couldn't have simply disintegrated, so where has it gone? This decade-old question is known as the problem of the "missing baryons."

Now, a team of astronomers led by Dr. Anjali Gupta may have just found the answer, at least for our galaxy.

The baryons, says Gupta, haven't disappeared from the Milky Way. Rather, a mass of up to sixty billion suns – well in excess of the matter contained in the entire galactic disk – is spread out over a halo of hot gas stretching all around us for hundreds of thousands of light-years.

This gas is reaching temperatures in the millions of degrees, and with a density so low that, even if it were present in other galaxies, we would probably have no way of detecting it.

"With reasonable assumptions, our observations imply a huge reservoir of hot gas around the Milky Way," said co-author Smita Mathur of Ohio State University in Columbus.

"It may extend for a few hundred thousand light-years around the Milky Way or it may extend farther into the surrounding local group of galaxies. Either way, its mass appears to be very large."

A paper detailing the study was published on The Astrophysical Journal.

Cat's Paw Nebula

The Cats Paw Nebula is revisited in a combination of exposures from the MPG/ESO 2.2-metre telescope and amateur astronomers Robert Gendler and Ryan M Hannahoe. 

The distinctive shape of the nebula is revealed in reddish puffy clouds of glowing gas against a dark sky dotted with stars.

Picture: ESO/AFP/GettyImages