Astronomers have discovered 300,000 hidden galaxies in a tiny corner of the sky



The universe just got a little more crowded with the discovery of more than 300,000 potential galaxies in a tiny corner of the northern sky.

A publication of data collected by the LOFAR (Low Frequency Array) telescope network in Europe has added extraordinary new levels of detail to the radio wave map across the cosmos, inspiring dozens of studies on topics ranging from magnetic fields with black holes.

These are moments like these, we should be grateful for our relative blindness to the radiation of the night sky – at least if we want to sleep at night. Invisible to the human eye, the Universe is actually inflamed by the low-frequency waves produced by the acceleration of particles and electromagnetic fields.

Measure that the radio hum requires a fairly sensitive equipment. The range of 20,000 LOFAR antennas spread over 48 stations in the Netherlands and abroad amounts to having a sensitive radio eye on the surface of our planet.

Among his many tasks is an intensive study of the northern night sky at radio frequencies of about 120 to 168 megahertz, which is expected to provide new information on a variety of low-brightness astronomical phenomena.

Until now, only about 20% of the survey is completed and, as a result, scientists around the world only have access to about 10% of the data available. This may not seem like much, but they clearly have a busy day.

The newspaper Astronomy and astrophysics has just published 26 studies based on this first publication of data, covering quasars, blazars, black holes and intergalactic electromagnetic fields.

Among the most revealing sources of the mosaic of sources, there are 325,694 points where the glow of radio waves reaches at least five times the background noise. About 70% of these can be related to an optical signal, so it is safe to say that these bright spots represent galaxies that we can add to our cosmic roadmap.

It is no secret that galaxies of sufficient size often contain gargantuan black holes that swallow anything within reach with such recklessness, they vomit jets of matter shining in the air. radio waves. What has not been clear is how strict this rule is and whether these essential black holes manage to erase their attitude.

This new data helps to persuade scientists that these monsters have a flawless appetite.

"LOFAR has a remarkable sensitivity and this allows us to see that these jets are present in all the most massive galaxies, which means that their black holes never stop eating," says astrophysicist Philip Best of the # 39, University of Edinburgh.

Identifying the locations of new galaxies not only helps us understand their internal structures, it also provides a valuable tool for understanding the vast expanses of nil that separate them.

Usually, radio waves are produced by the turbulence caused by collision of galaxies.

"What we're starting to see with LOFAR is that in some cases, clusters of galaxies that do not merge can also show this show, albeit at a very low level that was previously undetectable." , says astrophysicist Annalisa Bonafede of the University of Bologna.

"This discovery teaches us that in addition to fusion events, there are other phenomena that can trigger particle acceleration on a very large scale."

new field of galaxies (Rafael Mostert / LOFAR survey / Sloan Digital Sky DR13 survey)

Above: Gthe Abell 1314 cluster as designed by LOFAR. Gray indicates visible light, while orange tints indicate "hidden" radio transmissions, which completely changes the image.

LOFAR's sensitivity in the sky also helped researchers identify the weak predicted magnetic fields in an intergalactic space, but up to now too difficult to detect.

"Magnetic fields are invading the cosmos and we want to understand how that happened," said astronomer Shane O. Sullivan of the University of Hamburg.

Closer to home, the magnitude of the raw data collected by surveys such as this one requires new methods of information processing that not only takes time but does not consume too much time. # 39; energy.

SURF, the collaborative data management company, currently stores more than 20 petabytes of LOFAR information, which still accounts for just over half of the total.

"We have worked with SURF in the Netherlands to efficiently turn huge amounts of data into high quality images," says cosmologist Timothy Shimwell of the Netherlands Institute of Radioastronomy and the University of Leiden.

SURF's technology and processes make it possible to quickly reconstitute the numbers into a tool that can be used by various teams of researchers. In addition, everything is managed 100% renewable energy.

This is only the beginning. There is still a lot of sky to discover, which could reveal about 15 million new sources of radio waves, many of which date back to the dawn of the Universe.

This is a promising future for LOFAR sky study.

This research was published in Astronomy and astrophysics.


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