/PICS | SAs MeerKAT observes first image of Milky Way-like galaxies responsible for star formation

PICS | SAs MeerKAT observes first image of Milky Way-like galaxies responsible for star formation

South Africa’s world-class MeerKAT radio telescope has peered deep into space to observe distant Milky Way-like galaxies for the first time.

The MeerKAT (Karoo Array Telescope), which is made up of 64 linked radio telescopes, was used to observe stars formed between eight and 11 billion years ago – an era known as the “cosmic noon”.

“To make this image, we selected an area in the Southern Sky that contains no strong radio sources whose glare could blind a sensitive observation,” said team leader Dr Tom Mauch of the South African Radio Astronomy Observatory (Sarao) in Cape Town.

“These first results indicate that the star-formation rate around cosmic noon is even higher than was originally expected,” Allison Matthews, a PhD student at the University of Virginia, said of the observation.

READ | SA celebrates MeerKAT launch with dramatic Milky Way black hole image

But the image, nicknamed “DEEP2” is more than a pretty picture of the night sky.

“Because radio waves travel at the speed of light, this image is a time machine that samples star formation in these distant galaxies over billions of years,” said study co-author James Condon of the National Radio Astronomy Observatory in the US.

Star formation

READ | SA’s MeerKAT astronomers score massive win in discovering super magnetic star secrets

These images help astronomers look back into the early star formation of the universe as the radio waves travel at the speed of light.

“Because only short-lived stars that are less than 30 million years old send out radio waves, we know that the image is not contaminated by old stars. The radio light we see from each galaxy is therefore proportional to its star-forming rate at that moment in time,” said Condon.

Radio telescopes are ideal to see distant stars because they can peer through the gas and dust that would obscure observation for optical telescopes.

MeerKAT image of radio galaxies: Thousands of gala

MeerKAT image of radio galaxies: Thousands of galaxies are visible in this radio image covering a square degree of sky near the south celestial pole, made by the MeerKAT radio telescope array in South Africa. The brightest spots are luminous radio galaxies powered by supermassive black holes. The myriad faint dots are distant galaxies like our own Milky Way, too faint to have been detected before now, which reveal the star-formation history of the universe. Most galaxies are visible in the central part of the image, where the telescope is most sensitive. (Sarao, NRAO, AUI, NSF)

These Milky Way-like galaxies have been revealed to be responsible for most of the star formations in the universe.

“Previous images could only detect the tip of the iceberg, the rare and luminous galaxies that produced only a small fraction of the stars in the universe. What we see now is the complete picture: these faint dots are the galaxies that formed most of the stars in the universe,” said Matthews.

Composite of radio galaxies and MeerKAT telescope:

Composite of radio galaxies and MeerKAT telescope: Thousands of galaxies are visible in this radio image covering a square degree of sky near the south celestial pole, made by the MeerKAT radio telescope array (foreground) in the South African Karoo semi-desert. The brightest spots are luminous radio galaxies powered by supermassive black holes. (Sarao, NRAO, AUI, NSF)

The team published its work in The Astrophysical Journal after 130 hours of observation of the objects with the MeerKAT based near Carnarvon in the Northern Cape.

The instrument has delivered extraordinary observations since its inauguration in 2018 and will form part of the much larger Square Kilometre Array, or SKA, consisting of more than 3 000 linked radio telescopes.

“MeerKAT is the best radio array in the world for studies like this one because it is the first to use such a large number of extremely low-noise clear-aperture dishes,” said Sarao chief technologist Justin Jonas.

MeerKAT by the numbers:

Number of telescopes

64

Core telescopes

48

Dish diameter

13.5m

Reflector material

40 aluminium panels

Sub reflector

3.8m

Pedestal height

8m

Total height

19.5m

Weight

42 tons

Observational elevation range

15° to 88°

Digitisers per telescope

4

Buried fibre cables situated on site

170km

Number of internal sensors

150 000

Data

1 712 million samples per second

Total cost

R4.4bn

 

Original Source