An international group of astronomers has set another record by presenting the most distant galaxy ever observed. In fact, two of them. The light captured by the researchers left its source objects only about 330 million years after the Big Bang.
At first glance, it may not sound like a short time. But keep in mind that the Big Bang happened 13.8 billion years ago. If the Universe were a gentleman today aged 50, this would have happened when he was a baby just over a year old. And what is surprising, as with all babies, is that he reveals precocious skills. In this case, the ability to gestate galaxies like the ones that have been observed.
The stars, named HD1 and HD2, were discovered after more than 1,200 hours of observation time spread across various equipment, such as the Subaru and Vista telescopes, the UK Infrared Telescope and the Spitzer Space Telescope. The team also made follow-up observations with the Alma radio telescope array in Chile to confirm the distance and thus the age. In fact, HD1, apparently the most distant of them, is 100 million years older than GN-z11, the former distance record holder.
The method used to calculate the distance of these distant stars is the so-called redshift, as the light waves stretch as they travel across long stretches of expanding space, becoming increasingly reddish. In effect, the light that was born ultraviolet there in the far reaches of the cosmos is seen as infrared here.
Two papers, published in the Astrophysical Journal and the Monthly Notices of the Royal Astronomical Society Letters, explore the finding. The first one, whose first author is Yuichi Harikane, from the University of Tokyo, addresses the search and discovery itself. The second, led by Fabio Pacucci of the Harvard & Smithsonian Center for Astrophysics in the US, explores what these galaxies might be.
Note that they are much brighter than expected, which can be explained by an explosive formation of stars in these galaxies (although, for this hypothesis, they appear much brighter than other similar examples).
A more exciting alternative to explain the observed characteristics is the presence of stars of the first generation to appear in the Universe, the so-called Population III, which would be very different from today’s stars, with much greater mass and a similar brightness. Another possibility would be the presence of a large supermassive black hole with a mass of 100 million suns, which would be surprising considering the youthfulness of the cosmos at that time.
The result is a full plate for the James Webb Space Telescope, which already has an appointment, so to speak, with the galaxies HD1 and HD2, in order to obtain more information about these objects that reside on the border than we can observe with our telescopes.
This column is published on Mondays, in Folha Corrida.
Follow the Sidereal Messenger on Facebook, twitterInstagram and YouTube
