Astronomers confirmed the detection of the second galaxy in our distance

And the stars in it are quite old

In the large photograph on the left, the galaxies of the large cluster MACS J1149 + 2223 are mainly visible. Gravitational lensing of a giant cluster increased the light from the recently discovered MACS 1149-JD galaxy about 15 times. The upper part of the picture is shown in more detail in the upper right, and even more it is increased in the lower right.

We looked as far into space as the best of our telescopes allow us, but have not yet seen places where there would be no stars and galaxies. There is a large gap between the first galaxy we found, GN-z11 , which existed when the universe was only 400 million years old, and the residual glow of the Big Bang that has survived since the Universe was 380,000 years old. There must be some first stars between them, but we have no opportunity to directly look at such a distance. And until we have a telescope to them. James Webb , we can only handle indirect evidence.


Studying an increasing part of the universe, we look farther and farther into space, and therefore back in time. The telescope of James Webb will allow us to directly reach the depths to which the current equipment is not able to penetrate

But in the field of indirect testimony we have received a great deal of reinforcement. Scientists have just confirmed the discovery of the second-distant galaxy, MACS1149-JD1, whose light comes to us since the Universe was 530 Ma, or 4% of its present age. It is remarkable here that we were able to detect oxygen in it, and this is the first time that such a heavy element has been found in such a distant past. Based on our observations, we can conclude that this galaxy is at least 250 million years old - and this moves the evidence for the existence of the first stars further back.


A schematic diagram of the history of the universe, with an indication of reionization. Before the formation of stars or galaxies, the universe was full of neutral atoms blocking light. Most of the universe has not undergone reionization up to 550 Ma, but several regions were more fortunate, and they were reionized much earlier.

Based on the composition of the Universe: 68% of dark energy, 27% of dark matter, 4.9% of normal matter, 0.1% of neutrinos and ≈ 0.01% of radiation, we can simulate how and when stars should form in it galaxies. Since we can measure the initial properties at the age of 380,000 years directly, we just need to take into account the laws of physics and start evolution forward in time. Our best simulations show the remarkable history of the emergence of the cosmic web, the culmination of which leads to the appearance of galaxies and their clusters, separated by huge cosmic voids in the expanding universe with acceleration.



If the laws of physics are what we think they are, then we can expect a period — the dark ages — when gravity pulls matter into regions of higher density, but it has not yet collapsed, has not squeezed enough to form stars. The very first stars could form from 50 to 200 million years, and then a very large number of stars should have appeared in a very short time. The smallest clusters of stars merged into larger, and as a result, into the proto-galaxies - the building blocks of the galaxies we see today. As a result, after about 550 million years after the Big Bang, enough stars formed to clear the neutral atoms from the light blocking the Universe, and we can see all this using a sufficiently powerful optical telescope.


The artist's view of the early universe after the first trillions of stars formed, lived and died. The existence and life cycle of stars is the main process that enriches the Universe with elements beyond hydrogen and helium, and the radiation emitted by the first stars makes it transparent to visible light. We can not yet observe the population of the first stars directly

But when did these first stars catch fire? What are their properties, how do they differ from today? How quickly did they burn when the first stars formed with rocky planets and potential ingredients for life? Is there a preferred region in space for such processes?

Until now, we could look back up to 400 million years after the Big Bang, using NASA's best observations, finding young, already developed galaxies. Recently, we were able to measure directly a definite sign of stars that had formed even earlier: when the Universe was from 180 to 260 Ma. We thought that we would have to wait for the launch of the James Webb telescope to confirm these measurements.


A significant failure of the graph is a direct result of a recent study by Bowman and colleagues, which shows the signal of the 21-cm hydrogen line recorded when the universe was from 180 to 260 Ma. This corresponds to the appearance of the first wave of stars and galaxies in the Universe. Based on this evidence, the beginning of the “cosmic dawn” should be attributed to the redshift value ≈ 22.

But the new study of May 16, 2018, published in Nature, may contain the necessary confirmation that the stars really existed in those early times. There are many candidates, ultra-distant galaxies - with infrared or even infrared colors, talking about their extreme remoteness. But until these distances are confirmed, there is a chance that these are just quasi . This week, one of the candidates for the earliest galaxies really turned out to be a quasag ; this happens quite often and emphasizes that we need confirmation.


The cluster of galaxies MACS J1149.5 + 223 of an impressive size, whose light was 5 billion years old, was the goal of one of the Hubble Frontier Fields programs (border fields). This massive object subjects the light of the objects behind it to gravitational lensing, stretching and enlarging them, and allowing us to see more distant edges of space.

But the MACS1149-JD1 galaxy really turned out to be as far as we thought, and became the second most distant galaxy known. And in it we found not only the ingredients of the first stars, hydrogen and helium. There was oxygen there, and although it is the third most common element in the universe, it did not appear in the Big Bang, but only after the life and death of the first generation of stars.


Supernova remnants (left) and planetary nebulae (right) are two ways of processing by the stars of burnt heavy elements thrown into interstellar space and generating the next generation of stars and planets. The very first, clean stars had to appear before supernovae, planetary nebulae or neutron star fusions contaminated the interstellar space with heavy elements. The discovery of oxygen in such an ultradar galaxy and its brightness tells us that it is already hundreds of millions of years old.

Unmistakable signs of the presence of oxygen and the observed brightness of the galaxy, as well as signs of hydrogen, which helped to accurately determine the distance to it, were observed thanks to a combination of four remote observatories: ALMA , ESO VLT , Hubble and Spitzer . Brightness indicates that the stars in the galaxy have been forming for quite a long time, since it takes time to develop the stars to reach the observed level. This allows us to draw a picture of the cosmic dawn for this galaxy, corresponding to what we know: the first stars that formed this galaxy appeared 250 million years after the Big Bang.


The whole history of space is theoretically well known, but only qualitatively. Only by confirming and discovering the various stages of the past of our Universe with the help of observations, for example, the formation of the first stars and galaxies, can we truly understand our universe. The big bang sets a fundamental limit to how far we can see in any direction.

This is another step into the hitherto unknown cosmic depths. We have never seen such a distant galaxy with a confirmed stellar population of adult stars. As Richard Ellis , co-author of the study, writes :

Determining the time of the beginning of cosmic dawn is the holy grail of cosmology and the formation of galaxies. In the case of the MACS1149-JD1, we were able to probe the story beyond what we can see with the current equipment. Restored optimism about the fact that we are getting closer and closer to the direct observation of the emergence of starlight. Since we all consist of recycled stellar material, we are talking about finding our real origins.


The first stars and galaxies of the Universe were surrounded by neutral atoms, mainly hydrogen gas, absorbing starlight. We cannot yet observe these first stars directly, but we can observe what happens after a certain period of cosmic evolution, which allows us to assume when a large number of stars had formed.

For the first time, we can successfully assume that galaxies existed hundreds of millions of years earlier than we can see directly. We are closer than ever to answer the question of when the first stars and galaxies emerged from the darkness of the early Universe. And when the James Webb telescope is launched in 2020, we will know exactly what to expect when searching for answers to one of the greatest questions about space.