The Swift telescope has updated its own record by capturing light from the most distant object in the universe. The object exploded into a black hole just 350 million years after the Big Bang.
On the morning of Friday, February 5, at 7:18:43 Moscow time, the BAT gamma-ray telescope aboard the scientific satellite Swift noticed a sharp burst of gamma radiation from the direction of the constellation Leo. The flow of high-energy quanta grew for about eight seconds, and then began to fall; half a minute after the start, the heavenly fireworks in the gamma range ended.
Less than three minutes later, Swift had already turned his X-ray telescope towards the flare and saw a new source of X-ray quanta, the brightness of which was rapidly falling. There was no more doubt: it was a gamma-ray burst, a grandiose cosmic explosion marking the birth of a black hole somewhere in the depths of space. All the observatories of the world received circulars calling for observing GRB100205A (this designation was given to the outbreak) in the optical and infrared ranges. The reports specified that Swift's own optical telescope, UVOT, could not see anything at the site of the explosion - neither in optics nor in ultraviolet.
In a dense and warm universe
Redshift Astronomers measure distance using the redshift z, the scale for increasing light wavelengths. It shows how many times our world has increased during the journey of light. z=0 corresponds here and today, and if z is, say, three, the light was emitted when the universe was at z+1, that is, four times less. How much this is in light years depends on the history of the expansion of the universe.
There seems to be a very simple explanation for the failure of the small UVOT and many medium-sized terrestrial instruments trying to catch a cosmic flare: GRB100205A is the farthest burst on record. According to preliminary data, its redshift z is estimated at 11 to 13.5, which means that the black hole, the appearance of which he saluted, was born just 300-400 million years after the Big Bang. , GRB090423, caught by the same Swift last year, splashed into almost twice the older Universe: 630 million years separated it from the beginning of time.
350 million years is a very young age: at that time the Universe was 13 times smaller, which means 2,000 times denser than it is today! Hydrogen and helium, boiled in the first three minutes after the Big Bang, were just flowing into the growing potential holes of the very first dwarf galaxies, and there was nothing around except hydrogen and helium. And all this was immersed in a thermal bath of the ubiquitous cosmic microwave radiation, the temperature of which was almost 40 degrees Kelvin, and the density was 25 thousand times higher than now.
However, aloud astronomers have not yet announced a new record. Massive stars - and only they, according to modern ideas, are capable of generating gamma-ray bursts and turning into black holes - live only a few million years - just a little compared to the estimate of the age of the universe at the time of the explosion. But how they could have been born in that era - in warmth, without heavy elements, in galaxies of low density - is a big question. That is why scientists, with their conservatism, are still talking about a “candidate for gamma-ray bursts at z ~ 11–13.5”.
Circumstantial evidence
However, scientists really do not have direct evidence of a record range - for example, a spectrum in which lines shifted from positions measured in the laboratory by 12-14 times would be visible. But, as at the trial against Dmitry Karamazov, there is a lot of circumstantial evidence.
First, the already noted inability of most instruments to see the gamma-ray burst itself (or rather, its optical afterglow) even in the first hours after the flash. Secondly, there is a suspiciously small absorption of light in the X-ray range, which is typical for gamma-ray bursts that flare up in the early Universe, when there was still little substance around that could scatter X-rays. Thirdly, the complete absence of at least some traces of the gamma-ray burst parent galaxy in very deep images obtained by ground-based telescopes. Many instruments participating in the search would easily find typical galaxies even at distances of 12-12.5 billion light-years from Earth, but they see nothing.
What will drop In search of the most distant galaxies, astronomers use the so-called color "fallout" technique. It is based on the fact that the spectrum of any galaxy looks like a more or less smooth curve, in places jagged with spectral lines, but in the ultraviolet region at a wavelength of less than 121.6 nm, where the absorption of light by hydrogen increases significantly, the spectrum ends abruptly. At the same time, the spectrum of distant galaxies that we receive on Earth is shifted to the red region - over billions of years of travel through the Universe, the wavelength of each photon has increased as much as our entire expanding Universe. The farther away the object, the longer the light traveled and the greater the shift. Therefore, the spectrum of nearby galaxies ends in the ultraviolet, for distant ones - in the optical range, and for the most distant galaxies it moves to the infrared region of the spectrum.
And, finally, the "mathematical" proof - however, just as conclusive as Mitya Grushenka's letter. The eight-meter Gemini North telescope in the Hawaiian Islands, albeit 2.5 hours after the outbreak, still managed to aim at the explosion site and detect a rapidly fading object here. However, it was possible to see it only in the infrared range. And its brilliance in the K filter, at a wavelength of 2.2 microns, was almost four times higher than in the H filter, at a wavelength of 1.65 microns.
The simplest explanation for this jump is the absorption of shorter wavelength radiation by the resonant line of hydrogen, Ly α (pronounced "Lyman-alpha"). Only here in the laboratory reference system this line is at a wavelength of 0.1216 nm. If this line was dragged to the boundary between the H and K filters by the expansion of the Universe, then at the moment of its emission, our world should have been 12-14.5 times smaller than it is now (again, with a conservative analysis). This is where the redshift estimate z~11–13.5 comes from.
A matter of taste
However, objections can be found against this "evidence". An alternative model suggests that the light in the H filter was absorbed by dust located at a redshift of z~4. In this case, GRB100205A can be "only" 12 billion light-years from Earth - far, of course, but not a record.
True, the absorption in this case should be very significant, about 15-20 times, and where to get so much dust 1.7 billion years after the Big Bang is also not very clear. In addition, the absence in the images of any galaxy in which the necessary dust could live, and the relatively weak absorption of light in the X-ray range, also do not fit well with this explanation. But here it is necessary to choose from two unusual hypotheses the one that is the least implausible: a lot of dust in 1.7 billion years or the birth of a black hole in 350 million years from the creation of the world. As long as there are no new data, such a choice is, in fact, a matter of personal taste of theorists.
And the most annoying thing is that the necessary data may not appear very soon. Three weeks have passed since the gamma-ray burst, so that a noticeable optical afterglow from it has long faded. And now it takes a very, very long time to accumulate light in order to see a dusty galaxy at z~4. Or wait even longer until an instrument appears that can see the parent galaxy GRB100205A at z more than ten. And even the remnant of this explosion itself - after all, we will someday live to see such telescopes.
The science
A newly discovered celestial object is vying for the title of the most distant observed space object in the universe from us, astronomers have said. This object is a galaxy MACS0647-JD, which is located 13.3 billion light years from Earth.
The universe itself, according to scientists, is 13.7 billion years old, so the light from this galaxy that we can see today is its light from the very beginning of the formation of the cosmos.
Scientists observe object with NASA space telescopes Hubble and "Spitzer", as well as these observations were made possible with the help of a natural cosmic "magnifying lens". This lens is actually a huge cluster of galaxies, whose combined gravity warps space-time, producing the so-called gravitational lens. When light from a distant galaxy passes through such a lens on its way to Earth, it is amplified.
Here's what a gravitational lens looks like:
“Lenses like this can magnify the light of an object so much that no human-made telescope can do it., - He speaks Marc Postman, an astronomer at the Space Telescope Science Institute in Baltimore. - Without such a magnification, one must make a titanic effort to see such a distant galaxy."
The new distant galaxy is very small, much smaller than our Milky Way. scientists said. This object, judging by the light that has come down to us, is very young, it came to us from an era when the Universe itself was at the earliest stage of its development. She was only 420 million years old, which is 3 percent of her current age.
A small galaxy is only 600 light years wide, but as you know, the Milky Way is much larger - 150 thousand light years wide. Astronomers believe that MACS0647-JD eventually merged with other small galaxies to form a larger one.
Cosmic merger of galaxies
"This object is possibly one of the many building blocks of some larger galaxy, the researchers say. - Over the next 13 billion years, it could go through tens, hundreds or even thousands of mergers with other galaxies or their fragments."
Astronomers continue to observe even more distant objects as their observing techniques and instruments improve. The previous object that held the title of the most distant observable galaxy was the galaxy SXDF-NB1006-2, which is located at a distance of 12.91 billion light years from Earth. This object was seen with telescopes Subaru and "Kek" in Hawaii.
Astronomers have found the most distant known object in the universe. The age of the galaxy UDFy-38135539 is 13.1 billion years - that is, it formed just 600 million years after the Big Bang. The researchers described the galaxy they discovered in a journal article Nature. Briefly about the work writes New Scientist.
The first image of the galaxy was taken by the Hubble telescope in September 2009. The radiation of a very pale object was strongly shifted to the red region of the spectrum - such a shift is typical for ancient objects. The larger the offset, the older the object - and, therefore, the greater the distance the light traveled from the object to the observer. However, an alternative explanation is also possible - radiation with similar spectral characteristics can be emitted by objects like brown dwarfs located near the solar system.
To decide between these two possibilities, astronomers conducted continuous 16-hour observations of the object they found using the 8.2-meter telescope of the European Southern Observatory (ESO) in Chile. Analysis of the collected data on the spectrum of the object allowed scientists to establish that it is a galaxy, and it is 13.1 billion light-years away from the Earth (that is how many years it took for light to reach the telescope optics). The universe is believed to be about 13.7 billion years old.
According to the most commonly accepted hypotheses for the evolution of the universe, several hundred thousand years after the Big Bang, protons and electrons began to combine with each other and form hydrogen. After another 150 million years, the first galaxies began to form, and the space between them was filled with hydrogen, which absorbed the light of stars. However, gradually, under the influence of radiation from the stars, hydrogen was split into protons and electrons (this process is called reionization), and the Universe gradually became transparent. Intergalactic space was thought to have more or less cleared out about 800 million years after the Big Bang.
The fact that astronomers were able to see the galaxy UDFy-38135539 means that reionization was already in full swing when the universe was only 600 million years old (otherwise it would have been impossible to observe UDFy-38135539). The calculations of the authors of the study show that the radiation of this galaxy alone was not enough to clear the surrounding space, so astronomers suggest that neighboring star clusters "helped" UDFy-38135539.
So far, the most distant object found in the Universe is the gamma-ray burst GRB 090423, which occurred about 13.1 billion years ago (according to updated estimates, about 13 billion years ago).
Using data from the Hubble Space Telescope, astronomers have discovered the most distant object in our universe, a galaxy located 13.2 billion light-years from Earth."We went back in time, came very close to the first galaxies, which we believe formed approximately 200 to 300 million years after the Big Bang," RIA Novosti quoted one of the authors of the work, Garth Illingworth, as saying. The unique object turned out to be UDFj-39546284 - a record-breaking distant galaxy, which was distinguished by a relatively low rate of star formation. Comparison of data about it with information about other relatively closer and "older" galaxies showed that the rate of star formation in galaxies has increased tenfold in just 170 million years.
"That's amazing growth over a period that's only 1% of the current age of the universe," says Illingworth. According to scientists, these data are consistent with the hierarchical picture of galaxy formation, according to which galaxies grow and merge under the influence of dark matter gravity. The galaxy found by scientists is much smaller and lighter than modern spiral galaxies. So, our galaxy is about 100 times more massive.
The search for more and more distant space objects helps astronomers look into the distant past of the universe. Because the speed of light is finite, we see distant galaxies as they were in the distant past. Astronomers observe the UDFj-39546284 galaxy as it was when the universe was only 480 million years old.
The main indicator of the distance to distant galaxies is the redshift - the shift of lines in the spectrum due to the Doppler effect. The greater the redshift, the farther the space object, because with distance, according to Hubble's law, the escape velocity of galaxies increases. According to the authors of the discovery of the most distant galaxy, its redshift may be 10.3. However, these data are not final, since at the present stage of the development of astronomy, the exact measurement of redshift is an extremely difficult task. "Until the redshift is measured using spectroscopic methods, it remains just a candidate, although a good candidate," astrophysicist Sergei Popov of the Sternberg Astronomical Institute commented on the discovery.
If the redshift indicators of an open galaxy really turn out to be in the region of 9 - 10, then the object will be recognized as the most ancient in the Universe. In the meantime, this title was held by the galaxy UDFy-38135539, located 13 billion light years from Earth. It was discovered in October 2010 by astronomers from the European Southern Observatory (ESO). The redshift of this galaxy turned out to be 8.5549, and we see it as it was about 600 million years ago.
Image caption This star died just 520 million years after the Big Bang
A giant supernova explosion at the very edge of the observable universe was, apparently, the most distant event recorded by the telescope.
Astronomers believe that the death of this star, photographed by the American orbital observatory SWIFT, occurred just 520 million years after the Big Bang, in which our Universe was born.
This means that the light from the dying star traveled to Earth for 13.14 billion years.
The results of this study are published in the scientific journal Astrophysical Journal.
The discovered phenomenon has received the designation GRB 090429B. The letters GRB are an abbreviation for the words gamma-ray burst - a burst of gamma radiation - as astronomers designate such objects.
X-ray of the Universe
These bursts of gamma rays usually accompany extremely violent stellar processes, such as the end of life of giant stars.
"Probably it was a huge star, with a mass of 30 times more than our Sun," - said the leader of the research team, Dr. Antonino Cucchiara of the University of California at Berkeley.
Image caption The Swift satellite is a joint project between NASA and ESA“While we do not have sufficient data to attribute this star to the so-called Population III stars, that is, to the very first generation of stars that appeared in our Universe,” the scientist believes, “but we are certainly observing one of the earliest stages of star formation.” .
These flashes occur within a very short time, but their afterglow sometimes lasts for several days, which makes it possible to observe the development of the process using other telescopes and determine the distance to the gamma-ray burst.
Launched in 2004, the Swift satellite has the ability to quickly, less than a minute, optical and X-ray identification of bursts. Among his discoveries are powerful, sometimes multiple X-ray bursts in afterglows, as well as the detection of afterglows even before the end of the actual gamma radiation.
Race for antiquity
Astronomers are now competing in who will fix the most distant, and therefore the most ancient object in the universe.
The famous Hubble Space Telescope has much more powerful instruments for observing such distant objects, which were brought aboard by American astronauts in 2009.
How does a gamma-ray burst (GB) occur?
NASA scientists studying images taken by the Hubble telescope have already observed galaxies that are about the same distance from us as the gamma-ray object GRB 090429B.
Astronomers are interested in these extremely distant stars and star clusters because they expand our understanding of how the universe evolved.
Particular attention is drawn to the stars of the first generation. These bright blue variables originated from molecular clouds that formed early on shortly after the Big Bang.
These huge pulsating stars had a very short and turbulent cycle of development - only a few million years, giving rise to heavy elements during their death.
Their harsh ultraviolet radiation led to the reionization of the surrounding nebulae, which consisted mainly of hydrogen, stripping electrons from atoms, which in turn generated that extremely rarefied intergalactic plasma that surrounds the current generation of stars in our galaxy.
GRB 090429B is unlikely to be one of the very first stars in the universe, says Dr. Kukkiara. It is likely that even before that there were several generations of stars, about which we still do not know anything.
British and Italian engineers took part in the creation of the Swift orbital telescope. On board is a British X-ray camera that captures gamma-ray bursts, as well as components of an ultraviolet optical telescope.
