In young galaxies the stars are first formed in the center and only then spread further and mainly grow through galaxy mergers
When galaxies are born, do their stars form everywhere at once, or just in a small core area? Findings by an international group led by scientists from the Max Planck Institute for Astronomy have provided the first assigned evidence of star formation regions in newly formed galaxies, and indeed these are small regions - but also hyperactive that produce stars at an extremely high rate.
Galaxies, including our Milky Way, contain hundreds of billions of stars. How does such a vast galactic system form? Was the central region the first where the stars hatched? Or maybe the stars were formed at the same time all over the galaxy?
The researchers examined one of the most distant galaxies known - a quasar called J1148+5251. Light from this galaxy takes 12.8 billion years to reach Earth. The astronomical observations therefore show the galaxy as it was seen 12.8 billion years ago, thus providing a glimpse into the first stage of galactic evolution, less than a billion years after the Big Bang.
Using the IRAM Interpreter - German-French-Spanish radio telescope, the researchers were able to obtain images of an unusual type: they recorded the infrared radiation emitted by J1148+5251 at specific frequencies associated with ionized carbon atoms, which are a reliable marker of the star formation process.
The photographs provided details that make it possible, for the first time, to measure the size of the early star formation region. Using this information, the researchers were able to come to the conclusion that in the same strain, the stars were formed in the core region of J1148+5251 at a tremendous rate - faster than any star formation process, and almost one that conflicts with the laws of physics.
"The rate of star formation in this galaxy is amazing," said the lead researcher on the paper, Fabian Walter from the Max Planck Institute for Astronomy. "Every year, the center of this galaxy produces stars with a combined mass greater than a thousand suns." In contrast, the rate of star formation in our galaxy began at about one solar mass per year.
It has long been known that young galaxies can produce an enormous amount of new stars, but the overall activity is only one part of the picture. Without knowing the size of the star forming region, it is difficult to compare the star formation process in the early galaxies with the theoretical models or with star forming regions in our galaxy.
With a diameter of about 4,000 light-years (for comparison, the diameter of the Milky Way is 100 light-years), the star formation process in the core of the galaxy J1148+5251 is very productive. In fact, it is close to the limits set by the laws of nature. Stars form when cosmic clouds of gas and dust collapse under their own gravity. When such a cloud collapses, the temperature rises, and internal pressures begin to build. When the pressure reached certain levels, all other collapse stops, and no more stars can form. The result is an upper limit to the amount of stars that can form in a given space volume in a given time period.
Impressively, the star-forming core of J1148+5251 reaches this absolute limit. Such a level of activity is found in several areas of our galaxy, but only on a smaller scale. For example, there is an area within the Orion Nebula that is active at a similar rate. Walter explains: "However, in J1148+5251 we are discussing an aggregate volume of hundreds of millions of such areas. Previous observations of other galaxies of the same age led scientists to estimate the top possible rate at one-tenth that of J1148+5251.
The compact region of star formation in J1148+5251 provides data for researchers building models of young galaxies. According to this example, galaxies grow from within. In the early stage of star formation there is a core region where the stars are formed at the same time. The assumption is that these areas grow over time, mainly as a result of collisions and mergers between galaxies, and the result is the full and large galaxies of today.
The observational problem was that at a distance of 13 billion light-years, a star-forming region 4,000 light-years in diameter has an angular diameter of 0.27 seconds above - like a one-euro coin from 18 kilometers away. The characteristic wavelength of ionized carbon atoms is brighter than the rest of the galaxy. Due to the expansion of the universe, it has been shifted towards longer wavelengths of light as it makes its way to Earth. (redshift), and therefore it comes in the form of radio waves with a wavelength of one millimeter. However, because of this it is also difficult to separate fine details with a wavelength of one millimeter compared to visible light. The observations in this field became possible only in 2006, thanks to an upgrade in the IRAM interferometer - radio telescope on the plain of de Bour in the French Alps. In the future it is expected to be joined by the ALMA telescope currently being built in northern Chile.
And Walter concludes: "The first stage of galactic evolution, about a billion years after the Big Bang, will be a major area of research in the coming years. Our measurements open a new window into star formation regions in very young galaxies."
15 תגובות
You will benefit from:
I repeat - the only point at this stage is understanding reality.
To me it seems an important enough point in itself, but even if someone wants a more tangible benefit, you should know that even when they discovered the electron, they didn't think it would have any use.
Only when you discover something can you start thinking about what to do with it.
No, I mean is there any point in even looking for him? What kind of benefit could he bring to humanity? for promotion?
You will benefit from:
Although your question is not directly related to the discussion, it is merely a private case of the question "How does understanding reality and knowing the correct facts help humanity?".
Still have a question?
By the way - of course, proving the existence of dark matter is only one of the directions in which science can progress, when another direction is finding an explanation that would leave behind the dark matter.
In any case - what we are trying to do is to understand what is happening.
Question: How will proving the existence of dark matter help humanity? (besides dark matter engines)
To the cool commenter: Regarding the air above the barbecue, you are right. See the "fata morgana" phenomenon that occurs on the country's roads during the hot summer days.
http://he.wikipedia.org/wiki/%D7%A4%D7%98%D7%94_%D7%9E%D7%95%D7%A8%D7%92%D7%A0%D7%94
Guys, I have a question, although not so related to the article:
In all the real images of space, for example
http://en.wikipedia.org/wiki/File:Pleiades_large.jpg
You can see that there is such a + (plus) on the star, and that plus is inside a circle of a halo.
why is it?
And another question I've had about optics for some time now:
You noticed that when you put on the fire, then the light passing over the barbecue flickers.
According to the simplest explanation I could think of, it is possible that the hot air above the barbecue has a refractive index slightly different from that of lukewarm air, and therefore it is possible to refract and deflect the light rays above the barbecue.
Thanks in advance
Ami:
There is no good analogy between electrical signals and electromagnetic radiation in general and light in particular, and this is because the signals in question contain encoded information while the frequency is just a frequency.
The information can be lost in many ways - whether as a result of the quality of the conductor (when it passes through a conductor and splashes off its walls, it fights with itself and loses the "sharpness" of the signal - this is what happens with optical fibers) or as a result of temporary disturbances.
When we try to detect a frequency of light coming from a distance, we have all the time in the world at our disposal, and if there is a disturbance at a given moment, we can wait for the next moment.
Since there is no need to search for information, there is no need to worry about temporary changes in the strength of the signal - as long as the signal arrives - we discussed.
Thank you Michael R.
I have another question: we know, for example from the field of electricity, that signals fade and change shape as a function of their distance from the receiver. Exactly for this reason, every few kilometers there are amplification stations that return the distorted signal to its original form.
A. Is there no analogy at all between electrical signals and the radiation signals of substances
B. If so there are:
in 1. Do we know how a signal changes as a function of distance/time?
In 2. How do we know that?
Thanks in advance for your reply,
Ami Bachar
Ami:
The distance affects the strength of the signal but not its frequency, therefore - as long as it is received - there is no problem knowing what its frequency is.
The analysis of the spectrum takes into account the redshift and does not really depend on it because every substance emits radiation at several frequencies and the distances between them are what are used to identify it. These distances are maintained under the Doppler effect (moreover - after the material has been identified according to the intervals between the frequencies - it is possible to calculate the speed of its distance from us according to the Doppler shift between the received frequency and the original frequency emitted by the material).
Isn't there some problem with receiving such long waves (1mm) through the atmosphere?
There is no problem in calculating the redshift, since the expansion rate of the universe is not completely clear?
And finally, why carbon? I understand the comfort thing, but carbon is a very high level of compression. The main material is hydrogen and maybe helium. What do we know about the masking or superpositions between carbon and hydrogen at such distances? (Yes, I got confused and unclear, I know... I admit that I don't understand a thing and a half in this field, but nevertheless - the question still exists. How from such a great distance that requires such fine resolutions - a euro coin from 18 km away - can be separated In such a subtle way rare waves of carbon against the flow of the main waves of hydrogen for example and all the other isotopes up to carbon?)
Greetings friends,
Ami Bachar
a m:
It is actually written and I quote:
"Each year, the center of this galaxy produces stars with a combined mass greater than a thousand suns"
So what's the pace?
I couldn't understand what that amazing pace of creation is in terms of timing
or stars for a certain time
Physical logic also says that this is how things work: initially there is an increased acceleration in the short distances and as you get further away there is a slowdown.:),,obviously,,
God too was once fresh, fresh and 'super-quick' - possessing superpowers,, then he moved away,, grew old,, and lost his influence on the world,,:)
and,,'exclusion of a bearded face',,
You are right, God also did it in a few days (:
In the same way, you build a building in a year and live in it for fifty years or more until you tear it down
"Stars are formed at an enormous speed in fresh galaxies",, evidently, all cells in nature are also formed this way,,