This light is emitted by the gas around the hottest stars and is therefore particularly good for observing galaxies with a high probability of star formation.
To better understand observations of the most distant galaxies, an international team of astronomers has constructed a sample of local galaxies that can be studied in much greater detail.
The relationship between light and the physical properties of the galaxy
In a recently published study, astronomers discovered how the amount of light escaping from a galaxy is related to its physical properties. This result has implications for how we interpret observations of galaxies in the early universe.
One of the most useful ways to study galaxies in the early universe is to use a special type of ultraviolet light called “”. This light is emitted by the gas around the hottest stars and is therefore particularly good for observing galaxies with a high probability of star formation.
However, unlike other types of light, the exact wavelength and direction of travel depends on many physical processes inside and outside galaxies. Laman’s alpha light not only goes directly to our telescopes, but also follow a complicated path out of the galaxy.
The universe still has a lot to explore
The universe still has a lot to discover – (Photo: Internet).
Along the way, Laman’s alpha light passes through regions with different physical conditions, which not only affects the path of individual photonic light particles, but also changes their wavelength and even their absorption by an unspecified part light.
Lyman’s alpha light can pass through some hotter regions, some dustier, some with strong gas clouds… All of these physical conditions make it extremely difficult to interpret the Laman alpha light that we see. But if we get an accurate explanation of this body light, we will be generously rewarded because then we can learn more about the physical properties of the galaxy.
Explore our neighboring galaxies
The galaxies of the distant universe are faint and small, and therefore particularly difficult to observe. So an international team of astronomers set out to construct a “reference” galaxy sample from local galaxies in the vicinity of our own galaxy. Although they are still hundreds of millions of light-years away, they are close enough to be studied in more detail, with various telescopes around the world and in space.
The reference galaxy sample is called “Lyman Alpha Reference Model” or LARS, has revealed many interesting properties of galaxies that are extremely useful when observing more distant galaxies. In the latest study, led by Jens Melinder, a senior researcher at Stockholm University and published in the Astrophysical Journal supplement series, astronomers inferred how much light Lyman Alpha is streaming out of the galaxy and whether that is correlated with the various physical properties of the galaxy.
Melinder explains: “With these new observations, we have established a link between the amount of Lyman alpha escaping from galaxies and some of the physical properties of these galaxies. For example, there is a clear correlation between the amount of cosmic dust in a galaxy and the amount of Lyman alpha light it emits. This was expected, as dust absorbs light, but now we have quantified this effect.”
Astronomers have also found a link between the light emitted and the total mass of all stars in the galaxy, although less clearly. On the other hand, other properties, such as the number of new stars formed by the galaxy, do not appear to correlate with the amount of Lyman alpha leaking out of the galaxy.
Another interesting result is that galaxies observed in Lyman’s alpha light appear significantly larger than when observed at other wavelengths. This effect has already been observed and is in line with theoretical expectations.
Peter Laursen of the Center for Cosmic Dawn, who also participated in the study, explains: “We see a similar effect in computer simulations of the galaxy with calculations of how Lyman alpha moves through gas clouds in interstellar space. This confirms that we have a fairly good theoretical understanding of the process. physics in play.”
This effect is important to take into account when observing distant galaxies whose light coming from their periphery is too weak to be detected by the detectors. Quantification of the effect will be useful for future observations of the oldest and most distant galaxies.
Melinder says: “These results will help explain observations of very distant galaxies observed with the Hubble and James Webb space telescopes. Understanding the detailed astrophysics of this type of galaxy is important for developing theories about how early galaxies formed and evolved.”.
Article Source: 1thegioi
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This bright light is produced by the gas around the hottest stars, making it very convenient to observe galaxies that may be producing stars.