Hubble maps the giant halo around the Andromeda galaxy

Hubble maps the giant halo around the Andromeda galaxy

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Washington: In a historical study, scientists using NASA’s Hubble Space Telescope have mapped a giant envelope of gas called a halo around our nearest large galactic neighboring Andromeda galaxy.
Scientists were surprised to learn that this invisible, nearly invisible halo of circulating plasma spans 1.3 million light-years from the Milky Way, nearly half of our Milky Way, and 2 million light-years in some directions. This means that the halo of Andromeda is already hitting the halo of our own galaxy.
They also found that the halo has a layered structure, which consists of two main nests of gas and separate spheres. It is the most comprehensive study of the halo around the galaxy.
The team’s findings appear in a recent edition of The Astrophysical Journal.
“It is very important to understand the huge halt of gas surrounding the galaxies,” said Samantha Berić, co-investigator at Yale University in New Haven, Connecticut.
“This reservoir of gas contains fuel to create future stars within the galaxy, as well as outflows from events such as Ernova. It is full of clues about the past and future evolution of the galaxy , And we are finally able to study it great. In detail in our nearest Galactic neighbor, “Berek said.
Nicholas Lehner, the study leader at the University of Notre Dame in Indiana, said, “We detect the inner cover, which spans about one and a half million light-years, is far more complex and dynamic.”
Lehner said, “The outer shell is smooth and warm. This difference is a result of the effect of supernova activity in the galaxy’s disk that affects the inner halo more,” Lehner said.
One signature of this activity is the team’s discovery of massive amounts of heavy elements in the gaseous halo of Andromeda. The heavier elements are baked into the interiors of the stars and are then thrust into space – sometimes violently a star dies. The corona is contaminated with this material by stellar explosions.
The Andromeda galaxy, also known as the M31, has a majestic spiral of perhaps as many as 1 trillion stars and is comparable in size to our Milky Way. At a distance of 2.5 million light-years, it is so close to us that the Milky Way appears as a cigar-shaped smoke in the autumn sky. If its gaseous halo can be seen with the naked eye, it will be about three times the width of the Big Dipper. This would easily be the biggest feature on the night sky.
Through a program called Project AMIGA (Absorption Map of Ionized Gas in Andromeda), the study examined light from 43 quasars – the far-flung cores of active galaxies driven by black holes – located beyond Andromeda. Claire is scattered behind the halo, allowing scientists to investigate many areas.
Looking at the halo in the light of quasars, the team looked at how this light is absorbed by the Andromeda halo and how this absorption changes in different regions. The giant Andromeda corona is made up of very rare and ionized gas that does not emit radiation that is easily detectable. Therefore, detecting the absorption of light coming from a background source is a better way to investigate this material.
The researchers used the unique ability of Hubble’s Cosmic Origins Spectrograph (COS) to study ultraviolet light from quarries. Ultraviolet light is absorbed by the Earth’s atmosphere, making it impossible to observe with ground-based telescopes. The team used COS to detect ionized gas from carbon, silicon, and oxygen. An atom is ionized when radiation snatches one or more electrons from it.
Andromeda’s halo has been investigated by Lehner’s team. In 2015, he found that the Andromeda halo is large and large. But there was little indication of its complexity; Now, it has been mapped in more detail, determining its size and mass more accurately.
“Previously, there was little information – only six quasars – within 1 million light years of the Milky Way. This new program provides a great deal of information on this interior region of the Andromeda halo,” said co-investigator Jay Christopher Hawke. Also of Notre Dame.
“It is important to test the gas within this radius, because it represents some area of ​​influence of gravity for Andromeda,” Hawke said.
Because we live inside the Milky Way, scientists cannot easily interpret the sign of the halo of our own galaxy. However, they believe that the condition of Andromeda and the Milky Way is very similar because these two galaxies are quite similar. The two galaxies are on a collision course, and will form a massive elliptical galaxy starting around 4 billion years from now.
Scientists have studied the gaseous disclosure of more distant galaxies, but they are much smaller in the sky than on Earth, meaning that the number of bright enough background quasars to examine their aura is usually only one per galaxy. Spatial information is therefore essentially lost. With its proximity to Earth, Andromeda’s gaseous halo is larger on the sky, allowing far more extensive sampling.
“This is a truly unique experiment because only with Andromeda we know about its aura, not just with one or two visionlines, but over 40. It’s the complexity of a galaxy halo beyond our own Milky Way Is amazing to catch, ”Lehner said.
In fact, Andromeda is the only galaxy in the universe for which this experiment can now be conducted, and only with Hubble. With only an ultraviolet-sensitive future space telescope, scientists will be able to perform this type of experiment regularly beyond the nearly 30 galaxies included in the local cluster.
“So Project AMIGA also gave us a glimpse of the future,” Lehner said.


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