Galactic winds have limited the rate of star formation in the galaxy

Galactic winds have limited the rate of star formation in the galaxy
Optical image of the galaxy NGC 6240 obtained with the space telescope “Hubble”

Astronomers have found two merging galaxies NGC 6240 huge gas structure-the”butterfly” and two gas flow propagating away. It is expected that such flows inhibit the rate of star formation in the system, which is in the final stage of the merge, the article says, published in the journal Nature.

Today scientists know a lot of systems interacting galaxies in the Universe. If galaxies pass close enough to each other, they can collide or merge together. In this case occurs violation of the shapes of galaxies, the outflow of gas in intergalactic space or the “exhaustion” of gas clouds from a smaller galaxy in a great burst of star formation and the initiation of the merger of supermassive black holes located in the centers of galaxies. However, there are many unresolved problems, for example, remains unclear, as the flow of gas from the galaxy interact with the interstellar medium and what is the relationship between the rate of star formation and active galactic nuclei, where the black holes.

Galaxy NGC 6240 well suited to study the effects of fluxes and matter (“winds”) on the evolution of the galaxy. This galaxy is the result of a merger of two galaxies located in the constellation Ophiuchus, at a distance of 400 million light years from Earth. The process of merging galaxies began about 30 million years ago, caused a burst of star formation, and will be completed in a few hundred million years. In the heart of the system are two supermassive black holes, located at a distance of about 3000 light years apart, and they gradually become closer.

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The morphology of the galaxy NGC 6240, according to the telescope “Hubble”.

Observations of NGC 6240 were made by means of a space telescope “Hubble” and two spectrographs: SINFONI, set in one of the telescopes of the VLT complex, and DIS (Dual Imaging Spectrograph), installed in Observatory, Apache point.

In the Central region of the system has two active galactic nuclei of different types (LINER and Seyfert type II). Core surrounds the structure of the hot ionized gas, similar to a butterfly (the butterfly nebula), extending 30 thousand light years from the Central region. It traced the filaments, loops and bubbles, formed by shock waves and fluxes. The outflow of gas in the North-Western part of the “butterfly” was the result of the action of stellar winds or gas emissions, and for the formation of outflow in the North-Eastern part most likely responsible near the galactic nucleus. Both streams provide the mass loss of the galaxy in the form of gas up to 100 solar masses per year.

Galactic winds have limited the rate of star formation in the galaxy

Kinematic maps of the Central region in the galaxy NGC 6240: a) speed of the stars, b)speed of molecular hydrogen clouds c) the imposition of kinematic data on the “Hubble”.

F. Müller-Sánchez et al.\Nature, volume 556, pages 345-348 (2018)

NGC 6240 allows astronomers to observe the crucial stage of merging gas-rich galaxies, which starts to happen a suppression of the star formation rate due to the outflow of gas. It should be noted that only the extensive outflow of matter may limit the rate of star formation and the growth of the newly formed galaxy after the merger.

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Earlier we talked about how astronomers looked in the “cradle” of the jet near the black hole and showed view of the surroundings of the black hole at the center of the milky Way, and the success of the project “Radioastron”, which saw record the details of the structure of the jet near the supermassive black hole.


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