Galaxies pass through gas. In the case of the galaxy NGC 4383, the outflow of gas is 20,000 light-years across, which is more than 50 million suns.
But even this massive leak has been difficult to detect until now. Observing what these outflows are made of and how they are organized requires high-resolution instruments that can only see gas from relatively nearby galaxies, so information about them is limited. I am. This is unfortunate, because the gaseous outflows emitted by galaxies can tell us more about their star formation cycles.
The MAUVE (MUSE and ALMA Unveiling the Virgo Environment) program is currently trying to change that. MAUVE’s mission is to understand how the outflow of galaxies in the Virgo cluster affects star formation. NGC 4383 stood out to astronomer Adam Watts and his team at the University of Australia and the International Center for Radio Astronomy Research (ICRAR) because of its sheer size.
The elements that galaxies emit into space can reveal their potential to form (or stop forming) stars. “Understanding the physics of stellar feedback outflows is essential to completing the picture of galaxy evolution,” the researchers recently wrote in a study published in the Monthly Notices of the Royal Astronomical Society. Ta.
star potential
Stellar feedback is all the radiation, particle winds, and other material that a star blows into the interstellar medium, forming an outflow as huge as NGC 4383. Much of this material comes either from star-forming explosions or from within. When a massive star dies and becomes a supernova. This contains heavier elements that escape with the spill into space, where they float around indefinitely, possibly ending up in other galaxies.
Star formation in galaxies depends on several processes. Between the intergalactic and circumgalactic media, there is an appropriate balance of gas accretion (growth through added gas), consumption (burning of hydrogen and helium by stars), and expulsion (when interstellar gas is blown out of the galaxy). There must be. The gas surrounding the galaxy. Some of the gas and other materials that form stars, such as iron and other heavy elements, can be recycled from supernova explosions.
The gas supply is key because large amounts of gas will eventually collapse due to the enormous gravity, eventually forming stars. A lack of gas can suppress potential star formation.
Watts and his team believe that one source of the stellar feedback pushing star-forming gas out of NGC 4383 is multiple supernovae that occurred relatively nearby. A supernova forms a giant bubble of scorching hot gas that eventually shoots vertically out of the galactic disk and spreads out from above and below the galaxy.
The hot gas continues to advance into cooler regions of the interstellar medium, and its gravity pulls in more gas on its way out of the galaxy, increasing the total mass of the outflow (known as the mass loading). Losing large amounts of gas further reduces the chance of star formation.
lost in space
Outflow can be observed at different wavelengths. It can detect X-ray emissions from elements such as hydrogen and compounds such as carbon monoxide. Outflow observation using UV, optical, and infrared light is also possible. Some of the emission in this region has already been observed with other telescopes and was combined with his MAUVE imaging of the Virgo cluster and NGC 4383 at different wavelengths.
The problem with accurately observing spills is that spatial resolution of scattering material is notoriously difficult, meaning knowing the distance of the entire spill on a pixel-by-pixel basis. Mauve, NGC 4383, the Virgo cluster, was observed with a spatial resolution of approximately 261 light-years, so each pixel represents a square in space with sides measuring 261 light-years. The ionized gas clumps that appeared in these pixels told the researchers that there were bipolar outflows emanating from the top and bottom of the galaxy.
So, is star formation decreasing in NGC 4383 due to a large outflow of stellar material? It turns out that stars are actually forming at the edge of the galaxy. Although no stars form in the flow escaping the galaxy, there are still regions where there is enough accreted gas to produce stars.
These starbursts, or regions of rapid star formation, are also more than just supernovae, providing stellar feedback. “There is an extension of the blue knot that is much brighter in the near ultraviolet and is clear evidence of star formation occurring outside the galaxy’s body,” the researchers said in the same study.
What is unclear about NGC 4383 is whether the gas outflow was caused solely by stellar feedback, or whether gravitational interactions with another galaxy enhanced the existing gas outflow. There is probably evidence of this to the east, where disturbances in the gas suggest that nearby dwarf galaxies may have interacted with the gas. For now, the researchers believe the outflow is primarily caused by starbursts and supernovae.
There’s still a lot researchers want to know about NGC 4383 and its spill. As telescopes become more advanced and their spatial resolution improves, perhaps something else will be revealed within the gas cloud.