The Tilted Disk: The Milky Way’s Core Energy Reveals New Insight for the Entire Galaxy

At the center of the Milky Way, its core energy spreads outward as the source of the entire galaxy's power. A team from Embry-Riddle Aeronautical University report their latest findings of space's central energy.

The Milky Way contains a nucleus made of ionized hydrogen particles, which are highly energized do to the absence of electrons. Professor L. Matthew Haffner from the university said, 'Without an ongoing source of energy, free electrons usually find each other and recombine to return to a neutral state in a relatively short amount of time.' Seeing the new ionized gas will help them discover the source for such bizarre activity.

He collaborated with Dhanesh Krishnarao from the University of Wisconsin-Madison and UW-Whitewater Professor Bob Benjamin whose expertise includes the structure of gases and stars. Using the Wisconsin H-Alpha Mapper (WHAM) in Chile, they wanted to determine how much radiation, or energy, the center of the Milky Way contains.

Through the WHAM, they looked through a 'tattered dust cover,' where the Milky Way contains more than 200 billion stars and patches of space dust and gas. Benjamin sifted through 20 years of WHAM data and found a 'red flag,' or an odd shape sticking out of the Milky Way's center.

Taking a closer look, the team saw the red mark captured by the sensitive telescope was the ionized hydrogen gas. These peculiarly energized molecules were making its way towards Earth.

The Tilted Disk

Scientists call it the 'Tilted Disk' for being at a slight angle compared to the rest of the milky way. Using optical light, the team was able to study the Tilted Disk, formerly seen through infrared or radio light techniques.

'Being able to make these measurements in optical light allowed us to compare the nucleus of the Milky Way to other galaxies much more easily,' said Haffner. Previous studies have already measured ionized gas from the centers of galaxies elsewhere in the universe. This is the first time scientists directly compared their measurements of the Galaxy compared to the entire population of galaxies.

They created a 3-D model of the Milky Way's center by predicting the amount of ionized hydrogen would emit from the region. Using colors from hydrogen, nitrogen, and oxygen within the Tilted Disk allowed to compare and comprehend more of its composition.

Almost half of the hydrogen within the Milky Way's core is energized by an unknown source. Previously, scientists have only discovered the neutral or non-ionized gas in the middle of the Galaxy.

The Galaxy's Energy

Near the Milky Way's nucleus, Krishnarao shared, 'gas is ionized by newly forming stars, but as you move further away from the center, things get more extreme, and the gas becomes similar to a class of galaxies called LINERs, or low ionization (nuclear) emission regions.'

Due to the Earth's elliptical orbit, the structure looks like it's moving towards our planet. LINER galaxies make up about 30% of all galaxies with radiation in their centers, such as the Milky Way.

'Before this discovery by WHAM, the Andromeda Galaxy was the closest LINER spiral to us," Haffner said. 'But it's still millions of light-years away. With the nucleus of the Milky Way only tens of thousands of light-years away, we can now study a LINER region in more detail. Studying this extended ionized gas should help us learn more about the current and past environment in the center of our Galaxy.'

The level of radiation emitted by the Milky Way may reveal the source of its energy. Edwin Mierkiewicz, a physics professor, hopes that this may be discovered when the WHAM's successor telescope is built, enabling scientists to view interstellar gasses better and discover the source of the Galaxy's energy.