Harvard astronomers suggest the Milky Ways distorted shape is due to an irregular dark matter halo. The work likewise reinforces present thinking about how the galaxy evolved and might offer hints into some of the mysteries of dark matter.
Structure on that, the group presumed the very same shape for the dark matter halo, the larger entity that encompasses everything in and around the Milky Way. Dark matter makes up 80 percent of the galaxys mass however is undetectable because it does not communicate with light, so the shape of that halo should be presumed. Utilizing models to determine the orbits of stars within a slanted, elongate dark matter halo, the team discovered a near-perfect match to existing observations of a warped, flared galaxy.
Harvard astronomers recommend the Milky Ways warped shape is because of an irregular dark matter halo. This supports theories of a previous stellar collision and uses insights into the nature of dark matter. Credit: Stefan Payne-Wardenaar; Magellanic Clouds: Robert Gendler/ESO
Astronomers results reinforce the hypothesis of how our galaxy evolved.
The Milky Way is often depicted as a flat, spinning disk of dust, gas, and stars. But if you might zoom out and take an edge-on photo, it in fact has a distinctive warp– as if you attempted to twist and bend a vinyl LP.
Though researchers have actually long understood through observational data that the Milky Way is distorted and its edges are flared like a skirt, no one could discuss why.
Harvard Astronomers Discoveries
Now, Harvard astronomers at the Center for Astrophysics|Harvard and Smithsonian ( CfA) have carried out the very first computations that totally describe this phenomenon, with compelling proof indicating the Milky Ways envelopment in an off-kilter halo of dark matter. The work also bolsters existing believing about how the galaxy evolved and may use clues into some of the mysteries of dark matter.
The Milky Ways stellar disk is warped and flared, comparable to Galaxy ESO envisioned here. NASAs Hubble Space Telescope imaged this uncommon edge-on galaxy, revealing exceptional details of its warped dirty disc and showing how clashing galaxies trigger the birth of new stars.
The new computations were led by Jiwon Jesse Han, a Griffin Graduate School of Arts and Sciences trainee associated with the CfA. Released in the journal Nature Astronomy, the work consists of co-authors Charlie Conroy and Lars Hernquist, both professors members at the CfA and in the Department of Astronomy.
The Stellar Halo and Dark Matter
Our galaxy lies inside a scattered cloud called the stellar halo, which extends much farther out into the universe. In groundbreaking work released in 2015, the Harvard team deduced that the outstanding halo is tilted and elliptical in shape, like a zeppelin or football.
Building on that, the group assumed the very same shape for the dark matter halo, the bigger entity that includes whatever in and around the Milky Way. Dark matter comprises 80 percent of the galaxys mass however is unnoticeable since it doesnt connect with light, so the shape of that halo should be inferred. Using designs to calculate the orbits of stars within a slanted, oblong dark matter halo, the group found a near-perfect match to existing observations of a warped, flared galaxy.
Implications and Insights
” A slanted dark halo is actually relatively common in simulations, however no one had actually explored its effect on the Milky Way,” Conroy said. “It ends up that the tilt is a sophisticated method to describe both the magnitude and instructions of our galaxys wobbly disk.”
Scientists had long speculated that the Milky Way formed due to a galactic accident; the astronomers work further underscores that hypothesis.
” If the galaxy was just progressing on its own, it would have had this great, round halo, this great, flat disk,” Han said. “So the reality that the halo is slanted and has a football-like shape suggests that our galaxy experienced a merger event, where two galaxies collide.”
” It ends up that the tilt is a classy method to discuss both the magnitude and direction of our galaxys wobbly disk.”– Charlie Conroy, Department of Astronomy
Their estimation of the dark matter halos likely shape might also provide ideas regarding the residential or commercial properties and particle nature of dark matter itself, which remain unsolved mysteries in physics. “The reality that the galaxy is not spherical in our data indicates that there is some limitation to which dark matter can engage with itself,” Han explained.
Confidence in these findings might cause better methods to cleverly study the unobservable dark matter that makes up most of the universe. This consists of brand-new methods to choose up on kinematic signatures of dark sub-halos, which are miniature dark matter halos zipping around the galaxy.
Recommendation: “A tilted dark halo origin of the Galactic disk warp and flare” by Jiwon Jesse Han, Charlie Conroy and Lars Hernquist, 14 September 2023, Nature Astronomy.DOI: 10.1038/ s41550-023-02076-9.