The so-called Evil Eye galaxy (aka M64) is actually the outcome of two galaxies merging with one another. In front of the bright core of the galaxy, there’s a dark layer of absorbing dust, granting a truly sinister look to the entire cosmic structure.
The outer disk of the galaxy is rich in hydrogen, and it rotates in the opposite direction to its inner disk of stars, hinting at distinct origins. New research that ScienceAlert writes about has unveiled that the hydrogen gas in the outer disk originated from a smaller satellite dwarf galaxy that was consumed by M64, resulting in the darkening of its outskirts. This discovery offers a glimpse into the future of our own Milky Way galaxy, as the shredded satellite resembles the Small Magellanic Cloud, a dwarf galaxy destined to merge with the Milky Way in time.
For the new study in question, the scientists wrote, as ScienceAlert quotes:
We find evidence for a spectacular shell feature, and other tidal structures indicative of an ongoing, late-stage radial merger,
We estimate the stellar mass of the progenitor galaxy to be 500 million solar masses, with a metallicity of [M/H] ≃ −1 – very similar to the mass and metallicity of the Small Magellanic Cloud.
The mass of M64’s counter-rotating outer gas disk is also comparable to the gas mass of the Small Magellanic Cloud, suggesting that the likeliest origin of M64’s unique counter-rotating disk was a recent merger with a gas-rich satellite very similar to the Small Magellanic Cloud.
The new study was led by astronomer Adam Smercina from the University of Washington, and it provides valuable insights into the cosmic processes at play, and it has been accepted for publication in The Astrophysical Journal Letters. As for the detailed findings, they can be accessed on the preprint server arXiv.