Unveiling the Secrets of Spiral Galaxies with Unusual Azimuthal Asymmetry

Strategic Insights -

Researchers at Vilnius University have conducted a comprehensive study on spiral galaxies exhibiting unusual azimuthal asymmetry in oxygen abundance. Through the Mapping Nearby Galaxies at the Apache Point Observatory (MaNGA) survey, the team identified five galaxies displaying distinct azimuthal asymmetry in oxygen abundance. The study's findings suggest that the massive galaxy M-11761-12705's abundance properties can be attributed to low-metallicity gas infall and subsequent episodes of high star formation rate. For moderate-mass galaxies, the higher oxygen abundance in high-metallicity regions may be explained by either a delayed starburst or galactic winds with reduced efficiency. The research has been peer-reviewed and published in Astronomy & Astrophysics (2025; 700).

Key Takeaways:

  • The study identified five galaxies exhibiting unusual azimuthal asymmetry in oxygen abundance, with M-11761-12705 being a massive galaxy with a stellar mass of log(M-star/M-dot) = 11.6.
  • The research revealed two distinct peaks in the spaxel abundances histogram, with a difference of 0.06-0.08 dex between the high- and low-metallicity regions.
  • Galaxies exhibiting unusual azimuthal asymmetry were found to have higher oxygen abundance in high-metallicity regions and lower oxygen abundance in low-metallicity regions.
  • The massive galaxy M-11761-12705 showed that its abundance properties can be explained by low-metallicity gas infall and subsequent episodes of high star formation rate.
  • Moderate-mass galaxies can exhibit higher oxygen abundance in high-metallicity regions due to delayed starburst or galactic winds with reduced efficiency.
  • Two galaxies in the sample, M-8546-12704 and M-11761-12705, are members of galaxy pairs, but only the massive galaxy M-11761-12705 shows significant asymmetry.

Statistics:

  • The stellar masses of the five galaxies range from log(M-star/M-dot) = 10.1 to log(M-star/M-dot) = 11.6.
  • The difference between high- and low-metallicity regions is 0.06-0.08 dex.
  • The massive galaxy M-11761-12705 has a stellar mass of log(M-star/M-dot) = 11.6.

Sources:

  • Research Council of Lithuania (LMTLT)
  • National Aeronautics & Space Administration (NASA)
  • Alfred P. Sloan Foundation
  • National Science Foundation (NSF)
  • United States Department of Energy (DOE)
  • Center for High-Performance Computing at the University of Utah
  • NewsRx. Reports Outline Chemicals and Chemistry Findings from Vilnius University (Spiral Galaxies With Unusual Azimuthal Asymmetry In Oxygen Abundance). News of Science. October 26, 2025; p 3002.
  • Astronomy & Astrophysics. 2025; 700.