Wobbling Galaxy Spin Axes in Dense Environments

Jaehyun Lee, Suk Kim, Hyunjin Jeong, Rory Smith, Hoseung Choi, Ho Seong Hwang, Seok Joo Joo, Hak Sub Kim, Youngdae Lee, Sukyoung K. Yi

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13 Citations (Scopus)


The orientation of galaxy spin vectors within the large-scale structure has been considered an important test of our understanding of structure formation. We investigate the angular changes of galaxy spin vectors in clusters-denser environments than are normally focused upon-using hydrodynamic zoomed simulations of 17 clusters YZiCS and a set of complementary controlled simulations. The magnitude by which galaxies change their spin vector is found to be a function of their rotational support, with larger cumulative angular changes of spin vectors when they have initially lower V θ/σ. We find that both mergers and tidal perturbations can significantly swing spin vectors, with larger changes in spin vector for smaller pericenter distances. Strong tidal perturbations are also correlated with the changes in stellar mass and specific angular momentum of satellite galaxies. However, changes in spin vector can often result in a canceling out of previous changes. As a result, the integrated angular change is always much larger than the angular change measured at any instant. Also, overall, the majority of satellite galaxies do not undergo mergers or sufficiently strong tidal perturbation after infall into clusters, and thus they end up suffering little change to their spin vectors. Taken as a whole, these results suggest that any signatures of spin alignment from the large-scale structure will be preserved in the cluster environment for many gigayears.

Original languageEnglish
Article number69
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 2018 Sept 1

Bibliographical note

Funding Information:
We thank the anonymous referee for constructive comments that improved the clarity of the manuscript significantly. In particular, Section 3.5 is a result of the communication with the referee. H.J. acknowledges support from the Basic Science Research Program through the National Research Foundation (NRF) of Korea, funded by the Ministry of Education (NRF-2013R1A6A3A04064993). S.K.Y. acknowledges support from the National Research Foundation of Korea (NRF-2017R1A2A1A05001116). This study was performed under the umbrella of the joint collaboration between Yonsei University Observatory and the Korean Astronomy and Space Science Institute. The supercomputing time for numerical simulation was kindly provided by KISTI (KSC-2014-G2-003), and large data transfer was supported by KREONET, which is managed and operated by KISTI.

Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved..

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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