The MAGPI Survey: the evolution of galaxy spin-filament alignments since z~0.3
Abstract
We present measurements of galaxy spin-filament alignments at 0.20<z<0.42 using the MAGPI Survey, exploiting resolved stellar and ionised gas kinematics to reconstruct 3D spin axes. Cosmic filaments are identified using a stellar mass-matched constant-number-density population from the GAMA, MAGPI Redshift Survey and DESI datasets. We detect a flipping of the statistical alignment signal at z~0.3 as a function of M*: low-mass galaxies preferentially exhibit spins parallel to the direction of their host filaments, while high-mass galaxies tend towards perpendicular orientations. The transition mass is measured to be log(M{*,t}/Msun)~10.8, approximately 0.6 dex higher than the value for the SAMI Galaxy Survey at z~0.05. Bootstrap analysis gives 99.5% confidence that the transition mass is higher for MAGPI than SAMI. At fixed stellar mass MAGPI galaxies exhibit stronger parallel alignments than their SAMI counterparts, suggesting evolution of spin-filament alignments over the past ~3 Gyr. The gaseous component in MAGPI galaxies is more closely aligned with filaments than the stellar component, relative to a M*-matched SAMI sample. This indicates a stronger coupling between ionised gas and the large-scale structure at z~0.3, consistent with coherent gas accretion onto filaments remaining efficient at higher M*. At z~0 we detect a transition toward perpendicular alignments at lower M*, while the gas and stellar components exhibit similar alignments relative to filaments, likely due to the cumulative effects of mergers and secular evolution.
Related
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BibTeX
@misc{barsanti2026magpi,
title = {{The MAGPI Survey: the evolution of galaxy spin-filament alignments since z~0.3}},
author = {Stefania Barsanti and Andrew J. Battisti and Sabine Bellstedt and Matthew Colless and Scott M. Croom and Caroline Foster and Katherine E. Harborne and Claudia D. P. Lagos and J. Trevor Mendel and Matt S. Owers and Elmo Tempel and Emily Wisnioski and Iris Breda and Pratyush K. Das and Clotilde Laigle and Rhea-Silvia Remus and Gauri Sharma and Sabine Thater and Lucas M. Valenzuela and Jesse van de Sande and Glenn van de Ven and Daria Zakharova and Bodo L. Ziegler},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.00212},
eprint = {2611.00212},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.00212},
}
RIS
TY - UNPB
TI - The MAGPI Survey: the evolution of galaxy spin-filament alignments since z~0.3
AU - Stefania Barsanti
AU - Andrew J. Battisti
AU - Sabine Bellstedt
AU - Matthew Colless
AU - Scott M. Croom
AU - Caroline Foster
AU - Katherine E. Harborne
AU - Claudia D. P. Lagos
AU - J. Trevor Mendel
AU - Matt S. Owers
AU - Elmo Tempel
AU - Emily Wisnioski
AU - Iris Breda
AU - Pratyush K. Das
AU - Clotilde Laigle
AU - Rhea-Silvia Remus
AU - Gauri Sharma
AU - Sabine Thater
AU - Lucas M. Valenzuela
AU - Jesse van de Sande
AU - Glenn van de Ven
AU - Daria Zakharova
AU - Bodo L. Ziegler
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.00212
UR - https://arxiv.org/abs/2611.00212
AB - We present measurements of galaxy spin-filament alignments at 0.20<z<0.42 using the MAGPI Survey, exploiting resolved stellar and ionised gas kinematics to reconstruct 3D spin axes. Cosmic filaments are identified using a stellar mass-matched constant-number-density population from the GAMA, MAGPI Redshift Survey and DESI datasets. We detect a flipping of the statistical alignment signal at z~0.3 as a function of M*: low-mass galaxies preferentially exhibit spins parallel to the direction of their host filaments, while high-mass galaxies tend towards perpendicular orientations. The transition mass is measured to be log(M{*,t}/Msun)~10.8, approximately 0.6 dex higher than the value for the SAMI Galaxy Survey at z~0.05. Bootstrap analysis gives 99.5% confidence that the transition mass is higher for MAGPI than SAMI. At fixed stellar mass MAGPI galaxies exhibit stronger parallel alignments than their SAMI counterparts, suggesting evolution of spin-filament alignments over the past ~3 Gyr. The gaseous component in MAGPI galaxies is more closely aligned with filaments than the stellar component, relative to a M*-matched SAMI sample. This indicates a stronger coupling between ionised gas and the large-scale structure at z~0.3, consistent with coherent gas accretion onto filaments remaining efficient at higher M*. At z~0 we detect a transition toward perpendicular alignments at lower M*, while the gas and stellar components exhibit similar alignments relative to filaments, likely due to the cumulative effects of mergers and secular evolution.
ER -