GALAXY SPIN ALIGNMENT IN FILAMENTS AND SHEETS: OBSERVATIONAL EVIDENCE

Journal Article · Tue Oct 01 04:00:00 EDT 2013 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/775/2/L42· OSTI ID:22215452

Tempel, Elmo ^[1]

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1. Tartu Observatory, Observatooriumi 1, 61602 Tõravere (Estonia)

The properties of galaxies are known to be affected by their environment. One important question is how their angular momentum reflects the surrounding cosmic web. We use the Sloan Digital Sky Survey to investigate the spin axes of spiral and elliptical galaxies relative to their surrounding filament/sheet orientations. To detect filaments, a marked point process with interactions (the {sup B}isous model{sup )} is used. Sheets are found by detecting 'flattened' filaments. The minor axes of ellipticals are found to be preferentially perpendicular to hosting filaments. A weak correlation is found with sheets. These findings are consistent with the notion that elliptical galaxies formed via mergers, which predominantly occurred along the filaments. The spin axis of spiral galaxies is found to align with the host filament, with no correlation between spiral spin and sheet normal. When examined as a function of distance from the filament axis, a much stronger correlation is found in the outer parts, suggesting that the alignment is driven by the laminar infall of gas from sheets to filaments. When compared with numerical simulations, our results suggest that the connection between dark matter halo and galaxy spin is not straightforward. Our results provide an important input to the understanding of how galaxies acquire their angular momentum.

• OSTI ID: 22215452
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 775; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ALIGNMENT
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
CORRELATIONS
DISTANCE
FILAMENTS
GALAXIES
NONLUMINOUS MATTER
ORIENTATION
SKY
SPIN