62 research outputs found
Dependence of galactic bars on the tidal density field in the SDSS
As a key driver of the secular evolution of disc galaxies, bar formation is
potentially linked to the surrounding tidal field. We systematically
investigate the dependence of bars on both the small ()
and large-scale () tidal fields using galaxies observed
between by the Sloan Digital Sky Survey (SDSS). We
characterise bar strength using the ellipticity of the isophote that
corresponds to the bar, , derived from the galaxy image after
subtracting the 2D disc component. We demonstrate the efficacy of our bar
detection method by performing an extensive comparison with the visual
identifications from SDSS and the DESI Legacy Surveys. Using the Yang et al.
SDSS group catalogue, we confirm the results from a recent study that the
average of galaxies within interacting clusters is higher
than that within isolated ones at , but this small-scale tidal
enhancement of bars disappears after we increase the cluster sample by a factor
of five to . On large scales, we explore the dependence of
on , the tidal anisotropy of the density field
defined over . We do not detect any such dependence for
of the galaxies with . Intriguingly, among the
with , we detect some hint of a boost in bar strength in the
underdense regions and a suppression in the overdense regions. Combining our
results on both scales, we conclude that there is little evidence for the tidal
dependence of bar formation in the local Universe, except for the extremely
anisotropic environments.Comment: 16 pages, 14 figures. Comments are welcom
A broadband optical diode for linearly polarized light using symmetry-breaking metamaterials
1151Ysciescopu
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