Properties of Galaxies in Cosmic Filaments around the Virgo Cluster
Youngdae Lee, Suk Kim, Soo-Chang Rey, Jiwon Chung
Abstract
Abstract We present the properties of galaxies in filaments around the Virgo cluster with respect to their vertical distance from the filament spine using the NASA–Sloan Atlas catalog. The filaments are mainly composed of low-mass, blue dwarf galaxies. We observe that the g − r color of galaxies becomes blue and stellar mass decreases with increasing vertical filament distance. The galaxies were divided into higher-mass ( ) and lower-mass ( ) subsamples. We also examine the distributions of g − r color, stellar mass, H α equivalent width (EW(H α )), near-ultraviolet (NUV) − r color, and H i fraction of the two subsamples with the vertical distance. The lower-mass galaxies exhibit a negative g − r color gradient, whereas higher-mass galaxies have a flat g − r color distribution. We observe a negative EW(H α ) gradient for higher-mass galaxies, whereas lower-mass galaxies show no distinct EW(H α ) variation. In contrast, the NUV − r color distribution of higher-mass galaxies shows no strong trend, whereas the lower-mass galaxies show a negative NUV − r color gradient. We do not see clear gradients of H i fraction in either the higher- or lower-mass subsample. We propose that the negative color and stellar mass gradients of galaxies can be explained by mass assembly from past galaxy mergers at different vertical filament distances. In addition, galaxy interactions might be responsible for the contrasting features of EW(H α ) and NUV − r color distributions between the higher- and lower-mass subsamples. The distributions of H i fraction of the two subsamples suggest that the processes of ram pressure stripping and gas accretion may be ignored in the Virgo filaments.