Large-scale filamentary structures around the Virgo cluster revisited

We revisit the filamentary structures of galaxies around the Virgo cluster, exploiting a larger data set, based on the HyperLeda database, than previous studies. In particular, this includes a large number of low-luminosity galaxies, resulting in better sampled individual structures. We confirm seven known structures in the distance range 4 h⁻¹ Mpc < SGY < 16 h⁻¹ Mpc, now identified as filaments, where SGY is the axis of the supergalactic coordinate system roughly along the line of sight. The Hubble diagram of the filament galaxies suggests they are infalling toward the main body of the Virgo cluster. We propose that the collinear distribution of giant elliptical galaxies along the fundamental axis of the Virgo cluster is smoothly connected to two of these filaments (Leo II A and B). Behind the Virgo cluster (16 h⁻¹ Mpc < SGY < 27 h⁻¹ Mpc), we also identify a new filament elongated toward the NGC 5353/4 group ("NGC 5353/4 filament") and confirm a sheet that includes galaxies from the W and M clouds of the Virgo cluster ("W–M sheet"). In the Hubble diagram, the NGC 5353/4 filament galaxies show infall toward the NGC 5353/4 group, whereas the W–M sheet galaxies do not show hints of gravitational influence from the Virgo cluster. The filamentary structures identified can now be used to better understand the generic role of filaments in the build-up of galaxy clusters at z ≈ 0.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science, and Technology (2015R1A2A2A01006828). Support was also provided by the NRF of Korea to the Center for Galaxy Evolution Research (No. 2010-0027910). S. Kim acknowledges support from a National Junior Research Fellowship of NRF (No. 2011-0012618). H. Jeong acknowledges support from the NRF funded by the Ministry of Education (NRF- 2013R1A6A3A04064993). This study was also financially supported by the research fund of Chungnam National University in 2014. This work has been also supported by Science Fellowship of POSCO TJ Park Foundation and the NRF grant No. 2015R1D1A1A01060516. H. Jerjen acknowledges the support of the Australian Research Council through Discovery Project DP150100862