Galaxy And Mass Assembly (GAMA): the large-scale structure of galaxies and comparison to mock universes

• Published in: Monthly notices of the Royal Astronomical Society Vol. 438; no. 1; pp. 177 - 194
• Main Authors: Alpaslan, Mehmet, Robotham, Aaron S. G., Driver, Simon, Norberg, Peder, Baldry, Ivan, Bauer, Amanda E., Bland-Hawthorn, Joss, Brown, Michael, Cluver, Michelle, Colless, Matthew, Foster, Caroline, Hopkins, Andrew, Van Kampen, Eelco, Kelvin, Lee, Lara-Lopez, Maritza A., Liske, Jochen, Lopez-Sanchez, Angel R., Loveday, Jon, McNaught-Roberts, Tamsyn, Merson, Alexander, Pimbblet, Kevin
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 11.02.2014
• Subjects: Cosmology; Stars & galaxies; Universe; surveys; methods: observational; large-scale structure of Universe
• ISSN: 0035-8711; 1365-8711; 1365-2966; 1365-2966
• DOI: 10.1093/mnras/stt2136

From a volume-limited sample of 45 542 galaxies and 6000 groups with z ≤ 0.213, we use an adapted minimal spanning tree algorithm to identify and classify large-scale structures within the Galaxy And Mass Assembly (GAMA) survey. Using galaxy groups, we identify 643 filaments across the three equatorial GAMA fields that span up to 200 h −1 Mpc in length, each with an average of eight groups within them. By analysing galaxies not belonging to groups, we identify a secondary population of smaller coherent structures composed entirely of galaxies, dubbed 'tendrils' that appear to link filaments together, or penetrate into voids, generally measuring around 10 h −1 Mpc in length and containing on average six galaxies. Finally, we are also able to identify a population of isolated void galaxies. By running this algorithm on GAMA mock galaxy catalogues, we compare the characteristics of large-scale structure between observed and mock data, finding that mock filaments reproduce observed ones extremely well. This provides a probe of higher order distribution statistics not captured by the popularly used two-point correlation function.