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arXiv · 1711.05636

Galaxy and Mass Assembly (GAMA): Small-scale anisotropic galaxy clustering and the pairwise velocity dispersion of galaxies

J. Loveday·L. Christodoulou·P. Norberg·J. A. Peacock·I. K. Baldry·J. Bland-Hawthorn·M. J. I. Brown·M. Colless·S. P. Driver·B. W. Holwerda·A. M. Hopkins·P. R. Kafle·J. Liske·A. R. Lopez-Sanchez·E. N. Taylor
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Abstract

The galaxy pairwise velocity dispersion (PVD) can provide important tests of non-standard gravity and galaxy formation models. We describe measurements of the PVD of galaxies in the Galaxy and Mass Assembly (GAMA) survey as a function of projected separation and galaxy luminosity. Due to the faint magnitude limit ($r < 19.8$) and highly-complete spectroscopic sampling of the GAMA survey, we are able to reliably measure the PVD to smaller scales ($r_\bot = 0.01$ Mpc/h) than previous work. The measured PVD at projected separations $r_\bot <~ 1$ Mpc/h increases near-monotonically with increasing luminosity from $σ\approx 200$ km/s at $M_r = -17$ mag to $σ\approx 600$ km/s at $M_r \approx -22$ mag. Analysis of the Gonzalez-Perez (2014) GALFORM semi-analytic model yields no such trend of PVD with luminosity: the model over-predicts the PVD for faint galaxies. This is most likely a result of the model placing too many low-luminosity galaxies in massive halos.

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J. Loveday, L. Christodoulou, P. Norberg, J. A. Peacock, I. K. Baldry, J. Bland-Hawthorn, M. J. I. Brown, M. Colless, S. P. Driver, B. W. Holwerda, A. M. Hopkins, P. R. Kafle, J. Liske, A. R. Lopez-Sanchez, E. N. Taylor. 2017-11-15. Galaxy and Mass Assembly (GAMA): Small-scale anisotropic galaxy clustering and the pairwise velocity dispersion of galaxies. https://doi.org/10.1093/mnras%2Fstx2971

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