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The UV–optical colour dependence of galaxy clustering in the local universe

Loh, Yeong-Shang and Rich, R. Michael and Heinis, Sébastien and Scranton, Ryan and Mallery, Ryan P. and Salim, Samir and Martin, D. Christopher and Wyder, Ted and Arnouts, Stéphane and Barlow, Tom A. and Forster, Karl and Friedman, Peter G. and Morrissey, Patrick and Neff, Susan G. and Schiminovich, David and Seibert, Mark and Bianchi, Luciana and Donas, José and Heckman, Timothy M. and Lee, Young-Wook and Madore, Barry F. and Milliard, Bruno and Szalay, Alex S. and Welsh, Barry Y. (2010) The UV–optical colour dependence of galaxy clustering in the local universe. Monthly Notices of the Royal Astronomical Society, 407 (1). pp. 55-70. ISSN 0035-8711. doi:10.1111/j.1365-2966.2010.16908.x.

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We measure the UV-optical colour dependence of galaxy clustering in the local Universe. Using the clean separation of the red and blue sequences made possible by the NUV−r colour–magnitude diagram, we segregate the galaxies into red, blue and intermediate ‘green’ classes. We explore the clustering as a function of this segregation by removing the dependence on luminosity and by excluding edge-on galaxies as a means of a non-model dependent veto of highly extincted galaxies. We find that ξ(r_p, π) for both red and green galaxies shows strong redshift-space distortion on small scales – the ‘finger-of-God’ effect, with green galaxies having a lower amplitude than is seen for the red sequence, and the blue sequence showing almost no distortion. On large scales, ξ(r_p, π) for all three samples show the effect of large-scale streaming from coherent infall. On scales of 1 h^(−1) Mpc < r_p < 10 h^(−1) Mpc, the projected auto-correlation function w_p(r_p) for red and green galaxies fits a power law with slope γ ~ 1.93 and amplitude r_0 ~ 7.5 and 5.3, compared with γ ~ 1.75 and r_0 ~ 3.9 h^(−1) Mpc for blue sequence galaxies. Compared to the clustering of a fiducial L* galaxy, the red, green and blue have a relative bias of 1.5, 1.1 and 0.9, respectively. The w_p(r_p) for blue galaxies display an increase in convexity at ~ 1 h^(−1) Mpc, with an excess of large-scale clustering. Our results suggest that the majority of blue galaxies are likely central galaxies in less massive haloes, while red and green galaxies have larger satellite fractions, and preferentially reside in virialized structures. If blue sequence galaxies migrate to the red sequence via processes like mergers or quenching that take them through the green valley, such a transformation may be accompanied by a change in environment in addition to any change in luminosity and colour.

Item Type:Article
Related URLs:
URLURL TypeDescription
Rich, R. Michael0000-0003-0427-8387
Salim, Samir0000-0003-2342-7501
Martin, D. Christopher0000-0002-8650-1644
Forster, Karl0000-0001-5800-5531
Morrissey, Patrick0000-0001-8177-1023
Seibert, Mark0000-0002-1143-5515
Bianchi, Luciana0000-0001-7746-5461
Madore, Barry F.0000-0002-1576-1676
Additional Information:© 2010 The Authors. Journal compilation © 2010 RAS. Accepted 2010 April 22. Received 2010 April 20; in original form 2009 April 8. Article first published online: 17 June 2010. YSL would like to thank C. Hirata, S. Salim, C. Park, J. Kormendy and Z. Zheng for helpful discussions. This work has made extensive use of IDLUTILS8 and Goddard IDL libraries. RMR acknowledges support from grant GO-11182 from the Space Telescope Science Institute. GALEX is a NASA Small Explorer, launched in 2003 April. We gratefully acknowledge NASA’s support for construction, operation and science analysis for the GALEX mission, developed in cooperation with the Centre National d’Etudes Spatiales of France and the Korean Ministry of Science and Technology. Facilities: GALEX, SDSS
Group:Space Radiation Laboratory, Space Astrophysics Laboratory
Funding AgencyGrant Number
Space Telescope Science InstituteUNSPECIFIED
Subject Keywords:methods: statistical; galaxies: clusters: general; galaxies: elliptical and lenticular; galaxies: evolution
Issue or Number:1
Record Number:CaltechAUTHORS:20100915-141422615
Persistent URL:
Official Citation:Loh, Y.-S., Rich, R. M., Heinis, S., Scranton, R., Mallery, R. P., Salim, S., Martin, D. C., Wyder, T., Arnouts, S., Barlow, T. A., Forster, K., Friedman, P. G., Morrissey, P., Neff, S. G., Schiminovich, D., Seibert, M., Bianchi, L., Donas, J., Heckman, T. M., Lee, Y.-W., Madore, B. F., Milliard, B., Szalay, A. S. and Welsh, B. Y. (2010), The UV–optical colour dependence of galaxy clustering in the local universe. Monthly Notices of the Royal Astronomical Society, 407: 55–70. doi: 10.1111/j.1365-2966.2010.16908.x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:19975
Deposited By: Tony Diaz
Deposited On:16 Sep 2010 23:29
Last Modified:08 Nov 2021 23:56

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