Galaxy Zoo: Disentangling the Environmental Dependence of Morphology and Colour ⋆

By R. Skibba, S. P. Bamford, Robert Nichol, Chris J. Lintott, Dan Andreescu, E. Edmondson, P. Murray, M. Jordan Raddick, Kevin Schawinski, Anÿze Slosar and 3 more. 2008

188 citations recorded by the source corpus.

We analyze the environmental dependence of galaxy morphology and colour with two-point clustering statistics, using data from the Galaxy Zoo, the largest sample of visually classified morphologies yet compiled, extracted from the Sloan Digital Sky Survey. We present two-point correlation functions of spiral and early-type galaxies, and we quantify the correlation between morphology and environment with marked correlation functions. These yield clear and precise environmental trends across a wide range of scales, analogous to similar measurements with galaxy colours, indicating that the Galaxy Zoo classifications themselves are very precise. We measure morphology marked correlation functions at fixed colour and find that they are relatively weak, with the only residual correlation being that of red galaxies at small scales, indicating a morphology gradient within haloes for red galaxies. At fixed morphology, we find that the environmental dependence of colour remains strong, and these correlations remain for fixed morphology and luminosity. An implication of this is that much of the morphology–density relation is due to the relation between colour and density. Our results also have implications for galaxy evolution: the morphological transformation of galaxies is usually accompanied by a colour transformation, but not necessarily vice versa. A spiral galaxy may move onto the red sequence of the colour-magnitude diagram without quickly becoming an early-type. We analyze the significant population of red spiral galaxies, and present evidence that they tend to be located in moderately dense environments and are often satellite galaxies in the outskirts of haloes. Finally, we combine our results to argue that central and satellite galaxies tend to follow different evolutionary paths.

Subfields: Astronomy and Astrophysics, Ecology

View Paper: https://www.semanticscholar.org/paper/84516457cbe21b3f153f5e56828d5ca095057435

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Citations in the corpus

zCOSMOS – 10k-bright spectroscopic sample - The bimodality in the galaxy stellar mass function: exploring its evolution with redshift (2009, background): “Wolf et al. (2008) reach a similar conclusion in the cluster A901/2 at z ∼ 0.17: the rich red-spiral population at intermediate mass (log(M/M⊙)= [10, 11]) is more accurately explained if quenching is a slow process and morphological transformation is delayed even more (see also Skibba et al. 2009).”
The ATLAS3D project - VII. A new look at the morphology of nearby galaxies: the kinematic morphology-density relation (2011, background): “…of a tight and nearly universalT − Σ relation in all environments, extending to the group environment (e.g Postman & Geller 1984; Giovanelli et al. 1986), with samples of galaxies reaching up to 105 objects in the case of the Galaxy Zoo project (Bamford et al. 2009; Skibba et al. 2009).”
Measures of Galaxy Environment I - What is "Environment"? (2011, background): “…while the reverse is true for galaxies that have lower mass, are fainter, bluer and star forming (e.g. Norberg et al. 2002; Zehavi et al. 2005; Sheth et al. 2006; Li et al. 2006; Tinker et al. 2008; Ellison et al. 2009; Skibba & Sheth 2009; Skibba et al. 2009; de la Torre et al. 2011).”
GALAXY CLUSTERING IN THE COMPLETED SDSS REDSHIFT SURVEY: THE DEPENDENCE ON COLOR AND LUMINOSITY (2010, background): “(The two classification schemes are certainly not identical, however; see, e.g., Choi, Park, & Vogeley 2007; Bamford et al. 2009; Blanton & Moustakas 2009; Skibba et al. 2009).”
Rotation-invariant convolutional neural networks for galaxy morphology prediction (2015, background): “…have already been used in a wide variety of studies on galaxy structure, formation and evolution (Bamford et al. 2009; Lintott et al. 2009; Schawinski et al. 2009; Skibba et al. 2009; Darg et al. 2010; Masters et al. 2010, 2011; Simmons et al. 2013; Melvin et al. 2014; Willett et al. 2015).”
Galaxy Zoo: Passive Red Spirals . (2009, methodology): “We have already seen (Bamford et al. 2009; Skibba et al. 2009) that GZ1 red spirals are more common in high density regions (and conversely blue early-types are more common in low density regions; Schawinski et al. 2009b).”
THE GEMINI CLUSTER ASTROPHYSICS SPECTROSCOPIC SURVEY (GCLASS): THE ROLE OF ENVIRONMENT AND SELF-REGULATION IN GALAXY EVOLUTION AT z ∼ 1 (2011, background): “…mass. Galaxies in denser environments are redder (e.g., Kauffmann et al. 2004; Balogh et al. 2004b; Baldry et al. 2006; van den Bosch et al. 2008; Skibba et al. 2009; von der Linden et al. 2010), less star forming (e.g., Gómez et al. 2003; Kauffmann et al. 2004; Balogh et al. 2004a; Weinmann et…”
The green valley is a red herring: Galaxy Zoo reveals two evolutionary pathways towards quenching of star formation in early-and late-type galaxies (2014, background): “Similar results were reported previously by Skibba et al. (2009), who found that late-type quenching is associated with environment, and that late types may be able to quench without an associated morphological transformation.”
Galaxy Zoo 1: data release of morphological classifications for nearly 900 000 galaxies (2010, unknown): “2009 and Skibba et al. 2009).”
Structure and Kinematics of Early-Type Galaxies from Integral Field Spectroscopy (2016, result): “This general trend was subsequently confirmed with samples of ever increasing size, reaching a peak with the Galaxy Zoo sample of 105 galaxies (Bamford et al. 2009; Skibba et al. 2009).”
Galaxy pairs in the Sloan Digital Sky Survey – II. The effect of environment on interactions (2010, background): “…Geller 1984), the colours, morphologies and mean star formation rates of galaxies all clearly depend on their local environment (e.g Kauffmann et al. 2004; Balogh et al. 2004; Baldry et al. 2006; Weinmann et al. 2006; Park et al 2007; Skibba et al. 2009; Bamford et al. 2009 and references therein).”
THE EMISSION BY DUST AND STARS OF NEARBY GALAXIES IN THE HERSCHEL KINGFISH SURVEY (2011, background): “A number of KINGFISH galaxies appear to be similar to ‘passive disks’ and ‘red spirals’22 recently studied by other authors (e.g., Wolf et al. 2009; Skibba et al. 2009; van der Wel et al. 2009; Masters et al. 2010b; Bundy et al. 2010).”