Anisotropic infall in the outskirts of OmegaWINGS galaxy clusters. (arXiv:2002.07825v1 [astro-ph.GA])

Anisotropic infall in the outskirts of OmegaWINGS galaxy clusters. (arXiv:2002.07825v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Salerno_J/0/1/0/all/0/1">Juan Manuel Salerno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martinez_H/0/1/0/all/0/1">H&#xe9;ctor J. Mart&#xed;nez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Muriel_H/0/1/0/all/0/1">Hern&#xe1;n Muriel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Coenda_V/0/1/0/all/0/1">Valeria Coenda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vulcani_B/0/1/0/all/0/1">Benedetta Vulcani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Poggianti_B/0/1/0/all/0/1">Bianca Poggianti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moretti_A/0/1/0/all/0/1">Alessia Moretti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gullieuszik_M/0/1/0/all/0/1">Marco Gullieuszik</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fritz_J/0/1/0/all/0/1">Jacopo Fritz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bettoni_D/0/1/0/all/0/1">Daniela Bettoni</a>

We study the effects of the environment on galaxy quenching in the outskirts
of clusters at $0.04 < z < 0.08$. We use a subsample of 14 WINGS and OmegaWINGS
clusters that are linked to other groups/clusters by filaments and study
separately galaxies located in two regions in the outskirts of these clusters
according to whether they are located towards the filaments’ directions or not.
We also use samples of galaxies in clusters and field as comparison.
Filamentary structures linking galaxy groups/clusters were identified over the
Six Degree Field Galaxy Redshift Survey Data Release 3. We find a fraction of
passive galaxies in the outskirts of clusters intermediate between that of the
clusters and the field’s. We find evidence of a more effective quenching in the
direction of the filaments. We also analyse the abundance of post-starburst
galaxies in the outskirts of clusters focusing our study on two extreme sets of
galaxies according to their phase-space position: backsplash and true
infallers. We find that up to $sim70%$ of post-starburst galaxies in the
direction of filaments are likely backsplash, while this number drops to
$sim40%$ in the isotropic infall region. The presence of this small fraction
of galaxies in filaments that are falling into clusters for the first time and
have been recently quenched, supports a scenario in which a significant number
of filament galaxies have been quenched long time ago.

We study the effects of the environment on galaxy quenching in the outskirts
of clusters at $0.04 < z < 0.08$. We use a subsample of 14 WINGS and OmegaWINGS
clusters that are linked to other groups/clusters by filaments and study
separately galaxies located in two regions in the outskirts of these clusters
according to whether they are located towards the filaments’ directions or not.
We also use samples of galaxies in clusters and field as comparison.
Filamentary structures linking galaxy groups/clusters were identified over the
Six Degree Field Galaxy Redshift Survey Data Release 3. We find a fraction of
passive galaxies in the outskirts of clusters intermediate between that of the
clusters and the field’s. We find evidence of a more effective quenching in the
direction of the filaments. We also analyse the abundance of post-starburst
galaxies in the outskirts of clusters focusing our study on two extreme sets of
galaxies according to their phase-space position: backsplash and true
infallers. We find that up to $sim70%$ of post-starburst galaxies in the
direction of filaments are likely backsplash, while this number drops to
$sim40%$ in the isotropic infall region. The presence of this small fraction
of galaxies in filaments that are falling into clusters for the first time and
have been recently quenched, supports a scenario in which a significant number
of filament galaxies have been quenched long time ago.

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