Measuring the dynamical state of<i>Planck</i>SZ-selected clusters: X-ray peak – BCG offset

Rossetti, M.; Gastaldello, F.; Ferioli, Giovanni; Bersanelli, M.; Grandi, S. De; Eckert, D.; Ghizzardi, S.; Maino, D.; Molendi, S.

doi:10.1093/mnras/stw265

Cited by 112 publications

(123 citation statements)

References 80 publications

(99 reference statements)

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“…The definition of interacting or unrelaxed clusters varies between different works, some defining it from the existence of radio-emitting structures (Stroe et al 2017), symmetry of member galaxy distribution (Cohen et al 2014(Cohen et al , 2015Okabe et al 2019), and the dynamical state detected from Sunyaev-Zeldovich effect or X-ray emission (Rossetti et al 2016). Although the fraction of unrelaxed or interacting clusters is found to be ∼ 10% in Okabe et al (2019), some works find 40%, significantly more than what we found here.…”

Section: Cluster Identificationmentioning

confidence: 99%

Star Formation Enhancement in Barred Disk Galaxies in Interacting Galaxy Clusters

Yoon

2020

ApJ

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A recent study shows that bars can be induced via interaction of galaxy clusters, but it has been unclear if the bar formation by the interaction between clusters is related to the enhancement of star formation. We study galaxies in 105 galaxy clusters at 0.015 < z < 0.060 detected from Sloan Digital Sky Survey data, in order to examine whether the fraction of star-forming galaxies (f sf ) in 16 interacting clusters is enhanced compared with that of the other non-interacting clusters and to investigate the possible connection between the f sf enhancement and the bar formation in interacting clusters. We find that f sf is moderately higher (∼ 20%) in interacting clusters than in non-interacting clusters and that the enhancement of star formation in interacting clusters occurs only in moderatemass disk-dominated galaxies (10 10.0 ≤ M star /M < 10 10.4 and the bulge-to-total light ratio is ≤ 0.5). We also find that the enhancement of f sf in moderate-mass disk-dominated galaxies in interacting clusters is mostly due to the increase of the number of barred galaxies. Our result suggests that the cluster-cluster interaction can simultaneously induce bars and star formation in disk galaxies.

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Section: Cluster Identificationmentioning

confidence: 99%

Star Formation Enhancement in Barred Disk Galaxies in Interacting Galaxy Clusters

Yoon

2020

ApJ

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“…An important step for our strategy is the selection of the cluster center, which is a key ingredient of many studies on galaxy clusters (e.g., Cui et al 2016;Rossetti et al 2016, and references therein). For each halo we consider its members which have magnitudes brighter than H * (z s )+1.5 and we estimate its barycenter averaging the Cartesian coordinates of these members.…”

Section: Redefinition Of the Halo Catalogsmentioning

confidence: 99%

A new method to assign galaxy cluster membership using photometric redshifts

Castignani

Benoist

2016

A&A

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We introduce a new effective strategy to assign group and cluster membership probabilities Pmem to galaxies using photometric redshift information. Large dynamical ranges both in halo mass and cosmic time are considered. The method takes into account the magnitude distribution of both cluster and field galaxies as well as the radial distribution of galaxies in clusters using a non-parametric formalism, and relies on Bayesian inference to take photometric redshift uncertainties into account. We successfully test the method against 1, 208 galaxy clusters within redshifts z = 0.05−2.58 and masses 10 13.29−14.80 M drawn from wide field simulated galaxy mock catalogs mainly developed for the forthcoming Euclid mission. Median purity and completeness values of (55 +17 −15 )% and (95 +5 −10 )% are reached for galaxies brighter than 0.25L * within r200 of each simulated halo and for a statistical photometric redshift accuracy σ((zs −zp)/(1+zs)) = 0.03.The mean values p = 56% and c = 93% are consistent with the median and have negligible sub-percent uncertainties. Accurate photometric redshifts (σ((zs − zp)/(1 + zs)) 0.05) and robust estimates for the cluster redshift and cluster center coordinates are required. The dependence of the assignments on photometric redshift accuracy, galaxy magnitude and distance from the halo center, and halo properties such as mass, richness, and redshift are investigated. Variations in the mean values of both purity and completeness are globally limited to a few percent. The largest departures from the mean values are found for galaxies associated with distant z 1.5 halos, faint (∼ 0.25 L * ) galaxies, and those at the outskirts of the halo (at cluster-centric projected distances ∼ r200) for which the purity is decreased, ∆p 20% at most, with respect to the mean value. The proposed method is applied to derive accurate richness estimates. A statistical comparison between the true (Ntrue) vs. estimated richness (λ = Pmem) yields on average to unbiased results, Log(λ/Ntrue) = −0.0051 ± 0.15. The scatter around the mean of the logarithmic difference between λ and the halo mass is 0.10 dex for massive halos 10 14.5 M . Our estimates could therefore be useful to constrain the cluster mass function and to calibrate independent cluster mass estimates such as those obtained from weak lensing, Sunyaev-Zel'dovich, and X-ray studies. Our method can be applied to any list of galaxy clusters or groups in both present and forthcoming surveys such as SDSS, CFHTLS, Pan-STARRS, DES, LSST, and Euclid.

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“…The dynamically unrelaxed state of the cluster might also substantially affect the location of the brightest cluster galaxy (BCG; Lauer et al 2014), which we expect at the bottom of the gravitational potential well of the cluster (Lin & Mohr 2004): the BCG can be displaced from the peak of the projected galaxy density distribution (Beers & Geller 1983), from the peak of the X-ray emission (e.g., Rossetti et al 2016, and references therein), and from the global redshift of the cluster (Beers et al 1991;Zitrin et al 2012).…”

Section: Introductionmentioning

confidence: 98%

The Unrelaxed Dynamical Structure of the Galaxy Cluster Abell 85

Diaferio

Agulli

et al. 2016

ApJ

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For the first time, we explore the dynamics of the central region of a galaxy cluster within r 500 ∼600 h −1 kpc from its center by combining optical and X-ray spectroscopy. We use (1) the caustic technique, whichidentifies the cluster substructures and their galaxy members with optical spectroscopic data, and (2) the X-ray redshift fitting procedure, which estimates the redshift distribution of the intracluster medium (ICM). We use the spatial and redshift distributions of the galaxies and of the X-ray-emitting gas to associate the optical substructures to the X-ray regions. When we apply this approach to Abell 85 (A85), a complex dynamic structure of A85 emerges from our analysis: a galaxy group, with redshift z=0.0509±0.0021 is passing through the cluster center along the line of sight dragging part of the ICM present in the cluster core; two additional groups, at redshift z=0.0547±0.0022 and z=0.0570±0.0020, are going through the cluster in opposite directions, almost perpendicularly to the line of sight, and have substantially perturbed the dynamics of the ICM. An additional group in the outskirts of A85, at redshift z=0.0561±0.0023, is associated with a secondary peak of X-ray emission, at redshift = -+ z 0.0583 0.0047 0.0039 . Although our analysis and results on A85 need to be confirmed by high-resolution spectroscopy, they demonstrate how our new approach can be a powerful tool to constrain the formation history of galaxy clusters by unveiling their central and surrounding structures.

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Measuring the dynamical state ofPlanckSZ-selected clusters: X-ray peak – BCG offset

Cited by 112 publications

References 80 publications

Star Formation Enhancement in Barred Disk Galaxies in Interacting Galaxy Clusters

Star Formation Enhancement in Barred Disk Galaxies in Interacting Galaxy Clusters

A new method to assign galaxy cluster membership using photometric redshifts

The Unrelaxed Dynamical Structure of the Galaxy Cluster Abell 85

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