Mass Estimation of Merging Galaxy Clusters

Takizawa, Motokazu; Nagino, Ryo; Matsushita, Kyoko

doi:10.1093/pasj/62.4.951

Cited by 44 publications

(46 citation statements)

References 66 publications

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“…These values may be closer to the real values than those estimated from the galaxy velocity dispersions, since e.g. Takizawa et al (2010) found that for merging clusters X-ray derived masses were usually more reliable than virial mass estimations. However, as explained for example by Nagai et al (2007), although the total ICM mass can be measured quite accurately (to better than ∼6%) in clusters, the hydrostatic estimate of the gravitationally bound mass is biased low by about 5−20% throughout the virial region, primarily due to additional pressure support provided by subsonic bulk motions in the ICM, ubiquitous in our simulations even in relaxed systems.…”

Section: Search For Gravitationally Bound Structuresmentioning

confidence: 56%

The clusters Abell 222 and Abell 223: a multi-wavelength view

Durret¹,

Laganá²,

Adami³

et al. 2010

A&A

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Context. The Abell 222 and 223 clusters are located at an average redshift z ∼ 0.21 and are separated by 0.26 deg. Signatures of mergers have been previously found in these clusters, both in X-rays and at optical wavelengths, thus motivating our study. In X-rays, they are relatively bright, and Abell 223 shows a double structure. A filament has also been detected between the clusters both at optical and X-ray wavelengths. Aims. We analyse the optical properties of these two clusters based on deep imaging in two bands, derive their galaxy luminosity functions (GLFs) and correlate these properties with X-ray characteristics derived from XMM-Newton data. Methods. The optical part of our study is based on archive images obtained with the CFHT Megaprime/Megacam camera, covering a total region of about 1 deg 2 , or 12.3 × 12.3 Mpc 2 at a redshift of 0.21. The X-ray analysis is based on archive XMM-Newton images.Results. The GLFs of Abell 222 in the g and r bands are well fit by a Schechter function; the GLF is steeper in r than in g . For Abell 223, the GLFs in both bands require a second component at bright magnitudes, added to a Schechter function; they are similar in both bands. The Serna & Gerbal method allows to separate well the two clusters. No obvious filamentary structures are detected at very large scales around the clusters, but a third cluster at the same redshift, Abell 209, is located at a projected distance of 19.2 Mpc. X-ray temperature and metallicity maps reveal that the temperature and metallicity of the X-ray gas are quite homogeneous in Abell 222, while they are very perturbed in Abell 223. Conclusions. The Abell 222/Abell 223 system is complex. The two clusters that form this structure present very different dynamical states. Abell 222 is a smaller, less massive and almost isothermal cluster. On the other hand, Abell 223 is more massive and has most probably been crossed by a subcluster on its way to the northeast. As a consequence, the temperature distribution is very inhomogeneous. Signs of recent interactions are also detected in the optical data where this cluster shows a "perturbed" GLF. In summary, the multiwavelength analyses of Abell 222 and Abell 223 are used to investigate the connection between the ICM and the cluster galaxy properties in an interacting system.

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Section: Search For Gravitationally Bound Structuresmentioning

confidence: 56%

The clusters Abell 222 and Abell 223: a multi-wavelength view

Durret¹,

Laganá²,

Adami³

et al. 2010

A&A

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“…As shown by e.g. Takizawa, Nagino & Matsushita (2010), even mass estimates for spherical X-ray systems are not always recovered well. Recent simulations by Nelson et al (2011) have investigated in detail the evolution of the non-thermal support bias as a function of radius and of the merger stage.…”

Section: (I) X-ray and Weak-lensing Massesmentioning

confidence: 98%

Detailed Sunyaev-Zel'dovich study with AMI of 19 LoCuSS galaxy clusters: masses and temperatures out to the virial radius

Rodríguez‐Gonzálvez

Shimwell

Davies³

et al. 2012

Monthly Notices of the Royal Astronomical Society

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We present detailed 16‐GHz interferometric observations using the Arcminute Microkelvin Imager (AMI) of 19 clusters with LX > 7 × 1037 W (h50 = 1) selected from the Local Cluster Substructure Survey (LoCuSS; 0.142 ≤ z ≤ 0.295) and of Abell 1758b, which is in the field of view of Abell 1758a. We detect and resolve Sunyaev–Zel'dovich (SZ) signals towards 17 clusters, with peak surface brightnesses between 5σ and 23σ. We use a fast, Bayesian cluster analysis to obtain cluster parameter estimates in the presence of radio point sources, receiver noise and primordial cosmic microwave background (CMB) anisotropy. We fit isothermal β‐models to our data and assume the clusters are virialized (with all the kinetic energy in gas internal energy). Our gas temperature, TAMI, is derived from AMI SZ data and not from X‐ray spectroscopy. Cluster parameters internal to r500 are derived under the assumption of hydrostatic equilibrium. We find the following. (i) Different generalized Navarro–Frenk–White (gNFW) parametrizations yield significantly different parameter degeneracies. (ii) For h70 = 1, we find the classical virial radius, r200, to be typically 1.6 ± 0.1 Mpc and the total mass MT(r200) typically to be 2.0–2.5× MT(r500). (iii) Where we have found MT(r500) and MT(r200) X‐ray and weak‐lensing values in the literature, there is good agreement between weak‐lensing and AMI estimates (with MT, AMI /MT, WL =1.2−0.3+0.2 and 1.0 ± 0.1 for r500 and r200, respectively). In comparison, most Suzaku/Chandra estimates are higher than for AMI (with MT, X/MT, AMI = 1.7 ± 0.2 within r500), particularly for the stronger mergers. (iv) Comparison of TAMI to TX sheds light on high X‐ray masses: even at large radius, TX can substantially exceed TAMI in mergers. The use of these higher TX values will give higher X‐ray masses. We stress that large‐radius TAMI and TX data are scarce and must be increased. (v) Despite the paucity of data, there is an indication of a relation between merger activity and SZ ellipticity. (vi) At small radius (but away from any cooling flow) the SZ signal (and TAMI) is less sensitive to intracluster medium disturbance than the X‐ray signal (and TX) and, even at high radius, mergers affect n2‐weighted X‐ray data more than n‐weighted SZ, implying that significant shocking or clumping or both occur in even the outer parts of mergers.

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“…We summarize these subcluster properties in Table 3. We use the biweight analysis to mitigate outliers from affecting the estimates of the velocity dispersion and redshift, but this does not protect against the well known fact that mergers tend to bias high the velocity dispersion based mass estimates (Takizawa, Nagino & Matsushita 2010;Saro et al 2013). We discuss this in more detail in §6.3.…”

Section: Mcmc-gmm Analysismentioning

confidence: 99%

MC²: DYNAMICAL ANALYSIS OF THE MERGING GALAXY CLUSTER MACS J1149.5+2223

Golovich

Dawson

Wittman

et al. 2016

ApJ

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We present an analysis of the merging cluster MACS J1149.5+2223 using archival imaging from Subaru/Suprime-Cam and multi-object spectroscopy from Keck/DEIMOS and Gemini/GMOS. We employ two and three dimensional substructure tests and determine that MACS J1149.5+2223 is composed of two separate mergers between three subclusters occurring ∼1 Gyr apart. The primary merger gives rise to elongated X-ray morphology and a radio relic in the southeast. The brightest cluster galaxy is a member of the northern subcluster of the primary merger. This subcluster is very massive (16.7The southern subcluster is also very massive (10.8 +3.37−3.54 ×10 14 M ), yet it lacks an associated X-ray surface brightness peak, and it has been unidentified previously despite the detailed study of this Frontier Field cluster. A secondary merger is occurring in the north along the line of sight with a third, less massive, subcluster (1.2014 M ). We perform a MonteCarlo dynamical analysis on the main merger and estimate a collision speed at pericenter of 2770km s −1 . We show the merger to be returning from apocenter with core passage occurring 1.16Gyr before the observed state. We identify the line of sight merging subcluster in a strong lensing analysis in the literature and show that it is likely bound to MACS J1149 despite having reached an extreme collision velocity of ∼4000 km s −1 .

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Mass Estimation of Merging Galaxy Clusters

Cited by 44 publications

References 66 publications

The clusters Abell 222 and Abell 223: a multi-wavelength view

The clusters Abell 222 and Abell 223: a multi-wavelength view

Detailed Sunyaev-Zel'dovich study with AMI of 19 LoCuSS galaxy clusters: masses and temperatures out to the virial radius

MC²: DYNAMICAL ANALYSIS OF THE MERGING GALAXY CLUSTER MACS J1149.5+2223

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Mass Estimation of Merging Galaxy Clusters

Cited by 44 publications

References 66 publications

The clusters Abell 222 and Abell 223: a multi-wavelength view

The clusters Abell 222 and Abell 223: a multi-wavelength view

Detailed Sunyaev-Zel'dovich study with AMI of 19 LoCuSS galaxy clusters: masses and temperatures out to the virial radius

MC2: DYNAMICAL ANALYSIS OF THE MERGING GALAXY CLUSTER MACS J1149.5+2223

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MC²: DYNAMICAL ANALYSIS OF THE MERGING GALAXY CLUSTER MACS J1149.5+2223