We present the first detailed numerical modeling of the radio emission from MACS J0018.5+1626 as part of the Improved Constraints on Mergers with Sunyaev–Zel'dovich (SZ), Hydrodynamical Simulations, Optical, and X-ray (ICM-SHOX) project. By matching X-ray, thermal and kinetic SZ, optical, and lensing observables to simulations, the ICM-SHOX pipeline indicates that MACS J0018.5+1626 is undergoing a binary merger close to pericenter passage and is observed along a line of sight nearly aligned with the merger axis. We perform 3D magnetohydrodynamics simulations of binary cluster mergers coupled to tracer particles and a Fokker–Planck solver to model the radio emission. Exploring variations in the most likely initial conditions within the ICM-SHOX parameter space, such as the relative cluster velocity and impact parameter, we find that the resulting merger configuration consistently produces two merger-driven shocks with typical average Mach numbers M s ∼ 2 –3 with corresponding standard deviations of σ M ∼ 0.5 –1.5. Within this framework, we examine the cluster conditions under which standard diffusive shock acceleration can reproduce LOFAR observations. In particular, we discuss the possibility that the apparent radio halo seen by LOFAR arises from the superposition of two radio relics viewed nearly face on.
", "doi": "10.3847/1538-4357/ae8f3c", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2026-09-01", "series_number": "1", "volume": "1008", "issue": "1", "pages": "43" }, { "id": "authors:4tp8b-80m83", "collection": "authors", "collection_id": "4tp8b-80m83", "cite_using_url": "https://authors.library.caltech.edu/records/4tp8b-80m83", "type": "article", "title": "CHEX-MATE: Are we getting cluster thermodynamics right?", "author": [ { "family_name": "Seppi", "given_name": "R.", "orcid": "0009-0007-2187-4654" }, { "family_name": "Eckert", "given_name": "D.", "orcid": "0000-0001-7917-3892" }, { "family_name": "Rasia", "given_name": "E.", "orcid": "0000-0003-4175-002X" }, { "family_name": "Kay", "given_name": "S. T.", "orcid": "0000-0002-2277-9049" }, { "family_name": "Dolag", "given_name": "K.", "orcid": "0000-0003-1750-286X" }, { "family_name": "Biffi", "given_name": "V.", "orcid": "0000-0001-9260-3826" }, { "family_name": "Bahar", "given_name": "Y. E.", "orcid": "0000-0002-4893-7615" }, { "family_name": "Bourdin", "given_name": "H." }, { "family_name": "De Luca", "given_name": "F.", "orcid": "0000-0001-5573-726X" }, { "family_name": "De Petris", "given_name": "M.", "orcid": "0000-0001-7859-2139" }, { "family_name": "Ettori", "given_name": "S.", "orcid": "0000-0003-4117-8617" }, { "family_name": "Gaspari", "given_name": "M.", "orcid": "0000-0003-2754-9258" }, { "family_name": "Gastaldello", "given_name": "F.", "orcid": "0000-0002-9112-0184" }, { "family_name": "Ghirardini", "given_name": "V.", "orcid": "0000-0002-3736-8058" }, { "family_name": "Lovisari", "given_name": "L.", "orcid": "0000-0002-3754-2415" }, { "family_name": "Mazzotta", "given_name": "P.", "orcid": "0000-0002-5411-1748" }, { "family_name": "Pratt", "given_name": "G. W." }, { "family_name": "Pointecouteau", "given_name": "E.", "orcid": "0000-0001-8488-3645" }, { "family_name": "Rossetti", "given_name": "M.", "orcid": "0000-0002-9775-732X" }, { "family_name": "Sayers", "given_name": "J.", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "Sereno", "given_name": "M.", "orcid": "0000-0003-0302-0325" }, { "family_name": "Yepes", "given_name": "G.", "orcid": "0000-0001-5031-7936" } ], "abstract": "Context. Galaxy clusters offer powerful insights into the large-scale structure of the Universe and the physics of baryons in hot states. Their scientific exploitation, however, hinges on our ability to accurately measure key thermodynamic properties.
\nAims. In this work we assess the reliability of current analysis techniques in reconstructing these properties, with a particular focus on samples similar to those observed in the Cluster Heritage project with XMM-Newton (CHEX-MATE).
\nMethods. We developed a suite of dedicated end-to-end simulations of CHEX-MATE-like clusters selected from large-scale hydrodynamical simulations and processed through a newly developed realistic XMM-Newton simulator. We applied a full X-ray data analysis pipeline that includes imaging, spectral fitting, and profile reconstruction to the mock datasets.
\nResults. The gas density profiles can be robustly recovered across a wide radial range when using azimuthal mean surface brightness profiles. Our reconstruction techniques are able to reproduce the intrinsic density profile with the correct scatter, with deviations of at most 10% between 0.1 and 1 × R500c. The gas mass is reconstructed with better than 1% accuracy. The accurate measurement of temperature profiles is more challenging and possibly subject to biases, particularly in the presence of azimuthal variations and multi-temperature gas along the line of sight, which dominate over projection effects.
\nConclusions. Our results highlight the need for caution when interpreting cluster temperature measurements and underscore the value of tailored mock observations for understanding observational systematics. These findings also suggest that biases in X-ray temperature measurements alter the interpretation of the thermodynamical state of the intra-cluster medium, an outlook particularly relevant in light of recent low-velocity measurements from the XRISM mission.
", "doi": "10.1051/0004-6361/202558537", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-07", "volume": "711", "pages": "A213" }, { "id": "authors:8x1b7-8k377", "collection": "authors", "collection_id": "8x1b7-8k377", "cite_using_url": "https://authors.library.caltech.edu/records/8x1b7-8k377", "type": "article", "title": "CHEX-MATE: Cluster multi-probes in three dimensions (CLUMP-3D). II. Combined gas and dark matter analysis from X-ray, SZE, and WL", "author": [ { "family_name": "Gavidia", "given_name": "A.", "orcid": "0009-0000-3497-9470", "clpid": "Gavidia-Adriana" }, { "family_name": "Kim", "given_name": "J.", "orcid": "0000-0002-4274-9373" }, { "family_name": "Sayers", "given_name": "J.", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "Sereno", "given_name": "M.", "orcid": "0000-0003-0302-0325" }, { "family_name": "Chappuis", "given_name": "L.", "orcid": "0009-0005-9644-8858" }, { "family_name": "Eckert", "given_name": "D.", "orcid": "0000-0001-7917-3892" }, { "family_name": "Umetsu", "given_name": "K.", "orcid": "0000-0002-7196-4822" }, { "family_name": "Bourdin", "given_name": "H." }, { "family_name": "De Luca", "given_name": "F.", "orcid": "0000-0001-5573-726X" }, { "family_name": "Ettori", "given_name": "S.", "orcid": "0000-0003-4117-8617" }, { "family_name": "Gaspari", "given_name": "M.", "orcid": "0000-0003-2754-9258" }, { "family_name": "Gavazzi", "given_name": "R.", "orcid": "0000-0002-5540-6935" }, { "family_name": "Kay", "given_name": "S.", "orcid": "0000-0002-2277-9049" }, { "family_name": "Lovisari", "given_name": "L.", "orcid": "0000-0002-3754-2415" }, { "family_name": "Mazzotta", "given_name": "P.", "orcid": "0000-0002-5411-1748" }, { "family_name": "Pratt", "given_name": "G. W." }, { "family_name": "Rasia", "given_name": "E.", "orcid": "0000-0003-4175-002X" }, { "family_name": "Rossetti", "given_name": "M.", "orcid": "0000-0002-9775-732X" }, { "family_name": "Saxena", "given_name": "H.", "orcid": "0009-0006-8186-7440", "clpid": "Saxena-Harshda" } ], "abstract": "Under the standard model of hierarchical structure formation, the overall geometry of galaxy clusters is better described by a triaxial ellipse than by a sphere. As a result, the application of spherically symmetric models can result in significant biases, with masses derived from weak-lensing observations being particularly sensitive. These biases can be mitigated by fitting a triaxial model, but this requires deep multi-probe data along with a set of physically motivated models to describe them. We present a multi-probe triaxial analysis method based on the data available for galaxy clusters in the Cluster Heritage project with XMM-Newton – Mass Assembly and Thermodynamics at Endpoint of structure formation (CHEX-MATE), which includes X-ray data from XMM-Newton, Sunyaev-Zel’dovich effect maps from Planck and ACT, and weak-lensing data from Subaru. This work builds upon our previous development of a gas-only X-ray and Sunyaev-Zel’dovich triaxial fitting formalism in Paper I. After verifying our approach using mock observations of model clusters with known properties, we applied it to the CHEX-MATE galaxy cluster PSZ2 G313.33+61.13 (Abell 1689). We found that the cluster is elongated along the line of sight relative to the plane of sky by a factor of \u211bLP\u2004=\u20041.20\u2005±\u20050.04. As a result, the weak-lensing mass obtained from our triaxial fit, M200c = (13.88+1.73−1.43) × 1014 M\u2299, is significantly lower than the value of (17.77+2.00−1.75) × 1014 M\u2299 obtained from a spherically symmetric fit that otherwise employed the same method. Our triaxial fit finds a concentration of c200c = 8.66+2.08−1.70, consistent with the spherically symmetric value of 9.99+2.26−1.8, which suggests that the unexpectedly high concentration in Abell 1689 is not due to triaxiality and orientation. We also measured the nonthermal pressure fraction at radii between 0.18–1.37 Mpc and found a minimum of approximately 20% at intermediate radii, increasing to near 30% at the smallest and largest radii, and with a typical measurement precision of ±5%.
", "doi": "10.1051/0004-6361/202556431", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-06", "volume": "710", "pages": "A40" }, { "id": "authors:98xjd-rd160", "collection": "authors", "collection_id": "98xjd-rd160", "cite_using_url": "https://authors.library.caltech.edu/records/98xjd-rd160", "type": "article", "title": "Measuring the Temperature of Extremely Hot Shock-heated Gas in the Major Merger MACS J0717.5+3745 with Relativistic Corrections to the Sunyaev\u2013Zel'dovich Effect", "author": [ { "family_name": "Vaughan", "given_name": "Benjamin J.", "orcid": "0000-0002-9813-0270" }, { "family_name": "Sayers", "given_name": "Jack", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "Spencer", "given_name": "Locke", "orcid": "0000-0002-9941-2077" }, { "family_name": "Swidinksi", "given_name": "Nicholas" }, { "family_name": "Wills", "given_name": "Ryan", "orcid": "0009-0005-2265-2506" }, { "family_name": "Zemcov", "given_name": "Michael", "orcid": "0000-0001-8253-1451", "clpid": "Zemcov-Michael" }, { "family_name": "Arthur", "given_name": "Derek" }, { "family_name": "Butler", "given_name": "Victoria", "orcid": "0000-0002-0941-0407" }, { "family_name": "Feder", "given_name": "Richard M.", "orcid": "0000-0002-9330-8738" }, { "family_name": "Klyde", "given_name": "Daniel", "orcid": "0000-0002-5476-1898" }, { "family_name": "Lovisari", "given_name": "Lorenzo", "orcid": "0000-0002-3754-2415" }, { "family_name": "Mantz", "given_name": "Adam", "orcid": "0000-0002-8031-1217" }, { "family_name": "Silich", "given_name": "Emily M.", "orcid": "0000-0002-1616-5649", "clpid": "Silich-Emily-M" } ], "abstract": "The conversion of gravitational potential to kinetic energy results in an intracluster medium (ICM) gas with a characteristic temperature near 10 keV in the most massive galaxy clusters. X-ray observations, primarily from Chandra and XMM-Newton, have revealed a wealth of information about the thermodynamics of this gas. However, two regimes remain difficult to study with current instruments: superheated gas well above 10 keV generated by shocks from major mergers, and distant systems strongly impacted by cosmological dimming. Relativistic corrections to the Sunyaev–Zel’dovich effect (rSZe) produce a fractional spectral distortion in the cosmic microwave background at submillimeter and millimeter wavelengths that could offer a complementary probe of both high-temperature and high-redshift ICM gas. Here we describe multiband measurements of the rSZe, including observations from the Fourier Transform Spectrometer on the Herschel-SPIRE instrument, that constrain the ICM thermodynamics of the major merger MACS J0717.5+3745. Within the seven observed lines of sight, we find an average temperature of TrSZe = 15.1_(−3.3)^(+3.8) keV, which is consistent with the values obtained from X-ray measurements of the same regions, with TChandra = 18.0_(−1.1)^(+1.1) keV and TXMM = 13.9_(−0.9)^(+0.9) keV. This work demonstrates that the rSZe signal can be detected with moderate spectral resolution submillimeter data, while also establishing the utility of such measurements for probing superheated regions of the ICM.
", "doi": "10.3847/1538-4357/ae4483", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2026-03-20", "series_number": "1", "volume": "1000", "issue": "1", "pages": "123" }, { "id": "authors:kshma-vsd61", "collection": "authors", "collection_id": "kshma-vsd61", "cite_using_url": "https://authors.library.caltech.edu/records/kshma-vsd61", "type": "article", "title": "CHEX-MATE: New detections and properties of the radio diffuse emission in massive clusters with MeerKAT", "author": [ { "family_name": "Balboni", "given_name": "M.", "orcid": "0009-0001-3048-0020" }, { "family_name": "Gastaldello", "given_name": "F.", "orcid": "0000-0002-9112-0184" }, { "family_name": "Bonafede", "given_name": "A.", "orcid": "0000-0002-5068-4581" }, { "family_name": "Botteon", "given_name": "A.", "orcid": "0000-0002-9325-1567" }, { "family_name": "Bartalucci", "given_name": "I.", "orcid": "0000-0001-7703-9040" }, { "family_name": "Cassano", "given_name": "R.", "orcid": "0000-0003-4046-0637" }, { "family_name": "De Grandi", "given_name": "S.", "orcid": "0000-0002-6385-8501" }, { "family_name": "Ettori", "given_name": "S.", "orcid": "0000-0003-4117-8617" }, { "family_name": "Gaspari", "given_name": "M.", "orcid": "0000-0003-2754-9258" }, { "family_name": "Ghizzardi", "given_name": "S.", "orcid": "0000-0003-0879-7328" }, { "family_name": "Gitti", "given_name": "M.", "orcid": "0000-0002-0843-3009" }, { "family_name": "Johnston-Hollitt", "given_name": "M.", "orcid": "0000-0003-2756-8301" }, { "family_name": "Lovisari", "given_name": "L.", "orcid": "0000-0002-3754-2415" }, { "family_name": "Molendi", "given_name": "S.", "orcid": "0000-0002-2483-278X" }, { "family_name": "Pointecouteau", "given_name": "E.", "orcid": "0000-0001-8488-3645" }, { "family_name": "Pratt", "given_name": "G. W." }, { "family_name": "Riva", "given_name": "G.", "orcid": "0000-0001-6728-1714" }, { "family_name": "Rossetti", "given_name": "M.", "orcid": "0000-0002-9775-732X" }, { "family_name": "Sayers", "given_name": "J.", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "Sereno", "given_name": "M.", "orcid": "0000-0003-0302-0325" }, { "family_name": "van Weeren", "given_name": "R. J.", "orcid": "0000-0002-0587-1660" } ], "abstract": "Modern radio telescopes are revolutionising our understanding of non-thermal phenomena in galaxy clusters, collecting large samples of extended sources with unprecedented sensitivity and angular resolution. In this work, we present novel MeerKAT observations for a sample of 21 galaxy clusters that are part of the CHEX-MATE project. These systems were selected based on their high mass and displaying signs of dynamical activity. Thanks to the high-quality data at hand, we were able to detect extended radio emission in every target considered. We report two new halos, one new relic, and two new candidate relics. We also confirm a previous candidate halo and two candidate relics. After investigating the scaling relations with the cluster properties, we confirmed the presence of a radio halo power-mass correlation and relate it to a higher radio halo emissivity in more massive clusters. For radio relics, we highlight the MeerKAT capabilities to significantly extend the depth of radio observations to a new, unexplored field of low-radio power sources (\u22721023 W Hz−1 at 1.28 GHz). Thanks to such high-sensitivity data, we have found that the radio relic power can be characterised by a wide range of values for a given cluster mass and relic size. Ultimately, we discuss how current radio observations, in combination with large radio surveys, are increasingly capable of testing numerical simulation predictions and coming close to performing direct comparisons with their data, enabling new insights on the evolution of radio relics.
", "doi": "10.1051/0004-6361/202556148", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-03", "volume": "707", "pages": "A143" }, { "id": "authors:m9mn1-1z696", "collection": "authors", "collection_id": "m9mn1-1z696", "cite_using_url": "https://authors.library.caltech.edu/records/m9mn1-1z696", "type": "article", "title": "CHEX-MATE: Relationship between X-ray and millimetre inferences of galaxy cluster temperature profiles", "author": [ { "family_name": "De Luca", "given_name": "F.", "orcid": "0000-0001-5573-726X" }, { "family_name": "Bourdin", "given_name": "H." }, { "family_name": "Mazzotta", "given_name": "P.", "orcid": "0000-0002-5411-1748" }, { "family_name": "Luzzi", "given_name": "G.", "orcid": "0000-0001-5089-3730" }, { "family_name": "Campitiello", "given_name": "M. G.", "orcid": "0000-0001-5581-3349" }, { "family_name": "De Petris", "given_name": "M.", "orcid": "0000-0001-7859-2139" }, { "family_name": "Eckert", "given_name": "D.", "orcid": "0000-0001-7917-3892" }, { "family_name": "Ettori", "given_name": "S.", "orcid": "0000-0003-4117-8617" }, { "family_name": "Ferragamo", "given_name": "A.", "orcid": "0000-0002-7617-7932" }, { "family_name": "Forman", "given_name": "W." }, { "family_name": "Gaspari", "given_name": "M.", "orcid": "0000-0003-2754-9258" }, { "family_name": "Gastaldello", "given_name": "F.", "orcid": "0000-0002-9112-0184" }, { "family_name": "Ghizzardi", "given_name": "S.", "orcid": "0000-0003-0879-7328" }, { "family_name": "Gitti", "given_name": "M.", "orcid": "0000-0002-0843-3009" }, { "family_name": "Kay", "given_name": "S. T.", "orcid": "0000-0002-2277-9049" }, { "family_name": "Kim", "given_name": "J.", "orcid": "0000-0002-4274-9373" }, { "family_name": "Lovisari", "given_name": "L.", "orcid": "0000-0002-3754-2415" }, { "family_name": "Mac\u00edas-P\u00e9rez", "given_name": "J. F.", "orcid": "0000-0002-5385-2763" }, { "family_name": "Maughan", "given_name": "B. J.", "orcid": "0000-0003-0791-9098" }, { "family_name": "Mu\u00f1oz-Echeverr\u00eda", "given_name": "M.", "orcid": "0000-0002-5375-9083" }, { "family_name": "Oppizzi", "given_name": "F." }, { "family_name": "Pointecouteau", "given_name": "E." }, { "family_name": "Pratt", "given_name": "G. W." }, { "family_name": "Rasia", "given_name": "E.", "orcid": "0000-0003-4175-002X" }, { "family_name": "Rossetti", "given_name": "M.", "orcid": "0000-0002-9775-732X" }, { "family_name": "Saxena", "given_name": "H.", "orcid": "0009-0006-8186-7440", "clpid": "Saxena-Harshda" }, { "family_name": "Sayers", "given_name": "J.", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "Sereno", "given_name": "M.", "orcid": "0000-0003-0302-0325" } ], "abstract": "Thermodynamic profiles from X-ray and millimetre observations of galaxy clusters are often compared under the simplifying assumptions of a smooth, spherically symmetric intracluster medium. These approximations lead to expected discrepancies in the inferred profiles, which can provide insights into the cluster structure or cosmology. Motivated by this, we present a joint XMM-Newton and Planck analysis of 116 CHEX-MATE clusters to measure ηT\u2004=\u2004TX/TSZ,\u2006X, the ratio between spectroscopic X-ray temperatures and a temperature proxy derived from Sunyaev-Zel’dovich (SZ) pressures and X-ray densities. We considered relativistic corrections to the thermal SZ signal and implemented X-ray absorption by Galactic molecular hydrogen. The ηT distribution has a mean of 1.01\u2005±\u20050.03, with average changes of 8.1% and 2.7% when relativistic corrections and molecular hydrogen absorption are not included, respectively. The ηT distribution is positively skewed, with the scatter mostly affected by cluster morphology: relaxed clusters are closer to unity and less scattered than mixed and disturbed systems. We find little or no correlation with redshift, mass, or temperature.
", "doi": "10.1051/0004-6361/202557787", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-03", "volume": "707", "pages": "A32" }, { "id": "authors:g2t6x-ha559", "collection": "authors", "collection_id": "g2t6x-ha559", "cite_using_url": "https://authors.library.caltech.edu/records/g2t6x-ha559", "type": "article", "title": "CHEX-MATE: Towards a consistent universal pressure profile and cluster mass reconstruction", "author": [ { "family_name": "Mu\u00f1oz-Echeverr\u00eda", "given_name": "M.", "orcid": "0000-0002-5375-9083" }, { "family_name": "Pointecouteau", "given_name": "E.", "orcid": "0000-0001-8488-3645" }, { "family_name": "Pratt", "given_name": "G. W." }, { "family_name": "Mac\u00edas-P\u00e9rez", "given_name": "J.-F.", "orcid": "0000-0002-5385-2763" }, { "family_name": "Douspis", "given_name": "M.", "orcid": "0000-0003-4203-3954" }, { "family_name": "Salvati", "given_name": "L." }, { "family_name": "Bartalucci", "given_name": "I.", "orcid": "0000-0001-7703-9040" }, { "family_name": "Bourdin", "given_name": "H." }, { "family_name": "Clerc", "given_name": "N.", "orcid": "0000-0002-0296-1011" }, { "family_name": "De Luca", "given_name": "F.", "orcid": "0000-0001-5573-726X" }, { "family_name": "De Petris", "given_name": "M.", "orcid": "0000-0001-7859-2139" }, { "family_name": "Donahue", "given_name": "M." }, { "family_name": "Dupourqu\u00e9", "given_name": "S.", "orcid": "0000-0003-2715-8986" }, { "family_name": "Eckert", "given_name": "D.", "orcid": "0000-0001-7917-3892" }, { "family_name": "Ettori", "given_name": "S.", "orcid": "0000-0003-4117-8617" }, { "family_name": "Gaspari", "given_name": "M.", "orcid": "0000-0003-2754-9258" }, { "family_name": "Gastaldello", "given_name": "F.", "orcid": "0000-0002-9112-0184" }, { "family_name": "Gitti", "given_name": "M." }, { "family_name": "Gorce", "given_name": "A.", "orcid": "0000-0002-1712-737X" }, { "family_name": "Ili\u0107", "given_name": "S.", "orcid": "0000-0003-4285-9086" }, { "family_name": "Kay", "given_name": "S. T.", "orcid": "0000-0002-2277-9049" }, { "family_name": "Kim", "given_name": "J.", "orcid": "0000-0002-4274-9373" }, { "family_name": "Lovisari", "given_name": "L.", "orcid": "0000-0002-3754-2415" }, { "family_name": "Maughan", "given_name": "B. J.", "orcid": "0000-0003-0791-9098" }, { "family_name": "Mazzotta", "given_name": "P.", "orcid": "0000-0002-5411-1748" }, { "family_name": "McBride", "given_name": "L." }, { "family_name": "Melin", "given_name": "J.-B." }, { "family_name": "Oppizzi", "given_name": "F." }, { "family_name": "Rasia", "given_name": "E." }, { "family_name": "Rossetti", "given_name": "M.", "orcid": "0000-0002-9775-732X" }, { "family_name": "Saxena", "given_name": "H.", "orcid": "0009-0006-8186-7440", "clpid": "Saxena-Harshda" }, { "family_name": "Sayers", "given_name": "J.", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "Sereno", "given_name": "M.", "orcid": "0000-0003-0302-0325" }, { "family_name": "Tristram", "given_name": "M.", "orcid": "0000-0001-7276-8324" } ], "abstract": "In a self-similar paradigm of structure formation, the thermal pressure of the hot intra-cluster gas follows a universal distribution, once the profile of each cluster is normalised based on the proper mass and redshift dependencies. The reconstruction of such a universal pressure profile requires an individual estimate of the mass of each cluster. In this context, we present a method to jointly fit, for the first time, the universal pressure profile and individual cluster M500 masses over a sample of galaxy clusters, properly accounting for correlations between the profile shape and amplitude, and masses that scale the individual profiles. We demonstrate the power of the method and show that a consistent exploitation of the universal pressure profile and cluster mass estimates when modelling the thermal pressure in clusters is necessary to avoid biases. In particular, the method, informed by a cluster mass scale, outputs individual cluster masses with the same accuracy and greater precision than input masses. Using data from the Cluster HEritage project with XMM-Newton: Mass Assembly and Thermodynamics at the Endpoint of structure formation (CHEX-MATE), we investigate a sample of ∼25 galaxy clusters spanning mass and redshift ranges of 2 \u2272 M500/1014 M\u2299 \u2272 14 and 0.07\u2004<\u2004z\u2004<\u20040.6.
", "doi": "10.1051/0004-6361/202556045", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2025-12", "volume": "704", "pages": "A302" }, { "id": "authors:900e8-f6h40", "collection": "authors", "collection_id": "900e8-f6h40", "cite_using_url": "https://authors.library.caltech.edu/records/900e8-f6h40", "type": "article", "title": "CHEX-MATE: The impact of triaxiality and orientation on Planck SZ cluster selection and weak lensing mass measurements", "author": [ { "family_name": "Saxena", "given_name": "H.", "orcid": "0009-0006-8186-7440", "clpid": "Saxena-Harshda" }, { "family_name": "Sayers", "given_name": "J.", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "Gavidia", "given_name": "A.", "orcid": "0009-0000-3497-9470", "clpid": "Gavidia-Adriana" }, { "family_name": "Melin", "given_name": "J. -B." }, { "family_name": "Lau", "given_name": "E. T.", "orcid": "0000-0001-8914-8885" }, { "family_name": "Kim", "given_name": "J.", "orcid": "0000-0002-4274-9373" }, { "family_name": "Chappuis", "given_name": "L.", "orcid": "0009-0005-9644-8858" }, { "family_name": "Eckert", "given_name": "D.", "orcid": "0000-0001-7917-3892" }, { "family_name": "Ettori", "given_name": "S.", "orcid": "0000-0003-4117-8617" }, { "family_name": "Gaspari", "given_name": "M.", "orcid": "0000-0003-2754-9258" }, { "family_name": "Gastaldello", "given_name": "F.", "orcid": "0000-0002-9112-0184" }, { "family_name": "Giocoli", "given_name": "C.", "orcid": "0000-0002-9590-7961" }, { "family_name": "Kay", "given_name": "S.", "orcid": "0000-0002-2277-9049" }, { "family_name": "Lovisari", "given_name": "L.", "orcid": "0000-0002-3754-2415" }, { "family_name": "Maughan", "given_name": "B.", "orcid": "0000-0003-0791-9098" }, { "family_name": "Oppizzi", "given_name": "F.", "orcid": "0000-0003-3904-8370" }, { "family_name": "De Petris", "given_name": "M.", "orcid": "0000-0001-7859-2139" }, { "family_name": "Pratt", "given_name": "G. W." }, { "family_name": "Pointecouteau", "given_name": "E.", "orcid": "0000-0001-8488-3645" }, { "family_name": "Rasia", "given_name": "E.", "orcid": "0000-0003-4175-002X" }, { "family_name": "Rossetti", "given_name": "M.", "orcid": "0000-0002-9775-732X" }, { "family_name": "Sereno", "given_name": "M.", "orcid": "0000-0003-0302-0325" } ], "abstract": "Context. Galaxy cluster abundance measurements are a valuable tool for constraining cosmological parameters, such as the mass density (Ωm) and the density fluctuation amplitude (σ8). Wide-area surveys detect clusters based on observables, such as the total integrated Sunyaev-Zel’dovich effect signal (YSZ) in the case of Planck. Quantifying the survey selection function is necessary for cosmological analyses, with completeness representing the probability of detecting a cluster as a function of its intrinsic properties, such as YSZ and an angular scale θ500.
\nAims. We determine the completeness of the Planck-selected CHEX-MATE cluster catalog using mock observations of clusters with triaxial shapes and random orientations, with physically-motivated distributions of axial ratios. From these mocks, we derive the distribution of shapes and orientations of the detected clusters, along with any associated bias in weak-lensing-derived mass (MWL) due to this orientation-dependent selection (denoted as 1\u2005−\u2005bχ).
\nMethods. Employing a Monte Carlo method, we injected triaxial cluster profiles into random positions within the Planck all-sky maps and subsequently determined the completeness as a function of both geometry and SZ brightness. This result was then used to generate 1000 mock CHEX-MATE cluster catalogs. We computed MWL for these mock CHEX-MATE clusters and for equal-sized samples of randomly selected clusters with similar mass and redshift distributions.
\nResults. Cluster orientation impacts completeness, with a higher probability of detecting clusters elongated along the line of sight (LOS). This leads to 1\u2005−\u2005bχ values of 0−4% for CHEX-MATE clusters relative to a random population. The largest increase in MWL is observed in the lowest-mass objects, which are most impacted by orientation-related selection bias.
\nConclusions. Clusters in Planck SZ-selected catalogs are preferentially elongated along the LOS and have an average bias in MWL relative to randomly selected cluster samples. This bias is relevant for upcoming SZ surveys such as CMB-S4, and should be considered for surveys utilizing other probes for cluster detection, such as Euclid.
", "doi": "10.1051/0004-6361/202555719", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy and Astrophysics", "publication_date": "2025-08", "volume": "700", "pages": "A128" }, { "id": "authors:gmwe0-zc148", "collection": "authors", "collection_id": "gmwe0-zc148", "cite_using_url": "https://authors.library.caltech.edu/records/gmwe0-zc148", "type": "article", "title": "CHEX-MATE: Multiprobe analysis of Abell 1689", "author": [ { "family_name": "Chappuis", "given_name": "L.", "orcid": "0009-0005-9644-8858" }, { "family_name": "Eckert", "given_name": "D.", "orcid": "0000-0001-7917-3892" }, { "family_name": "Sereno", "given_name": "M.", "orcid": "0000-0003-0302-0325" }, { "family_name": "Gavidia", "given_name": "A.", "orcid": "0009-0000-3497-9470", "clpid": "Gavidia-Adriana" }, { "family_name": "Sayers", "given_name": "J.", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "Kim", "given_name": "J.", "orcid": "0000-0002-4274-9373" }, { "family_name": "Rossetti", "given_name": "M.", "orcid": "0000-0002-9775-732X" }, { "family_name": "Umetsu", "given_name": "K.", "orcid": "0000-0002-7196-4822" }, { "family_name": "Saxena", "given_name": "H.", "orcid": "0009-0006-8186-7440", "clpid": "Saxena-Harshda" }, { "family_name": "Bartalucci", "given_name": "I.", "orcid": "0000-0001-7703-9040" }, { "family_name": "Gavazzi", "given_name": "R.", "orcid": "0000-0002-5540-6935" }, { "family_name": "Rowlands Doblas", "given_name": "A.", "orcid": "0009-0008-4089-2054" }, { "family_name": "Pointecouteau", "given_name": "E.", "orcid": "0000-0001-8488-3645" }, { "family_name": "Ettori", "given_name": "S.", "orcid": "0000-0003-4117-8617" }, { "family_name": "Pratt", "given_name": "G. W." }, { "family_name": "Bourdin", "given_name": "H." }, { "family_name": "Cassano", "given_name": "R." }, { "family_name": "De Luca", "given_name": "F.", "orcid": "0000-0001-5573-726X" }, { "family_name": "De Petris", "given_name": "M.", "orcid": "0000-0001-7859-2139" }, { "family_name": "Donahue", "given_name": "M." }, { "family_name": "Gaspari", "given_name": "M.", "orcid": "0000-0003-2754-9258" }, { "family_name": "Gastaldello", "given_name": "F.", "orcid": "0000-0002-9112-0184" }, { "family_name": "Ghirardini", "given_name": "V.", "orcid": "0000-0002-3736-8058" }, { "family_name": "Gitti", "given_name": "M.", "orcid": "0000-0002-0843-3009" }, { "family_name": "Maughan", "given_name": "B.", "orcid": "0000-0003-0791-9098" }, { "family_name": "Mazzotta", "given_name": "P.", "orcid": "0000-0002-5411-1748" }, { "family_name": "Oppizzi", "given_name": "F." }, { "family_name": "Rasia", "given_name": "E.", "orcid": "0000-0003-4175-002X" }, { "family_name": "Radovich", "given_name": "M.", "orcid": "0000-0002-3585-866X" } ], "abstract": "The nature of the elusive dark matter can be probed by comparing the predictions of the cold dark matter framework with the gravitational field of massive galaxy clusters. However, a robust test of dark matter can only be achieved if the systematic uncertainties in the reconstruction of the gravitational potential are minimized. Techniques based on the properties of intracluster gas rely on the assumption that the gas is in hydrostatic equilibrium within the potential well, whereas gravitational lensing is sensitive to projection effects. Here we attempt to minimize systematics in galaxy cluster mass reconstructions by jointly exploiting the weak gravitational lensing signal and the properties of the hot intracluster gas determined from X-ray and millimeter (Sunyaev-Zel’dovich) observations. We constructed a model to fit the multiprobe information within a common framework, accounting for non-thermal pressure support and elongation of the dark matter halo along the line of sight. We then applied our framework to the massive cluster Abell 1689, which features unparalleled multiwavelength data. In accordance with previous works, we find that the cluster is significantly elongated along the line of sight. Accounting for line-of-sight projections, we require a non-thermal pressure support of 30\u2005−\u200540% at r500 to match the gas and weak lensing observables. The joint model retrieves a concentration c200\u2004∼\u20047, which is lower and better agrees with the concentration-mass relation than the high concentration retrieved from weak lensing data alone under the assumption of spherical symmetry (c200\u2004∼\u200415). Applying our method to a larger sample will allow us to study the shape of dark matter mass profiles and the level of non-thermal pressure support in galaxy clusters at the same time.
", "doi": "10.1051/0004-6361/202554743", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy and Astrophysics", "publication_date": "2025-07", "volume": "699", "pages": "A141" }, { "id": "authors:aqy85-nh795", "collection": "authors", "collection_id": "aqy85-nh795", "cite_using_url": "https://authors.library.caltech.edu/records/aqy85-nh795", "type": "article", "title": "CHEX-MATE: Exploring the kinematical properties of Planck galaxy clusters", "author": [ { "family_name": "Pizzuti", "given_name": "Lorenzo", "orcid": "0000-0001-5654-7580" }, { "family_name": "Barrena", "given_name": "Rafael", "orcid": "0000-0003-4969-232X" }, { "family_name": "Sereno", "given_name": "Mauro", "orcid": "0000-0003-0302-0325" }, { "family_name": "Streblyanska", "given_name": "Alina", "orcid": "0000-0001-8876-9102" }, { "family_name": "Ferragamo", "given_name": "Antonio", "orcid": "0000-0002-7617-7932" }, { "family_name": "Maurogordato", "given_name": "Sophie", "orcid": "0000-0002-5477-8454" }, { "family_name": "Cappi", "given_name": "Alberto", "orcid": "0000-0002-9200-7167" }, { "family_name": "Ettori", "given_name": "Stefano", "orcid": "0000-0003-4117-8617" }, { "family_name": "Pratt", "given_name": "Gabriel W." }, { "family_name": "Castignani", "given_name": "Gianluca", "orcid": "0000-0001-6831-0687" }, { "family_name": "Donahue", "given_name": "Megan", "orcid": "0000-0002-2808-0853" }, { "family_name": "Eckert", "given_name": "Dominique", "orcid": "0000-0001-7917-3892" }, { "family_name": "Gastaldello", "given_name": "Fabio", "orcid": "0000-0002-9112-0184" }, { "family_name": "Gavazzi", "given_name": "Raphael", "orcid": "0000-0002-5540-6935" }, { "family_name": "Haines", "given_name": "Christopher P.", "orcid": "0000-0002-8814-8960" }, { "family_name": "Kay", "given_name": "Scott T.", "orcid": "0000-0002-2277-9049" }, { "family_name": "Lovisari", "given_name": "Lorenzo", "orcid": "0000-0002-3754-2415" }, { "family_name": "Maughan", "given_name": "Ben J.", "orcid": "0000-0003-0791-9098" }, { "family_name": "Pointecouteau", "given_name": "Etienne", "orcid": "0000-0001-8488-3645" }, { "family_name": "Rasia", "given_name": "Elena", "orcid": "0000-0003-4175-002X" }, { "family_name": "Radovich", "given_name": "Mario", "orcid": "0000-0002-3585-866X" }, { "family_name": "Sayers", "given_name": "Jack", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" } ], "abstract": "We analysed the kinematical properties of the CHEX-MATE galaxy cluster sample. Our study is based on the radial velocities retrieved from the SDSS DR18, DESI, and NED spectroscopic databases and new data obtained with the 10.4 m GTC and ESO-NTT telescopes. We derived cluster mass profiles for 75 clusters using the MG-MAMPOSST procedure, which recovers the gravitational potential and the anisotropy profiles from line-of-sight velocities and projected positions of galaxy members. The standard Navarro–Frenk–White (NFW) model and the Burkert model, with flatter cores than the NFW, both adequately fit the kinematic data, with only a marginal statistical preference for one model over the other. An estimation of the mass bias (1−B1) = M500SZ/M500M was performed via a comparison with Sunyaev-Zel’dovich–X-ray-calibrated mass estimates, resulting in a value of 0.54\u2005±\u20050.11 when four evidently disturbed clusters are removed from the sample. We assessed the dynamical state of the clusters by inferring the Anderson-Darling coefficient (A2) and the fraction of galaxies in substructures (fsub). Except for a few cases, we find relatively low values for A2, which suggests that CHEX-MATE clusters are not too far from relaxation. Moreover, no significant trends emerge between A2 and \u2006fsub, nor between the log-masses estimated by MG-MAMPOSST and those based on the Sunyaev–Zel’dovich effect calibrated through X-rays measurements. We studied the concentration–mass relation for the sample; despite the large scatter, we observe signs of an increasing trend for high-mass clusters, in agreement with recent theoretical expectations. Finally, our analysis of the radial anisotropy profiles of member galaxies – stacked in five bins of mass and redshift – reveals that orbits tend to be isotropic at the centre and more radial towards the edge, as found in previous studies. A slight trend of increasing radial orbits at r200 is observed in clusters with larger velocity dispersions.
", "doi": "10.1051/0004-6361/202555417", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy and Astrophysics", "publication_date": "2025-07", "volume": "699", "pages": "A88" }, { "id": "authors:dtv8c-ydb44", "collection": "authors", "collection_id": "dtv8c-ydb44", "cite_using_url": "https://authors.library.caltech.edu/records/dtv8c-ydb44", "type": "article", "title": "Flat Silicon Gradient Index Lens With Deep Reactive-Ion-Etched Three-Layer Antireflection Structure for Millimeter and Submillimeter Wavelengths", "author": [ { "family_name": "Defrance", "given_name": "Fabien", "orcid": "0000-0002-3746-5296", "clpid": "Defrance-Fabien" }, { "family_name": "Jung-Kubiak", "given_name": "Cecile", "orcid": "0000-0003-2745-6342", "clpid": "Jung-Kubiak-Cecile" }, { "family_name": "Gill", "given_name": "John", "clpid": "Gill-John" }, { "family_name": "Rahiminejad", "given_name": "Sofia", "orcid": "0000-0001-8094-7189", "clpid": "Rahiminejad-Sofia" }, { "family_name": "Macioce", "given_name": "Theodore", "orcid": "0000-0002-3156-6627", "clpid": "Macioce-Theodore" }, { "family_name": "Sayers", "given_name": "Jack", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "Chattopadhyay", "given_name": "Goutam", "orcid": "0000-0001-7942-5025", "clpid": "Chattopadhyay-Goutam" }, { "family_name": "Golwala", "given_name": "Sunil R.", "orcid": "0000-0002-1098-7174", "clpid": "Golwala-S-R" } ], "abstract": "In this article, we present the design, fabrication, and characterization of a 100 mm diameter, flat, gradient-index (GRIN) lens fabricated with high-resistivity silicon, combined with a three-layer antireflection (AR) structure optimized for 160–355 GHz. Multidepth, deep reactive-ion etching enables patterning of silicon wafers with subwavelength structures (posts or holes) to locally change the effective refractive index and, thus, create AR layers and a radial index gradient. The structures are nonresonant and, for sufficiently long wavelengths, achromatic. Hexagonal holes varying in size with distance from the optical axis create a parabolic index profile decreasing from 3.15 at the center of the lens to 1.87 at the edge. The AR structure consists of square holes and cross-shaped posts. We have fabricated a lens consisting of a stack of five 525 μm thick GRIN wafers and one AR wafer on each face. We have characterized the lens over the frequency range 220–330 GHz, obtaining behavior consistent with Gaussian optics down to −14 dB and transmittance of 99±3%.
", "doi": "10.1109/TTHZ.2025.3555418", "issn": "2156-342X", "publisher": "IEEE", "publication": "IEEE Transactions on Terahertz Science and Technology", "publication_date": "2025-07", "series_number": "4", "volume": "15", "issue": "4", "pages": "679-693" }, { "id": "authors:1ckqv-4n153", "collection": "authors", "collection_id": "1ckqv-4n153", "cite_using_url": "https://authors.library.caltech.edu/records/1ckqv-4n153", "type": "article", "title": "CHEX-MATE: The intracluster medium entropy distribution in the gravity-dominated regime", "author": [ { "family_name": "Riva", "given_name": "G.", "orcid": "0000-0001-6728-1714" }, { "family_name": "Pratt", "given_name": "G. W." }, { "family_name": "Rossetti", "given_name": "M.", "orcid": "0000-0002-9775-732X" }, { "family_name": "Bartalucci", "given_name": "I.", "orcid": "0000-0001-7703-9040" }, { "family_name": "Kay", "given_name": "S. T.", "orcid": "0000-0002-2277-9049" }, { "family_name": "Rasia", "given_name": "E.", "orcid": "0000-0003-4175-002X" }, { "family_name": "Gavazzi", "given_name": "R.", "orcid": "0000-0002-5540-6935" }, { "family_name": "Umetsu", "given_name": "K.", "orcid": "0000-0002-7196-4822" }, { "family_name": "Arnaud", "given_name": "M." }, { "family_name": "Balboni", "given_name": "M.", "orcid": "0009-0001-3048-0020" }, { "family_name": "Bonafede", "given_name": "A.", "orcid": "0000-0002-5068-4581" }, { "family_name": "Bourdin", "given_name": "H." }, { "family_name": "De Grandi", "given_name": "S.", "orcid": "0000-0002-6385-8501" }, { "family_name": "De Luca", "given_name": "F.", "orcid": "0000-0001-5573-726X" }, { "family_name": "Eckert", "given_name": "D.", "orcid": "0000-0001-7917-3892" }, { "family_name": "Ettori", "given_name": "S.", "orcid": "0000-0003-4117-8617" }, { "family_name": "Gaspari", "given_name": "M.", "orcid": "0000-0003-2754-9258" }, { "family_name": "Gastaldello", "given_name": "F.", "orcid": "0000-0002-9112-0184" }, { "family_name": "Ghirardini", "given_name": "V." }, { "family_name": "Ghizzardi", "given_name": "S.", "orcid": "0000-0003-0879-7328" }, { "family_name": "Gitti", "given_name": "M.", "orcid": "0000-0002-0843-3009" }, { "family_name": "Lovisari", "given_name": "L.", "orcid": "0000-0002-3754-2415" }, { "family_name": "Maughan", "given_name": "B. J.", "orcid": "0000-0003-0791-9098" }, { "family_name": "Mazzotta", "given_name": "P.", "orcid": "0000-0002-5411-1748" }, { "family_name": "Molendi", "given_name": "S." }, { "family_name": "Pointecouteau", "given_name": "E.", "orcid": "0000-0001-8488-3645" }, { "family_name": "Sayers", "given_name": "Jack", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "Sereno", "given_name": "M.", "orcid": "0000-0003-0302-0325" }, { "family_name": "Towler", "given_name": "I.", "orcid": "0000-0001-8667-2470" } ], "abstract": "We characterise the intracluster gas entropy profiles of 32 very high-mass (M500\u2004>\u20047.75\u2005×\u20051014 M\u2299) Planck SZ-detected galaxy clusters (HIGHMz), selected from the CHEX-MATE sample, allowing us to study the intracluster medium (ICM) entropy distribution in a regime where non-gravitational effects are expected to be minimised. Using XMM-Newton measurements, we determined the entropy profiles up to ∼R500 for all objects. We assessed the relative role of gas density and temperature measurements on the uncertainty in entropy reconstruction, showing that in the outer regions the largest contribution comes from the temperature. The scaled profiles exhibit a large dispersion in the central regions, but converge rapidly to the value expected from simple gravitational collapse beyond the core regions. We quantified the correlation between the ICM morphological parameters and scaled entropy as a function of radius, showing that centrally peaked objects have low central entropy, while morphologically disturbed objects have high central entropy. We compared the scaled HIGHMz entropy profiles to results from other observational samples, finding differences in normalisation, which appear linked to the average mass of the samples in question. Combining HIGHMz with other samples, we found that a weaker mass dependence than self-similar in the scaling (Am\u2004∼\u2004−0.25) allows us to minimise the dispersion in the radial range [0.3\u2005−\u20050.8]\u2006R500 for clusters spanning over a decade in mass. The deviation from self-similar predictions is radially dependent and is more pronounced at small and intermediate radii than at R500. We also investigated the distribution of central entropy K0, finding no evidence for bimodality in the data and outer slope α, which peaks at α\u2004∼\u20041.1 with tails at both low and high α that correlate with dynamical state. Using weak-lensing masses for half of the sample, we found an indication for a small suppression of the scatter (∼30%) beyond the core when using masses derived from YX in the rescaling. Finally, we compared our results to recent cosmological numerical simulations from THE THREE HUNDRED and MACSIS, finding good agreement with the observational data in this mass regime. These results provide a robust observational benchmark in the gravity-dominated regime, and will serve as a future reference for samples at lower masses, higher redshifts, and for ongoing work using cosmological numerical simulations.
", "doi": "10.1051/0004-6361/202451455", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy and Astrophysics", "publication_date": "2024-11", "volume": "691", "pages": "A340" }, { "id": "authors:7zhx0-mvp60", "collection": "authors", "collection_id": "7zhx0-mvp60", "cite_using_url": "https://authors.library.caltech.edu/records/7zhx0-mvp60", "type": "article", "title": "ICM-SHOX. I. Methodology Overview and Discovery of a Gas\u2013Dark Matter Velocity Decoupling in the MACS J0018.5+1626 Merger", "author": [ { "family_name": "Silich", "given_name": "Emily M.", "orcid": "0000-0002-1616-5649", "clpid": "Silich-Emily-M" }, { "family_name": "Bellomi", "given_name": "Elena", "orcid": "0000-0001-6411-3686", "clpid": "Bellomi-Elena" }, { "family_name": "Sayers", "given_name": "Jack", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-J" }, { "family_name": "ZuHone", "given_name": "John", "orcid": "0000-0003-3175-2347", "clpid": "ZuHone-John" }, { "family_name": "Chadayammuri", "given_name": "Urmila", "orcid": "0000-0003-2521-506X", "clpid": "Chadayammuri-Urmila" }, { "family_name": "Golwala", "given_name": "Sunil", "orcid": "0000-0002-1098-7174", "clpid": "Golwala-S-R" }, { "family_name": "Hughes", "given_name": "David", "clpid": "Hughes-David" }, { "family_name": "Monta\u00f1a", "given_name": "Alfredo", "orcid": "0000-0003-4229-381X", "clpid": "Monta\u00f1a-Alfredo" }, { "family_name": "Mroczkowski", "given_name": "Tony", "orcid": "0000-0003-3816-5372", "clpid": "Mroczkowski-Tony" }, { "family_name": "Nagai", "given_name": "Daisuke", "orcid": "0000-0002-6766-5942", "clpid": "Nagai-Daisuke" }, { "family_name": "S\u00e1nchez-Arg\u00fcelles", "given_name": "David", "orcid": "0000-0002-7344-9920", "clpid": "S\u00e1nchez-Arg\u00fcelles-David" }, { "family_name": "Stanford", "given_name": "S. A.", "orcid": "0000-0003-0122-0841", "clpid": "Stanford-Spencer-A" }, { "family_name": "Wilson", "given_name": "Grant", "orcid": "0000-0003-2705-9152", "clpid": "Wilson-Grant" }, { "family_name": "Zemcov", "given_name": "Michael", "orcid": "0000-0001-8253-1451", "clpid": "Zemcov-Michael" }, { "family_name": "Zitrin", "given_name": "Adi", "orcid": "0000-0002-0350-4488", "clpid": "Zitrin-Adi" } ], "abstract": "Galaxy cluster mergers are rich sources of information to test cluster astrophysics and cosmology. However, cluster mergers produce complex projected signals that are difficult to interpret physically from individual observational probes. Multi-probe constraints on the gas and dark matter (DM) cluster components are necessary to infer merger parameters that are otherwise degenerate. We present Improved Constraints on Mergers with SZ, Hydrodynamical simulations, Optical, and X-ray (ICM-SHOX), a systematic framework to jointly infer multiple merger parameters quantitatively via a pipeline that directly compares a novel combination of multi-probe observables to mock observables derived from hydrodynamical simulations. We report a first application of the ICM-SHOX pipeline to MACS J0018.5+1626, wherein we systematically examine simulated snapshots characterized by a wide range of initial parameters to constrain the MACS J0018.5+1626 merger geometry. We constrain the epoch of MACS J0018.5+1626 to the range 0–60 Myr post-pericenter passage, and the viewing angle is inclined ≈27°–40° from the merger axis. We obtain constraints for the impact parameter (\u2272250 kpc), mass ratio (≈1.5–3.0), and initial relative velocity when the clusters are separated by 3 Mpc (≈1700–3000 km s−1). The primary and secondary clusters initially (at 3 Mpc) have gas distributions that are moderately and strongly disturbed, respectively. We discover a velocity space decoupling of the DM and gas distributions in MACS J0018.5+1626, traced by cluster-member galaxy velocities and the kinematic Sunyaev–Zel'dovich effect, respectively. Our simulations indicate this decoupling is dependent on the different collisional properties of the two distributions for particular merger epochs, geometries, and viewing angles.
\nContext. Galaxy clusters grow through the accretion of mass over cosmic time. Their observed properties are then shaped by how baryons distribute and energy is diffused. Thus, a better understanding of spatially resolved, projected thermodynamic properties of the intra-cluster medium (ICM) may provide a more consistent picture of how mass and energy act locally in shaping the X-ray observed quantities of these massive virialized or still collapsing structures.
\nAims. We study the perturbations in the temperature (and density) distribution to evaluate and characterize the level of inhomogeneities and the related dynamical state of the ICM.
\nMethods. We obtain and analyze the temperature and density distribution for 28 clusters (2.4\u2005×\u20051014\u2006M\u2299\u2004<\u2004M500\u2004<\u20041.2\u2005×\u20051015\u2006M\u2299; 0.07\u2004<\u2004z\u2004<\u20040.45) selected from the CHEX-MATE sample. We use these spatially resolved two-dimensional distributions to measure the global and radial scatter and identify the regions that deviate the most from the average distribution. During this process, we introduce three dynamical state estimators and produce “clean” temperature profiles after removing the most deviant regions.
\nResults. We find that the temperature distribution of most of the clusters is skewed towards high temperatures and is well described by a log-normal function. There is no indication that the number of regions deviating more than 1σ from the azimuthal value is correlated with the dynamical state inferred from morphological estimators. The removal of these regions leads to local temperature variations up to 10–20% and an average increase of ∼5% in the overall cluster temperatures. The measured relative intrinsic scatter within R500, σT,\u2006int/T, has values of 0.17−0.05+0.08, and is almost independent of the cluster mass and dynamical state. Comparing the scatter of temperature and density profiles to hydrodynamic simulations, we constrain the average Mach number regime of the sample to \u1e403D\u2005=\u20050.36−0.09+0.16. We infer the ratio between the energy in turbulence and the thermal energy, and translate this ratio in terms of a predicted hydrostatic mass bias b, estimating an average value of b\u2004∼\u20040.11 (covering a range between 0 and 0.37) within R500.
\nConclusions. This study provides detailed temperature fluctuation measurements for 28 CHEX-MATE clusters which can be used to study turbulence, derive the mass bias, and make predictions on the scaling relation properties.
", "doi": "10.1051/0004-6361/202346651", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2024-02", "volume": "682", "pages": "A45" } ]