287 research outputs found
SkyPy
No full textA package for modelling the UniverseSkyPy Collaboration, Adam Amara, Lucia F. de la Bella, Simon Birrer, Sarah Bridle, Juan Pablo Cordero, Ginevra Favole, Ian Harrison, Ian Harry, William G. Hartley, Coleman Krawczyk, Andy Lundgren, Brian Nord, Laura Nuttall, Richard P. Rollins, Philipp Sudek, Sut-Ieng Tam, Nicolas Tessore, Keiichi Umetsu, … Laura Wolz. (2025). SkyPy (v0.5.5). Zenodo. https://doi.org/10.5281/zenodo.1484012
CLUMP-3D: three-dimensional lensing and multi-probe analysis of MACS J1206.2−0847, a remarkably regular cluster
Get PDFMulti-wavelength techniques can probe the distribution and the physical properties of baryons and dark matter in galaxy clusters from the inner regions out to the peripheries. We present a full three-dimensional analysis combining strong and weak lensing, X-ray surface brightness and temperature, and the Sunyaev–Zel'dovich effect. The method is applied to MACS J1206.2−0847, a remarkably regular, face-on, massive, M_(200) = (1.1 ± 0.2) × 10^(15) M⊙ h^(−1), cluster at z = 0.44. The measured concentration, c_(200) = 6.3 ± 1.2, and the triaxial shape are common to haloes formed in a Λ cold dark matter scenario. The gas has settled in and follows the shape of the gravitational potential, which is evidence of pressure equilibrium via the shape theorem. There is no evidence for significant non-thermal pressure and the equilibrium is hydrostatic
Inside a Beehive. The Multiple Merging Processes in the Galaxy Cluster Abell 2142
Get PDFTo investigate the dynamics of the galaxy cluster A2142, we compile an extended catalog of 2239 spectroscopic redshifts of sources, including 237 newly measured redshifts, within 30 arcmin from the cluster center. With the σ-plateau algorithm from the caustic method, we identify 868 members and a number of substructures in the galaxy distribution both in the outskirts, out to ∼3.5 Mpc from the cluster center, and in the central region. In the outskirts, one substructure overlaps a falling clump of gas previously identified in the X-ray band. These substructures suggest the presence of multiple minor mergers, which are responsible for the complex dynamics of A2142, and the absence of recent or ongoing major mergers. We show that the distribution of the galaxies in the cluster core and in several substructures is consistent with the mass distribution inferred from the weak-lensing signal. Moreover, we use spatially resolved X-ray spectroscopy to measure the redshift of different regions of the intracluster medium within ∼3 arcmin from the cluster center. We find a ring of gas near the two X-ray cold fronts identified in previous analyses and measure a velocity of this ring of 810 - 330 km s-1larger than the cluster mean velocity. Our analysis suggests the presence of another ring surrounding the core, whose velocity is 660 - 300 km s-1larger than the cluster velocity. These X-ray features are not associated with any optical substructures, and support the core-sloshing scenario suggested in previous work
THREE-DIMENSIONAL MULTI-PROBE ANALYSIS OF THE GALAXY CLUSTER A1689
Get PDFWe perform a three-dimensional multi-probe analysis of the rich galaxy cluster A1689, one of the most powerful known lenses on the sky, by combining improved weak-lensing data from new wide-field BVRCi'z' Subaru/ Suprime-Cam observations with strong-lensing, X-ray, and Sunyaev–Zel’dovich effect (SZE) data sets. We reconstruct the projected matter distribution from a joint weak-lensing analysis of two-dimensional shear and azimuthally integrated magnification constraints, the combination of which allows us to break the mass-sheet degeneracy. The resulting mass distribution reveals elongation with an axis ratio of ∼0.7 in projection, aligned well with the distributions of cluster galaxies and intracluster gas. When assuming a spherical halo, our full weaklensing analysis yields a projected halo concentration of c^2D_200c = 8.9 ± 1.1 (c^2D_vir ~ 11), consistent with and improved from earlier weak-lensing work. We find excellent consistency between independent weak and strong lensing in the region of overlap. In a parametric triaxial framework, we constrain the intrinsic structure and geometry of the matter and gas distributions, by combining weak/strong lensing and X-ray/SZE data with minimal geometric assumptions. We show that the data favor a triaxial geometry with minor–major axis ratio 0.39±0.15 and major axis closely aligned with the line of sight (22°±10°). We obtain a halo mass M_200c = (1.2 ± 0.2) × 10^15 Mʘ h^-1 and a halo concentration c_200c = 8.4 ± 1.3, which overlaps with the ≳1σ tail of the predicted distribution. The shape of the gas is rounder than the underlying matter but quite elongated with minor–major axis ratio 0.60 ± 0.14. The gas mass fraction within 0.9Mpc is 10 ^+3_-2 %, a typical value for high-mass clusters. The thermal gas pressure contributes to ∼60% of the equilibrium pressure, indicating a significant level of non-thermal pressure support. When compared to Planckʼs hydrostatic mass estimate, our lensing measurements yield a spherical mass ratio of M_Planck / M_GL = 0.70 ± 0.15 and 0.58 ± 0.10 with and without corrections for lensing projection effects, respectively.The work is partially supported by the Ministry of Science and Technology of Taiwan under
the grant MOST 103-2112-M-001-030-MY3. M. S. acknowledges financial contributions from contracts ASI/INAF I/023/ 12/0, by the PRIN MIUR 2010–2011 “The dark universe and the cosmic evolution of baryons: from current surveys to Euclid” and by the PRIN INAF 2012 “The universe in the box: multiscale simulations of cosmic structure.” M. N. acknowledges financial support from PRIN INAF 2014. J. M. D. acknowledges support of the consolider project CSD2010-00064 and AYA2012-39475-C02-01 funded by the Ministerio de Economia y Competitividad. N. O. is supported by a Grant-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (26800097). This work was partially supported by “World Premier International Research Center Initiative (WPI Initiative)” and the Funds for
the Development of Human Resources in Science and Technology under MEXT, Japan. This research was performed while T. M. held a National Research Council Research Associateship Award at the Naval Research Laboratory (NRL). We thank John Carlstrom, Megan Gralla, Marshall Joy, Dan Marrone, and the entire SZA and OVRO/BIMA teams for providing the SZA and OVRO/BIMA data used in this study. Support for the SZA observations presented in this work was provided by NSF through award AST-0838187 and PHY-0114422 at the University of Chicago. The OVRO and BIMA observations presented here were supported by National Science Foundation grants AST 99-81546 and 02-28963
Cluster Lensing Mass Inversion (CLUMI+): Combining Dynamics and Weak Lensing around Galaxy Clusters
No full textWe present clumi+ , a self-consistent, multiprobe methodology for reconstructing the mass distribution in and around galaxy clusters by combining gravitational lensing and dynamical observations. Building on the joint likelihood framework of K. Umetsu, clumi+ integrates weak-lensing shear and magnification data with projected escape velocity measurements in the cluster infall region, yielding tighter constraints on the gravitational potential without relying on equilibrium assumptions. The mass distribution is modeled using a flexible, piecewise-defined convergence profile that characterizes the azimuthally averaged surface mass density within the lensing field, transitioning to a projected power-law form at larger radii where phase-space constraints complement lensing. Additional strong-lensing constraints are incorporated via central aperture-mass measurements, enabling full-scale mass reconstruction from the cluster core to the outskirts. We validate clumi+ using synthetic weak-lensing and phase-space data for a massive cluster from the IllustrisTNG simulations, demonstrating unbiased recovery of projected and three-dimensional mass profiles and achieving 10%–30% improvement in precision at large radii. As a case study, we apply clumi+ to A2261, combining Subaru and Hubble Space Telescope weak+strong-lensing data with spectroscopic measurements from the Hectospec Cluster Survey. This analysis demonstrates the power of multiprobe, equilibrium-free modeling for robust cluster mass reconstruction
Model-Free Multi-Probe Lensing Reconstruction of Cluster Mass Profiles
No full text[[sponsorship]]天文及天文物理研究所[[note]]已出版;[SCI];有審查制度;具代表性[[note]]http://gateway.isiknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Drexel&SrcApp=hagerty_opac&KeyRecord=0004-637X&DestApp=JCR&RQ=IF_CAT_BOXPLO
A Magnified Young Galaxy from about 500 Million Years after the Big Bang
No full text[[sponsorship]]天文及天文物理研究所[[note]]已出版;[SCI];有審查制度;具代表性[[note]]http://gateway.isiknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Drexel&SrcApp=hagerty_opac&KeyRecord=0028-0836&DestApp=JCR&RQ=IF_CAT_BOXPLO
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