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Title: The Projected Dark and Baryonic Ellipsoidal Structure of 20 CLASH Galaxy Clusters

We reconstruct the two-dimensional (2D) matter distributions in 20 high-mass galaxy clusters selected from the CLASH survey by using the new approach of performing a joint weak gravitational lensing analysis of 2D shear and azimuthally averaged magnification measurements. This combination allows for a complete analysis of the field, effectively breaking the mass-sheet degeneracy. In a Bayesian framework, we simultaneously constrain the mass profile and morphology of each individual cluster, assuming an elliptical Navarro–Frenk–White halo characterized by the mass, concentration, projected axis ratio, and position angle (PA) of the projected major axis. We find that spherical mass estimates of the clusters from azimuthally averaged weak-lensing measurements in previous work are in excellent agreement with our results from a full 2D analysis. Combining all 20 clusters in our sample, we detect the elliptical shape of weak-lensing halos at the 5σ significance level within a scale of 2 $$\mathrm{Mpc}\,{h}^{-1}$$. The median projected axis ratio is 0.67 ± 0.07 at a virial mass of $${M}_{\mathrm{vir}}=(15.2\pm 2.8)\times {10}^{14}\,{M}_{\odot }$$, which is in agreement with theoretical predictions from recent numerical simulations of the standard collisionless cold dark matter model. We also study misalignment statistics of the brightest cluster galaxy, X-ray, thermal Sunyaev–Zel'dovich effect, and strong-lensing morphologies with respect to the weak-lensing signal. Among the three baryonic tracers studied here, we find that the X-ray morphology is best aligned with the weak-lensing mass distribution, with a median misalignment angle of $$| {\rm{\Delta }}\mathrm{PA}| =21^\circ \pm 7^\circ $$. We also conduct a stacked quadrupole shear analysis of the 20 clusters assuming that the X-ray major axis is aligned with that of the projected mass distribution. In conclusion, this yields a consistent axis ratio of 0.67 ± 0.10, suggesting again a tight alignment between the intracluster gas and dark matter.
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  1. Academia Sinica, Taipei (Taiwan). Inst. of Astronomy and Astrophysics
  2. Istituto Nazionale di Astrofisica (INAF), Bologna (Italy). Osservatorio di Astrofisica e Scienza dello Spazio di Bologna; Univ. di Bologna (Italy). Dipartimento di Fisica e Astronomia
  3. Durham Univ. (United Kingdom). Centre for Extragalactic Astronomy
  4. Yunnan Univ., Kunming (China). South-Western Inst. for Astronomy Research; Peking Univ., Beijing (China). School of Physics, Dept. of Astronomy
  5. Istituto Nazionale di Astrofisica (INAF), Bologna (Italy). Osservatorio di Astrofisica e Scienza dello Spazio di Bologna
  6. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., CA (United States). KIPAC, Physics Dept.
  7. Dept. of Astrophysical Sciences, Princeton, NJ (United States)
  8. Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy
  9. NAF-Osservatorio Astronomico di Bologna, Bologna (Italy)
  10. Univ. of Arizona, Tucson, AZ (United States)
  11. Space Telescope Science Inst., Baltimore, MD (United States)
  12. Univ. of Basque Country UPV/EHU, Bilbao (Spain). Dept. of Theoretical Physics; IKERBASQUE, Basque Foundation for Science, Bilbao (Spain)
  13. Ben-Gurion Univ. of the Negev, Be'er-Sheva (Israel). Physics Dept.
  14. Univ. Observatory Munich, Munich (Germany); INAF-Osservatorio Astronomico di Trieste, Trieste (Italy)
  15. Inst. de Astrofìsica de Andalucia (CSIC), Granada (Spain)
  16. INAF-Osservatorio Astronomico di Capodimonte, Napoli (Italy)
  17. Univ. of Oxford (United Kingdom)
  18. Univ. de Sao Paulo, Sao Paulo (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas
  19. INAF-Osservatorio Astronomico di Trieste, Trieste (Italy)
  20. Univ. di Ferrara, Ferrara (Italy)
  21. California Inst. of Technology (CalTech), Pasadena, CA (United States). Division of Physics, Math, and Astronomy
  22. Univ.-Sternwarte, Munchen (Germany); Max-Planck-Inst. fur extraterrestrische Physik, Garching (Germany)
Publication Date:
Grant/Contract Number:
AC02-76SF00515; PF5-160138; NAS8-03060; MOST 106-2119-M-001-031-MY3; MOST 103-2112-M-001-030-MY3; MOST 106-2628- M-001-003-MY3; ASI-INAF I/009/10/0; NARO15 ASIINAF I/037/12/0; ASI 2015-046-R.0; ASI-INAF n.2017-14-H.0.
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 860; Journal Issue: 2; Journal ID: ISSN 1538-4357
Institute of Physics (IOP)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE; National Aeronautic and Space Administration (NASA); Italian Ministry of Foreign Affairs and International Cooperation, Directorate General for Country Promotion
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; cosmology: observations; dark matter; galaxies: clusters: general; galaxies: clusters: intracluster medium; gravitational lensing: weak
OSTI Identifier: