Brightest cluster galaxies trace weak lensing mass bias and halo triaxiality in the three hundred project

Journal Article · Mon Apr 11 00:00:00 EDT 2022 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/stac997· OSTI ID:1975819

Herbonnet, Ricardo ^[1]; Crawford, Adrian ^[2]; Avestruz, Camille ^[3]; Rasia, Elena ^[4]; Giocoli, Carlo ^[5]; Meneghetti, Massimo ^[6]; von der Linden, Anja ^[7]; Cui, Weiguang ^[8]; Yepes, Gustavo ^[9]

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1. Stony Brook University, NY (United States); University of Michigan, Ann Arbor MI
2. University of Michigan, Ann Arbor, MI (United States); University of Virginia, Charlottesville, VA (United States)
3. University of Michigan, Ann Arbor, MI (United States)
4. National Institute for Astrophysics, Astronomical Observatory of Trieste (INAF-OATs) (Italy); Institute for Fundamental Physics of the Universe (IFPU), Trieste (Italy)
5. INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna (Italy); INFN – Sezione di Bologna (Italy)
6. INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna (Italy)
7. Stony Brook University, NY (United States)
8. University of Edinburgh (United Kingdom)
9. Universidad Autonoma de Madrid (Spain)

Galaxy clusters have a triaxial matter distribution. The weak-lensing signal, an important part in cosmological studies, measures the projected mass of all matter along the line of sight, and therefore changes with the orientation of the cluster. Studies suggest that the shape of the brightest cluster galaxy (BCG) in the centre of the cluster traces the underlying halo shape, enabling a method to account for projection effects. We use 324 simulated clusters at four redshifts between 0.1 and 0.6 from ‘The Three Hundred Project’ to quantify correlations between the orientation and shape of the BCG and the halo. We find that haloes and their embedded BCGs are aligned, with an average ~20 degree angle between their major axes. The bias in weak lensing cluster mass estimates correlates with the orientation of both the halo and the BCG. Mimicking observations, we compute the projected shape of the BCG, as a measure of the BCG orientation, and find that it is most strongly correlated to the weak-lensing mass for relaxed clusters. We also test a 2D cluster relaxation proxy measured from BCG mass isocontours. The concentration of stellar mass in the projected BCG core compared to the total stellar mass provides an alternative proxy for the BCG orientation. We find that the concentration does not correlate to the weak-lensing mass bias, but does correlate with the true halo mass. Here, these results indicate that the BCG shape and orientation for large samples of relaxed clusters can provide information to improve weak-lensing mass estimates.

• Research Organization: University of Michigan, Ann Arbor, MI (United States)
• Sponsoring Organization: China Manned Space Project; Ministerio de Ciencia, Innovación y Universidades/Fondo Europeo de Desarrollo Regional; USDOE Office of Science (SC)
• Grant/Contract Number: SC0018053; SC0019193
• OSTI ID: 1975819
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 2 Vol. 513; ISSN 0035-8711
• Publisher: Oxford University Press
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
galaxies: clusters: general
galaxies: haloes
galaxies: structure
gravitational lensing: weak
methods: numerical