hybrid-lenstool: a self-consistent algorithm to model galaxy clusters with strong- and weak-lensing simultaneously

ABSTRACT We present a new galaxy cluster lens modelling approach, hybrid-lenstool, that is implemented in the publicly available modelling software lenstool. hybrid-lenstool combines a parametric approach to model the core of the cluster, and a non-parametric (free-form) approach to model the outskirts. hybrid-lenstool optimizes both strong- and weak-lensing constraints simultaneously (Joint-Fit), providing a self-consistent reconstruction of the cluster mass distribution on all scales. In order to demonstrate the capabilities of the new algorithm, we tested it on a simulated cluster. hybrid-lenstool yields more accurate reconstructed mass distributions than the former Sequential-Fit approach where the parametric and the non-parametric models are optimized successively. Indeed, we show with the simulated cluster that the mass density profile reconstructed with a Sequential-Fit deviates from the input by 2–3σ at all scales while the Joint-Fit gives a profile that is within 1–1.5σ of the true value. This gain in accuracy is consequential for recovering mass distributions exploiting cluster lensing and therefore for all applications of clusters as cosmological probes. Finally we found that the Joint-Fit approach yields shallower slope of the inner density profile than the Sequential-Fit approach, thus revealing possible biases in previous lensing studies.

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Testing the reliability of fast methods for weak lensing simulations: wl-moka on pinocchio

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1538 ◽

2020 ◽

Vol 496 (2) ◽

pp. 1307-1324

Author(s):

Carlo Giocoli ◽

Pierluigi Monaco ◽

Lauro Moscardini ◽

Tiago Castro ◽

Massimo Meneghetti ◽

...

Keyword(s):

Large Scale ◽

Initial Conditions ◽

Mass Density ◽

Cosmological Parameters ◽

Power Spectra ◽

Mass Function ◽

Parametric Models ◽

Weak Lensing ◽

Approximate Methods ◽

Percent Accuracy

ABSTRACT The generation of simulated convergence maps is of key importance in fully exploiting weak lensing by large-scale structure (LSS) from which cosmological parameters can be derived. In this paper, we present an extension of the pinocchio code that produces catalogues of dark matter haloes so that it is capable of simulating weak lensing by Modify LSS into Large Scale Structures (LSS). Like wl-moka, the method starts with a random realization of cosmological initial conditions, creates a halo catalogue and projects it on to the past light-cone, and paints in haloes assuming parametric models for the mass density distribution within them. Large-scale modes that are not accounted for by the haloes are constructed using linear theory. We discuss the systematic errors affecting the convergence power spectra when Lagrangian perturbation theory at increasing order is used to displace the haloes within pinocchio, and how they depend on the grid resolution. Our approximate method is shown to be very fast when compared to full ray-tracing simulations from an N-body run and able to recover the weak lensing signal, at different redshifts, with a few percent accuracy. It also allows for quickly constructing weak lensing covariance matrices, complementing pinocchio’s ability of generating the cluster mass function and galaxy clustering covariances and thus paving the way for calculating cross-covariances between the different probes. This work advances these approximate methods as tools for simulating and analysing survey data for cosmological purposes.

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DOPING: A NEW NON-PARAMETRIC DEPROJECTION SCHEME

International Journal of Modern Physics D ◽

10.1142/s0218271808011948 ◽

2008 ◽

Vol 17 (02) ◽

pp. 195-201 ◽

Cited By ~ 1

Author(s):

DALIA CHAKRABARTY ◽

LAURA FERRARESE

Keyword(s):

Surface Brightness ◽

Likelihood Function ◽

Three Dimensional ◽

Galaxy Cluster ◽

Brightness Distribution ◽

Free Form ◽

Intrinsic Geometry ◽

In Doping ◽

Intrinsic Shape ◽

Non Parametric

We present a new non-parametric deprojection algorithm, DOPING (Deprojection of Observed Photometry using an INverse Gambit), which is designed to extract the three-dimensional luminosity density distribution ρ, from the observed surface brightness profile of an astrophysical system such as a galaxy or a galaxy cluster, in a generalised geometry, while taking into account changes in the intrinsic shape of the system. The observable is the 2D surface brightness distribution of the system. While the deprojection schemes presented hitherto have always worked within the limits of an assumed intrinsic geometry, in DOPING, geometry and inclination can be provided as inputs. The ρ that is most likely to project to the observed brightness data is sought; the maximisation of the likelihood is performed with the Metropolis algorithm. Unless the likelihood function is maximised, ρ is tweaked in shape and amplitude, while maintaining positivity, but otherwise the luminosity distribution is allowed to be completely free-form. Tests and applications of the algorithm are discussed.

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The Pseudo-evolution of Galaxy-cluster Masses and Its Connection to Mass Density Profile

The Astrophysical Journal ◽

10.3847/1538-4357/ab3855 ◽

2019 ◽

Vol 883 (1) ◽

pp. 36

Author(s):

Masato Shirasaki

Keyword(s):

Density Profile ◽

Mass Density ◽

Galaxy Cluster ◽

Mass Density Profile

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Measuring the surface mass density ellipticity of redMaPPer galaxy clusters using weak-lensing

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3570 ◽

2020 ◽

Author(s):

Elizabeth J Gonzalez ◽

Martín Makler ◽

Diego García Lambas ◽

Martín Chalela ◽

Maria E S Pereira ◽

...

Keyword(s):

Galaxy Clusters ◽

Mass Distribution ◽

Mass Density ◽

Outer Region ◽

Galaxy Cluster ◽

Weak Lensing ◽

Membership Probability ◽

Surface Mass ◽

Surface Mass Density ◽

Inner Region

Abstract In this work we study the shape of the projected surface mass density distribution of galaxy clusters using weak-lensing stacking techniques. In particular, we constrain the average aligned component of the projected ellipticity, ε, for a sample of redMaPPer clusters (0.1 ≤ z < 0.4). We consider six different proxies for the cluster orientation and measure ε for three ranges of projected distances from the cluster centres. The mass distribution in the inner region (up to 700 kpc) is better traced by the cluster galaxies with a higher membership probability, while the outer region (from 700 kpc up to 5 Mpc) is better traced by the inclusion of less probable galaxy cluster members. The fitted ellipticity in the inner region is ε = 0.21 ± 0.04, in agreement with previous estimates. We also study the relation between ε and the cluster mean redshift and richness. By splitting the sample in two redshift ranges according to the median redshift, we obtain larger ε values for clusters at higher redshifts, consistent with the expectation from simulations. In addition, we obtain higher ellipticity values in the outer region of clusters at low redshifts. We discuss several systematic effects that might affect the measured lensing ellipticities and their relation to the derived ellipticity of the mass distribution.

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Strong lensing models of eight CLASH clusters from extensive spectroscopy: Accurate total mass reconstructions in the cores

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935454 ◽

2019 ◽

Vol 632 ◽

pp. A36 ◽

Cited By ~ 11

Author(s):

G. B. Caminha ◽

P. Rosati ◽

C. Grillo ◽

G. Rosani ◽

K. I. Caputi ◽

...

Keyword(s):

Total Mass ◽

High Efficiency ◽

Mass Density ◽

Mean Value ◽

Parametric Models ◽

Large Field ◽

Redshift Range ◽

Multiple Images ◽

Mass Distributions ◽

Strong Lensing

We carried out a detailed strong lensing analysis of a sub-sample of eight galaxy clusters of the Cluster Lensing And Supernova survey with Hubble (CLASH) in the redshift range of zcluster = [0.23 − 0.59] using extensive spectroscopic information, primarily from the Multi Unit Spectroscopic Explorer (MUSE) archival data and complemented with CLASH-VLT redshift measurements. The observed positions of the multiple images of strongly lensed background sources were used to constrain parametric models describing the cluster total mass distributions. Different models were tested in each cluster depending on the complexity of its mass distribution and on the number of detected multiple images. Four clusters show more than five spectroscopically confirmed multiple image families. In this sample, we did not make use of families that are only photometrically identified in order to reduce model degeneracies between the values of the total mass of a cluster source redshifts, in addition to systematics due to the potential misidentifications of multiple images. For the remaining four clusters, we used additional families without any spectroscopic confirmation to increase the number of strong lensing constraints up to the number of free parameters in our parametric models. We present spectroscopic confirmation of 27 multiply lensed sources, with no previous spectroscopic measurements, spanning over the redshift range of zsrc = [0.7 − 6.1]. Moreover, we confirm an average of 48 galaxy members in the core of each cluster thanks to the high efficiency and large field of view of MUSE. We used this information to derive precise strong lensing models, projected total mass distributions, and magnification maps. We show that, despite having different properties (i.e. number of mass components, total mass, redshift, etc.), the projected total mass and mass density profiles of all clusters have very similar shapes when rescaled by independent measurements of M200c and R200c. Specifically, we measured the mean value of the projected total mass of our cluster sample within 10 (20)% of R200c to be 0.13 (0.32) of M200c, with a remarkably small scatter of 5 (6)%. Furthermore, the large number of high-z sources and the precise magnification maps derived in this work for four clusters add up to the sample of high-quality gravitational telescopes to be used to study the faint and distant Universe.

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Galaxy cluster mass density profile derived using the submillimetre galaxies magnification bias

Astronomy and Astrophysics ◽

10.1051/0004-6361/202141905 ◽

2021 ◽

Author(s):

L. Fernandez ◽

M. M. Cueli ◽

J. Gonzalez-Nuevo ◽

L. Bonavera ◽

D. Crespo ◽

...

Keyword(s):

Density Profile ◽

Mass Density ◽

Galaxy Cluster ◽

Cluster Mass ◽

Mass Density Profile

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Dissecting the Strong-lensing Galaxy Cluster MS 0440.5+0204. I. The Mass Density Profile

The Astrophysical Journal ◽

10.3847/1538-4357/ab9635 ◽

2020 ◽

Vol 897 (1) ◽

pp. 4

Author(s):

Tomás Verdugo ◽

Eleazar R. Carrasco ◽

Gael Foëx ◽

Verónica Motta ◽

Percy L. Gomez ◽

...

Keyword(s):

Density Profile ◽

Mass Density ◽

Galaxy Cluster ◽

Strong Lensing ◽

Mass Density Profile

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Reconciling galaxy cluster shapes, measured by theorists versus observers

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3193 ◽

2020 ◽

Vol 500 (2) ◽

pp. 2627-2644

Author(s):

David Harvey ◽

Andrew Robertson ◽

Sut-Ieng Tam ◽

Mathilde Jauzac ◽

Richard Massey ◽

...

Keyword(s):

Hubble Space Telescope ◽

Orientation Angle ◽

Galaxy Cluster ◽

Galactic Nuclei ◽

Weak Lensing ◽

Strongly Correlated ◽

The Bahamas ◽

Cluster Galaxy ◽

Moments Of Inertia ◽

X Ray

ABSTRACT If properly calibrated, the shapes of galaxy clusters can be used to investigate many physical processes: from feedback and quenching of star formation, to the nature of dark matter. Theorists frequently measure shapes using moments of inertia of simulated particles’. We instead create mock (optical, X-ray, strong-, and weak-lensing) observations of the 22 most massive ($\sim 10^{14.7}\, \mathrm{ M}_\odot$) relaxed clusters in the BAHAMAS simulations. We find that observable measures of shape are rounder. Even when moments of inertia are projected into 2D and evaluated at matched radius, they overestimate ellipticity by 56 per cent (compared to observable strong lensing) and 430 per cent (compared to observable weak lensing). Therefore, we propose matchable quantities and test them using observations of eight relaxed clusters from the Hubble Space Telescope (HST) and Chandra X-Ray Observatory. We also release our HST data reduction and lensing analysis software to the community. In real clusters, the ellipticity and orientation angle at all radii are strongly correlated. In simulated clusters, the ellipticity of inner (<rvir/20) regions becomes decoupled: for example, with greater misalignment of the central cluster galaxy. This may indicate overly efficient implementation of feedback from active galactic nuclei. Future exploitation of cluster shapes as a function of radii will require better understanding of core baryonic processes. Exploitation of shapes on any scale will require calibration on simulations extended all the way to mock observations.

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Gravitational Lensing Studies of High Resolution Cluster Simulations

Symposium - International Astronomical Union ◽

10.1017/s0074180900216744 ◽

2005 ◽

Vol 201 ◽

pp. 476-477

Author(s):

Lindsay King ◽

Douglas Clowe ◽

Peter Schneider ◽

Volker Springel

Keyword(s):

High Resolution ◽

Gravitational Lensing ◽

Particle Mass ◽

Weak Lensing ◽

Reconstruction Technique ◽

Ongoing Work ◽

Non Parametric

In our ongoing work, we use high resolution cluster simulations to study gravitational lensing. These simulations have a softening length of 0.7 h-1 kpc and a particle mass of 4.68 × 107M⊙ (Springel 1999). Questions that can be addressed include the accuracy with which substructure on various scales can be recovered using the information from lensing. This is very important in determining the power of lensing in studying the evolution of cluster substructure as a function of redshift. We briefly consider how a weak lensing non-parametric reconstruction technique and the Map-statistic can be applied to the simulations.

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