Free-form grale lens inversion of galaxy clusters with up to 1000 multiple images

Ghosh, Agniva; Williams, Liliya L. R.; Liesenborgs, Jori

doi:10.1093/mnras/staa962

Cited by 25 publications

(12 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is natural to ask how image constraints affect the construction of a reliable lens model, by which it is meant that the source plane positions, redshifts, and/or magnification factors are accurately recovered. In one study, Ghosh et al (2020) analyzed simulations of clusters and found that introducing additional image constraints generally increased the accuracy of the mass map. To quantify the systematics of image constraints, Johnson & Sharon (2016) analyzed the strong-lensing model of a single simulation of a single cluster hundreds of times, differing only the amounts and types of lensing evidence.…”

Section: Introductionmentioning

confidence: 99%

Possible Ongoing Merger Discovered by Photometry and Spectroscopy in the Field of the Galaxy Cluster PLCK G165.7+67.0

Pascale

Frye

Dai

et al. 2022

ApJ

View full text Add to dashboard Cite

We present a detailed study of the Planck-selected binary galaxy cluster PLCK G165.7+67.0 (G165; z = 0.348). A multiband photometric catalog is generated incorporating new imaging from the Large Binocular Telescope/Large Binocular Camera and Spitzer/IRAC to existing imaging. To cope with the different image characteristics, robust methods are applied in the extraction of the matched-aperture photometry. Photometric redshifts are estimated for 143 galaxies in the 4 arcmin2 field of overlap covered by these data. We confirm that strong-lensing effects yield 30 images of 11 background galaxies, of which we contribute new photometric redshift estimates for three image multiplicities. These constraints enable the construction of a revised lens model with a total mass of M 600 kpc = (2.36 ± 0.23) × 1014 M ⊙. In parallel, new spectroscopy using MMT/Binospec and archival data contributes thirteen galaxies that meet our velocity and transverse radius criteria for cluster membership. The two cluster components have a pair-wise velocity of ≲100 km s−1, favoring an orientation in the plane of the sky with a transverse velocity of 100–1700 km s−1. At the same time, the brightest cluster galaxy (BCG) is offset in velocity from the systemic mean value, suggesting dynamical disturbance. New LOFAR and Very Large Array data uncover head-tail radio galaxies in the BCG and a large red galaxy in the northeast component. From the orientation and alignment of the four radio trails, we infer that the two cluster components have already traversed each other, and are now exiting the cluster.

show abstract

Section: Introductionmentioning

confidence: 99%

Possible Ongoing Merger Discovered by Photometry and Spectroscopy in the Field of the Galaxy Cluster PLCK G165.7+67.0

Pascale

Frye

Dai

et al. 2022

ApJ

View full text Add to dashboard Cite

show abstract

“…(In the rest of the paper, we refer to H0LiCOW/SHARP/COSMOGRAIL/STRIDES collectively as TD-COSMO (Millon et al 2019)). Measurements of H 0 using time delay lenses also have been investigated by other collaborations (Paraficz & Hjorth 2010;Ghosh et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Time Delay Lens Modelling Challenge

Ding,

Treu,

Birrer

et al. 2020

Preprint

View full text Add to dashboard Cite

In recent years, breakthroughs in methods and data have enabled gravitational time delays to emerge as a very powerful tool to measure the Hubble constant H 0 . However, published stateof-the-art analyses require of order 1 year of expert investigator time and up to a million hours of computing time per system. Furthermore, as precision improves, it is crucial to identify and mitigate systematic uncertainties. With this time delay lens modelling challenge we aim to assess the level of precision and accuracy of the modelling techniques that are currently fast enough to handle of order 50 lenses, via the blind analysis of simulated datasets presented in paper I. The results in Rung 1 and Rung 2 show that methods that use only the point source positions tend to have lower precision (10 − 20%) while remaining accurate. In Rung 2, the methods that exploit the full information of the imaging and kinematic datasets can recover H 0 within the target accuracy (| A| < 2%) and precision (< 6% per system), even in the presence of poorly known point spread function and complex source morphology. A post-unblinding analysis of Rung 3 showed the numerical precision of the ray-traced cosmological simulations to be insufficient to test lens modelling methodology at the percent level, making the results difficult to interpret. A new challenge with improved simulations is needed to make further progress in the investigation of systematic uncertainties. For completeness, we present the Rung 3 results in an appendix, and use them to discuss various approaches to mitigating against similar subtle data generation effects in future blind challenges.

show abstract

“…With increasing number of multiple images observed by future telescopes, see e.g. Ghosh et al (2020), our observationbased approach can equip an increasing lensing region with lensmodel-independent properties. Thereby, we will be able to replace assumption-based lens properties by evidence-based properties in a growing lensing region.…”

Section: Brief Outline Of Parts I To Vimentioning

confidence: 99%

Generalised model-independent characterisation of strong gravitational lenses VII: impact of source properties and higher-order lens properties on the local lens reconstruction

Wagner

2022

Preprint

View full text Add to dashboard Cite

We investigate the impact of higher-order gravitational lens properties and properties of the background source on our approach to directly infer local lens properties from observables in multiple images of strong gravitationally lensed extended, static background sources developed in papers I to VI. As the degeneracy between local lens and source properties only allows to determine relative local lens properties between the multiple image positions, we cannot distinguish common scalings and distortions caused by lensing from intrinsic source characteristics. The consequences of this degeneracy for lens modelling and our approach and ways to break it are detailed here. We also set up quantitative measures around the critical curve to find clear limits on the validity of the approximation that source properties are negligible to infer local lens properties at critical points. The impact of the source on the local lens properties depends on the reduced shear at the image position and the amplitude and orientation of the source ellipticity, as we derive in this paper. Similarly, we investigate the role of third-order lens properties (flexion), in two galaxy-cluster simulations and in the Lenstoolreconstruction of the galaxy-cluster lens CL0024. In all three cases, we find that flexion is negligible in over 90% of all pixels of the lensing region for our current imprecision of local lens properties of about 10%. Decreasing the imprecision to 2%, higher-order terms start to play a role, especially in regions with shear components close to zero.

show abstract

Free-form grale lens inversion of galaxy clusters with up to 1000 multiple images

Cited by 25 publications

References 66 publications

Possible Ongoing Merger Discovered by Photometry and Spectroscopy in the Field of the Galaxy Cluster PLCK G165.7+67.0

Possible Ongoing Merger Discovered by Photometry and Spectroscopy in the Field of the Galaxy Cluster PLCK G165.7+67.0

Time Delay Lens Modelling Challenge

Generalised model-independent characterisation of strong gravitational lenses VII: impact of source properties and higher-order lens properties on the local lens reconstruction

Contact Info

Product

Resources

About