All Outputs (17)

Lopsidedness in early-type galaxies: the role of the m = 1 multipole in isophote fitting and strong lens modelling (2025)
Journal Article
Amvrosiadis, A., Nightingale, J. W., He, Q., Robertson, A., Lange, S., Frenk, C. S., Cole, S., Massey, R., & Poci, A. (2025). Lopsidedness in early-type galaxies: the role of the m = 1 multipole in isophote fitting and strong lens modelling. Monthly Notices of the Royal Astronomical Society, 540(4), 3281-3288. https://doi.org/10.1093/mnras/staf857

The surface brightness distribution of massive early-type galaxies (ETGs) often deviates from a perfectly elliptical shape. To capture these deviations in their isophotes during an ellipse fitting analysis, Fourier modes of order are often used. In s... Read More about Lopsidedness in early-type galaxies: the role of the m = 1 multipole in isophote fitting and strong lens modelling.

Galaxy mass modelling from multiwavelength JWST strong lens analysis: dark matter substructure, angular mass complexity, or both? (2025)
Journal Article
Lange, S. C., Amvrosiadis, A., Nightingale, J. W., He, Q., Frenk, C. S., Robertson, A., Cole, S., Massey, R., Cao, X., Li, R., & Wang, K. (2025). Galaxy mass modelling from multiwavelength JWST strong lens analysis: dark matter substructure, angular mass complexity, or both?. Monthly Notices of the Royal Astronomical Society, 539(2), 704-726. https://doi.org/10.1093/mnras/staf491

We analyse two galaxy-scale strong gravitational lenses, SPT0418-47 and SPT2147-50, using JWST NIRCam imaging across multiple filters. To account for angular complexity in the lens mass distribution, we introduce multipole perturbations with orders m... Read More about Galaxy mass modelling from multiwavelength JWST strong lens analysis: dark matter substructure, angular mass complexity, or both?.

The onset of bar formation in a massive galaxy at z ∼ 3.8 (2025)
Journal Article
Amvrosiadis, A., Lange, S., Nightingale, J. W., He, Q., Frenk, C. S., Oman, K. A., Smail, I., Swinbank, A. M., Fragkoudi, F., Gadotti, D. A., Cole, S., Borsato, E., Robertson, A., Massey, R., Cao, X., & Li, R. (2025). The onset of bar formation in a massive galaxy at z ∼ 3.8. Monthly Notices of the Royal Astronomical Society, 537(2), 1163-1181. https://doi.org/10.1093/mnras/staf048

We examine the morphological and kinematical properties of SPT-2147, a strongly lensed, massive, dusty, star-forming galaxy at z = 3.762. Combining data from JWST, Hubble Space Telescope, and ALMA, we study the galaxy’s stellar emission, dust continu... Read More about The onset of bar formation in a massive galaxy at z ∼ 3.8.

Unveiling lens light complexity with a novel multi-Gaussian expansion approach for strong gravitational lensing (2024)
Journal Article
He, Q., Nightingale, J. W., Amvrosiadis, A., Robertson, A., Cole, S., Frenk, C. S., Massey, R., Li, R., Cao, X., Lange, S. C., & França, J. P. C. (2024). Unveiling lens light complexity with a novel multi-Gaussian expansion approach for strong gravitational lensing. Monthly Notices of the Royal Astronomical Society, 532(2), 2441-2462. https://doi.org/10.1093/mnras/stae1577

In a strong gravitational lensing system, the distorted light from a source is analysed to infer the properties of the lens. However, light emitted by the lens itself can contaminate the image of the source, introducing systematic errors in the analy... Read More about Unveiling lens light complexity with a novel multi-Gaussian expansion approach for strong gravitational lensing.

Strong gravitational lensing’s ‘external shear’ is not shear (2024)
Journal Article
Etherington, A., Nightingale, J., Massey, R., Tam, S.-I., Cao, X., Niemiec, A., He, Q., Robertson, A., Li, R., Amvrosiadis, A., Cole, S., Diego, J., Frenk, C., Frye, B., Harvey, D., Jauzac, M., Koekemoer, A., Lagattuta, D., Lange, S., Limousin, M., …Steinhardt, C. (2024). Strong gravitational lensing’s ‘external shear’ is not shear. Monthly Notices of the Royal Astronomical Society, 531(3), 3684-3697. https://doi.org/10.1093/mnras/stae1375

The distribution of mass in galaxy-scale strong gravitational lenses is often modelled as an elliptical power-law plus ‘external shear’, which notionally accounts for neighbouring galaxies and cosmic shear along our line of sight. A small amount of e... Read More about Strong gravitational lensing’s ‘external shear’ is not shear.

Scanning for dark matter subhaloes in Hubble Space Telescope imaging of 54 strong lenses (2023)
Journal Article
Nightingale, J. W., He, Q., Cao, X., Amvrosiadis, A., Etherington, A., Frenk, C. S., Hayes, R. G., Robertson, A., Cole, S., Lange, S., Li, R., & Massey, R. (2024). Scanning for dark matter subhaloes in Hubble Space Telescope imaging of 54 strong lenses. Monthly Notices of the Royal Astronomical Society, 527(4), 10480-10506. https://doi.org/10.1093/mnras/stad3694

The cold dark matter (DM) model predicts that every galaxy contains thousands of DM subhaloes; almost all other DM models include a physical process that smooths away the subhaloes. The subhaloes are invisible, but could be detected via strong gravit... Read More about Scanning for dark matter subhaloes in Hubble Space Telescope imaging of 54 strong lenses.

Abell 1201: detection of an ultramassive black hole in a strong gravitational lens (2023)
Journal Article
Nightingale, J., Smith, R. J., He, Q., O’Riordan, C. M., Kegerreis, J. A., Amvrosiadis, A., Edge, A. C., Etherington, A., Hayes, R. G., Kelly, A., Lucey, J. R., & Massey, R. J. (2023). Abell 1201: detection of an ultramassive black hole in a strong gravitational lens. Monthly Notices of the Royal Astronomical Society, 521(3), 3298-3322. https://doi.org/10.1093/mnras/stad587

Supermassive black holes (SMBHs) are a key catalyst of galaxy formation and evolution, leading to an observed correlation between SMBH mass MBH and host galaxy velocity dispersion σe. Outside the local Universe, measurements of MBH are usually only p... Read More about Abell 1201: detection of an ultramassive black hole in a strong gravitational lens.

Beyond the bulge–halo conspiracy? Density profiles of early-type galaxies from extended-source strong lensing (2023)
Journal Article
Etherington, A., Nightingale, J. W., Massey, R., Robertson, A., Cao, X., Amvrosiadis, A., Cole, S., Frenk, C. S., He, Q., Lagattuta, D. J., Lange, S., & Li, R. (2023). Beyond the bulge–halo conspiracy? Density profiles of early-type galaxies from extended-source strong lensing. Monthly Notices of the Royal Astronomical Society, 521(4), 6005-6018. https://doi.org/10.1093/mnras/stad582

Observations suggest that the dark matter and stars in early-type galaxies ‘conspire’ to produce a surprisingly simple distribution of total mass, ρ(r) ∝ ρ−γ, with γ ≈ 2. We measure the distribution of mass in 48 early-type galaxies that gravitationa... Read More about Beyond the bulge–halo conspiracy? Density profiles of early-type galaxies from extended-source strong lensing.

PyAutoGalaxy: Open-Source Multiwavelength Galaxy Structure & Morphology (2023)
Journal Article
Nightingale, J. W., Amvrosiadis, A., Hayes, R. G., He, Q., Etherington, A., Cao, X., Cole, S., Frawley, J., Frenk, C. S., Lange, S., Li, R., Massey, R. J., Negrello, M., & Robertson, A. (2023). PyAutoGalaxy: Open-Source Multiwavelength Galaxy Structure & Morphology. The Journal of Open Source Software, 8(81), Article 4475. https://doi.org/10.21105/joss.04475

Nearly a century ago, Edwin Hubble famously classified galaxies into three distinct groups: ellipticals, spirals and irregulars (Hubble, 1926). Today, by analysing millions of galaxies with advanced image processing techniques Astronomers have expand... Read More about PyAutoGalaxy: Open-Source Multiwavelength Galaxy Structure & Morphology.

Testing strong lensing subhalo detection with a cosmological simulation (2022)
Journal Article
He, Q., Nightingale, J., Robertson, A., Amvrosiadis, A., Cole, S., Frenk, C. S., Massey, R., Li, R., Amorisco, N. C., Metcalf, R. B., Cao, X., & Etherington, A. (2023). Testing strong lensing subhalo detection with a cosmological simulation. Monthly Notices of the Royal Astronomical Society, 518(1), 220-239. https://doi.org/10.1093/mnras/stac2779

Strong gravitational lensing offers a compelling test of the cold dark matter paradigm, as it allows for subhaloes with masses of ∼109 M⊙ and below to be detected. We test commonly-used techniques for detecting subhaloes superposed in images of stron... Read More about Testing strong lensing subhalo detection with a cosmological simulation.

Automated galaxy-galaxy strong lens modelling: No lens left behind (2022)
Journal Article
Etherington, A., Nightingale, J. W., Massey, R., Cao, X., Robertson, A., Amorisco, N. C., Amvrosiadis, A., Cole, S., Frenk, C. S., He, Q., Li, R., & Tam, S.-I. (2022). Automated galaxy-galaxy strong lens modelling: No lens left behind. Monthly Notices of the Royal Astronomical Society, 517(3), 3275-3302. https://doi.org/10.1093/mnras/stac2639

The distribution of dark and luminous matter can be mapped around galaxies that gravitationally lens background objects into arcs or Einstein rings. New surveys will soon observe hundreds of thousands of galaxy lenses, and current, labour-intensive a... Read More about Automated galaxy-galaxy strong lens modelling: No lens left behind.

Galaxy–galaxy strong lens perturbations: line-of-sight haloes versus lens subhaloes (2022)
Journal Article
He, Q., Li, R., Frenk, C. S., Nightingale, J., Cole, S., Amorisco, N. C., Massey, R., Robertson, A., Etherington, A., Amvrosiadis, A., & Cao, X. (2022). Galaxy–galaxy strong lens perturbations: line-of-sight haloes versus lens subhaloes. Monthly Notices of the Royal Astronomical Society, 512(4), 5862-5873. https://doi.org/10.1093/mnras/stac759

We rederive the number density of intervening line-of-sight haloes relative to lens subhaloes in galaxy-galaxy strong lensing observations, where these perturbers can generate detectable image fluctuations. Previous studies have calculated the detect... Read More about Galaxy–galaxy strong lens perturbations: line-of-sight haloes versus lens subhaloes.

Systematic Errors Induced by the Elliptical Power-law model in Galaxy–Galaxy Strong Lens Modeling (2022)
Journal Article
Cao, X., Li, R., Nightingale, J., Massey, R., Robertson, A., Frenk, C. S., Amvrosiadis, A., Amorisco, N. C., He, Q., Etherington, A., Cole, S., & Zhu, K. (2022). Systematic Errors Induced by the Elliptical Power-law model in Galaxy–Galaxy Strong Lens Modeling. Research in Astronomy and Astrophysics, 22(2), https://doi.org/10.1088/1674-4527/ac3f2b

The elliptical power-law (EPL) model of the mass in a galaxy is widely used in strong gravitational lensing analyses. However, the distribution of mass in real galaxies is more complex. We quantify the biases due to this model mismatch by simulating... Read More about Systematic Errors Induced by the Elliptical Power-law model in Galaxy–Galaxy Strong Lens Modeling.

A forward-modelling method to infer the dark matter particle mass from strong gravitational lenses (2022)
Journal Article
He, Q., Robertson, A., Nightingale, J., Cole, S., Frenk, C. S., Massey, R., Amvrosiadis, A., Li, R., Cao, X., & Etherington, A. (2022). A forward-modelling method to infer the dark matter particle mass from strong gravitational lenses. Monthly Notices of the Royal Astronomical Society, 511(2), 3046-3062. https://doi.org/10.1093/mnras/stac191

A fundamental prediction of the cold dark matter (CDM) model of structure formation is the existence of a vast population of dark matter haloes extending to subsolar masses. By contrast, other dark matter models, such as a warm thermal relic (WDM), p... Read More about A forward-modelling method to infer the dark matter particle mass from strong gravitational lenses.

Halo concentration strengthens dark matter constraints in galaxy-galaxy strong lensing analyses (2021)
Journal Article
Amorisco, N. C., Nightingale, J., He, Q., Amvrosiadis, A., Cao, X., Cole, S., Etherington, A., Frenk, C. S., Li, R., Massey, R., & Robertson, A. (2022). Halo concentration strengthens dark matter constraints in galaxy-galaxy strong lensing analyses. Monthly Notices of the Royal Astronomical Society, 510, 2464-2479. https://doi.org/10.1093/mnras/stab3527

A defining prediction of the cold dark matter cosmological model is the existence of a very large population of low-mass haloes. This population is absent in models in which the dark matter particle is warm (WDM). These alternatives can, in principle... Read More about Halo concentration strengthens dark matter constraints in galaxy-galaxy strong lensing analyses.

PyAutoLens: Open-Source Strong Gravitational Lensing (2021)
Journal Article
Nightingale, J., Hayes, R., Kelly, A., Amvrosiadis, A., Etherington, A., He, Q., Li, N., Cao, X., Frawley, J., Cole, S., Enia, A., Frenk, C., Harvey, D., Li, R., Massey, R., Negrello, M., & Robertson, A. (2021). PyAutoLens: Open-Source Strong Gravitational Lensing. The Journal of Open Source Software, 6(58), Article 2825. https://doi.org/10.21105/joss.02825

Strong gravitational lensing, which can make a background source galaxy appears multiple times due to its light rays being deflected by the mass of one or more foreground lens galaxies, provides astronomers with a powerful tool to study dark matter,... Read More about PyAutoLens: Open-Source Strong Gravitational Lensing.

Constraining the inner density slope of massive galaxy clusters (2020)
Journal Article
He, Q., Li, H., Li, R., Frenk, C. S., Schaller, M., Barnes, D., Bahé, Y., Kay, S. T., Gao, L., & Vecchia, C. D. (2020). Constraining the inner density slope of massive galaxy clusters. Monthly Notices of the Royal Astronomical Society, 496(4), 4717-4733. https://doi.org/10.1093/mnras/staa1769

We determine the inner density profiles of massive galaxy clusters (M200 > 5 × 1014 M⊙) in the Cluster-EAGLE (C-EAGLE) hydrodynamic simulations, and investigate whether the dark matter density profiles can be correctly estimated from a combination of... Read More about Constraining the inner density slope of massive galaxy clusters.