Thomas Edward Collett Portrait

Professor Thomas Collett

Professor of Astrophysics

Thomas.Collett@port.ac.uk

PhD Supervisor

View my research outputs
Faculty of Technology Cosmology and astrophysics Institute of Cosmology and Gravitation

Biography

I am an astrophysicist and cosmologist studying how dark energy is affecting the expansion of the Universe. I do this using a phenomenon called strong gravitational lensing, where the path of light from a background galaxy is bent by a massive foreground galaxy to produce multiple images of the background source. The location where the lensed images form is sensitive to the cosmological parameters and the dark matter distribution in the lens galaxy and throughout the Universe. I’m trying to probe all three with observations from the world's leading telescopes.

My research has been funded by the Royal Astronomical Society, University of Portsmouth, Science and Technolody Facilities Council and the Royal Society.

I won the Winton prize in 2020 and the Murdin prize in 2014.

I'm particularly proud of the following papers:

The most precise test of how mass warps spacetime over extragalactic scales

A large catalogue of new gravitational lenses discovered using machine learning

A cosmological model independent measurement of the Hubble constant

A measurement of the equation of state of dark energy from a double source plane lens 

Research outputs

2026

iPTF16geu through the lens of thermonuclear explosion models

De Murieta, A. S., Magee, M. R., Li, T., Collett, T. E., Johansson, J.

1 Feb 2026, In: Monthly Notices of the Royal Astronomical Society. 546, 2, 16p., stag091

Research output: Article

The AGEL Survey Data Release 2: A gravitational lens sample for galaxy evolution and cosmology

Barone, T. M., Vasan, K. C., Tran, K. V., Kacprzak, G. G., Glazebrook, K., Jones, T., Bowden, D. J., Dalessandro, F., Sahu, N., Skobe, H., Allen, R. J., Baker, M. M., Ballard, D. J., Chen, Y., Collett, T. E., Ferrami, G., González, J., Gottemoller, W., Harshan, A., Huang, X., Iwamoto, L., Jacobs, C., Jeltema, T. E., Gupta, K. R., Lewis, G. F., Lopez, S., Nanayakkara, T., Nielsen, N. M., O’Donnell, J., Qu, H., Rhoades, S., Shajib, A. J., Sweet, S. M., Tejos, N.

2 Jan 2026, In: Astronomical Journal. 171, 1, 23p., 57

Research output: Article

2025

Lensed stars in galaxy-galaxy strong lensing - A JWST prediction for the Cosmic Horseshoe

Li, S. K., Weisenbach, L., Collett, T. E., Diego, J. M., Lim, J., Broadhurst, T. J., Chow, A., Enzi, W. J., Kelly, P. L., Melo-Carneiro, C. R., Palencia, J. M., Williams, L. L., Zhang, J.

5 Dec 2025, In: Monthly Notices of the Royal Astronomical Society. 544, 4, p. 4469-4481, 13p.

Research output: Article

TiDES: The 4MOST Time Domain Extragalactic Survey

Frohmaier, C., Vincenzi, M., Sullivan, M., Hönig, S. F., Smith, M., Addison, H., Collett, T., Dimitriadis, G., Ellis, R. S., Gandhi, P., Graur, O., Hook, I., Kelsey, L., Kim, Y. L., Lidman, C., Maguire, K., Makrygianni, L., Martin, B., Möller, A., Nichol, R. C., Nicholl, M., Schady, P., Simmons, B. D., Smartt, S. J., Tempel, E., Wiseman, P.

10 Oct 2025, In: The Astrophysical Journal. 992, 1, 18p., 158

Research output: Article

The La Silla Schmidt Southern Survey

Miller, A. A., Abrams, N. S., Aldering, G., Anand, S., Angus, C. R., Arcavi, I., Baltay, C., Bauer, F. E., Brethauer, D., Bloom, J. S., Bommireddy, H., Catelan, M., Chornock, R., Clark, P., Collett, T. E., Dimitriadis, G., Faris, S., Forster, F., Franckowiak, A., Galbany, L., Galleguillos, R. B., Goobar, A., Graur, O., Gutierrez, C. P., Hall, S., Hammerstein, E., Herner, K. R., Hook, I. M., Huston, M. J., Johansson, J., Kilpatrick, C. D., Kim, A. G., Knop, R. A., Kowalski, M. P., Kwok, L. A., LeBaron, N., Lin, K. W., Liu, C., Lu, J. R., Lu, W., Lunnan, R., Maguire, K., Makrygianni, L., Margutti, R., Maoz, D., Veres, P. M., Moore, T., Nayana, A. J., Nicholl, M., Nordin, J., Pignata, G., Polin, A., Poznanski, D., Prieto, J. L., Rabinowitz, D. L., Rehemtulla, N., Rigault, M., Ryczanowski, D., Sarin, N., Schulze, S., Shah, V. G., Sheng, X., Shilling, S. P. R., Simmons, B. D., Singh, A., Smith, G. P., Smith, M., Sollerman, J., Soumagnac, M. T., Stubbs, C. W., Sullivan, M., Suresh, A., Trakhtenbrot, B., Ward, C., Wiston, E., Xiong, H., Yao, Y., Nugent, P. E.

29 Sep 2025, In: Publications of the Astronomical Society of the Pacific. 137, 9, 30p., 094204

Research output: Article

Cosmography with the double-source-plane strong gravitational lens AGEL150745+052256

Sahu, N., Shajib, A. J., Tran, K. V., Skobe, H., Rhoades, S., Jones, T., Glazebrook, K., Collett, T. E., Suyu, S. H., Vasan G. C, K., Barone, T. M., Bowden, D. J., Ballard, D., Kacprzak, G. G., Sweet, S. M., Lewis, G. F., Nanayakkara, T.

20 Sep 2025, In: Astrophysical Journal. 991, 1, 17p., 72

Research output: Article

The revolution in strong lensing discoveries from Euclid

Lines, N. E., Li, T., Collett, T. E., Holloway, P., Nightingale, J. W., Rojas, K., Verma, A., Walmsley, M.

18 Aug 2025, In: Nature Astronomy. 9, 8, p. 1116-1122, 7p.

Research output: Article

Unveiling a 36 billion solar mass black hole at the centre of the Cosmic Horseshoe gravitational lens

Melo-Carneiro, C. R., Collett, T. E., Oldham, L. J., Enzi, W., Furlanetto, C., Chies-Santos, A. L., Li, T.

7 Aug 2025, In: Monthly Notices of the Royal Astronomical Society. 541, 4, p. 2853-2871, 19p.

Research output: Article

Euclid Quick Data Release (Q1). The strong-lensing discovery engine B. Early strong-lens candidates from the visual inspection of galaxies with a high-velocity dispersion

Collaboration, E., Rojas, K., Collett, T. E., Barroso, J. A. A., Nightingale, J. W., Stern, D., Moustakas, L. A., Schuldt, S., Despali, G., Melo, A., Walmsley, M., Ballard, D. J., Enzi, W. J. R., Li, T., de Murieta, A. S., Andika, I. T., Clément, B., Courbin, F., Ecker, L. R., Gavazzi, R., Jackson, N., Kovács, A., Matavulj, P., Meneghetti, M., Serjeant, S., Sluse, D., Tortora, C., Verma, A., Marchetti, L., O'Riordan, C. M., McCarthy, K., Suyu, S. H., Metcalf, R. B., Aghanim, N., Altieri, B., Amara, A., Andreon, S., Auricchio, N., Aussel, H., Baccigalupi, C., Baldi, M., Balestra, A., Bardelli, S., Casas, S., Nichol, R. C., Percival, W. J., Schewtschenko, J. A., Gaztanaga, E., Nadathur, S., Naidoo, K.

24 Jul 2025, In: Astronomy and Astrophysics

Research output: Article

Euclid Quick Data Release (Q1). The Strong Lensing Discovery Engine C - Finding lenses with machine learning

Collaboration, E., Lines, N. E. P., Collett, T. E., Walmsley, M., Rojas, K., Li, T., Leuzzi, L., Manjón-García, A., Vincken, S. H., Wilde, J., Holloway, P., Verma, A., Metcalf, R. B., Andika, I. T., Melo, A., Melchior, M., Sánchez, H. D., Díaz-Sánchez, A., Barroso, J. A. A., Clément, B., Krawczyk, C., Pearce-Casey, R., Serjeant, S., Courbin, F., Despali, G., Gavazzi, R., Schuldt, S., Degaudenzi, H., Ecker, L. R., Enzi, W. J. R., Finner, K., Galan, A., Giocoli, C., Hogg, N. B., Jahnke, K., Kruk, S., Mahler, G., More, A., Nagam, B. C., Pearson, J., de Murieta, A. S., Weisenbach, L., Amara, A., Casas, S., Nichol, R. C., Percival, W. J., Schewtschenko, J. A., Gaztanaga, E., Nadathur, S., Naidoo, K.

17 Jun 2025, In: Astronomy and Astrophysics

Research output: Article

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