Professor Geraint Lewis
People_

Professor Geraint Lewis

Professor
Phone
+61 2 9351 5184
Fax
+61 2 9351 7726
Address
A28 - Physics Building
The University of Sydney
Professor Geraint Lewis

Professor Geraint Lewis undertakes a broad spectrum of research. On the largest scales, his program involves looking at the influence of dark energy and dark matter on the evolution and ultimate fate of the Universe. Another aspect of his research uses the phenomenon of gravitational lensing to probe the nature and distribution of the pervasive dark matter, and employing individual stars to magnify the hearts of quasars, the most luminous objects in the Universe. Closer to home, Geraint's research focuses upon Galactic cannibalism, where small dwarf galaxies are torn apart by the much more massive Milky Way and Andromeda Galaxy. Using telescopes from around the world, including the 10-m Keck telescope in Hawaii, he has mapped the tell-tale signs of tidal disruption and destruction, providing important clues to how large galaxies have grown over time.

Project titleResearch student
Kinematic analysis of the Milky Way stellar streamsTim ADAMS
Testing the cosmological principle with synthetic galaxy and supernova catalogues. On the effect of cosmic structure on dipole measurements.Mali LAND-STRYKOWSKI
Confronting the Cosmological PrincipleVasudev MITTAL
Philosophical Aspects of the Higgs BosonOmar MUHIEDDINE
Bayesian Inference in Tests of the Cosmological PrincipleOliver OAYDA
Reconstructing the dark matter properties of lensing galaxies in the strong gravitational lensing regime.Huimin QU

Selected publications

Publications

Books

  • Lewis, G., Barnes, L. (2016). A fortunate Universe: Life in a Finely Tuned Cosmos. Cambridge: Cambridge University Press. [More Information]

Book Chapters

  • Lewis, G. (2003). Galactic Cannibalism: A Universe of Islands. In Nicholls, Pailthorpe (Eds.), From Zero to Infinity, (pp. 181-193). Sydney: Science Foundation for Physics.

Journals

  • Callingham, J., Boehm, C., Eckert, D., Jauzac, M., Lagattuta, D., Mahler, G., Hilton, M., Lewis, G., Ettori, S. (2024). A full reconstruction of two galaxy clusters intra-cluster medium with strong gravitational lensing. Monthly Notices of the Royal Astronomical Society, 528(2), 1711-1736. [More Information]
  • Sahu, N., Barone, T., Baker, A., Skobe, H., Derkenne, C., Lewis, G., Sweet, S., Lopez, S., Tran, K., Suyu, S., et al (2024). AGEL: Is the Conflict Real? Investigating Galaxy Evolution Models Using Strong Lensing at 0.3 < z < 0.9. The Astrophysical Journal, 970(1), 86. [More Information]
  • Tuntsov, A., Lewis, G., Walker, M. (2024). Free-floating ‘planets’ in the macrolensed quasar Q2237+0305. Monthly Notices of the Royal Astronomical Society, 528(2), 1979-1996. [More Information]

Conferences

  • Oirschot,, P., Kwan,, J., Lewis, G. (2015). Another coincidence problem for ?CDM? The 13th Marcel Grossmann Meeting: On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proceedings of the MG13 Meeting on General Relativity, 2012, : Education and research in Computer Aided Architectural Design in Europe.
  • Manos, S., Lewis, G. (2006). A Combinatorial Genetic Algorithm for the Configuration of the 2dF/AAOmega Spectrograph at the Anglo-Australian Observatory. GECCO 2006: Genetic and Evolutionary Computation Conference, New York, New York: Association for Computing Machinery (ACM).

2024

  • Callingham, J., Boehm, C., Eckert, D., Jauzac, M., Lagattuta, D., Mahler, G., Hilton, M., Lewis, G., Ettori, S. (2024). A full reconstruction of two galaxy clusters intra-cluster medium with strong gravitational lensing. Monthly Notices of the Royal Astronomical Society, 528(2), 1711-1736. [More Information]
  • Sahu, N., Barone, T., Baker, A., Skobe, H., Derkenne, C., Lewis, G., Sweet, S., Lopez, S., Tran, K., Suyu, S., et al (2024). AGEL: Is the Conflict Real? Investigating Galaxy Evolution Models Using Strong Lensing at 0.3 < z < 0.9. The Astrophysical Journal, 970(1), 86. [More Information]
  • Tuntsov, A., Lewis, G., Walker, M. (2024). Free-floating ‘planets’ in the macrolensed quasar Q2237+0305. Monthly Notices of the Royal Astronomical Society, 528(2), 1979-1996. [More Information]

2023

  • Kelsey, L., Galbany, L., Graur, O., Kessler, R., Lidman, C., Möller, A., Popovic, B., Rose, B., Scolnic, D., Smith, M., Lewis, G., et al (2023). Concerning colour: The effect of environment on type Ia supernova colour in the dark energy survey. Monthly Notices of the Royal Astronomical Society, 519(2), 3046-3063. [More Information]
  • Grayling, M., Frohmaier, C., Graur, O., Kelsey, L., Lidman, C., Popovic, B., Smith, M., Toy, M., Tucker, B., Zontos, Z., Lewis, G., et al (2023). Core-collapse supernovae in the Dark Energy Survey: luminosity functions and host galaxy demographics. Monthly Notices of the Royal Astronomical Society, 520(1), 684-701. [More Information]
  • Lewis, G., Brewer, B. (2023). Detection of the cosmological time dilation of high-redshift quasars. Nature Astronomy, 7(10), 1265-1269. [More Information]

2022

  • Nandakumar, G., Hayden, M., Sharma, S., Buder, S., Asplund, M., Bland-Hawthorn, J., De Silva, G., D’Orazi, V., Freeman, K., Kos, J., Lewis, G., Stello, D., Tepper Garcia, T., et al (2022). Combined APOGEE-GALAH stellar catalogues using the Cannon. Monthly Notices of the Royal Astronomical Society, 513(1), 232-255. [More Information]
  • Tavangar, K., Ferguson, P., Shipp, N., Drlica-Wagner, A., Koposov, S., Erkal, D., Balbinot, E., García-Bellido, J., Kuehn, K., Lewis, G., et al (2022). From the Fire: A Deeper Look at the Phoenix Stream. The Astrophysical Journal, 925(2), 118. [More Information]
  • Shajib, A., Glazebrook, K., Barone, T., Lewis, G., Jones, T., Tran, K., Buckley-Geer, E., Collett, T., Frieman, J., Jacobs, C. (2022). LensingETC: A Tool to Optimize Multifilter Imaging Campaigns of Galaxy-scale Strong Lensing Systems. The Astrophysical Journal, 938(2). [More Information]

2021

  • Li, T., Koposov, S., Erkal, D., Ji, A., Shipp, N., Pace, A., Hilmi, T., Kuehn, K., Lewis, G., Mackey, D., Wan, Z., Bland-Hawthorn, J., Sharma, S., et al (2021). Broken into pieces: ATLAS and Aliqa Uma as one single stream. The Astrophysical Journal, 911(2), 149. [More Information]
  • Kos, J., Bland-Hawthorn, J., Hayden, M., Lewis, G., Sharma, S., et al (2021). Erratum: The GALAH survey: Chemical homogeneity of the Orion complex (Monthly Notices of the Royal Astronomical Society (2021) 506 ((4232-4250) DOI: 10.1093/mnras/stab1767). Monthly Notices of the Royal Astronomical Society, 508(4), 4969. [More Information]
  • Dam, L., Bolejko, K., Lewis, G. (2021). Exploring the redshift-space peculiar velocity field and its power spectrum. Journal of Cosmology and Astroparticle Physics, 2021 (9), 18. [More Information]

2020

  • Ng, A., Lewis, G. (2020). A geometric probe of cosmology - I. Gravitational lensing time delays and quasar reverberation mapping. Monthly Notices of the Royal Astronomical Society, 492(1), 1102-1109. [More Information]
  • Wan, Z., Guglielmo, M., Lewis, G., Mackey, D., Ibata, R. (2020). A SkyMapper view of the large magellanic cloud: The dynamics of stellar populations. Monthly Notices of the Royal Astronomical Society, 492(1), 782-795. [More Information]
  • List, F., Lewis, G. (2020). A unified framework for 21 cm tomography sample generation and parameter inference with progressively growing GANs. Monthly Notices of the Royal Astronomical Society, 493, 5913-5927. [More Information]

2019

  • List, F., Bhat, I., Lewis, G. (2019). A black box for dark sector physics: Predicting dark matter annihilation feedback with conditional GANs. Monthly Notices of the Royal Astronomical Society, 490(3), 3134-3143. [More Information]
  • Casey, A., Lattanzio, J., Aleti, A., Dowe, D., Bland-Hawthorn, J., Buder, S., Lewis, G., Martell, S., Nordlander, T., Simpson, J., Sharma, S., et al (2019). A Data-driven Model of Nucleosynthesis with Chemical Tagging in a Lower-dimensional Latent Space. The Astrophysical Journal, 887(1), 1-17. [More Information]
  • Preston, J., Collins, M., Ibata, R., Tollerud, E., Michael Rich, R., Bonaca, A., McConnachie, A., Mackey, D., Lewis, G., Martin, N., et al (2019). A dwarf disrupting - Andromeda XXVII and the North West Stream. Monthly Notices of the Royal Astronomical Society, 490(2), 2905-2917. [More Information]

2018

  • Herron, C., Gaensler, B., Lewis, G., McClure-Griffiths, N. (2018). Advanced Diagnostics for the Study of Linearly Polarized Emission. I. Derivation. The Astrophysical Journal, 853(1), 1-10. [More Information]
  • Herron, C., Burkhart, B., Gaensler, B., Lewis, G., McClure-Griffiths, N., Bernardi, G., Carretti, E., Haverkorn, M., Kesteven, M., Poppi, S., et al (2018). Advanced Diagnostics for the Study of Linearly Polarized Emission. II. Application to Diffuse Interstellar Radio Synchrotron Emission. The Astrophysical Journal, 855(1), 1-33. [More Information]
  • Lewis, G., Barnes, L., Sticka, M. (2018). Bell's Spaceships: The Views from Bow and Stern. Publications of the Astronomical Society of Australia, 35, 1-7. [More Information]

2017

  • Diakogiannis, F., Lewis, G., Ibata, R., Guglielmo, M., Kafle, P., Wilkinson, M., Power, C. (2017). A novel JEAnS analysis of the Fornax dwarf using evolutionary algorithms: Mass follows light with signs of an off-centre merger. Monthly Notices of the Royal Astronomical Society, 470(2), 2034-2053. [More Information]
  • Martin, N., Weisz, D., Albers, S., Bernard, E., Collins, M., Dolphin, A., Ferguson, A., Ibata, R., Laevens, B., Lewis, G., et al (2017). A Rogues' Gallery of Andromeda's Dwarf Galaxies. I. A Predominance of Red Horizontal Branches. The Astrophysical Journal, 850(1), 1-10. [More Information]
  • Tie, S., Martini, P., Mudd, D., Ostrovski, F., Reed, S., Lidman, C., Kochanek, C., Davis, T., Sharp, R., Lewis, G., et al (2017). A Study of Quasar Selection in the Supernova Fields of the Dark Energy Survey. Astronomical Journal, 153(3), 1-15. [More Information]

2016

  • Fung, K., Clark, H., Lewis, G., Wu, X. (2016). A computational approach to the twin paradox in curved spacetime. European Journal of Physics, 37(5), 1-12. [More Information]
  • Lewis, G., Barnes, L. (2016). A fortunate Universe: Life in a Finely Tuned Cosmos. Cambridge: Cambridge University Press. [More Information]
  • Thomas, G., Ibata, R., Famaey, B., Martin, N., Lewis, G. (2016). Exploring the reality of density substructures in the Palomar 5 stellar stream. Monthly Notices of the Royal Astronomical Society, 460(3), 2711-2719. [More Information]

2015

  • Oirschot,, P., Kwan,, J., Lewis, G. (2015). Another coincidence problem for ?CDM? The 13th Marcel Grossmann Meeting: On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proceedings of the MG13 Meeting on General Relativity, 2012, : Education and research in Computer Aided Architectural Design in Europe.
  • Collins, M., Martin, N., Rich, M., Ibata, R., Chapman, S., McConnachie, A., Ferguson, A., Irwin, M., Lewis, G. (2015). Comparing the observable properties of dwarf galaxies on and off the andromeda plane. Astrophysical Journal Letters, 799(1), 1-6. [More Information]
  • Ibata, R., Famaey, B., Lewis, G., Ibata, N., Martin, N. (2015). EPPUR SI MUOVE: POSITIONAL AND KINEMATIC CORRELATIONS OF SATELLITE PAIRS IN THE LOW Z UNIVERSE. The Astrophysical Journal, 805(1), 1-10. [More Information]

2014

  • Guglielmo, M., Lewis, G., Bland-Hawthorn, J. (2014). A genetic approach to the history of the Magellanic Clouds. Monthly Notices of the Royal Astronomical Society, 444(2), 1759-1774. [More Information]
  • Crnojević, D., Ferguson, A., Irwin, M., McConnachie, A., Bernard, E., Fardal, M., Ibata, R., Lewis, G., Martin, N., Navarro, J., et al (2014). A PAndAS view of M31 dwarf elliptical satellites: NGC 147 and NGC 185. Monthly Notices of the Royal Astronomical Society, 445(4), 3862-3877. [More Information]
  • Ibata, R., Ibata, N., Lewis, G., Martin, N., Conn, A., Elahi, P., Arias, V., Fernando, N. (2014). A thousand shadows of andromeda: Rotating planes of satellites in the millennium-II cosmological simulation. Astrophysical Journal Letters, 784(1), 1-5. [More Information]

2013

  • Collins, M., Chapman, S., Rich, R., Ibata, R., Martin, N., Irwin, M., Bate, N., Lewis, G., Penarrubia, J., Arimoto, N., et al (2013). A kinematic study of the andromeda dwarf spheroidal system. The Astrophysical Journal, 768(2), 1-36. [More Information]
  • Mackey, A., Huxor, A., Martin, N., Ferguson, A., Dotter, A., McConnachie, A., Ibata, R., Irwin, M., Lewis, G., Sakari, C., et al (2013). A peculiar faint satellite in the remote outer halo of M31. Astrophysical Journal Letters, 770(2), 1-3. [More Information]
  • Ibata, R., Lewis, G., Conn, A., Irwin, M., McConnachie, A., Chapman, S., Collins, M., Fardal, M., Ferguson, A., Ibata, N., et al (2013). A vast, thin plane of corotating dwarf galaxies orbiting the Andromeda galaxy. Nature, 493(7430), 62-65. [More Information]

2012

  • Conn, A., Ibata, R., Lewis, G., Parker, Q., Zucker, D., Martin, N., McConnachie, A., Irwin, M., Tanvir, N., Fardal, M., et al (2012). A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude. II. Distances to the Satellites of M31. The Astrophysical Journal, 758(1), 1-19. [More Information]
  • McMonigal, B., Lewis, G., O'Byrne, P. (2012). Alcubierre warp drive: On the matter of matter. Physical Review D, 85(6), 1-11. [More Information]
  • Fogarty, L., Bland-Hawthorn, J., Croom, S., Green, A., Bryant, J., Lawrence, J., Richards, S., Allen, J., Bauer, A., Birchall, M., Lewis, G., Trowland, H., Leon-Saval, S., Min, S., Trinh, C., et al (2012). First science with SAMI: A serendipitously discovered galactic wind in ESO 185-G031. The Astrophysical Journal, 761(2), 1-12. [More Information]

2011

  • Conn, A., Lewis, G., Ibata, R., Parker, Q., Zucker, D., McConnachie, A., Martin, N., Irwin, M., Tanvir, N., Fardal, M., et al (2011). A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude. I. The Astrophysical Journal, 740(69), 1-11. [More Information]
  • Conn, B., Pasquali, A., Pompei, E., Lane, R., Chene, A., Smith, R., Lewis, G. (2011). A new collisional ring galaxy at z = 0.111: Auriga's Wheel. The Astrophysical Journal, 741(2), 80-1-80-6. [More Information]
  • Lane, R., Kiss, L., Lewis, G., Ibata, R., Siebert, A., Bedding, T., Szekely, G., Szabo, G. (2011). AAOmega spectroscopy of 29 351 stars in fields centered on ten Galactic globular clusters. Astronomy & Astrophysics, 530, A31-1-A31-6. [More Information]

2010

  • Collins, M., Chapman, S., Irwin, M., Martin, N., Ibata, R., Zucker, D., Blain, A., Ferguson, A., Lewis, G., McConnachie, A., et al (2010). A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII and And XIII. Monthly Notices of the Royal Astronomical Society, 407(4), 2411-2433. [More Information]
  • Lane, R., Brewer, B., Kiss, L., Lewis, G., Ibata, R., Siebert, A., Bedding, T., Szekely, P., Szabo, G. (2010). AAOMEGA observations of 47 tucanae: Evidence for a past merger? Astrophysical Journal Letters, 711(2), L122-L126. [More Information]
  • Bate, N., Fluke, C., Barsdell, B., Garsden, H., Lewis, G. (2010). Computational advances in gravitational microlensing: A comparison of CPU, GPU, and parallel, large data codes. New Astronomy, 15(8), 726-734. [More Information]

2009

  • Letarte, B., Chapman, S., Collins, M., Ibata, R., Irwin, M., Ferguson, A., Lewis, G., Martin, N., McConnachie, A., Tanvir, N. (2009). A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And XV and And XVI. Monthly Notices of the Royal Astronomical Society, 400(3), 1472-1478. [More Information]
  • Collins, M., Chapman, S., Irwin, M., Ibata, R., Martin, N., Ferguson, A., Huxor, A., Lewis, G., Mackey, A., McConnachie, A., et al (2009). A spectroscopic survey of EC4, an extended cluster in Andromeda's halo. Monthly Notices of the Royal Astronomical Society, 396(3), 1619-1628. [More Information]
  • Richardson, J., Ferguson, A., Mackey, A., Irwin, M., Chapman, S., Huxor, A., Ibata, R., Lewis, G., Tanvir, N. (2009). An HST/ACS view of the inhomogenous outer halo of M31. Monthly Notices of the Royal Astronomical Society, 396(4), 1842-1850. [More Information]

2008

  • Riechers, D., Walter, F., Brewer, B., Carilli, C., Lewis, G., Bertoldi, F., Cox, P. (2008). A MOLECULAR EINSTEIN RING AT z=4.12: IMAGING THE DYNAMICS OF A QUASAR HOST GALAXY THROUGH A COSMIC LENS. The Astrophysical Journal, 686(2), 851-858. [More Information]
  • McConnachie, A., Huxor, A., Martin, N., Irwin, M., Chapman, S., Fahlman, G., Ferguson, A., Ibata, R., Lewis, G., Richer, H., et al (2008). A Trio of New Local Group Galaxies with Extreme Properties. The Astrophysical Journal, 688(2), 1009-1020. [More Information]
  • Cioni, M., Irwin, M., Ferguson, A., McConnachie, A., Conn, B., Huxor, A., Ibata, R., Lewis, G., Tanvir, N. (2008). AGB stars as tracers of metallicity and mean age across M 33. Astronomy & Astrophysics, 487(1), 131-146. [More Information]

2007

  • Martin, N., Ibata, R., Chapman, S., Irwin, M., Lewis, G. (2007). A Keck/DEIMOS spectroscopic survey of faint Galactic satellites: searching for the least massive dwarf galaxies. Monthly Notices of the Royal Astronomical Society, 380(1), 281-300. [More Information]
  • Kiss, L., Sznekely, P., Bedding, T., Bakos, G., Lewis, G. (2007). A wide-field kinematic survey for tidal tails around five globular clusters. The Astrophysical Journal, 659(2), L129-L132. [More Information]
  • Mackey, A., Huxor, A., Ferguson, A., Tanvir, N., Irwin, M., Ibata, R., Bridges, T., Johnson, R., Lewis, G. (2007). ACS photometry of newly discovered globular clusters in the outer halo of M31. The Astrophysical Journal, 655(2), L85-L88. [More Information]

2006

  • Manos, S., Lewis, G. (2006). A Combinatorial Genetic Algorithm for the Configuration of the 2dF/AAOmega Spectrograph at the Anglo-Australian Observatory. GECCO 2006: Genetic and Evolutionary Computation Conference, New York, New York: Association for Computing Machinery (ACM).
  • Chapman, S., Ibata, R., Lewis, G., Ferguson, A., Irwin, M., McConnachie, A., Tanvir, N. (2006). A kinematically selected, metal-poor stellar halo in the ourskirts of M31. The Astrophysical Journal, 653(1), 255-266. [More Information]
  • Ibata, R., Chapman, S., Irwin, M., Lewis, G., Martin, N. (2006). A near-zero velocity dispersion stellar component in the Canes Venatici dwarf spheroidal galaxy. Monthly Notices of the Royal Astronomical Society, 373, L70-L74. [More Information]

2005

  • Chapman, S., Ibata, R., Lewis, G., Ferguson, A., Irwin, M., McConnachie, A., Tanvir, N. (2005). A Keck deimos kinematic study of Andromeda IX: Dark matter on the smallest galactic scales. The Astrophysical Journal, 632(2), L87-L90. [More Information]
  • Irwin, M., Ferguson, A., Ibata, R., Lewis, G., Tanvir, N. (2005). A minor-axis surface brightness profile for M31. The Astrophysical Journal, 628(2), L105-L108. [More Information]
  • Huxor, A., Tanvir, N., Irwin, M., Ibata, R., Collett, J., Ferguson, A., Bridges, T., Lewis, G. (2005). A new population of extended, luminous star clusters in the halo of M31. Monthly Notices of the Royal Astronomical Society, 360(3), 1007-1012. [More Information]

2004

  • Martin, N., Ibata, R., Bellazzini, M., Lewis, G., Irwin, M., Dehnen, W. (2004). A Dwarf Galaxy Remnant In Canis Major: The Fossil Of An In-Plane Accretion On To The Milky Way. Monthly Notices of the Royal Astronomical Society, 348(1), 12-23. [More Information]
  • Knebe, A., Gill, S., Gibson, B., Lewis, G., Ibata, R., Dopita, M. (2004). Anisotropy In The Distribution Of Satellite Galaxy Orbits. The Astrophysical Journal, 603(1), 7-11. [More Information]
  • Tuntsov, A., Lewis, G., Ibata, R., Kneib, J. (2004). Detecting Compact Dark Matter Galaxy Clusters Via Gravitational Microlensing: A2218 And A370. Monthly Notices of the Royal Astronomical Society, 353(3), 853-866. [More Information]

2003

  • Carilli, C., Lewis, G., Djorgovski, S., Mahabal, A., Cox, P., Bertoldi, F., Omont, A. (2003). A molecular einstein ring: Imaging a starburst disk surrounding a quasi-stellar object. Science, 300(5620), 773-775. [More Information]
  • Lewis, G. (2003). Galactic Cannibalism: A Universe of Islands. In Nicholls, Pailthorpe (Eds.), From Zero to Infinity, (pp. 181-193). Sydney: Science Foundation for Physics.
  • Zhao, H., Ibata, R., Lewis, G., Irwin, M. (2003). Kinematic outliers in the large magellanic cloud: constraints on star-star microlensing. Monthly Notices of the Royal Astronomical Society, 339(3), 701-706. [More Information]

2002

  • Lewis, G., Irwin, M., Ibata, R., Gibson, B. (2002). AAT/WFI Observations of the Extragalactic HI Cloud HIPASS J1712-64. Publications of the Astronomical Society of Australia (PASA).
  • Lewis, G., Ibata, R. (2002). An investigation of gravitational lens determinations of H-0 in quintessence cosmologies. Monthly Notices of the Royal Astronomical Society, 337(1), 26-33. [More Information]
  • Ferguson, A., Irwin, M., Rodrigo, A., Lewis, G., Tanvir, N. (2002). Evidence for stellar substructure in the halo and outer disk of m31. Astronomical Journal, 124, 1452-1463. [More Information]

Selected Grants

2025

  • Cosmic Dipole Tension, Lewis G, School of Physics/Physics Research Seed Funding Scheme

2022

  • Seeing Dark with Light: Revealing the Milky Way with Stellar Streams, Lewis G, Australian Research Council (ARC)/Discovery Projects (DP)

Related research articles

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