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Dr Cullan Howlett

Senior Research Fellow in Cosmology

Physics
Faculty of Science
c.howlett@uq.edu.au
0420766717

Overview

I am a Senior Research Fellow in Cosmology based in the School of Mathematics and Physics. I work on making maps of the positions and motions of millions of galaxies in our Universe to uncover how it has evolved since the Big Bang. Current observations suggest 95% of our Universe consists of ellusive Dark Matter and Dark Energy; we can detect these by the influence they have on the light from galaxies, stars and that permeates the background Universe itself, but they don't emit light themselves and we have no idea yet what they are. My research seeks to uncover these using the largest galaxy surveys in the world.

I have been involved in planning, carrying out, and analysing a large number of these surveys. I currently working groups in the American-led Dark Energy Spectroscopic Instrument (DESI) project, the WALLABY survey based in Western Australia, and the 4MOST Hemisphere Survey (4HS) which will be carried out from Chile. Combined, these will produce the most detailed maps of galaxy positions and motions ever created --- over 40,000,000 unique galaxies!

My personal research makes use of state-of-the art computing techniques to simulate the distributions of these galaxies, their properties, and how fast they are moving. I then analyse these distributions using different statistical techniques and compare to the real data. The properties of Dark Matter and Dark Energy and all the other things that make up our Universe can then be extracted by modelling these statistics with theoretical models, or looking for discrepancies between the simulations and the data. My hope is that by doing so, we are currently on the cusp of uncovering something fundamental about how the Universe came to be the way it is today, and what will happen to it in the future.

Academic Background

  • Undergraduate: MPhys 1st Class Honours - University of Sussex, 2008-2012
  • Postgraduate: PhD - University of Portmouth, 2012-2016
  • Research Associate - University of Western Australia, 2015-2019
  • Research Fellow in Cosmology - University of Queensland, 2019-

Research Interests

  • Testing gravity using galaxy positions and motions
    One compelling way to explain dark matter and dark energy is that our current theory of gravity (General Relativity) doesn't work on scales much larger than the Solar system. One of my interests is developing different models and understanding how they can be proven or disproven with galaxy properties.
  • Fast simulations of large scale structure
    Current state of the art simulations are able to simulate the distributions of billions of galaxies, but these are very slow and can take weeks to run on the largest supercomputers. I'm interested in new approximate ways for generating these simulations or cool computational techniques such as machine learning, that can be run in a fraction of the time, or on fewer processors.
  • New statistical methods for analysing distributions of galaxies
    In addition to theoretical developments, I'm interested in looking for new statistical ways to use the galaxy data we have to give us insight into the Universe.
  • Gravitational waves
    Gravitational waves, first detected in 2015 are the new hot topic in physics and offer interesting ways to test cosmology. I'm interested in creating simulated catalogues of gravitational waves and using these to working out what cosmological insights gravitational waves can bring

Research Impacts

The nature of dark matter and dark energy is the biggest question in modern science. Are they particles we haven't discovered yet, or perhaps a misunderstanding of our fundamental pillars of physics (Einstein's theory of General Relativity or Quantum Mechanics). We don't know, but the answer is out there, and it's likely profound. It will change everything we know about physics, and with this understanding could come unimagined new ideas and technologies. In the same way that our modern understanding of the atom and electromagnetism has lead to the technologic marvels we have today that would seem wonderous to someone 200 years ago, in 200 years from now who knows where an understanding of the Dark parts of our Universe will take us.

In order to unlock this information, cosmologists including myself have to come up with new techniques for supercomputing, for dealing with big data problems, and for mining every possible piece of data from the surveys we have. The statistics, methods and codes we develop are cutting edge and can often be used in fields outside astronomy (for instance in finance, environmental science, business planning, and even tackling pandemics...)

Publications

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Grants

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Supervision

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Available Projects

  • Testing gravity with the distributions of galaxies

    Maps of the positions of millions of galaxies in our Universe are used to refine our understanding of its components and evolution. However, these experiments have left us with more questions than answers. What is the nature of dark energy and dark matter? Is Einstein’s theory of General Relativity correct on scales beyond our solar system?

    Upcoming surveys aim to answer these questions. But understanding how the distributions and motions of galaxies relate to fundamental physics and how to sift through this enormous amount of data to uncover the truth requires improving our analysis techniques and developing new ways to use the data.

    Many projects are available under this theme, with different emphasis on mathematical theory, data analysis or computer programming. They could involve improving and speeding up methods for simulating the Universe on supercomputers. Or developing new mathematical models for describing how galaxies cluster and move relative to each other. Or, they could involve using real measurements of positions and velocities of galaxies we are currently obtaining or working towards with surveys such as the Dark Energy Spectroscopic Instrument, WALLABY, or the 4MOST Hemisphere Survey.

  • Cosmology with gravitational waves

    Gravitational waves are ripples in space-time that propogate away from massive compact objects as they merge, to hopefully, eventually, be detected here on Earth by the LIGO/Virgo gravitational wave detectors. Gravitational waves hold information on some of the most exotic objects in the Universe such as black holes and neutron stars. They can also be used to test cosmological models, particularly because they act as "Standard Sirens" - the gravitational waveform tells us how far away the merging objects are which then can be used to work out how fast the Universe is expanding and how fast it's large scale structures are growing.

    This project will look at techniques for extracting Standard Siren measurements from gravitational waves. In particular, developing simulated catalogues of gravitational wave events and then using these simulations to work out how best to extract cosmology from the real data. This project brings together a range of fields, from understanding the details of how black holes and neutron stars are formed, to theoretical modelling of future cosmology studies that might be possible once we have hundreds of gravitational waves.

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Publications

Featured Publications

Journal Article

  • Ho’oleilana: An Individual Baryon Acoustic Oscillation?

    Tully, R. Brent, Howlett, Cullan and Pomarède, Daniel (2023). Ho’oleilana: An Individual Baryon Acoustic Oscillation?. Astrophysical Journal, 954 (2) 169. doi: 10.3847/1538-4357/aceaf3

  • Can Einstein (rings) surf Gravitational Waves?

    Giani, Leonardo, Howlett, Cullan and Davis, Tamara M. (2023). Can Einstein (rings) surf Gravitational Waves?. The Open Journal of Astrophysics, 6. doi: 10.21105/astro.2302.10472

  • Target selection for the DESI peculiar velocity survey

    Saulder, Christoph, Howlett, Cullan, Douglass, Kelly A, Said, Khaled, BenZvi, Segev, Ahlen, Steven, Aldering, Greg, Bailey, Stephen, Brooks, David, Davis, Tamara M, de la Macorra, Axel, Dey, Arjun, Font-Ribera, Andreu, Forero-Romero, Jaime E, Gontcho, Satya Gontcho A, Honscheid, Klaus, Kim, Alex G, Kisner, Theodore, Kremin, Anthony, Landriau, Martin, Levi, Michael E, Lucey, John, Meisner, Aaron M, Miquel, Ramon, Moustakas, John, Myers, Adam D, Palanque-Delabrouille, Nathalie, Percival, Will, Poppett, Claire ... Zou, Hu (2023). Target selection for the DESI peculiar velocity survey. Monthly Notices of the Royal Astronomical Society, 525 (1), 1106-1125. doi: 10.1093/mnras/stad2200

  • Exploring binary black hole mergers and host galaxies with Shark and COMPAS

    Rauf, Liana, Howlett, Cullan, Davis, Tamara M. and Lagos, Claudia D. P. (2023). Exploring binary black hole mergers and host galaxies with Shark and COMPAS. Monthly Notices of the Royal Astronomical Society, 523 (4), 5719-5737. doi: 10.1093/mnras/stad1757

  • Cross-correlating radial peculiar velocities and CMB lensing convergence

    Giani, Leonardo, Howlett, Cullan, Ruggeri, Rossana, Bianchini, Federico, Said, Khaled and M. Davis, Tamara (2023). Cross-correlating radial peculiar velocities and CMB lensing convergence. Journal of Cosmology and Astroparticle Physics, 2023 (05) 002, 002. doi: 10.1088/1475-7516/2023/05/002

  • WALLABY pre-pilot and pilot survey: the Tully Fisher relation in Eridanus, Hydra, Norma and NGC4636 fields

    Courtois, Hélène M, Said, Khaled, Mould, Jeremy, Jarrett, T H, Pomarède, Daniel, Westmeier, Tobias, Staveley-Smith, Lister, Dupuy, Alexandra, Hong, Tao, Guinet, Daniel, Howlett, Cullan, Deg, Nathan, For, Bi-Qing, Kleiner, Dane, Koribalski, Bärbel, Lee-Waddell, Karen, Rhee, Jonghwan, Spekkens, Kristine, Wang, Jing, Wong, O I, Bigiel, Frank, Bosma, Albert, Colless, Matthew, Davis, Tamara, Holwerda, Benne, Karachentsev, Igor, Kraan-Korteweg, Renée C, McQuinn, Kristen B W, Meurer, Gerhardt ... Taylor, Edward (2023). WALLABY pre-pilot and pilot survey: the Tully Fisher relation in Eridanus, Hydra, Norma and NGC4636 fields. Monthly Notices of the Royal Astronomical Society, 519 (3), 4589-4607. doi: 10.1093/mnras/stac3246

  • Cosmicflows-4

    Tully, R. Brent, Kourkchi, Ehsan, Courtois, Hélène M., Anand, Gagandeep S., Blakeslee, John P., Brout, Dillon, Jaeger, Thomas de, Dupuy, Alexandra, Guinet, Daniel, Howlett, Cullan, Jensen, Joseph B., Pomarède, Daniel, Rizzi, Luca, Rubin, David, Said, Khaled, Scolnic, Daniel and Stahl, Benjamin E. (2023). Cosmicflows-4. The Astrophysical Journal, 944 (1) 94, 1-31. doi: 10.3847/1538-4357/ac94d8

  • The DESI survey validation: results from visual inspection of bright galaxies, luminous red galaxies, and emission-line galaxies

    Lan, Ting-Wen, Tojeiro, R., Armengaud, E., Prochaska, J. Xavier, Davis, T. M., Alexander, David M., Raichoor, A., Zhou, Rongpu, Yèche, Christophe, Balland, C., BenZvi, S., Berti, A., Canning, R., Carr, A., Chittenden, H., Cole, S., Cousinou, M.-C., Dawson, K., Dey, Biprateep, Douglass, K., Edge, A., Escoffier, S., Glanville, A., A Gontcho, S. Gontcho, Guy, J., Hahn, C., Howlett, C., Hwang, Ho Seong, Jiang, L. ... Zhou, Zhimin (2023). The DESI survey validation: results from visual inspection of bright galaxies, luminous red galaxies, and emission-line galaxies. The Astrophysical Journal, 943 (1) 68. doi: 10.3847/1538-4357/aca5fa

  • Using peculiar velocity surveys to constrain the growth rate of structure with the wide-angle effect

    Lai, Yan, Howlett, Cullan and Davis, Tamara M. (2023). Using peculiar velocity surveys to constrain the growth rate of structure with the wide-angle effect. Monthly Notices of the Royal Astronomical Society, 518 (2), 1840-1858. doi: 10.1093/mnras/stac3252

  • Full-shape galaxy power spectra and the curvature tension

    Glanville, Aaron, Howlett, Cullan and Davis, Tamara (2022). Full-shape galaxy power spectra and the curvature tension. Monthly Notices of the Royal Astronomical Society, 517 (2), 3087-3100. doi: 10.1093/mnras/stac2891

  • Overview of the instrumentation for the Dark Energy Spectroscopic Instrument

    Abareshi, B., Aguilar, J., Ahlen, S., Alam, Shadab, Alexander, David M., Alfarsy, R., Allen, L., Prieto, C. Allende, Alves, O., Ameel, J., Armengaud, E., Asorey, J., Aviles, Alejandro, Bailey, S., Balaguera-Antolínez, A., Ballester, O., Baltay, C., Bault, A., Beltran, S. F., Benavides, B., BenZvi, S., Berti, A., Besuner, R., Beutler, Florian, Bianchi, D., Blake, C., Blanc, P., Blum, R., Bolton, A. ... Zu, Y. (2022). Overview of the instrumentation for the Dark Energy Spectroscopic Instrument. The Astronomical Journal, 164 (5) 207, 1-62. doi: 10.3847/1538-3881/ac882b

  • H i HOD. I. The halo occupation distribution of H i Galaxies

    Qin, Fei, Howlett, Cullan, Stevens, Adam R. H. and Parkinson, David (2022). H i HOD. I. The halo occupation distribution of H i Galaxies. The Astrophysical Journal, 937 (2) 113, 1-15. doi: 10.3847/1538-4357/ac8b6f

  • The Sloan Digital Sky Survey peculiar velocity catalogue

    Howlett, Cullan, Said, Khaled, Lucey, John R., Colless, Matthew, Qin, Fei, Lai, Yan, Tully, R. Brent and Davis, Tamara M. (2022). The Sloan Digital Sky Survey peculiar velocity catalogue. Monthly Notices of the Royal Astronomical Society, 515 (1), 953-976. doi: 10.1093/mnras/stac1681

  • Using peculiar velocity surveys to constrain neutrino masses

    Whitford, Abbé M., Howlett, Cullan and Davis, Tamara M. (2022). Using peculiar velocity surveys to constrain neutrino masses. Monthly Notices of the Royal Astronomical Society, 513 (1), 345-362. doi: 10.1093/mnras/stac783

  • WALLABY Pilot Survey: Public release of HI kinematic models for more than 100 galaxies from phase 1 of ASKAP pilot observations

    Deg, N., Spekkens, K., Westmeier, T., Reynolds, T. N., Venkataraman, P., Goliath, S., Shen, A. X., Halloran, R., Bosma, A., Catinella, B, de Blok, W. J. G., Dénes, H., DiTeodoro, E. M., Elagali, A., For, B.-Q., Howlett, C, Józsa, G. I. G., Kamphuis, P., Kleiner, D., Koribalski, B, Lee-Waddell, K., Lelli, F., Lin, X., Murugeshan, C., Oh, S., Rhee, J., Scott, T. C., Staveley-Smith, L., van der Hulst, J. M. ... Wong, O. I. (2022). WALLABY Pilot Survey: Public release of HI kinematic models for more than 100 galaxies from phase 1 of ASKAP pilot observations. Publications of the Astronomical Society of Australia, 39 e059, 1-17. doi: 10.1017/pasa.2022.43

  • WALLABY pilot survey: public release of H i data for almost 600 galaxies from phase 1 of ASKAP pilot observations

    Westmeier, T., Deg, N., Spekkens, K., Reynolds, T. N., Shen, A. X., Gaudet, S., Goliath, S., Huynh, M. T., Venkataraman, P., Lin, X., O’Beirne, T., Catinella, B., Cortese, L., Dénes, H., Elagali, A., For, B.-Q., Józsa, G. I. G., Howlett, C., van der Hulst, J. M., Jurek, R. J., Kamphuis, P., Kilborn, V. A., Kleiner, D., Koribalski, B. S., Lee-Waddell, K., Murugeshan, C., Rhee, J., Serra, P., Shao, L. ... Said, K. (2022). WALLABY pilot survey: public release of H i data for almost 600 galaxies from phase 1 of ASKAP pilot observations. Publications of the Astronomical Society of Australia, 39 e058. doi: 10.1017/pasa.2022.50

  • Cosmic flow measurement and mock sampling algorithm of Cosmicflows-4 Tully−Fisher catalog

    Qin, Fei, Parkinson, David, Howlett, Cullan and Said, Khaled (2021). Cosmic flow measurement and mock sampling algorithm of Cosmicflows-4 Tully−Fisher catalog. The Astrophysical Journal, 922 (1) 59. doi: 10.3847/1538-4357/ac249d

  • Strengthening the bound on the mass of the lightest neutrino with terrestrial and cosmological experiments

    Stöcker, Patrick, Balázs, Csaba, Bloor, Sanjay, Bringmann, Torsten, Gonzalo, Tomás E., Handley, Will, Hotinli, Selim, Howlett, Cullan, Kahlhoefer, Felix, Renk, Janina J., Scott, Pat, Vincent, Aaron C., White, Martin and The GAMBIT Cosmology Workgroup (2021). Strengthening the bound on the mass of the lightest neutrino with terrestrial and cosmological experiments. Physical Review D, 103 (12) 123508. doi: 10.1103/physrevd.103.123508

  • The effect of systematic redshift biases in BAO cosmology

    Glanville, Aaron, Howlett, Cullan and Davis, Tamara M. (2021). The effect of systematic redshift biases in BAO cosmology. Monthly Notices of the Royal Astronomical Society, 503 (3), 3510-3521. doi: 10.1093/mnras/stab657

  • CosmoBit: A GAMBIT module for computing cosmological observables and likelihoods

    Renk, Janina J., Stöcker, Patrick, Bloor, Sanjay, Hotinli, Selim, Balázs, Csaba, Bringmann, Torsten, Gonzalo, Tomás E., Handley, Will, Hoof, Sebastian, Howlett, Cullan, Kahlhoefer, Felix, Scott, Pat, Vincent, Aaron C. and White, Martin (2021). CosmoBit: A GAMBIT module for computing cosmological observables and likelihoods. Journal of Cosmology and Astroparticle Physics, 2021 (2) 022, 022-022. doi: 10.1088/1475-7516/2021/02/022

  • Constraining the growth rate of structure with phase correlations

    Byun, Joyce, Franco, Felipe Oliveira, Howlett, Cullan, Bonvin, Camille and Obreschkow, Danail (2020). Constraining the growth rate of structure with phase correlations. Monthly Notices of the Royal Astronomical Society, 497 (2), 1765-1790. doi: 10.1093/mnras/staa2020

  • WALLABY – an SKA Pathfinder H I survey

    Koribalski, Bärbel S., Staveley-Smith, L., Westmeier, T., Serra, P., Spekkens, K., Wong, O. I., Lee-Waddell, K., Lagos, C. D.P., Obreschkow, D., Ryan-Weber, E. V., Zwaan, M., Kilborn, V., Bekiaris, G., Bekki, K., Bigiel, F., Boselli, A., Bosma, A., Catinella, B., Chauhan, G., Cluver, M. E., Colless, M., Courtois, H. M., Crain, R. A., de Blok, W. J.G., Dénes, H., Duffy, A. R., Elagali, A., Fluke, C. J., For, B. Q. ... Wolf, C. (2020). WALLABY – an SKA Pathfinder H I survey. Astrophysics and Space Science, 365 (7) 118. doi: 10.1007/s10509-020-03831-4

  • Standard siren speeds: improving velocities in gravitational-wave measurements of H0

    Howlett, Cullan and Davis, Tamara M. (2020). Standard siren speeds: improving velocities in gravitational-wave measurements of H0. Monthly Notices of the Royal Astronomical Society, 492 (3), 3803-3815. doi: 10.1093/mnras/staa049

  • BARRY and the BAO Model Comparison

    Hinton, Samuel R., Howlett, Cullan and Davis, Tamara M. (2020). BARRY and the BAO Model Comparison. Monthly Notices of the Royal Astronomical Society, 493 (3), 4078-4093. doi: 10.1093/mnras/staa361

  • Multiwavelength consensus of large-scale linear bias

    Pan, Hengxing, Obreschkow, Danail, Howlett, Cullan, Lagos, Claudia del P., Elahi, Pascal J., Baugh, Carlton and Gonzalez-Perez, Violeta (2020). Multiwavelength consensus of large-scale linear bias. Monthly Notices of the Royal Astronomical Society, 493 (1), 747-764. doi: 10.1093/mnras/staa222

  • Can redshift errors bias measurements of the Hubble Constant?

    Davis, Tamara M., Hinton, Samuel R., Howlett, Cullan and Calcino, Josh (2019). Can redshift errors bias measurements of the Hubble Constant?. Monthly Notices of the Royal Astronomical Society, 490 (2), 2948-2957. doi: 10.1093/mnras/stz2652

  • The redshift-space momentum power spectrum II: measuring the growth rate from the combined 2MTF and 6dFGSv surveys

    Qin, Fei, Howlett, Cullan and Staveley-Smith, Lister (2019). The redshift-space momentum power spectrum II: measuring the growth rate from the combined 2MTF and 6dFGSv surveys. Monthly Notices of the Royal Astronomical Society, 487 (4) stz1576, 5235-5247. doi: 10.1093/mnras/stz1576

  • The redshift-space momentum power spectrum – I. Optimal estimation from peculiar velocity surveys

    Howlett, Cullan (2019). The redshift-space momentum power spectrum – I. Optimal estimation from peculiar velocity surveys. Monthly Notices of the Royal Astronomical Society, 487 (4) stz1403, 5209-5234. doi: 10.1093/mnras/stz1403

  • 2MTF - VII. 2MASS Tully-Fisher survey final data release: distances for 2,062 nearby spiral galaxies

    Hong, Tao, Staveley-Smith, Lister, Masters, Karen L, Springob, Christopher M, Macri, Lucas M, Koribalski, Bärbel S, Jones, D Heath, Jarrett, Tom H, Crook, Aidan C, Howlett, Cullan and Qin, Fei (2019). 2MTF - VII. 2MASS Tully-Fisher survey final data release: distances for 2,062 nearby spiral galaxies. Monthly Notices of the Royal Astronomical Society, 487 (2), 2061-2069. doi: 10.1093/mnras/stz1413

  • Bulk flow and shear in the local Universe: 2MTF and COSMICFLOWS-3

    Qin, Fei, Howlett, Cullan, Staveley-Smith, Lister and Hong, Tao (2019). Bulk flow and shear in the local Universe: 2MTF and COSMICFLOWS-3. Monthly Notices of the Royal Astronomical Society, 482 (2), 1920-1930. doi: 10.1093/mnras/sty2826

  • Bulk flow in the combined 2MTF and 6dFGSv surveys

    Qin, Fei, Howlett, Cullan, Staveley-Smith, Lister and Hong, Tao (2018). Bulk flow in the combined 2MTF and 6dFGSv surveys. Monthly Notices of the Royal Astronomical Society, 477 (4), 5150-5166. doi: 10.1093/mnras/sty928

  • Cosmological constraints from fourier phase statistics

    Ali, Kamran, Obreschkow, Danail, Howlett, Cullan, Bonvin, Camille, Llinares, Claudio, Oliveira Franco, Felipe and Power, Chris (2018). Cosmological constraints from fourier phase statistics. Monthly Notices of the Royal Astronomical Society, 479 (2), 2743-2753. doi: 10.1093/mnras/sty1696

  • A short research note on calculating exact distribution functions and random sampling for the 3D NFW profile

    Robotham, A. S. G. and Howlett, Cullan (2018). A short research note on calculating exact distribution functions and random sampling for the 3D NFW profile. Research Notes of the AAS, 2 (2), 55. doi: 10.3847/2515-5172/aacc70

  • Galaxy two-point covariance matrix estimation for next generation surveys

    Howlett, Cullan and Percival, Will J. (2017). Galaxy two-point covariance matrix estimation for next generation surveys. Monthly Notices of the Royal Astronomical Society, 472 (4), 4935-4952. doi: 10.1093/mnras/stx2342

  • 2MTF-VI. Measuring the velocity power spectrum

    Howlett, Cullan, Staveley-Smith, Lister, Elahi, Pascal J., Hong, Tao, Jarrett, Tom H., Jones, D. Heath, Koribalski, Barbel S., Macri, Lucas M., Masters, Karen L. and Springob, Christopher M. (2017). 2MTF-VI. Measuring the velocity power spectrum. Monthly Notices of the Royal Astronomical Society, 471 (3), 3135-3151. doi: 10.1093/mnras/stx1521

  • The Taipan Galaxy Survey: Scientific Goals and Observing Strategy

    da Cunha, Elisabete, Hopkins, Andrew M., Colless, Matthew, Taylor, Edward N., Blake, Chris, Howlett, Cullan, Magoulas, Christina, Lucey, John R., Lagos, Claudia, Kuehn, Kyler, Gordon, Yjan, Barat, Dilyar, Bian, Fuyan, Wolf, Christian, Cowley, Michael J., White, Marc, Achitouv, Ixandra, Bilicki, Maciej, Bland-Hawthorn, Joss, Bolejko, Krzysztof, Brown, Michael J. I., Brown, Rebecca, Bryant, Julia, Croom, Scott, Davis, Tamara M., Driver, Simon P., Filipovic, Miroslav D., Hinton, Samuel R., Johnston-Hollitt, Melanie ... Watson, Fred (2017). The Taipan Galaxy Survey: Scientific Goals and Observing Strategy. Publications of the Astronomical Society of Australia, 34 e047, 1-28. doi: 10.1017/pasa.2017.41

  • Measuring the growth rate of structure with type IA supernovae from LSST

    Howlett, Cullan, Robotham, Aaron S. G., Lagos, Claudia D. P. and Kim, Alex G. (2017). Measuring the growth rate of structure with type IA supernovae from LSST. Astrophysical Journal, 847 (2) aa88c8, 128. doi: 10.3847/1538-4357/aa88c8

  • Cosmological forecasts for combined and next-generation peculiar velocity surveys

    Howlett, Cullan, Staveley-Smith, Lister and Blake, Chris (2017). Cosmological forecasts for combined and next-generation peculiar velocity surveys. Monthly Notices of the Royal Astronomical Society, 464 (3), 2517-2544. doi: 10.1093/mnras/stw2466

  • Cosmology with peculiar velocities: observational effects

    Andersen, P., Davis, T. M. and Howlett, C. (2016). Cosmology with peculiar velocities: observational effects. Monthly Notices of the Royal Astronomical Society, 463 (4), 4083-4092. doi: 10.1093/mnras/stw2252

  • Cosmological implications of baryon acoustic oscillation measurements

    Aubourg, Éric, Bailey, Stephen, Bautista, Julian E., Beutler, Florian, Bhardwaj, Vaishali, Bizyaev, Dmitry, Blanton, Michael, Blomqvist, Michael, Bolton, Adam S., Bovy, Jo, Brewington, Howard, Brinkmann, J., Brownstein, Joel R., Burden, Angela, Busca, Nicolás G., Carithers, William, Chuang, Chia-Hsun, Comparat, Johan, Croft, Rupert A. C., Cuesta, Antonio J., Dawson, Kyle S., Delubac, Timothée, Eisenstein, Daniel J., Font-Ribera, Andreu, Ge, Jian, Le Goff, J. M., Gontcho, Satya Gontcho A., Gott, J. Richard, Gunn, James E. ... Zhao, Gong-Bo (2015). Cosmological implications of baryon acoustic oscillation measurements. Physical Review D - Particles, Fields, Gravitation and Cosmology, 92 (12) 123516. doi: 10.1103/PhysRevD.92.123516

  • Reconstruction in Fourier space

    Burden, A., Percival, W. J. and Howlett, C. (2015). Reconstruction in Fourier space. Monthly Notices of the Royal Astronomical Society, 453 (1), 456-468. doi: 10.1093/mnras/stv1581

  • Galaxy and mass assembly (GAMA): End of survey report and data release 2

    Liske, J., Baldry, I. K., Driver, P., Tuffs, R. J., Alpaslan, M., Andrae, E., Brough, S., Cluver, M. E., Grootes, M. W., Gunawardhana, M. L. P., Kelvin, L. S., Loveday, J., Robotham, A. S. G., Taylor, E. N., Bamford, S. P., Bland-Hawthorn, J., Brown, M. J. I., Drinkwater, M. J., Hopkins, A. M., Meyer, M. J., Norberg, P., Peacock, J. A., Agius, N. K., Andrews, S. K., Bauer, A. E., Ching, J. H. Y., Colless, M., Conselice, C. J., Croom, S. M. ... Wright, A. H. (2015). Galaxy and mass assembly (GAMA): End of survey report and data release 2. Monthly Notices of the Royal Astronomical Society, 452 (2), 2087-2126. doi: 10.1093/mnras/stv1436

  • L-PICOLA: a parallel code for fast dark matter simulation

    Howlett, C., Manera, M. and Percival, W. J. (2015). L-PICOLA: a parallel code for fast dark matter simulation. Astronomy and Computing, 12, 109-126. doi: 10.1016/j.ascom.2015.07.003

  • The clustering of the SDSS DR7 main Galaxy sample - I. A 4 per cent distance measure at z=0.15

    Ross, Ashley J., Samushia, Lado, Howlett, Cullan, Percival, Will J., Burden, Angela and Manera, Marc (2015). The clustering of the SDSS DR7 main Galaxy sample - I. A 4 per cent distance measure at z=0.15. Monthly Notices of the Royal Astronomical Society, 449 (1), 835-847. doi: 10.1093/mnras/stv154

  • The clustering of the SDSS main galaxy sample - II. Mock galaxy catalogues and a measurement of the growth of structure from redshift space distortions at z=0.15

    Howlett, Cullan, Ross, Ashley J., Samushia, Lado, Percival, Will J. and Manera, Marc (2015). The clustering of the SDSS main galaxy sample - II. Mock galaxy catalogues and a measurement of the growth of structure from redshift space distortions at z=0.15. Monthly Notices of the Royal Astronomical Society, 449 (1), 848-866. doi: 10.1093/mnras/stu2693

  • The clustering of galaxies in the SDSS-III baryon oscillation spectroscopic survey: Mock galaxy catalogues for the low-redshift sample

    Manera, Marc, Samushia, Lado, Tojeiro, Rita, Howlett, Cullan, Ross, Ashley J., Percival, Will J., Gil-Marín, Hector, Brownstein, Joel R., Burden, Angela and Montesano, Francesco (2015). The clustering of galaxies in the SDSS-III baryon oscillation spectroscopic survey: Mock galaxy catalogues for the low-redshift sample. Monthly Notices of the Royal Astronomical Society, 447 (1), 437-445. doi: 10.1093/mnras/stu2465

  • The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: galaxy clustering measurements in the low-redshift sample of Data Release 11

    Tojeiro, Rita, Ross, Ashley J., Burden, Angela, Samushia, Lado, Manera, Marc, Percival, Will J., Beutler, Florian, Brinkmann, J., Brownstein, Joel R., Cuesta, Antonio J., Dawson, Kyle, Eisenstein, Daniel J., Ho, Shirley, Howlett, Cullan, McBride, Cameron K., Montesano, Francisco, Olmstead, Matthew D., Parejko, John K., Reid, Beth, Sanchez, Ariel G., Schlegel, David J., Schneider, Donald P., Tinker, Jeremy L., Magana, Mariana Vargas and White, Martin (2014). The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: galaxy clustering measurements in the low-redshift sample of Data Release 11. Monthly Notices of the Royal Astronomical Society, 440 (3), 2222-2237. doi: 10.1093/mnras/stu371

  • The clustering of galaxies in the SDSS-III baryon oscillation spectroscopic survey: Baryon acoustic oscillations in the data releases 10 and 11 galaxy samples

    Anderson, Lauren, Aubourg, Élric, Bailey, Stephen, Beutler, Florian, Bhardwaj, Vaishali, Blanton, Michael, Bolton, Adam S., Brinkmann, J., Brownstein, Joel R., Burden, Angela, Chuang, Chia-Hsun, Cuesta, Antonio J., Dawson, Kyle S., Eisenstein, Daniel J., Escoffier, Stephanie, Gunn, James E., Guo, Hong, Ho, Shirley, Honscheid, Klaus, Howlett, Cullan, Kirkby, David, Lupton, Robert H., Manera, Marc, Maraston, Claudia, McBride, Cameron K., Mena, Olga, Montesano, Francesco, Nichol, Robert C., Nuza, Sebastián E. ... Zhao, Gong-Bo (2014). The clustering of galaxies in the SDSS-III baryon oscillation spectroscopic survey: Baryon acoustic oscillations in the data releases 10 and 11 galaxy samples. Monthly Notices of the Royal Astronomical Society, 441 (1), 24-62. doi: 10.1093/mnras/stu523

  • CMB power spectrum parameter degeneracies in the era of precision cosmology

    Howlett, Cullan, Lewis, Antony, Hall, Alex and Challinor, Anthony (2012). CMB power spectrum parameter degeneracies in the era of precision cosmology. Journal of Cosmology and Astroparticle Physics, 2012 (4) 027, 027-027. doi: 10.1088/1475-7516/2012/04/027

Conference Publication

  • Understanding cosmological measurements with a large number of mock galaxy catalogues

    Manera, M., Percival, W. J., Ross, Ashley, Tojeiro, R., Samushia, L., Howlett, C., Vargas-Magaña, M., Burden, A. and SDSS-III BOSS Galaxy Working Group (2014). Understanding cosmological measurements with a large number of mock galaxy catalogues. 306th Symposium of The International-Astronomical-Union (IAU), Lisbon, Portugal, 25-29 May 2014. CAMBRIDGE: Cambridge University Press (CUP). doi: 10.1017/s1743921314013738

Grants (Administered at UQ)

PhD and MPhil Supervision

Note for students: Dr Cullan Howlett is not currently available to take on new students.

Current Supervision

  • Modelling exotic cosmological models in the era of next generation galaxy surveys

    Doctor Philosophy — Principal Advisor

    Other advisors:

  • Using the motions of galaxies to probe fundamental physics

    Doctor Philosophy — Principal Advisor

    Other advisors:

  • Investigating Gravitational Wave Cosmology with Simulated Data

    Doctor Philosophy — Principal Advisor

    Other advisors:

  • Cosmology with the Dark Energy Survey

    Doctor Philosophy — Associate Advisor

    Other advisors:

  • Measuring Neutrino Mass with the Dark Energy Spectroscopic Instrument

    Doctor Philosophy — Associate Advisor

    Other advisors:

Completed Supervision

Possible Research Projects

Note for students: The possible research projects listed on this page may not be comprehensive or up to date. Always feel free to contact the staff for more information, and also with your own research ideas.

Dr Cullan Howlett is not currently available to take on new students.

  • Testing gravity with the distributions of galaxies

    Maps of the positions of millions of galaxies in our Universe are used to refine our understanding of its components and evolution. However, these experiments have left us with more questions than answers. What is the nature of dark energy and dark matter? Is Einstein’s theory of General Relativity correct on scales beyond our solar system?

    Upcoming surveys aim to answer these questions. But understanding how the distributions and motions of galaxies relate to fundamental physics and how to sift through this enormous amount of data to uncover the truth requires improving our analysis techniques and developing new ways to use the data.

    Many projects are available under this theme, with different emphasis on mathematical theory, data analysis or computer programming. They could involve improving and speeding up methods for simulating the Universe on supercomputers. Or developing new mathematical models for describing how galaxies cluster and move relative to each other. Or, they could involve using real measurements of positions and velocities of galaxies we are currently obtaining or working towards with surveys such as the Dark Energy Spectroscopic Instrument, WALLABY, or the 4MOST Hemisphere Survey.

  • Cosmology with gravitational waves

    Gravitational waves are ripples in space-time that propogate away from massive compact objects as they merge, to hopefully, eventually, be detected here on Earth by the LIGO/Virgo gravitational wave detectors. Gravitational waves hold information on some of the most exotic objects in the Universe such as black holes and neutron stars. They can also be used to test cosmological models, particularly because they act as "Standard Sirens" - the gravitational waveform tells us how far away the merging objects are which then can be used to work out how fast the Universe is expanding and how fast it's large scale structures are growing.

    This project will look at techniques for extracting Standard Siren measurements from gravitational waves. In particular, developing simulated catalogues of gravitational wave events and then using these simulations to work out how best to extract cosmology from the real data. This project brings together a range of fields, from understanding the details of how black holes and neutron stars are formed, to theoretical modelling of future cosmology studies that might be possible once we have hundreds of gravitational waves.

This staff member is a UQ Expert for media in the following fields:

Astronomy, Astrophysics, Cosmology, Dark matter, Dark energy

They are happy to lend their expertise to your articles or broadcasts and share their research discoveries and insights with the community via media channels.

For additional assistance with story ideas, general advice and information or help with seeking further experts, please email the UQ Media Team or telephone (07) 3365 1120.

Links

ORCID: 0000-0002-1081-9410

Scopus ID: 55205036000

Google Scholar ID: M624RNMAAAAJ

Personal Profile: Link

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