I’m a Schmidt “AI in Science” Fellow in the University of Chicago’s Kavli Institute for Cosmological Physics.

I work broadly within the realm of gravitational-wave astronomy. Nearly infinitesimal ripples in the fabric of spacetime, gravitational waves are generated by the most cataclysmic events in the Universe, including the explosions of stars and the relativistic collisions of black holes. My interests lie in the continued search for gravitational waves, the development of new and more powerful detection methods, and the use of gravitational waves as tools with which to answer novel astrophysical questions.

Before the KICP, I worked as a Research Fellow at the Flatiron Institute’s Center for Computational Astrophysics. I completed my Ph.D. in Physics at Caltech, after obtaining an M.Phil. in Astronomy at the University of Cambridge (funded by a Churchill Scholarship). Before Cambridge, I attended Carleton College in Northfield, MN.


Selected Publications


  • Gravitational waves carry information beyond effective spin parameters but it is hard to extract.
    S. Miller, Z. Koe, T. Callister, K. Chatziioannou. Submitted to Phys. Rev. D. ArXiv 2401.05613


  • A New Probe of Gravitational Parity Violation Through (Non-)Observation of the Stochastic Gravitational- Wave Background.
    T. Callister, L. Jenks, D. Holz, N. Yunes. Submitted to Phys. Rev. X. ArXiv 2312.12532
  • The metallicity dependence and evolutionary times of merging binary black holes: Combined constraints from individual gravitational-wave detections and the stochastic background.
    K. Turbang, M. Lalleman, T. Callister, N. van Remortel. Submitted to ApJ. ArXiv 2310.17625
  • A parameter-free tour of the binary black hole population.
    T. Callister, W. Farr. Phys. Rev. X (In Press). ArXiv 2302.07289
  • The population of merging compact binaires inferred using gravitational waves through GWTC-3.
    LIGO, Virgo, and KAGRA Collaborations (Writing Team & Core Analyst). Phys. Rev. X 13, 011048 (2023). ArXiv: 2111.03634


  • No evidence that the majority of black holes in binaries have zero spin.
    T. Callister, S. Miller, K. Chatziioannou, W. Farr. Astrophys. J. Letters 937, L13 (2022). ArXiv 2205.08574
  • The binary black hole spin distribution likely broadens with redshift.
    S. Biscoveanu, T. Callister, C. J. Haster, et al. Astrophys. J. Letters 932, L19 (2022) ArXiv: 2204.01578
  • Gravitational-wave geodesy: Defining false alarm probabilies with respect to correlated noise.
    K. Janssens, T. Callister, N. Christensen, et al. Phys. Rev. D 105, 082001 (2022). ArXiv: 2112.03560
  • The redshift evolution of the binary black hole merger rate: a weighty matter.
    L. van Son, S. de Mink, T. Callister, et al. Astrophysical J. 931, 17 (2022). ArXiv: 2110.01634
  • LIGO-Virgo correlations between mass ratio and effective inspiral spin: testing the active galactic nuclei channel.
    B. McKernan, K. E. S. Ford, T. Callister, et al. Mon. Not. Roy. Astron. Soc. 514, 3886 (2022). ArXiv: 2107.07551


  • Who Ordered That? Unequal-mass binary black hole mergers have larger effective spins.
    T. Callister, C. J. Haster, K. Y. Ng, S. Vitale, and W. Farr. Astrophysical J. Letters 922, L5 (2021). ArXiv: 2106.00521
  • Prospects of gravitational-wave detections from common-envelope evolution with LISA.
    M. Renzo, T. Callister, K. Chatziioannou, L. A. C. van Son, et al. Astrophysical J. 919, 128 (2021). ArXiv: 2102.00078
  • State of the field: Binary black hole spins, natal kicks, and prospects for isolated field formation after GWTC-2.
    T. Callister, W. M. Farr, M. Renzo. Astrophysical J. 920, 157 (2021). ArXiv: 2011.09570
  • A Thesaurus for Common Priors in Gravitational-Wave Astronomy.
    T. Callister. ArXiv Note: 2104.09508
  • Implications for first-order cosmological phase transitions from the third LIGO-Virgo observing run.
    A. Romero, K. Martinovic, T. Callister, et al. Physical Review Letters 126, 151301 (2021). ArXiv: 2102.01714
  • Upper Limits on the Isotropic Gravitational-Wave Background from Advanced LIGO's and Advanced Virgo's Third Observing Run.
    LIGO, Virgo, and KAGRA Collaborations (Writing Team & Core Analyst). Phys. Rev. D 104, 022004 (2021). ArXiv: 2101.12130
  • When are LIGO/Virgo's Big Black-Hole Mergers?
    M. Fishbach, Z. Doctor, T. Callister, et al. Astrophys. J. 912, 98 (2021). ArXiv: 2101.07699
  • Joint constraints on the field-cluster mixing fraction, common envelope efficiency, and globular cluster radii from a population of binary hole mergers via deep learning.
    K. Wong, K. Breivik, K. Kremer, T. Callister. Phys. Rev. D 103, 083021 (2021). ArXiv: 2011.03564
  • Population Properties of Compact Objects from the Second LIGO-Virgo Gravitational-Wave Transient Catalog.
    LIGO Scientific Collaboration and Virgo Collaboration (Writing Team & Core Analyst). Astrophys. J. Letters 913, L7 (2021). ArXiv: 2010.14533


  • Shouts and Murmurs: Combining Individual Gravitational-Wave Sources with the Stochastic Background to Measure the History of Binary Black Hole Mergers.
    T. Callister, M. Fishbach, D. Holz, W. Farr. Astrophys. J. Letters 896, L32 (2020). ArXiv: 2003.12152
  • The Low Effective Spin of Binary Black Holes and Implications for Individual Gravitational-Wave Events.
    S. Miller, T. A. Callister, W. Farr. Astrophys. J. 895, 128 (2020). ArXiv: 2001.06051


  • A First Search for Prompt Radio Emission from a Gravitational-Wave Event.
    T. A. Callister, M. M. Anderson, G. Hallinan, et al. Astrophys. J. Letters 877, L39 (2019). ArXiv: 1903.06786
  • A search for the isotropic stochastic background using data from Advanced LIGO’s second observing run.
    LIGO Scientific Collaboration and Virgo Collaboration (Writing Team & Core Analyst). Phys. Rev. D 100, 061101 (2019). ArXiv: 1903.02886
  • First Search for a Stochastic Gravitational-Wave Background from Ultralight Bosons.
    L. Tsukada, T. Callister, A. Matas, P. Meyers. Phys. Rev. D 99, 103015 (2019). ArXiv: 1812.09622


  • Gravitational-Wave Geodesy: A New Tool for Validating Detection of the Stochastic Gravitational-Wave Background.
    T. A. Callister, M. W. Coughlin, J. B. Kanner. Astrophys. J. Letters 869, L28 (2018). ArXiv: 1808.03716
  • A Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background. LIGO Scientific Collaboration and Virgo Collaboration (Lead Author). Phys. Rev. Lett. 120, 201102 (2018). ArXiv: 1802.10194
  • Identification and mitigation of narrow spectral artifacts that degrade searches for persistent gravitational waves in the first two observing runs of Advanced LIGO.
    P. B. Covas et al. (incl. T. Callister) Phys. Rev. D 97, 082002 (2018). ArXiv: 1801.07204


  • Polarization-based tests of gravity with the stochastic gravitational-wave background. T. Callister, S. A. Biscoveanu, N. Christensen, M. Isi, A. Matas, et al. Phys. Rev. X 7, 041058 (2017). ArXiv: 1704.08373
  • Observing gravitational waves with a single detector. T. A. Callister, J. B. Kanner, T. J. Massinger, S. Dhurandhar, and A. J. Weinstein. Class. Quantum Grav. 34, 155007 (2017). ArXiv: 1704.00818


  • Limits of astrophysics with gravitational-wave backgrounds.
    T. Callister, L. Sammut, S. Qiu, I. Mandel, and E. Thrane. Phys. Rev. X 6, 031018 (2016). ArXiv: 1604.02513
  • Gravitational-wave constraints on the progenitors of fast radio bursts.
    T. Callister, J. Kanner, and A. Weinstein. Astrophys. J. Letters 825, L12 (2016). ArXiv: 1603.08867