Simon Fraser University
SFU Cosmology Seminars

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Tuesday, 12 May 2020, 12:00 in Zoom

Prof. Levon Pogosian (SFU)

Relieving the Hubble tension with primordial magnetic fields

The standard cosmological model determined from the accurate cosmic microwave background measurements made by the Planck satellite implies a value of the Hubble constant H0 that is 4.4 standard deviations lower than the one determined from Type Ia supernovae. The Planck best fit model also predicts higher values of the matter density fraction Ωm and clustering amplitude σ8 compared to those obtained from the Dark Energy Survey Year 1 data. Here we show that accounting for the enhanced recombination rate due to additional small-scale inhomogeneities in the baryon density may solve both the H0 and the σ8-Ωm tensions. The additional baryon inhomogeneities can be induced by primordial magnetic fields present in the plasma prior to recombination. The required field strength to solve the Hubble tension is just what is needed to explain the existence of galactic, cluster, and extragalactic magnetic fields without relying on dynamo amplification. Our results show clear evidence for this effect and motivate further detailed studies of primordial magnetic fields, setting several well-defined targets for future observations.

Seminars in 2019:

2019-09-10 14:30 in P8445B - Gabor Kunstatter (University of Winnipeg/SFU): What can quantum gravity tell us about the beginning and end of time?
2019-09-17 14:30 in P8445B - Andrei Frolov (SFU): Dust is everywhere
2019-10-08 14:30 in P8445B - Douglas Scott (UBC): Evaporating evidence for Hawking points
2019-10-22 14:30 in P8445B - Arif Babul (UVic): Cosmology with galaxy clusters
2019-11-19 14:30 in P8445B - Richard Shaw (UBC): Probing Dark Energy with CHIME
2019-11-26 14:30 in P8445B - Joanna Woo (SFU): Primer on machine learning for astronomy
2019-12-03 14:30 in P8445B - Ludovic Van Waerbeke (UBC): Axion Quark Nuggets: a candidate for baryonic, cold and strongly interacting dark matter
2020-01-20 15:00 in P8445B - Francesc Ferrer (Washington University): Gravitational wave signals of early universe axion dynamics
2020-02-14 14:30 in C9000 - Katie Mack (North Carolina State University): Dark matter: a cosmological perspective (physics colloquium)
2020-02-26 14:30 in P8445B - Paul Wiegert (University of Western Ontario): Interstellar asteroids and comets: what are they and where do they come from?
2020-02-28 14:30 in C9000 - Sara Ellison (University of Victoria): Clash of the Titans: Galaxy mergers in the nearby Universe (physics colloquium)
2020-05-12 12:00 in Zoom - Levon Pogosian (SFU): Relieving the Hubble tension with primordial magnetic fields
2020-05-19 12:00 in Zoom - José Tomas Gálvez Ghersi (University of Mississippi): Numerical renormalization group-based approach to secular perturbation theory
2020-06-02 12:00 in Zoom - Leo Stein (University of Mississippi): Gravitational-wave tests of GR with simulations of beyond-GR theories
2020-06-16 12:00 in Zoom - Andrei Frolov (Simon Fraser Univeristy): Primordial non-Gaussianity from preheating
2020-07-02 14:30 in Zoom - Jack Gegenberg (University of New Brunswick): Collapse of a rotating shell in 3+1 dimensions (special seminar)
2020-07-07 12:00 in Zoom - Joanna Woo (Simon Fraser Univeristy): Machine learning as a tool for astrophysics
2020-07-28 12:00 in Zoom - José Tomas Gálvez Ghersi (University of Mississippi): A fixed point for black hole distributions

[ See complete seminar archives | iCal feed ]

Modified by Andrei Frolov <frolov@sfu.ca> on 2023-11-01