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12–14 Mar 2025
University of Helsinki
Europe/Helsinki timezone

Fishing for light dark matter with pulsars (via Zoom)

13 Mar 2025, 14:00
45m
E204 (University of Helsinki)

E204

University of Helsinki

Gustaf Hällströmin katu 2, 00560 Helsinki
Invited talk Invited talk

Speaker

Nataliya Porayko (SAI)

Description

Pulsars, which are very rapidly spinning neutron stars, can be instrumental in solving the puzzle, which has perplexed the minds of the scientific community for almost a century – dark matter (DM). In the talk I will mainly focus on the light DM candidates that can be searched for in pulsar observables. The ultralight scalar field DM (also known as "fuzzy" DM), consisting of bosons with extremely low masses of m ∼ 1022 eV, solves some of the problems of the conventional cold DM hypothesis. It was shown by Khmelnitsky and Rubakov (2014) that such DM in the Milky Way induces oscillating gravitational potentials, leaving characteristic imprints in the time of arrivals of radio pulses from pulsars. In addition (Ivanov et al 2019, Castillo et al. 2022), the coupling of axion-like particles to photons alters the polarization properties of light, i.e. the plane of polarization of linearly polarized beam propagating through the axion field starts to oscillate with typical frequencies of 108105 Hz. Searches for these two effects were performed in the data of the European Pulsar Timing Array (EPTA), and stringent constraints on the DM density and coupling constant between photons and axion-like particles have been set. In addition, traces of QCD axions with masses of around ~ μeV can be searched for with the spectroscopic observations of pulsars. We discuss the systematics and artifacts in pulsar data that can mimic the signal of interest and possible methods to avoid the existing biases.

Presentation materials

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