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A repeating fast radio burst associated with a persistent radio source
C-H Niu1, K Aggarwal2,3, D Li4,5,6
1National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China.
Nature
|June 8, 2022
Summary
Fast radio bursts (FRBs) can help study the universe. However, a repeating FRB, 20190520B, shows a high dispersion measure from its host galaxy, challenging previous assumptions.
Area of Science:
- Astrophysics
- Cosmology
- Radio Astronomy
Background:
- Fast radio bursts (FRBs) are utilized to probe the intergalactic medium's ionized baryon content.
- Host galaxy contributions to dispersion measure (DM) are generally considered minor.
- Previous studies noted extreme environments and persistent radio sources for some FRBs.
Purpose of the Study:
- To report the detection and localization of a repeating FRB, 20190520B.
- To investigate the host galaxy properties and dispersion measure contribution of FRB 20190520B.
- To assess the impact of host galaxy DM on FRB redshift estimations.
Main Methods:
- Detection and precise localization of the repeating FRB 20190520B.
- Identification of a co-located compact, persistent radio source.
- Association with a dwarf host galaxy and measurement of its redshift (0.241 ± 0.001).
Main Results:
- FRB 20190520B is co-located with a persistent radio source.
- The host galaxy exhibits a high specific-star-formation rate.
- An exceptionally high host-galaxy dispersion measure (DM ≈ 1.2 × 10^4 pc cm⁻³) was measured, significantly exceeding the intergalactic medium contribution.
Conclusions:
- The host galaxy DM for FRB 20190520B is nearly an order of magnitude higher than the average for known FRB host galaxies.
- This finding challenges the assumption that the intergalactic medium dominates the total dispersion measure for all FRBs.
- Accurate host galaxy identification is crucial for reliable FRB redshift determinations.
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