A census of baryons in the Universe from localized fast radio bursts

Macquart, Jean–Pierre; Prochaska, J. Xavier; McQuinn, Matthew; Bannister, K. W.; Bhandari, Shivani; Day, Cherie K.; Deller, Adam T.; Ekers, R. D.; James, C. W.; Marnoch, Lachlan; Osłowski, S.; Phillips, Chris; Ryder, S. D.; Scott, Danica R.; Shannon, R. M.; Tejos, Nicolás

doi:10.1038/s41586-020-2300-2

Cited by 512 publications

(645 citation statements)

References 62 publications

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“…Some FRBs show no evidence for scintillation (which may be masked by the instrumental resolution) (e.g., Ravi 2019) and others show scintillation that is constant across multiple components (e.g., Farah et al 2018Farah et al , 2019. However, FRB 190611, a two-component burst detected by ASKAP and tentatively localized to a host galaxy at z=0.378 (Macquart et al 2020), shows qualitative similarities with the picture described here (Day et al 2020). The two components separated by ∼1 ms show evidence of scintillation from the Milky Way ISM (consistent between the two components) in addition to an overall envelope that has a central frequency 48 MHz higher for the latter component (Day et al 2020).…”

Section: Extragalactic Frbsmentioning

confidence: 65%

Scintillation Can Explain the Spectral Structure of the Bright Radio Burst from SGR 1935+2154

Simard

Ravi

2020

ApJL

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The discovery of a fast radio burst (FRB) associated with a magnetar in the Milky Way by the Canadian Hydrogen Intensity Mapping Experiment FRB collaboration (CHIME/FRB) and the Survey for Transient Astronomical Radio Emission 2 has provided an unprecedented opportunity to refine FRB emission models. The burst discovered by CHIME/FRB shows two components with different spectra. We explore interstellar scintillation as the origin for this variation in spectral structure. Modeling a weak scattering screen in the supernova remnant associated with the magnetar, we find that a superluminal apparent transverse velocity of the emission region of >9.5c is needed to explain the spectral variation. Alternatively, the two components could have originated from independent emission regions >8.3×10 4 km apart. These scenarios may arise in "far-away" models where the emission originates from well beyond the magnetosphere of the magnetar (for example, through a synchrotron maser mechanism set up by an ultrarelativistic radiative shock), but not in "close-in" models of emission from within the magnetosphere. If further radio observations of the magnetar confirm scintillation as the source of the observed variation in spectral structure, this scattering model thus constrains the location of the emission region.

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Section: Extragalactic Frbsmentioning

confidence: 65%

Scintillation Can Explain the Spectral Structure of the Bright Radio Burst from SGR 1935+2154

Simard

Ravi

2020

ApJL

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“…In projecting electron density the measurement appeals to a flat ΛCDM CMB-fitted model (Planck collaboration [8]). Presently, ω b,0 is extracted from the ASKAP data in [59] to be consistent with CMB fits and BBN albeit subject to a 50% error which is expected to decrease with the advent of more powerful radio observatories such as SKA.…”

Section: Su(2) Cmb Fit Of Cosmological Parameters To Planck Datamentioning

confidence: 85%

“…This results is disputed in [58]. In [59] the missing baryon problem is addressed by the measurement of electron column density within the intergalactic medium using the dispersion of localised radio bursts with z ≤ 0.522. In projecting electron density the measurement appeals to a flat ΛCDM CMB-fitted model (Planck collaboration [8]).…”

Section: Su(2) Cmb Fit Of Cosmological Parameters To Planck Datamentioning

confidence: 99%

An SU(2) Gauge Principle for the Cosmic Microwave Background: Perspectives on the Dark Sector of the Cosmological Model

Hofmann¹

2020

Universe

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We review consequences for the radiation and dark sectors of the cosmological model arising from the postulate that the Cosmic Microwave Background (CMB) is governed by an SU(2) rather than a U(1) gauge principle. We also speculate on the possibility of actively assisted structure formation due to the de-percolation of lump-like configurations of condensed ultralight axions with a Peccei–Quinn scale comparable to the Planck mass. The chiral-anomaly induced potential of the axion condensate receives contributions from SU(2)/SU(3) Yang–Mills factors of hierarchically separated scales which act in a screened (reduced) way in confining phases.

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“…It is clear that FRBs are at cosmological distances, now revealing the baryonic content of the universe on gigaparsec scales (Macquart et al 2020). Assuming a typical redshift for a gravitational lens of z l = 0.4, the corresponding physical time units is (Eqn.…”

Section: Observabilitymentioning

confidence: 99%

Gravitational microlensing time delays at high optical depth: image parities and the temporal properties of fast radio bursts

Lewis

2020

Monthly Notices of the Royal Astronomical Society

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Due to differing gravitational potentials and path lengths, gravitational lensing induces time delays between multiple images of a source which, for solar mass objects, is of order ∼10−5 seconds. If an astrophysically compact source, such as a Fast Radio Burst (FRB), is observed through a region with a high optical depth of such microlensing masses, this gravitational lensing time delay can be imprinted on short timescale transient signals. In this paper, we consider the impact of the parity of the macroimage on the resultant microlensing time delays. It is found that this parity is directly imprinted on the microlensing signal, with macroimages formed at minima of the time arrival surface beginning with the most highly magnified microimages and then progressing to the fainter microimages. At macroimages at the maxima of the time arrival surface, this situation is reversed, with fainter images observed first and finishing with the brightest microimages. For macroimages at saddle-points, the signal again begins with fainter images, followed by brighter images before again fading through the fainter microimages. The growing populations of cosmologically distant bursty transient sources will undoubtedly result in the discovery of strong lensed, multiply imaged FRBs, which will be susceptible to microlensing by compact masses. With the temporal resolution being offered my modern and future facilities, the detection of microlensing induced time delays will reveal the parities of the gravitational lens macroimages, providing additional constraints on macrolensing mass models and improving the efficacy of these transient sources as a cosmological probes.

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A census of baryons in the Universe from localized fast radio bursts

Cited by 512 publications

References 62 publications

Scintillation Can Explain the Spectral Structure of the Bright Radio Burst from SGR 1935+2154

Scintillation Can Explain the Spectral Structure of the Bright Radio Burst from SGR 1935+2154

An SU(2) Gauge Principle for the Cosmic Microwave Background: Perspectives on the Dark Sector of the Cosmological Model

Gravitational microlensing time delays at high optical depth: image parities and the temporal properties of fast radio bursts

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