The Second Radio Synchrotron Background Workshop: Conference Summary and Report

Singal, J.; Fornengo, N.; Regis, Marco; Bernardi, G.; Bordenave, David D.; Branchini, E.; Cappelluti, N.; Caputo, Andrea; Carucci, Isabella P.; Chluba, Jens; Cuoco, A.; DiLullo, Christopher; Fialkov, Anastasia; Hale, C. L.; Harper, Stuart E.; Heston, S.; Holder, Gil; Kogut, A.; Krause, Martin; Leahy, J. P.; Mittal, Shikhar; Monsalve, Raul A.; Piccirilli, G.; Pinetti, Elena; Recchia, S.; Taoso, Marco; Todarello, E.

doi:10.1088/1538-3873/acbdbf

Cited by 12 publications

(2 citation statements)

References 280 publications

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“…In the faintest regime, the connection of counts with the isotropic radio background is somewhat puzzling. Indeed, an apparent bright high Galactic latitude diffuse radio zero level has been reported by different experiments (see [2] for a recent review). The ARCADE 2 collaboration highlighted the fact that such emission is significantly brighter than expected contributions both of Galactic and extragalactic origin [3].…”

Section: Introductionmentioning

confidence: 81%

Constraining below-threshold radio source counts with machine learning

Todarello,

Scaffidi,

Regis

et al. 2024

J. Cosmol. Astropart. Phys.

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We propose a machine-learning-based technique to determine the number density of radio sources as a function of their flux density, for use in next-generation radio surveys. The method uses a convolutional neural network trained on simulations of the radio sky to predict the number of sources in several flux bins. To train the network, we adopt a supervised approach wherein we simulate training data stemming from a large domain of possible number count models going down to fluxes a factor of 100 below the threshold for source detection. We test the model reconstruction capabilities as well as benchmark the expected uncertainties in the model predictions, observing good performance for fluxes down to a factor of ten below the threshold. This work demonstrates that the capabilities of simple deep learning models for radio astronomy can be useful tools for future surveys.

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Section: Introductionmentioning

confidence: 81%

Constraining below-threshold radio source counts with machine learning

Todarello,

Scaffidi,

Regis

et al. 2024

J. Cosmol. Astropart. Phys.

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“…Both concerns and the rebuttal have been addressed respectively in [30][31][32]. It is anyway important that a few experiments, in addition to SARAS 3, are underway to test the EDGES claimed anomaly in next years, including: the Large-aperture Experiment to Detect the Dark Ages (LEDA) [33], the Mapper of the IGM Spin Temperature (MIST) [34], Probing Radio Intensity at High-Z from Marion (PRIZM) [35], the Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) [36], and Hydrogen Epoch of Reionization Array (HERA) [37]. Moreover, space and lunar-based global 21 cm experiments, such as Discovering Sky at the Longest wavelength (DSL) [38], the Lunar Surface Electromagnetic Experiment (LuSEE) [39] and Probing ReionizATion of the Universe using Signal from Hydrogen (PRATUSH) [40], are also planned to start operating in the next few years.…”

Section: Jcap04(2024)046mentioning

confidence: 99%

Relic neutrino decay solution to the excess radio background

Bhupal Dev,

Bari,

Martínez-Soler

et al. 2024

J. Cosmol. Astropart. Phys.

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The excess radio background detected by ARCADE 2 represents a puzzle within the standard cosmological model. There is no clear viable astrophysical solution, and therefore, it might indicate the presence of new physics. Radiative decays of a relic neutrino ν_i (either i=1, or i=2, or i=3) into a sterile neutrino ν_ s, assumed to be quasi-degenerate, provide a solution that currently evades all constraints posed by different cosmological observations and reproduces very well the ARCADE 2 data. We find a very good fit to the ARCADE 2 data with best fit values τ_i = 1.46 × 10^21 s and Δ m_i = 4.0 × 10^-5 eV, where τ_i is the lifetime and Δ m_i is the mass difference between the decaying active neutrino and the sterile neutrino. On the other hand, if relic neutrino decays do not explain ARCADE 2 data, then these place a stringent constraint Δ m_i^3/2τ_i ≳ 2 × 10^14 eV^3/2 s in the range 1.4 × 10^-5 eV<Δ m_i < 2.5 × 10^-4 eV. The solution also predicts a stronger 21 cm absorption global signal than the predicted one from the ΛCDM model, with a contrast brightness temperature T_21 = -238^+21_-20 mK (99% C.L.) at redshift z≃ 17. This is in mild tension with the even stronger signal found by the EDGES collaboration, T_21 = - 500^+200_-500 mK, suggesting that this might have been overestimated, possibly receiving a contribution from some unidentified foreground source.

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Uncertainties of the 30–408 MHz Galactic emission as a calibration source for radio detectors in astroparticle physics

Büsken,

Fodran,

Huege

2023

A&A

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Context. Arrays of radio antennas have proven to be successful in astroparticle physics with the observation of extensive air showers initiated by high-energy cosmic rays in the Earth’s atmosphere. Accurate determination of the energy scale of the primary particles’ energies requires an absolute calibration of the radio antennas for which, in recent years, the utilization of the Galactic emission as a reference source has emerged as a potential standard. Aims. To apply the “Galactic calibration” a proper estimation of the systematic uncertainties on the prediction of the Galactic emission from sky models is necessary, which we aim to quantify on a global level and for the specific cases of selected radio arrays. We further aim to determine the influence of additional natural radio sources on the Galactic calibration. Methods. We compared seven different sky models that predict the full-sky Galactic emission in the frequency range from 30 to 408 MHz. We made an inventory of the reference maps on which they rely and used the output of the models to determine their global level of agreement. We subsequently took typical sky exposures and the frequency bands of selected radio arrays into account and repeated the comparison for each of them. Finally, we studied and discuss the relative influence of the quiet Sun, the ionosphere, and Jupiter. Results. We find a systematic uncertainty of 14.3% on the predicted power from the Galactic emission, which scales to approximately half of that value as the uncertainty on the determination of the energy of cosmic particles. When looking at the selected radio arrays, the uncertainty on the predicted power varies between 11.7% and 21.5%. The influence of the quiet Sun turns out to be insignificant at the lowest frequencies but increases to a relative contribution of ~30% around 400 MHz.

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The Second Radio Synchrotron Background Workshop: Conference Summary and Report

Cited by 12 publications

References 280 publications

Constraining below-threshold radio source counts with machine learning

Constraining below-threshold radio source counts with machine learning

Relic neutrino decay solution to the excess radio background

Uncertainties of the 30–408 MHz Galactic emission as a calibration source for radio detectors in astroparticle physics

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