Fundamental Physics with the Square Kilometre Array

Weltman, A.; Bull, P.; Camera, S.; Kelley, K.; Padmanabhan, H.; Pritchard, J.; Raccanelli, A.; Riemer-Sørensen, S.; Shao, L.; Andrianomena, S.; Athanassoula, E.; Bacon, D.; Barkana, R.; Bertone, G.; Bonvin, C.; Bosma, A.; Brüggen, M.; Burigana, C.; Bœhm, C.; Calore, F.; Cembranos, J. A. R.; Clarkson, C.; Connors, R. M. T.; de la Cruz-Dombriz, Á.; Dunsby, P. K. S.; Fonseca, J.; Fornengo, N.; Gaggero, D.; Harrison, I.; Larena, J.; Ma, Y. -Z.; Maartens, R.; Méndez-Isla, M.; Mohanty, S. D.; Murray, S. G.; Parkinson, D.; Pourtsidou, A.; Quinn, P. J.; Regis, M.; Saha, P.; Sahlén, M.; Sakellariadou, M.; Silk, J.; Trombetti, T.; Vazza, F.; Venumadhav, T.; Vidotto, F.; Villaescusa-Navarro, F.; Wang, Y.; Weniger, C.; Wolz, L.; Zhang, F.; Gaensler, B. M.

doi:10.48550/arxiv.1810.02680

Cited by 24 publications

(27 citation statements)

References 399 publications

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“…The large field-of-view Xray instrument eROSITA 1 , recently launched, will soon give an unprecedented high-energy map up to 10 keV (Merloni et al 2012), allowing us to search for faint X-ray counterparts along the whole Galactic plane. Data from the Square Kilometre Array (Weltman et al 2018) are also very promising to help identify γ-ray sources. Thus, future VHE observations and multiwavelength data exploitation supported by new generation instruments will probably reveal the nature of a significant number of unidentified TeV sources in order to assess their importance within the issue of the origin of the Galactic CRs.…”

Section: Discussionmentioning

confidence: 99%

Multiwavelength constraints on the unidentified Galactic TeV sources HESS J1427$-$608, HESS J1458$-$608, and new VHE $γ$-ray source candidates

Devin,

Renaud,

Lemoine-Goumard

et al. 2021

Preprint

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Aims. Among the γ-ray sources discovered at high and very-high energies, a large fraction still lack a clear identification. In particular, the H.E.S.S. Galactic Plane Survey (HGPS) revealed 78 TeV sources among which 47 are not clearly associated with a known object. Multiwavelength data can help identify the origin of the very-high energy γ-ray emission, although some bright TeV sources have been detected without clear counterparts. We present a multiwavelength approach to constrain the origin of the emission from unidentified HGPS sources. Methods. We present a generic pipeline that explores a large database of multiwavelength archival data toward any region in the Galactic plane. Along with a visual inspection of the retrieved multiwavelength observations to search for faint and uncataloged counterparts, we derive a radio spectral index that helps disentangle thermal from nonthermal emission and a mean magnetic field through X-ray and TeV data in case of a leptonic scenario. We also search for a spectral connection between the GeV and the TeV regimes with the Fermi-LAT cataloged sources that may be associated with the unidentified HGPS source. We complete the association procedure with catalogs of known objects (supernova remnants, pulsar wind nebulae, H ii regions, etc.) and with the source catalogs from instruments whose data are retrieved.Results. The method is applied on two unidentified sources, namely HESS J1427−608 and HESS J1458−608, for which the multiwavelength constraints favor the pulsar wind nebula (PWN) scenario. We model their broadband nonthermal spectra in a leptonic scenario with a magnetic field B 10 µG, which is consistent with that obtained from ancient PWNe. We place both sources within the context of the TeV PWN population to estimate the spin-down power and the characteristic age of the putative pulsar. We also shed light on two possibly significant γ-ray excesses in the HGPS: the first is located in the south of the unidentified source HESS J1632−478 and the second is spatially coincident with the synchrotron-emitting supernova remnant G28.6−0.1. The multiwavelength counterparts found toward both γ-ray excesses make these promising candidates for being new very-high energy γ-ray sources.

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Section: Discussionmentioning

confidence: 99%

Multiwavelength constraints on the unidentified Galactic TeV sources HESS J1427$-$608, HESS J1458$-$608, and new VHE $γ$-ray source candidates

Devin,

Renaud,

Lemoine-Goumard

et al. 2021

Preprint

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“…The gravitational wave signal of Set 1 is within the reach of future experiments such as LISA [64,65], DECIGO [66,67], and BBO [68][69][70]. For Set 2, the signal crosses the sensitivity bound of SKA [136][137][138] in addition to that of LISA, DECIGO, and BBO. FIG.…”

Section: Detectability Of Induced Gravitational Wavesmentioning

confidence: 91%

Primordial blackholes from Gauss-Bonnet-corrected single field inflation

Kawai,

Kim

2021

Preprint

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Primordial blackholes formed in the early Universe via gravitational collapse of over-dense regions may contribute a significant amount to the present dark matter relic density. Inflation provides a natural framework for the production mechanism of primordial blackholes. For example, single field inflation models with a fine-tuned scalar potential may exhibit a period of ultra-slow-roll, during which the curvature perturbation may be enhanced to become seeds of the primordial blackholes formed as the corresponding scales reenter the horizon. In this work we propose an alternative mechanism for the primordial blackhole formation. We consider a model in which a scalar field is coupled to the Gauss-Bonnet term, and show that primordial blackholes may be seeded when a scalar potential term and the Gauss-Bonnet coupling term are nearly balanced. Large curvature perturbation in this model not only leads to the production of primordial blackholes but it also sources gravitational waves at the second order. We calculate the present density parameter of the gravitational waves and discuss the detectability of the signals by comparing them with sensitivity bounds of future gravitational wave experiments.

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“…We consider a fiducial experiment with T sys = 40 K and satisfying θ B (z) = 20 arcmin at z = 6.1. We take 5 redshift bins in the range z ∈ [4,11] with redshift depth ∆z = 1, and model the CMB noise as…”

Section: Forecastmentioning

confidence: 99%

“…A wide range of cosmological and astrophysical information can be derived from it. Previous work focused primarily on the intensity signal, showing its potential power in constraining fundamental physics [4,5], star and galaxy formation [6], and intergalactic medium [7].…”

Section: Introductionmentioning

confidence: 99%

Cross-correlation of the Polarizations of the 21-cm and Cosmic Microwave Backgrounds

Ji¹,

Hotinli²,

Kamionkowski³

2021

Preprint

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The polarization of the 21-cm radiation from the epoch of reionization arises from Thomson scattering of 21-cm photons from free electrons and provides information that complements that from the intensity fluctuation. Previous work showed that a direct detection of this signal will be difficult, and hinted that the signal might be enhanced via correlation with other tracers. Here, we discuss the cross-correlation between the cosmic microwave background (CMB) polarization and the 21-cm polarization. We treat reionization using an analytical model with parameters calibrated by seminumerical simulations. We then derive the cross-correlation angular power spectrum using the totalangular-momentum formalism. We also provide a noise analysis to test against two closely related, but subtly different, null hypotheses. First, we assume no reionization as a null hypothesis, and determine how well this null hypothesis could be ruled out by an observed 21cm-CMB polarization correlation. Second, we determine how well the null hypothesis of no 21-cm polarization can be ruled out by seeking the cross-correlation, assuming reionization is established from the CMB. We find that the first question could be answered by a synergy of ambitious next-generation 21-cm and CMB missions, whereas the second question will still remain out of reach.

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Fundamental Physics with the Square Kilometre Array

Cited by 24 publications

References 399 publications

Multiwavelength constraints on the unidentified Galactic TeV sources HESS J1427$-$608, HESS J1458$-$608, and new VHE $γ$-ray source candidates

Multiwavelength constraints on the unidentified Galactic TeV sources HESS J1427$-$608, HESS J1458$-$608, and new VHE $γ$-ray source candidates

Primordial blackholes from Gauss-Bonnet-corrected single field inflation

Cross-correlation of the Polarizations of the 21-cm and Cosmic Microwave Backgrounds

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