Surprise, p-value, s-value and a diagnostic procedure to detect not informative experiments

Recchia, Daniela Rodrigues; Ostermann, Thomas; Garćıa, Jesús E.

doi:10.1063/1.4951926

Cited by 6 publications

(10 citation statements)

References 4 publications

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“…This is the expected behaviour since higher energy CREs have larger Larmour radii and, consequently, larger mean free paths, such that they scatter less often. From theory, depending on which kind of turbulence is assumed, µ is expected to be in the range from 0.3 to 0.6 (Strong et al 2007), although such a relation may be seen only for CREs in excess of a few GeV (Recchia et al 2016).…”

Section: Cosmic-ray Diffusion Modelmentioning

confidence: 99%

Calibrating the relation of low-frequency radio continuum to star formation rate at 1 kpc scale with LOFAR

Heesen

Buie

Huff

et al. 2019

A&A

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Context. Radio continuum (RC) emission in galaxies allows us to measure star formation rates (SFRs) unaffected by extinction due to dust, of which the low-frequency part is uncontaminated from thermal (free-free) emission. Aims. We calibrate the conversion from the spatially resolved 140 MHz RC emission to the SFR surface density (Σ SFR ) at 1 kpc scale. Radio spectral indices give us, by means of spectral ageing, a handle on the transport of cosmic rays using the electrons as a proxy for GeV nuclei. Methods. We used recent observations of three galaxies (NGC 3184, 4736, and 5055) from the LOFAR Two-metre Sky Survey (LoTSS), and archival LOw-Frequency ARray (LOFAR) data of NGC 5194. Maps were created with the facet calibration technique and converted to radio Σ SFR maps using the Condon relation. We compared these maps with hybrid Σ SFR maps from a combination of GALEX far-ultraviolet and Spitzer 24 µm data using plots tracing the relation at the highest angular resolution allowed by our data at 1.2 × 1.2-kpc 2 resolution. Results. The RC emission is smoothed with respect to the hybrid Σ SFR owing to the transport of cosmic-ray electrons (CREs) away from star formation sites. This results in a sublinear relation (Σ SFR ) RC ∝ [(Σ SFR ) hyb ] a , where a = 0.59 ± 0.13 (140 MHz) and a = 0.75 ± 0.10 (1365 MHz). Both relations have a scatter of σ = 0.3 dex. If we restrict ourselves to areas of young CREs (α > −0.65; I ν ∝ ν α ), the relation becomes almost linear at both frequencies with a ≈ 0.9 and a reduced scatter of σ = 0.2 dex. We then simulate the effect of CRE transport by convolving the hybrid Σ SFR maps with a Gaussian kernel until the RC-SFR relation is linearised; CRE transport lengths are l = 1-5 kpc. Solving the CRE diffusion equation, assuming dominance of the synchrotron and inverse-Compton losses, we find diffusion coefficients of D = (0.13-1.5) × 10 28 cm 2 s −1 at 1 GeV. Conclusions. A RC-SFR relation at 1.4 GHz can be exploited to measure SFRs at redshift z ≈ 10 using 140 MHz observations.

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Section: Cosmic-ray Diffusion Modelmentioning

confidence: 99%

Calibrating the relation of low-frequency radio continuum to star formation rate at 1 kpc scale with LOFAR

Heesen

Buie

Huff

et al. 2019

A&A

View full text Add to dashboard Cite

show abstract

“…A different class of solutions invoke the breakdown of the hypothesis of a spatially constant diffusion coefficient. For instance, [154] proposed a correlation between the diffusion coefficient parallel to the galactic plane and the source density in order to account for both the CR density gradient and the small observed The data points are from [145] and [146], while the curves refer to the results of [156].…”

Section: Fig 17mentioning

confidence: 99%

“…In the context of models of CR transport with self-generated diffusion and advection the CR accumulation and the harder spectra in the inner Galaxy find a relatively simple explanation [156]: waves are excited more easily where there is more injection, so that the diffusion coefficient is correspondingly smaller and CRs are accumulated there for longer times resulting in a higher CR density. At the same time, advection with self-generated waves remains dominant up to higher energies, thereby implying harder CR spectra.…”

Section: Fig 17mentioning

confidence: 99%

Selected Topics in Cosmic Ray Physics

Aloisio

Blasi

Mitri

et al. 2018

Multiple Messengers and Challenges in Astroparticle Physics

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The search for the origin of cosmic rays is as active as ever, mainly driven by new insights provided by recent pieces of observation. Much effort is being channelled in putting the so called supernova paradigm for the origin of galactic cosmic rays on firmer grounds, while at the highest energies we are trying to understand the observed cosmic ray spectra and mass composition and relating them to potential sources of extragalactic cosmic rays. Interestingly, a topic that has acquired a dignity of its own is the investigation of the transition region between the galactic and extragalactic components, once associated with the ankle and now increasingly thought to be taking place at somewhat lower energies. Here we summarize recent developments in the observation and understanding of galactic and extragalactic cosmic rays and we discuss the implications of such findings for the modelling of the transition between the two.

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“…The escaped electrons, if diffused to Earth, should contribute to the local cosmic ray positron spectrum, suggesting that the Vela X PWN may be one of the positron contributors (Hinton et al 2011). However, AMS-02 measurement shows that the positron fraction saturates at ∼ 300 GeV and likely drops above ∼ 500 GeV (Recchia et al 2018;Aguilar et al 2019), disfavoring the pulsars and PWNe as the origin of the positron excess. Tibaldo et al (2018) found that the TeV nebula of the Vela X PWN has a very hard spectrum above 100 GeV.…”

Section: Introductionmentioning

confidence: 99%

On the Gamma-Ray Nebula of Vela Pulsar. I. Very Slow Diffusion of Energetic Electrons within the TeV Nebula

Bao

Liu

Chen

2019

ApJ

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High-energy particle transport in pulsar wind nebulae (PWNe) plays an essential role in explaining the characteristics revealed in multiwavelength observations. In this paper, the TeV-gamma-ray-emitting electrons in the Vela X PWN are approximated to be injected impulsively when the cocoon is formed due to the interaction between the SNR reverse shock and the PWN. By solving the diffusion-loss equation analytically, we reproduce the broadband spectral energy distribution and surface brightness profile simultaneously. The diffusion coefficient of TeV electrons and positrons, which is well constrained by the spectral and spatial properties of the TeV nebula, is thus determined to be 1 × 10 26 cm 2 s −1 for 10 TeV electrons and positrons. This coefficient is more than three orders of magnitude lower than that in the interstellar medium, in agreement with a constraint recently obtained from HAWC observations of a TeV nebula associated with the Geminga pulsar. These results suggest that slow diffusion of high-energy particles might be common in PWNe.

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Surprise, p-value, s-value and a diagnostic procedure to detect not informative experiments

Cited by 6 publications

References 4 publications

Calibrating the relation of low-frequency radio continuum to star formation rate at 1 kpc scale with LOFAR

Calibrating the relation of low-frequency radio continuum to star formation rate at 1 kpc scale with LOFAR

Selected Topics in Cosmic Ray Physics

On the Gamma-Ray Nebula of Vela Pulsar. I. Very Slow Diffusion of Energetic Electrons within the TeV Nebula

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