Galactic Cosmic-Ray Confinement Time: [ITAL]Ulysses[/ITAL] High Energy Telescope Measurements of the Secondary Radionuclide [TSUP]10[/TSUP]B[CLC]e[/CLC]

Connell, J. J.

doi:10.1086/311437

Cited by 112 publications

(113 citation statements)

References 12 publications

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“…Low-energy data points include ACE data, taken during the solar minimum period 1997−1998(de Nolfo et al 2006. Close to submission of this paper, another ACE analysis was published (George et al 2009 Off-diagonal plots show the 2D marginalised posterior PDFs for the parameters in the same column and same line respectively.…”

Section: Sensitivity To the Choice Of The B/c Datasetmentioning

confidence: 99%

“…For 10 Be/ 9 Be, the data are taken from balloon flights (Hagen et al 1977;Buffington et al 1978;Webber & Kish 1979), including the ISOMAX balloon-borne instrument (Hams et al 2004), and from the IMP-7/8 (Garcia-Munoz et al 1977), ISEE-3 (Wiedenbeck & Greiner 1980), Ulysses (Connell 1998), Voyager (Lukasiak et al 1999), and ACE spacecrafts (Yanasak et al 2001). For 26 Al/ 27 Al, the data consist of a series of balloon flights (Webber 1982), and the ISEE-3 (Wiedenbeck 1983), Voyager (Lukasiak et al 1994), Ulysses , and ACE spacecrafts (Yanasak et al 2001).…”

Section: D2 Isotopic and Elemental Ratios Of Radioactive Speciesmentioning

confidence: 99%

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A Markov Chain Monte Carlo technique to sample transport and source parameters of Galactic cosmic rays

Putze

Derome

Maurin

2010

A&A

150

191

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Context. Ongoing measurements of the cosmic radiation (nuclear, electronic, and γ-ray) are providing additional insight into cosmicray physics. A comprehensive picture of these data relies on an accurate determination of the transport and source parameters of propagation models. Aims. A Markov Chain Monte Carlo method is used to obtain these parameters in a diffusion model. By measuring the B/C ratio and radioactive cosmic-ray clocks, we calculate their probability density functions, placing special emphasis on the halo size L of the Galaxy and the local underdense bubble of size r h . We also derive the mean, best-fit model parameters and 68% confidence level for the various parameters, and the envelopes of other quantities. Methods. The analysis relies on the USINE code for propagation and on a Markov Chain Monte Carlo technique previously developed by ourselves for the parameter determination. Results. The B/C analysis leads to a most probable diffusion slope δ = 0.86 +0.04 −0.04 for diffusion, convection, and reacceleration, or δ = 0.234 +0.006 −0.005 for diffusion and reacceleration. As found in previous studies, the B/C best-fit model favours the first configuration, hence pointing to a high value for δ. These results do not depend on L, and we provide simple functions to rescale the value of the transport parameters to any L. A combined fit on B/C and the isotopic ratios ( 10 Be/ 9 Be, 26 Al/ 27 Al, 36 Cl/Cl) leads to L = 8 +8 −7 kpc and r h = 120 +20 −20 pc for the best-fit model. This value for r h is consistent with direct measurements of the local interstallar medium. For the model with diffusion and reacceleration, L = 4 +1 −1 kpc and r h = 3 +70 −3 pc (consistent with zero). We vary δ, because its value is still disputed. For the model with Galactic winds, we find that between δ = 0.2 and 0.9, L varies from O(0) to O(2) if r h is forced to be 0, but it otherwise varies from O(0) to O(1) (with r h ∼ 100 pc for all δ > ∼ 0.3). The results from the elemental ratios Be/B, Al/Mg, and Cl/Ar do not allow independent checks of this picture because these data are not precise enough. Conclusions. We showed the potential and usefulness of the Markov Chain Monte Carlo technique in the analysis of cosmic-ray measurements in diffusion models. The size of the diffusive halo depends crucially on the value of the diffusion slope δ, and also on the presence/absence of the local underdensity damping effect on radioactive nuclei. More precise data from ongoing experiments are expected to clarify this issue.

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Section: Sensitivity To the Choice Of The B/c Datasetmentioning

confidence: 99%

Section: D2 Isotopic and Elemental Ratios Of Radioactive Speciesmentioning

confidence: 99%

A Markov Chain Monte Carlo technique to sample transport and source parameters of Galactic cosmic rays

Putze

Derome

Maurin

2010

A&A

150

191

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“…Both energy-dependent diffusion and advection in a galactic outflow likely contribute. In the Galaxy, the diffusive escape timescale for 10 GeV protons is inferred to be diA $ 3 ; 10 7 yr near the solar circle (Garcia-Munoz et al 1977;Connell 1998). Such protons interact with a mean total column density of $10 g cm À2 before escaping, and the column decreases at higher energies roughly as E À1 = 2 (e.g., Engelmann et al 1990;Webber et al 2003).…”

Section: Starburst Galaxies As Cosmic Ray Calorimetersmentioning

confidence: 99%

The Starburst Contribution to the Extragalactic γ‐Ray Background

Thompson

Quataert

Waxman

2007

ApJ

178

236

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Cosmic-ray protons interacting with gas at the mean density of the interstellar medium (ISM) in starburst galaxies lose energy rapidly via inelastic collisions with ambient nuclei. The resulting pions produce secondary electrons and positrons, high-energy neutrinos, and -ray photons. We estimate the cumulative -ray emission from starburst galaxies. We find a total integrated background above 100 MeVof F % 10 À6 GeV cm À2 s À1 sr À1 and a corresponding specific intensity at GeV energies of I % 10 À7 GeV cm À2 s À1 sr À1 . Starbursts may thus account for a significant fraction of the extragalactic -ray background. We show that the FIR-radio correlation provides a strong constraint on the -ray emission from starburst galaxies because pions decay into both -rays and radio-emitting electron/ positron pairs. We identify several nearby systems where the potential for observing -ray emission is the most favorable (M82, NGC 253, and IC 342), predict their fluxes, and predict a linear FIRY -ray correlation for the densest starbursts. If established, the FIRY -ray correlation would provide strong evidence for the ''calorimeter'' theory of the FIR-radio correlation and would imply that cosmic rays in starburst galaxies interact with gas at approximately the mean density of the ISM, thereby providing an important constraint on the physics of the ISM in starbursts.

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“…The result (e.g., Simpson & Garcia-Munoz 1988;Lukasiak et al 1994;Connell 1998) is thatρ 0.3ρg, i.e., cosmic rays encounter a mean density about 1/3 of that of the interstellar medium in the disk (ng 1 cm −3 ). This is usually interpreted to mean that the cosmic rays spend a significant part of their lives outside of the disk and in the halo, where the gas density is much lower.…”

Section: Cosmic Ray Data and Energy Requirementsmentioning

confidence: 99%

Standard cosmic ray energetics and light element production

Fields

Olive

Cassé

et al. 2001

A&A

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Abstract. The recent observations of an approximately linear relationship between both Be and B and iron in metal-poor stars has led to a reassessment of the origin of the light elements in the early Galaxy. In addition to standard secondary production of BeB, it is necessary to introduce a production mechanism which is independent of the interstellar metallicity (primary), and in which freshly synthesized C, O and He are accelerated by supernova shock waves. Primary mechanisms are expected to be dominant at low metallicity. At metallicities higher than [O/H] > ∼ −1.75, some existing data indicate that secondary production is dominant. In this paper, we focus on the secondary process, related to the standard Galactic cosmic rays, and we examine the cosmic ray energy requirements for both present and past epochs. We find the power input to maintain the present-day Galactic cosmic ray flux is about 1.5 10 41 erg/s = 5 10 50 erg/century; this estimate includes energy losses from both the escape of high-energy particle and ionization losses from low-energy particles. This implies that, if supernovae are the sites of cosmic ray acceleration, the fraction of explosion energy going to accelerated particles is about ∼30%, a value which we obtain consistently both from considering the present cosmic ray flux and confinement and from the present 9 Be and 6 Li abundances. Using the abundances of 9 Be (and 6 Li) in metal-poor halo stars, we extend the analysis to show the effect of the interstellar gas mass on the standard Galactic cosmic ray energetic constraints on models of Li, Be, and B evolution. The efficiency of the beryllium production per erg may be enhanced in the past by a factor of about 10; thus the energetic requirement by itself cannot be used to rule out a secondary origin of light elements. Only a clear and indisputable observational determination of the O-Fe relation in the halo will discriminate between the two processes.

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Galactic Cosmic-Ray Confinement Time: [ITAL]Ulysses[/ITAL] High Energy Telescope Measurements of the Secondary Radionuclide [TSUP]10[/TSUP]B[CLC]e[/CLC]

Cited by 112 publications

References 12 publications

A Markov Chain Monte Carlo technique to sample transport and source parameters of Galactic cosmic rays

A Markov Chain Monte Carlo technique to sample transport and source parameters of Galactic cosmic rays

The Starburst Contribution to the Extragalactic γ‐Ray Background

Standard cosmic ray energetics and light element production

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