Revisiting the Impact of Axions in the Cooling of White Dwarfs

Melendez, Brenda; Bertolami, Marcelo M. Miller; Althaus, L. G.

doi:10.48550/arxiv.1210.0263

Cited by 5 publications

(7 citation statements)

References 14 publications

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“…4 [74] serves as an additional cooling mechanism for WD and can reduce the tension between current model predictions and data [75]. This issue is, however, subject to ongoing discussion [76].…”

Section: Resultsmentioning

confidence: 99%

First lower limits on the photon-axion-like particle coupling from very high energy gamma-ray observations

2013

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The intrinsic flux of very high-energy (VHE, energy 100 GeV) γ-rays from extragalactic sources is attenuated due to pair production in the interaction with photons of the extragalactic background light (EBL). Depending on the distance of the source, the Universe should be opaque to VHE photons above a certain energy. However, indications exist that the Universe is more transparent than previously thought. A recent statistical analysis of a large sample of VHE spectra shows that the correction for absorption with current EBL models is too strong for the data points with the highest attenuation. An explanation might be the oscillation of VHE photons into hypothetical axionlike particles (ALPs) in ambient magnetic fields. This mechanism would decrease the opacity, as ALPs propagate unimpeded over cosmological distances.Here, a large sample of VHE γ-ray spectra obtained with imaging air Cherenkov telescopes is used to set, for the first time, lower limits on the photon-ALP coupling constant gaγ over a large range of ALP masses. The conversion in different magnetic field configurations, including intracluster and intergalactic magnetic fields together with the magnetic field of the Milky Way, is investigated taking into account the energy dependence of the oscillations. For optimistic scenarios of the intervening magnetic fields, a lower limit on gaγ of the order of 10 −12 GeV −1 is obtained, whereas more conservative model assumptions result in gaγ 2 × 10 −11 GeV −1 . The latter value is within reach of future dedicated ALP searches.

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Section: Resultsmentioning

confidence: 99%

First lower limits on the photon-axion-like particle coupling from very high energy gamma-ray observations

2013

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“…In the last few years some astrophysical anomalies have found plausible explanations in terms of axion/ALPs suggesting target areas in parameter space reachable by near-future experiments. We refer here to the apparent non-standard energy loss of white dwarf stars, e.g., [34][35][36][37][38] (see however [39]) and the anomalous transparency of the Universe for TeV gamma rays, e.g., [40][41][42][43][44][45]. The required coupling strengths seem within reach in controlled laboratory experiments at the intensity frontier, and can serve as useful benchmarks, c.f.…”

Section: Hints From Astrophysicsmentioning

confidence: 99%

Dark Sectors and New, Light, Weakly-Coupled Particles

Essig¹,

Jaros²,

Wester³

et al. 2013

Preprint

317

518

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Dark sectors, consisting of new, light, weakly-coupled particles that do not interact with the known strong, weak, or electromagnetic forces, are a particularly compelling possibility for new physics. Nature may contain numerous dark sectors, each with their own beautiful structure, distinct particles, and forces. This review summarizes the physics motivation for dark sectors and the exciting opportunities for experimental exploration. It is the summary of the Intensity Frontier subgroup "New, Light, Weakly-coupled Particles" of the Community Summer Study 2013 (Snowmass). We discuss axions, which solve the strong CP problem and are an excellent dark matter candidate, and their generalization to axion-like particles. We also review dark photons and other dark-sector particles, including sub-GeV dark matter, which are theoretically natural, provide for dark matter candidates or new dark matter interactions, and could resolve outstanding puzzles in particle and astro-particle physics. In many cases, the exploration of dark sectors can proceed with existing facilities and comparatively modest experiments. A rich, diverse, and lowcost experimental program has been identified that has the potential for one or more game-changing discoveries. These physics opportunities should be vigorously pursued in the US and elsewhere.

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“…One possibility is cooling by emission of 'axions' (e.g. Isern et al 2008;Melendez et al 2012), a light pseudoscalar particle postulated by the Peccei-Quinn theory. Isern et al (2008) argue that the rising slope of the WDLF at M bol < 13 is independent of age, with the shape determined solely by WD cooling rates.…”

Section: Introductionmentioning

confidence: 99%

The star formation history of the solar neighbourhood from the white dwarf luminosity function

Rowell¹

2013

Monthly Notices of the Royal Astronomical Society

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The termination in the white dwarf luminosity function is a standard diagnostic tool for measuring the total age of nearby stellar populations. In this paper, an algorithm is presented for inverting the full white dwarf luminosity function to obtain a maximum likelihood estimate of the time varying star formation rate of the host stellar population. Tests with synthetic data demonstrate that the algorithm converges over a wide class of underlying star formation rate forms. The algorithm successfully estimates the moving average star formation rate as a function of lookback time in the presence of realistic measurement noise, though suffers from degeneracies around discontinuities in the underlying star formation rate. The inversion results are most sensitive to the choice of white dwarf cooling models, with the models produced by different groups giving quite different results. The results are relatively insensitive to the progenitor metallicity, initial mass function, initial-final mass relation and ratio of H/He atmosphere white dwarfs. Application to two independent determinations of the Solar neighbourhood white dwarf luminosity function gives similar results. The star formation rate has a bimodal form, with broad peaks at 2-3 Gyr and 7-9 Gyr in the past, separated by a significant lull of magnitude 30-90% depending on choice of cooling models. The onset of star formation occurs around 8-10 Gyr ago. The total integrated star formation rate is ∼ 0.014 stars/pc 3 in the Solar neighbourhood, for stars more massive than 0.6M ⊙ .

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Revisiting the Impact of Axions in the Cooling of White Dwarfs

Cited by 5 publications

References 14 publications

First lower limits on the photon-axion-like particle coupling from very high energy gamma-ray observations

First lower limits on the photon-axion-like particle coupling from very high energy gamma-ray observations

Dark Sectors and New, Light, Weakly-Coupled Particles

The star formation history of the solar neighbourhood from the white dwarf luminosity function

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