Constraining axion-like-particles with hard X-ray emission from magnetars

Fortin, Jean-François; Sinha, Kuver

doi:10.1007/jhep06(2018)048

Cited by 54 publications

(57 citation statements)

References 62 publications

(130 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, it was pointed out in [19] that vacuum birefringence effects from quantum electrodynamics (QED), in the presence of strong magnetic fields, stymie the axion-photon conversion process. The result is that the axion-induced X-ray flux from NSs is expected to be neg-arXiv:1903.05088v1 [hep-ph] 12 Mar 2019 ligible for a QCD axion, but the flux may still be significant for ALPs [20]. We will discuss these QED effects for MWDs below.…”

Section: W T U B E W G X D C Q 4 E L T Q 4 I U K K J Y U H O H O F S mentioning

confidence: 99%

X-Ray Signatures of Axion Conversion in Magnetic White Dwarf Stars

Dessert

Long

2019

Phys. Rev. Lett.

View full text Add to dashboard Cite

White dwarf (WD) stars may radiate keV-energy axions produced in their stellar cores. This has been extensively studied as an extra channel by which WDs may cool, with some analyses even suggesting that axions can help explain the observed WD luminosity function. We show that the radiated axions may convert into X-rays in the strong magnetic fields surrounding the WDs, leading to observable X-ray signatures. We use Suzaku observations of the WD RE J0317-853 to set the strongest constraints to-date on the combination of the axionelectron (gaee) times axion-photon (gaγγ) couplings, and we show that dedicated observations of magnetic WDs by telescopes such as Chandra, XMM-Newton, and NuSTAR could increase the sensitivity to |gaeegaγγ| by over an order of magnitude, allowing for a definitive test of the axion-like-particle explanation of the stellar cooling anomalies.

show abstract

Section: W T U B E W G X D C Q 4 E L T Q 4 I U K K J Y U H O H O F S mentioning

confidence: 99%

X-Ray Signatures of Axion Conversion in Magnetic White Dwarf Stars

Dessert

Long

2019

Phys. Rev. Lett.

View full text Add to dashboard Cite

show abstract

“…We utilize the methods of our previous paper [6] to display the dependence of R on the photon energy as well as ALP parameters. As a benchmark point, we take the CAST-allowed values for the ALP mass and coupling, m a = 10 −8 keV and g/e = 5 × 10 −17 keV −1 , respectively.…”

Section: 2)mentioning

confidence: 99%

“…Our paper is organized as follows. In Section 2, we recapitulate the ALP-photon coupled system and the results of [6]. In Section 3, we perform the calculation of the Stokes parameters.…”

Section: 2)mentioning

confidence: 99%

“…The evolution of the ALP-photon system in the magnetic field of the magnetar is conveniently described in terms of a set of first-order differential equations coupling the amplitudes and phase difference of the ALP and photon fields. This parametrization has been shown to drastically simplify numerical analyses of the system [6]. The uncorrelated production mechanism of ALPs and photons alluded to above allows us to average over the initial phase differences.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

X-ray polarization signals from magnetars with axion-like-particles

Fortin

Sinha

2019

J. High Energ. Phys.

Self Cite

View full text Add to dashboard Cite

Axion-like-particles (ALPs) produced in the core of a magnetar can convert to photons in the magnetosphere, giving rise to novel features in the X-ray spectrum. Since ALPs only mix with the parallel mode of the photon, the polarization of the soft and hard X-ray spectra is predicted to have an O-mode component, in addition to the mainly X-mode component given by most astrophysical models. The relative strength of the O-mode component depends on the intensity of ALPs produced in the core and the probability of conversion. We quantify our results by considering X-ray emission produced both by astrophysical processes and by ALP-photon conversion, in an uncorrelated fashion, and in different relative proportions, which we parametrize by the angle χ 0 . We then define a normalized astrophysics-subtracted Stokes parameter R which only acquires non-zero values in the presence of ALP-photon conversion. We find, remarkably, that the parameter R factorizes into a product of the ALP-to-photon conversion probability and cos(2χ 0 ) and display R, as well as the usual Stokes parameter Q, as a function of the photon energy and relative fractions of ALP and photon intensities. For benchmark points currently allowed by the CAST experiment, the O-mode prediction can be tested in future X-ray polarimeters and used either to constrain ALPs or find evidence for them.July 2018

show abstract

“…More attention has been paid to axion to X-ray photon inter-conversion in pulsars [64] and in axion like particle (ALP) to X-ray conversion in the higher B field (20 × 10 14 G) of magnetars by [65]. [65] finds P a → γ =0.225 for ω = 3 keV (the peak emission) and P a → γ = 0.025 for ω = 200 keV when T c =50−250 keV. The lower B field of our sample notwithstanding (average B=2.78 × 10 12 G) such values of P a → γ and T c could yield constraints on m a in the classic axion search range using the alternative model ( Fig.…”

Section: Energy Differential Fluxmentioning

confidence: 99%

Constraining the axion mass through gamma-ray observations of pulsars

2019

View full text Add to dashboard Cite

We analyze 9 years of pass 8 Fermi -LAT data in the 60−500 MeV range and determine flux upper limits (UL) for 17 gamma-ray dark pulsars as a probe of axions produced by nucleon-nucleon Bremsstrahlung in the pulsar core. Using a previously published axion decay gamma-ray photon flux model for pulsars which relies on a high core temperature of 20 MeV, we improve the determination of the UL axion mass (m a ), at 95 percent confidence level, to 9.6 × 10 -3 eV, which is a factor of 8 improvement on previous results. We show that the axion emissivity (energy loss rate per volume) at realistic lower pulsar core temperatures of 4 MeV or less is reduced to such an extent that axion emissivity and the gamma-ray signal becomes negligible. We consider an alternative emission model based on energy loss rate per mass to allow m a to be constrained with Fermi -LAT observations. This model yields a plausible UL m a of 10 -6 eV for pulsar core temperature <0.1 MeV but knowledge of the extent of axion to photon conversion in the pulsar B field would be required to make a precise UL axion mass determination. The peak of axion flux is likely to produce gamma-rays in the ≤ 1 MeV energy range and so future observations with medium energy gamma-ray missions, such as AMEGO and e-ASTROGAM, will be vital to further constrain UL m a .

show abstract

Constraining axion-like-particles with hard X-ray emission from magnetars

Cited by 54 publications

References 62 publications

X-Ray Signatures of Axion Conversion in Magnetic White Dwarf Stars

X-Ray Signatures of Axion Conversion in Magnetic White Dwarf Stars

X-ray polarization signals from magnetars with axion-like-particles

Constraining the axion mass through gamma-ray observations of pulsars

Contact Info

Product

Resources

About