THE X-RAY LINE FEATURE AT 3.5 KeV IN GALAXY CLUSTER SPECTRA

Phillips, K. J. H.; Sylwester, B.; Sylwester, J.

doi:10.1088/0004-637x/809/1/50

Cited by 29 publications

(30 citation statements)

References 34 publications

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“…Ref. [632] analyze high-resolution solar flare spectra and find that the coronal potassium abundance is a factor of 9-11 higher than the photospheric abundances assumed in the above analyzes, offering a explanation as to why the flux of these lines may be brighter than expected. It is, however, not clear why the solar corona should exhibit similar isotopic abundances to the IGM, as the metallicity is generally expected to be higher near stars.…”

Section: 5 Kev Linementioning

confidence: 88%

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A White Paper on keV sterile neutrino Dark Matter

Adhikari

Agostini

et al. 2017

J. Cosmol. Astropart. Phys.

372

316

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Abstract. We present a comprehensive review of keV-scale sterile neutrino Dark Matter, collecting views and insights from all disciplines involved -cosmology, astrophysics, nuclear, and particle physics -in each case viewed from both theoretical and experimental/observational perspectives. After reviewing the role of active neutrinos in particle physics, astrophysics, and cosmology, we focus on sterile neutrinos in the context of the Dark Matter puzzle. Here, we first review the physics motivation for sterile neutrino Dark Matter, based on challenges and tensions in purely cold Dark Matter scenarios. We then round out the discussion by critically summarizing all known constraints on sterile neutrino Dark Matter arising from astrophysical observations, laboratory experiments, and theoretical considerations. In this context, we provide a balanced discourse on the possibly positive signal from X-ray observations. Another focus of the paper concerns the construction of particle physics models, aiming to explain how sterile neutrinos of keV-scale masses could arise in concrete settings beyond the Standard Model of elementary particle physics. The paper ends with an extensive review of current and future astrophysical and laboratory searches, highlighting new ideas and their experimental challenges, as well as future perspectives for the discovery of sterile neutrinos.

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Section: 5 Kev Linementioning

confidence: 88%

“…More recently, two papers have argued for potential astrophysical origins in the 3.5 keV line [632,633]. Ref.…”

Section: 5 Kev Linementioning

confidence: 99%

A White Paper on keV sterile neutrino Dark Matter

Adhikari

Agostini

et al. 2017

J. Cosmol. Astropart. Phys.

372

316

View full text Add to dashboard Cite

show abstract

“…First of all, the excess has not been found in dwarf galaxy observations [46][47][48][49]. Furthermore, it was argued that the signal could arise due to an incomplete subtraction of atomic lines [50,51] and that it does not have the right morphology expected by the DM profile [52,53] (although both criticisms have been challenged as well [54,55]). Currently, it seems very hard to draw definite conclusions from the status of the emission line, as poor statistics leave room for interpretation.…”

Section: The 355 Kev Line Signalmentioning

confidence: 99%

Astrophysical constraints on resonantly produced sterile neutrino dark matter

Schneider

2016

J. Cosmol. Astropart. Phys.

121

160

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Resonantly produced sterile neutrinos are considered an attractive dark matter (DM) candidate only requiring a minimal, well motivated extension to the standard model of particle physics. With a particle mass restricted to the keV range, sterile neutrinos are furthermore a prime candidate for warm DM, characterised by suppressed matter perturbations at the smallest observable scales. In this paper we take a critical look at the validity of the resonant scenario in the context of constraints from structure formation. We compare predicted and observed number of Milky-Way satellites and we introduce a new method to generalise existing Lyman-α limits based on thermal relic warm DM to the case of resonant sterile neutrino DM. The tightest limits come from the Lyman-α analysis, excluding the entire parameter space (at 2-σ confidence level) still allowed by X-ray observations. Constraints from Milky-Way satellite counts are less stringent, leaving room for resonant sterile neutrino DM most notably around the suggested line signal at 7.1 keV. *

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“…A photospheric argon abundance is expected if the low-FIP elements are enhanced in the corona. Recently, Phillips et al (2015) found very high potassium abundances in flares, which impact the interpretation of galaxy cluster spectra. This emphasizes the importance of solar abundance variations to astrophysics in general.…”

Section: Introductionmentioning

confidence: 99%

The Mysterious Case of the Solar Argon Abundance Near Sunspots in Flares

Doschek

Warren

2016

ApJ

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Recently we discussed an enhancement of the abundance of Ar XIV relative to Ca XIV near a sunspot during a flare, observed in spectra recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The observed Ar XIV/Ca XIV ratio yields an argon/calcium abundance ratio seven times greater than expected from the photospheric abundance. Such a large abundance anomaly is unprecedented in the solar atmosphere. We interpreted this result as being due to an inverse first ionization potential (FIP) effect. In the published work, two lines of Ar XIV were observed, and one line was tentatively identified as an Ar XI line. In this paper, we report observing a similar enhancement in a full-CCD EIS flare spectrum in 13 argon lines that lie within the EIS wavelength ranges. The observed lines include two Ar XI lines, four Ar XIII lines, six Ar XIV lines, and one Ar XV line. The enhancement is far less than reported in Doschek et al. but exhibits similar morphology. The argon abundance is close to a photospheric abundance in the enhanced area, and the abundance could be photospheric. This enhancement occurs in association with a sunspot in a small area only a few arcseconds (1″ = about 700 km) in size. There is no enhancement effect observed in the normally high-FIP sulfur and oxygen line ratios relative to lines of low-FIP elements available to EIS. Calculations of path lengths in the strongest enhanced area in Doschek et al. indicate a depletion of low-FIP elements.

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THE X-RAY LINE FEATURE AT 3.5 KeV IN GALAXY CLUSTER SPECTRA

Cited by 29 publications

References 34 publications

A White Paper on keV sterile neutrino Dark Matter

A White Paper on keV sterile neutrino Dark Matter

Astrophysical constraints on resonantly produced sterile neutrino dark matter

The Mysterious Case of the Solar Argon Abundance Near Sunspots in Flares

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