English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We further explore a scenario in which the recently observed 3.55 keV photonline arises from dark matter decay to an axion-like particle (ALP) of energy3.55 keV, which then converts to a photon in astrophysical magnetic fields.This ALP scenario is well-motivated by the observed morphology of the 3.55 keVflux. For this scenario we study the expected flux from dark matter decay inthe galactic halos of both the Milky Way and Andromeda (M31). The Milky Waymagnetic field is asymmetric about the galactic centre, and so the resulting3.55 keV flux morphology differs significantly from the case of direct darkmatter decay to photons. However the Milky Way magnetic field is not largeenough to generate an observable signal, even with ASTRO-H. In contrast, M31has optimal conditions for ALP to photon conversion and the intrinsic signalfrom M31 becomes two orders of magnitude larger than for the Milky Way,comparable to that from clusters and consistent with observations.

3.55 keV photon lines from axion to photon conversion in the Milky Way and M31