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Newsletter January 2026

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Description

This is January’s edition of the newsletter of the COST action. The aim is to keep you updated on recent and upcoming conferences and postdoc positions on subjects related to WISPs.

 

 

Cosmic Wispers preprints

 

The spectrum of axions in a scaling string network

José Correia, Mark Hindmarsh, Joanes Lizarraga, Asier Lopez-Eiguren, Kari Rummukainen, Jon Urrestilla

https://arxiv.org/abs/2512.13653

In this publication we investigate the emission of axions by a network of cosmic strings in the post-inflationary scenario. We use extreme-scale $12288^3$ simulations, a novel model for the spectrum and new observables. We observe convergence towards a self-similar axion spectrum, with a logarithmic form consistent with approximately scale-invariant emission by the strings. A cleaner observable makes clear the evolution towards an axion number density of $n_{ax}=1.66(17)f_a H^2$, in units of axion decay constant $f_a$ and Hubble rate $H$.



Search for Axion-Like Particles from Nearby Pre-Supernova Stars

Saurabh Mittal, Thomas Siegert, Francesca Calore, Pierluca Carenza, Laura Eisenberger, Maurizio Giannotti, Alessandro Lella, Alessandro Mirizzi, Dimitris Tsatsis, Hiroki Yoneda

https://arxiv.org/abs/2512.19298

Axion-like particles (ALPs) are hypothetical pseudoscalar bosons that arise in many extensions of the Standard Model and can be well-motivated dark matter candidates. Nearby massive stars in the late stages of stellar evolution provide a promising environment for enhanced ALP production due to their high core temperatures and densities. In this work, we search for a combined signal of ALP-induced hard X-ray and soft $\gamma$-ray emission from 18 nearby pre-supernova stars, with data derived from the public INTEGRAL/SPI 22-year database. We find that the hard X-ray and soft $\gamma$-ray fluxes of all selected stars are consistent with zero within uncertainties. We provide upper limits on the continuum flux as well as the 511\,keV and 1809\,keV lines from these sources. The combined estimate on the upper limit of the product $g_{a\gamma} \times g_{ae}$ is $(0.008 - 2) \times 10^{-24}~\mathrm{GeV}^{-1}$ (95\% C.I.) and the ALP-photon coupling $g_{a\gamma} = (0.13 - 1.26) \times 10^{-11}~\mathrm{GeV}^{-1}$ (95\% C.I.) up to a mass of $m_a \leqq 10^{-11}$ eV for different times to core-collapse and different magnetic field models. Our results are among the strongest limits on the ALP coupling constants in the literature. We also provide conservative limits on the coupling constants $g_{a\gamma} \times g_{ae}$ of $(0.27 - 1.25) \times 10^{-24}~\mathrm{GeV}^{-1}$ (95\% C.I.) by assuming all stars but one to be in the early He burning phase. 



We encourage participants in the COST action to send us a small summary, typically smaller than the abstract, of their own articles that will appear in the arXiv (after they appear, with their arXiv numbers). The summary will be disseminated in the newsletter.

Send email to 

Alessandro Lella alessandro.lella@ba.infn.it

Damiano Fiorillo damianofg@gmail.com

with subject: preprint summary for Cosmic WISPers newsletter.




PhD/Postdoc/Junior Positions

  • February

    • Post-Doctoral Researcher Positions in Application of Simulation-based inference to Cosmology and Astroparticle Physics link

    • Postdoctoral positions in particle physics phenomenology, astroparticle physics and cosmology, Chungnam Natl. U. (CNU) link

    • Junior research fellows on theoretical nuclear physics, nuclear astrophysics, astroparticle physics and cosmology, Institute of Physics, Academia Sinica, Taiwan link

  • March

    • Postdoctoral positions, University of Minnesota, Minneapolis link

    • Postdoctoral position, Max Planck Institute, Garching link

  • April

    • Postdoctoral positions in supernova neutrino physics, Beijing link

    • Postdoctoral positions for cosmic exotic particle search, USTC, Hefei link




Conferences

  • Febuary

    • Cosmic WIPSers Working Group Meeting link

  • March

    • GGI PhD School on "Theoretical Aspects of Astroparticle Physics, Cosmology and Gravitation" link

    • 60th Rencontres de Moriond on Very High Energy Phenomena in the Universe: Moriond VHEPU 2026 link

    • 2nd UNDARK School link

  • April

    • 7th Edition of the international conference Progress on Old and New Themes in cosmology (PONT 2026) link

  • May

    • SCALE 2026: Strings & Cosmology – All Lengths Explored (SCALE) link

    • Planck2026 & 6th EuCAPT Symposium link

  • June

    • 16th International Workshop on the Identification of Dark Matter 2026 (IDM 2026) link

    • 32nd International Conference on Neutrino Physics and Astrophysics (Neutrino 2026) link

    • PASCOS 2026: The 31st International Symposium on Particles, Strings, and Cosmology (PASCOS2026) link

    • Invisibles 26 link

    • 4th Training School of the COST Action CA21106: Cosmic WISPers link

    • 4th General Meeting of the COST Action: Cosmic WISPers (CA21106) link

    • Primordial Cosmology: Novel Perspectives from Scattering Amplitudes, Holography and the Bootstrap link

  • July

    • Exploring New Frontiers in Cosmology: GGI Workshop link

    • Dark Matter and Stars: Multi-Messenger Probes of Dark Matter and Modified Gravity (icdms2026) link

    • Axions in Seoul 2026: Frontiers in Theory, Cosmology, and Experiment (AiS 2026) link

  • August

    • XVI International Conference on Gravitation, Astrophysics and Cosmology (ICGAC16) link

    • Invisibles 26 link