BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Newsletter February 2026 DTSTART:20260225T090000Z DTEND:20260225T110000Z DTSTAMP:20260416T055300Z UID:indico-event-51111@agenda.infn.it DESCRIPTION:Dear all\,\nThis is February’s edition of the newsletter of the COST action. The aim is to keep you updated on recent and upcoming con ferences and postdoc positions on subjects related to WISPs.\n \nCosmic W ispers preprints\nThe gravitational wave landscape of cosmic string networ ks with varying tension\nLuca Brunelli\, Filippo Revello\, Gonzalo Villa\n https://arxiv.org/abs/2601.10790\nWe fully classify the phenomenology of g ravitational wave emission from scaling cosmic string networks with varyin g tension and compute the spectral indices of the resulting stochastic bac kgrounds. In string compactifications\, periods of varying tension occur w hen moduli acquire a time-dependence. We present concrete examples in type IIB string theory as D3- and NS5- branes wrapping internal cycles\, which become dynamical due to the effect of moduli potentials. Moreover\, we us e Swampland constraints to derive general bounds on the allowed time-varia tion of the effective string tension in FLRW backgrounds and on the result ing spectral indices\n\nResonant Axion-Photon Conversion in the Early Insp iral of Neutron Star Binaries\nD. Suárez-Fontanella\, M. Ángeles Pérez- García\, C. Albertus\nhttps://arxiv.org/abs/2602.15065\nWe consider the e arly binary neutron star inspiral phase as a scenario to probe environment al axion--photon resonant conversion. For this we approximately model the merger site electromagnetic fields as the superposition of two rotating di polar stellar magnetic fields at the thousand--km scale when both magnetos pheres are not largely distorted. We capture the time-sliced near-zone mag netospheric geometry relevant for axion--photon mixing. Plasma effects are incorporated through an effective Goldreich--Julian charge density\, used to determine the effective plasma frequency and the location of resonant conversion surfaces. Our results show that axion--photon resonant conversi on in binary magnetospheres mostly occurs on extended peanut-shaped surfac es whose global geometry evolves as the binary inspiral evolves. As a cons equence\, the total electromagnetic power emitted through axion--photon co nversion exhibits a characteristic dependence on axion mass and a slow tem poral modulation correlated with the gravitational wave frequency emission . This feature is potentially detectable for ma∈[50\,170]μeV and set ga γ≲10−11 GeV−1 as it lies within the sensitivity limits of current o r planned radio observation missions. In light of our results we discuss t he opportunity of binary neutron star inspirals as time-dependent\, multim essenger probes of axion physics\, and motivate coordinated searches combi ning gravitational wave observations with radio and millimeter wavelength electromagnetic measurements\n\nGravitational-Wave Signals for Supernova E xplosions of Three-Dimensional Progenitors\nAlessandro Lella\, Giuseppe Lu cente\, Daniel Kresse\, Robert Glas\, H.-Thomas Janka\, Alessandro Mirizzi \nhttps://arxiv.org/abs/2602.02651\nCore-collapse supernovae (SNe) are sou rces of gravitational waves (GWs) produced by hydrodynamical instabilities and highly time-dependent anisotropies of the neutrino radiation. In this work we analyze both contributions to the GW signal for two state-of-the- art three-dimensional (3D) SN models computed with the Prometheus-Vertex n eutrino-hydrodynamics code. In contrast to the far majority of models anal yzed for GWs so far\, our core-collapse simulations were started with 12.2 8 M_sun (18.88 M_sun) progenitors\, whose final hour (7 min) of convective oxygen-shell burning was computed in 3D and featured a vigorous oxygen-ne on shell merger. The corresponding large-scale asymmetries in the oxygen l ayer are conducive to buoyancy-aided neutrino-driven explosions. The model s were continuously evolved in 3D from the pre-collapse evolution until 5. 11 s (1.68 s) after the core bounce. The GW signals result from the well-k nown dynamical phenomena in the SN core such as prompt postshock convectio n\, neutrino-driven convection\, the standing accretion shock instability\ , proto-neutron star oscillations\, and anisotropic ejecta expansion. They do not exhibit any new or specific features that can be unambiguously con nected to the powerful pre-collapse activity in the progenitors\, but we i dentify interesting differences compared to results in the literature. We also discuss measurement prospects by interferometers\, confirming that GW signals from future Galactic SNe will be detectable with existing and nex t-generation experiments working in the frequency range f ~ 1-2000 Hz.\n\n Stochastic galactic supernova flux of semi-relativistic particles\nDavid A lonso-González\, David Cerdeño\, Marina Cermeño\, Andres D. Perez\nhttp s://arxiv.org/abs/2602.17597\nThis work studies the flux of semi-relativis tic particles from past galactic core-collapse supernovae reaching terrest rial detectors. We derive a numerical simulation of the full galactic supe rnova history and show that the resulting flux at Earth is intrinsically s tochastic rather than smooth\, as it is shaped by the narrow energy contri butions of individual events. This leads to important consequences for the expected spectral features in terrestrial experiments and for interpretin g constraints on light exotic particles. The code used to generate our sim ulation is shared open access.\nWe encourage participants in the COST acti on to send us a small summary\, typically smaller than the abstract\, of t heir own articles that will appear in the arXiv (after they appear\, with their arXiv numbers). The summary will be disseminated in the newsletter.\ nSend email to \nAlessandro Lella alessandro.lella@ba.infn.it\nDamiano Fi orillo damianofg@gmail.com\nwith subject: preprint summary for Cosmic WISP ers newsletter.\n\nPhD/Postdoc/Junior Positions\n\n\nFebruary\n\n\n\nPostd octoral positions in particle physics phenomenology\, astroparticle physic s and cosmology\, Chungnam Natl. U. (CNU) link\n\n\nJunior research fellow s on theoretical nuclear physics\, nuclear astrophysics\, astroparticle ph ysics and cosmology\, Institute of Physics\, Academia Sinica\, Taiwan link \n\n\n\nMarch\n\n\n\nPostdoctoral positions\, University of Minnesota\, Mi nneapolis link\n\n\nPostdoctoral position\, Max Planck Institute\, Garchin g link\n\n\n\nApril\n\n\n\nPostdoctoral positions in supernova neutrino ph ysics\, Beijing link\n\n\nPostdoctoral positions for cosmic exotic particl e search\, USTC\, Hefei link\n\n\n\nMay\n\n\n\nPhD positions in Astrophysi cs\, Cosmology and Gravitation\, Espirito Santo Univeristy\, South America . link\n\n\n\n\nConferences\n\n\nMarch\n\n\n\nGGI PhD School on "Theoretic al Aspects of Astroparticle Physics\, Cosmology and Gravitation" link\n\n\ n60th Rencontres de Moriond on Very High Energy Phenomena in the Universe: Moriond VHEPU 2026 link\n\n\n2nd UNDARK School link\n\n\n\nApril\n\n\n\n7 th Edition of the international conference Progress on Old and New Themes in cosmology (PONT 2026) link\n\n\n\nMay\n\n\n\nUniVersum VII -- Naples 20 26 link\n\n\nSCALE 2026: Strings & Cosmology – All Lengths Explored (SCA LE) link\n\n\nPlanck2026 & 6th EuCAPT Symposium link\n\n\n\nJune\n\n\n\n16 th International Workshop on the Identification of Dark Matter 2026 (IDM 2 026) link\n\n\n32nd International Conference on Neutrino Physics and Astro physics (Neutrino 2026) link\n\n\nPASCOS 2026: The 31st International Symp osium on Particles\, Strings\, and Cosmology (PASCOS2026) link\n\n\nBlack Holes & Cosmology 2026 (BHCos26) link\n\n\n4th Training School of the COST Action CA21106: Cosmic WISPers link\n\n\n4th General Meeting of the COST Action: Cosmic WISPers (CA21106) link\n\n\nPrimordial Cosmology: Novel Per spectives from Scattering Amplitudes\, Holography and the Bootstrap link\n \n\n\nJuly\n\n\n\nExploring New Frontiers in Cosmology: GGI Workshop link\ n\n\nDark Matter and Stars: Multi-Messenger Probes of Dark Matter and Modi fied Gravity (icdms2026) link\n\n\nAxions in Seoul 2026: Frontiers in Theo ry\, Cosmology\, and Experiment (AiS 2026) link\n\n\n\nAugust\n\n\n\nXVI I nternational Conference on Gravitation\, Astrophysics and Cosmology (ICGAC 16) link\n\n\nInvisibles 26 link\n\n\nListening to the Cosmos: New Frontie rs in Gravitational Wave Physics link\n\n\nCOSMO-26: 29th International Co nference on Particle Physics & Cosmology link\n\n\n\nSeptember\n\n\n\nEric e International School/Workshop of Nuclear Physics\, 47th course on 'Neutr inos in Cosmology\,in Astro-\, Particle- and Nuclear Physics' link\n\n\n\n November\n\n\n\n21st Patras Workshop on Axions\, WIMPs and WISPs link\n\n\ n\n\n\nhttps://agenda.infn.it/event/51111/ URL:https://agenda.infn.it/event/51111/ END:VEVENT END:VCALENDAR