Can the periodic spectral modulations of the 236 SETI candidate Sloan   Survey stars be due to Dark Matter effects?
  The search for dark matter (DM) is one of the most active and challenging areas of current research. Possible DM candidates are ultralight fields such as axions and weak interacting massive particles (WIMPs). Axions piled up in the center of stars are supposed to generate matter/DM configurations with oscillating geometries at a very rapid frequency, which is a multiple of the axion mass $m_B$ [1,2]. Borra and Trottier recently found peculiar ultrafast periodic spectral modulations in $236$ main sequence stars in the sample of $2.5$ million spectra of galactic halo stars of the Sloan Digital Sky Survey that were interpreted as optical signals from extraterrestrial civilizations, possible candidates for the search for extraterrestrial intelligence (SETI) program [3]. We argue, instead, that this could be the first indirect evidence of bosonic axion-like DM fields inside main sequence stars, with a stable radiative nucleus, where a stable DM core can be hosted. These oscillations were not observed in earlier stellar spectral classes probably because of the impossibility of starting a stable oscillatory regime due to the presence of chaotic motions in their convective nuclei. The axion mass values, $(50 < m_B < 2.4 \times 10^{3})~ \mathrm{\mu eV}$, obtained from the frequency range observed by Borra and Trottier, $(0.6077< f <0.6070$) THz, agree with the recent theoretical results from high-temperature lattice quantum chromodynamics [4,5]. 
Fabrizio Tamburini (1,2) and Ignazio Licata (3,4,5) ((1) ZKM - Zentrum   f\"ur Kunst und Medientechnologie, (2) MSC - bw, St...
astro-ph.SR gr-qc