2 papers
astro-ph.CO2026
Blue-tilted spectral running and the JWST early galaxy tension
Mikage U. Kobayashi, Gen Chiaki, Kazutaka Kimura +4
Recently, the James Webb Space Telescope (JWST) collaboration has found the unexpectedly large abundance of massive galaxies with stellar masses of at high…
astro-ph.CO2025
NANOGrav 15-year gravitational-wave signals from binary supermassive black-holes seeded by primordial black holes, and implications for the origins of Little Red Dots
Mikage U. Kobayashi, Kazunori Kohri
In this paper, we explain the recently reported a nHz-band gravitational-wave background from NANOGrav 15-year through the merger of binary super-massive black holes with masses of…