3 papers
gr-qc2026
Scalar charge bounds for extremal black hole formation
Berend Schneider
I prove that a collapsing charged scalar field with scalar charge that forms an exactly extremal Reissner--Nordström black hole à la Kehle--Unger with radius m…
astro-ph.HE2026
A fast X-ray transient with chromatic flares: signatures of violent collisions induced by late-time central engine reactivation
Shao-Yu Fu, Cui-Yuan Dai, Ai-Ling Wang +57
Extragalactic Fast X-ray Transients (EFXTs) represent an emerging class of high-energy phenomena characterized by X-ray outbursts lasting from tens to hundreds of seconds. However,…
gr-qc2026
Self-gravitating thin shells are dynamically unstable on all angular scales
Tristan Pitre, Berend Schneider, Eric Poisson
We establish the dynamical instability of a static, spherically symmetric, and infinitesimally thin shell in general relativity. The shell is made up of a perfect fluid with a baro…