Axion-sourced fireballs from supernovae

Investigating the gamma-ray burst from decaying MeV-scale axion-like particles produced in supernova explosions

“…The other, semi-transparent regions are constraints from the energy ALPs could deposit in low-energy SNe (orange) and the diffuse gamma-ray flux due to decays of ALPs produced in all past SNe (yellow), both from ref. [10]; anomalous cooling during the SN explosion leading to a shorter neutrino burst following SN 1987A (brown) [16]; changes in the evolution of horizontal branch stars (purple) [6,8,35]; the non-observation of X-rays after the multi-messenger observation GW170817 of a neutron star merger [36]; the irreducible cosmic ALP density from freezein production (blue) [37]; as well as from the dissociation of light elements during BBN (green) [3]. Note that the BBN bound is the most conservative one presented in ref.…”

“…5 Recently, it was pointed out in ref. [36] that in a small part of the parameter space seemingly excluded by the decay bound, the local density of gamma-ray photons produced by the decaying ALPs outside the SN could in fact be high enough to form a QED plasma through rapid pair-creation γγ → e + e − . This "fireball" would radiate energy in the form of x-ray photons of which essentially none would have been detected by SMM such that the bound we derive here does in fact not apply as it is.…”

“…This "fireball" would radiate energy in the form of x-ray photons of which essentially none would have been detected by SMM such that the bound we derive here does in fact not apply as it is. However, considering the non-observations of x-ray photons in the energy range 0.2-2 MeV by the Pierre Venus Orbiter, also such ALPs that lead to fireball formation are in fact excluded [36]. Since the parameter region in question is rather small, lies entirely inside the decay bound, and is also excluded by observations, we do not study this phenomenology further.…”

Primordial black hole dark matter from catastrogenesis with unstable pseudo-Goldstone bosons

“…The stability of these pGBs depends on their mass and couplings. Axion-like particles with a coupling to photons are probed by beam-dump experiments [55][56][57][58][59], supernovae [60][61][62][63][64][65][66] and JCAP06(2023)055 neutron star mergers [67] up to several hundreds MeV, while cosmological observations [68,69] reach even larger masses, above a TeV, for very small couplings [68,69]. Colliders can exclude masses up to the TeV scale [70,71], though only for large couplings (this implies e.g.…”

Spectra of axions emitted from main sequence stars

“…These are characterized by a stellar-evolution model, a stellar initial mass function, and a star formation rate. The StAB will contribute to the diffuse extragalactic axion background together with other potential cosmic axion sources, which include supernovae [46][47][48][49][50][51][52], dark matter [53][54][55][56][57][58], dark energy fluctuations [59,60], primordial black holes [61,62], and various other astrophysical [63,64] and early universe [65][66][67][68][69][70][71] processes. One can in principle distinguish the StAB from other axion backgrounds based on their spectra and spatial distributions.…”