X-ray insights into local Hyper-Eddington Narrow Line Seyfert 1 galaxies

Narrow-Line Seyfert 1 galaxies (NLS1s) are among the best local laboratories for studying super-Eddington (S-E) accretion onto supermassive black holes (SMBHs). I present recent results from a systematic broad-band X-ray campaign on eight bona fide S-E AGN from the SEAMBH sample, observed with simultaneous XMM–Newton and NuSTAR (plus Swift for some targets). These sources, with Eddington ratios up to λEdd ≈426, exhibit steep primary continua, strong relativistic reflection, and, in several cases, low coronal temperatures. A particularly remarkable case is IRAS 04416+1215, a hyper-Eddington NLS1 (λEdd ≈ 426), which shows multiphase ionized winds, a prominent soft excess, and the lowest coronal temperature ever measured in an AGN (kTe ≈ 3 keV), consistent with a hybrid pair-dominated plasma. Our analysis reveals a positive correlation between photon index and Eddington ratio, supporting the scenario in which intense disc radiation enhances Compton cooling of the corona in S-E systems.