The X-ray weakness of little red dots and JWST-selected AGN: Comparison with local AGN in different accretion regimes

We investigate the origin of the observed X-ray weakness in high z little red dots (LRDs) and other JWST-selected broad line active galactic nuclei (AGN) by comparing their X-ray and optical properties with those of a diverse sample of low z AGN, including super-Eddington accreting massive black holes (SEAMBHs), narrow-line Seyfert 1 galaxies (NLS1s), and type I AGN from large surveys (e.g. BASS, SDSS). Using a heterogeneous set of AGN samples spanning a wide range of redshift and accretion rates, we examine the relations between X-ray luminosity (łx), broad ), and we explore whether high z sources may represent analogues of local highly accreting systems. While a few LRDs and JWST-selected AGN are consistent with the SEAMBH population in the łx/łha versus λ_̊m Edd plane, most lie below it, suggesting either more extreme accretion conditions, suppressed coronal emission or heavy obscuration. We identify an anti-correlation between łx/łha and λ_̊m Edd in the low z, high-λ_̊m Edd subsample of sources, consistent with theoretical expectations of slim-disc accretion. We further show that, for SEAMBHs, line luminosity (łha), Eddington ratio (λ_̊m Edd), bolometric luminosity (L_̊m bol), and X-ray-to-bolometric luminosity correction (κ_ bol,X bolometric luminosities underestimate spectral energy distribution-based values even after dust correction, reinforcing the need for SED-based estimates. We find that SEAMBHs, LRDs, and JWST-selected AGN occupy a similar high-κ_ bol,X regime, indicating that the relative deficit of X-ray emission compared to the bolometric output could potentially support the view that suppression of the hot corona emission is a common feature of highly accreting systems across cosmic time. However, the X-ray measurements of high z sources are largely based on observed upper limits and generally do not account for heavy or Compton-thick obscuration, in which case the intrinsic łx could be substantially higher than observed. Our results are consistent with the idea that the observed X-ray weakness of LRDs and JWST-selected AGN may be linked to the physics of highly accreting SMBHs, but alternative explanations, including heavy obscuration, systematics in BH mass estimates, or a combination of intrinsic coronal suppression and absorption, remain viable. Moreover, observational limitations at high z, including instrumental sensitivity and the steep X-ray spectra expected for highly accreting systems, likely further suppress the detected X-ray signal. Disentangling the roles of accretion physics and obscuration will require deeper, higher-resolution X-ray observations with next-generation facilities, which will be crucial for establishing whether these sources represent genuine high z counterparts of local highly accreting AGN.