SDSS-V: Revealing a weak accretion state in X-ray selected red quasars

Red quasars (rQSOs) have been recognized as a short-lived stage in the evolutionary cycle of Active Galactic Nuclei (AGN), with fundamental differences in their intrinsic properties compared to blue quasars (bQSOs). We present the first large X-ray sample of 380 rQSOs, selected from the eROSITA/SDSS-V collaboration, providing uniform X-ray detection with optical spectroscopy across half the sky. We combine X-ray imaging, optical spectroscopy, and multi-wavelength photometry to probe the accretion, absorption, spectroscopic, and host properties of rQSOs compared to a bQSO sample. Independent Component Analysis is used to reconstruct optical spectra in a data-driven approach while accounting for dust reddening and host contamination. rQSOs are intrinsically X-ray fainter than bQSOs, with a higher fraction found at lower X-ray luminosities. We investigate the relative X-ray strength of rQSOs by measuring the spectral slope indicator αOX. Despite their suppressed X-ray emission, rQSOs are not optically faint, but show low αOX values and higher dust-corrected optical luminosities, indicating weak X-ray emission relative to their bright optical continua. X-ray spectral measurements reveal large gas column densities relative to optical reddening due to dust, implying that X-ray absorption could arise from dust-free gas close to the supermassive Black Hole (BH) rather than a classical dusty torus, while the dust responsible for optical reddening likely resides on host-galaxy scales or is associated with dusty gas carried in disc winds. rQSOs trace a phase of suppressed BH assembly relative to stellar mass growth, suggesting that they may represent a distinct evolutionary stage where BH accretion is suppressed while the host galaxy continues to grow.