Little Red Dots as Obscured Little Blue Dots: A Super-Eddington Unification Model

Abstract

We investigate whether Little Red Dots (LRDs) are the dust-reddened, high-inclination counterparts of compact, blue broad-line AGNs (Little Blue Dots, LBDs) powered by super-Eddington accretion. We model the central engine as a geometrically thick, radiation--pressure supported accretion flow whose funnel produces strongly anisotropic, intrinsically blue ionizing continua, coupled to an equatorially concentrated broad-line region (BLR) and dusty reprocessing clouds with modest covering factor. Using inclination-dependent SEDs as input to Cloudy, we show that the extreme broad Halpha EWs of JWST LRDs can be reproduced with global BLR covering factors of only C_{BLR}~ 0.1, fully consistent with standard Type~1 AGNs and far below unity. Large Balmer EWs arise because self-shadowing suppresses the high-inclination optical continuum while the BLR is illuminated by an ionizing-rich EUV SED. Weak high-ionization lines (e.g. He II 4686) follow from the orientation-dependent suppression of the XUV/soft X-ray continuum toward equatorial directions, without requiring a fully enclosing gaseous "cocoon''. Applying a gray dust attenuation law with A_V~3 along high-inclination (LRD-selected) sightlines, our fiducial model reproduces the V-shaped UV-optical continua of LRDs and the large Balmer decrements; strong Balmer breaks arise only along the most obscured sightlines. A compact equatorial dust structure with modest global covering factor intercepts and reradiates only a small fraction of the bolometric luminosity, yielding a modest hot-dust bump and far-IR/sub-mm output consistent with current measurements and limits and implying small dust masses. This single-framework model links LRD and LBD observables through orientation, predicting correlated trends in Halpha EW, Balmer decrement, Balmer break, high-ionization line strengths, and IR emission.