Bridging Quasars and Little Red Dots: Insights into Broad-Line AGNs at $z=5-8$ from the First JWST COSMOS-3D Dataset

Understand

We report the discovery of 13 broad-line AGNs at $z = 5 - 8$ from the first 10% data of the JWST Cycle 3 Treasury Program COSMOS-3D.

• These AGNs are identified by their broad H$\alpha$ or H$\beta$ emission lines through the NIRCam grism wide-field slitless spectroscopy.
• One object at $z = 7.646$ with broad H$\beta$ emission has an F444W magnitude of 23.6 mag, making it one of the brightest $z > 7.5$ broad-line AGNs yet known.
• Among the 13 AGNs, 10 objects have reddened optical continua with slopes $\beta_{\rm opt}>0$.