Speaker
Description
Weak-emission-line quasars (WLQs) represent an extreme subclass of active galactic nuclei (AGNs), displaying unusually faint or absent emission lines despite luminous quasar-like continua. The source SDSS J101353.45+492758.1 is a particularly striking example, characterized by a nearly lineless UV–optical spectrum and a pronounced X-ray weakness.
We first analyze its broadband spectral energy distribution (SED) using relativistic thin-disk (kerrbb) and multicomponent AGN (relagn) models. Both approaches consistently indicate a black hole mass of ∼ 2 × 10^9 M_sun and a moderate accretion rate (m_dot ≈ 0.1). However, the fits require a strongly suppressed or absent hot corona, while the inclusion of a warm, optically thick Comptonizing region significantly improves the agreement with the data. These results support an intrinsically X-ray weak nature.
To further investigate the origin of the extreme emission-line weakness, we are conducting dedicated photoionization simulations with Cloudy. Using SEDs motivated by our observational modeling, we explore how variations in coronal strength, warm Comptonization, and possible geometrical configurations affect the predicted equivalent widths of key emission lines (e.g., C IV, Mg II).
This combined SED and photoionization approach provides new insight into the coupling between the accretion flow, coronal structure, and line-emitting gas in X-ray-weak quasars, and highlights SDSS J101353.45+492758.1 as a valuable laboratory for understanding the physical diversity of WLQs.