The effect of the broad-line region with geometrical structures on gamma-ray absorption in blazars

The broad-line region (BLR) is an important component of blazars, especially for flat spectrum radio quasars. The soft photons arising from the BLR will substantially affect the transparency of the gamma-ray photons produced in the relativistic jet. We study the effect of the geometrical structure of the BLR on the absorption of gamma-rays. We find that the gamma-ray optical depth strongly depends on the geometrical structure of the BLR. For a flat BLR geometry, gamma-ray photons with specified energies could escape transparently even if their emission region is located inside the cavity of the BLR.