The broad line region and dust torus structure of the Seyfert 1 WPVS48

TL;DR

This study uses reverberation mapping data to investigate the structure of the broad line region and dust torus in the Seyfert 1 galaxy WPVS48, revealing a bowl-shaped geometry that explains observed echo characteristics.

Contribution

It provides the first detailed geometric model of the BLR and dust torus in WPVS48, supporting a bowl-shaped toroidal structure based on reverberation mapping results.

Findings

Hα BLR lags the continuum by ~18 days

Dust emission lags range from 70 to 90 days in IR bands

IR echoes are sharp, Hα echo is smeared

Abstract

Optical and near-mid-infrared reverberation mapping data obtained at Universit\"{a}tssternwarte Bochum in Chile and with the Spitzer Space Telescope allow us to explore the geometry of both the H$\alpha$ BLR and the dust torus for the nearby Seyfert 1 galaxy WPVS\,48. On average, the H$\alpha$ variations lag the blue AGN continuum by about 18 days, while the dust emission variations lag by 70 days in the J+K and by 90 days in the L+M bands. The IR echoes are sharp, while the H$\alpha$ echo is smeared. This together favours a bowl-shaped toroidal geometry where the dust sublimation radius is defined by a bowl surface, which is virtually aligned with a single iso-delay surface, thus leading to the sharp IR echoes. The BLR clouds, however, are located inside the bowl and spread over a range of iso-delay surfaces, leading to a smeared echo.