[3] The nucleus sits in a barred spiral galaxy, close to face-on and not typical for optically selected unobscured Seyferts.

[6][7] A 2021 study shows that the X-ray spectrum in Markarian 817 is highly absorbed and there are new blueshifted, broad, and narrow UV absorption lines, suggesting a dust-free, ionized obscurer that is located in the inner broad-line region, partially covering the central source.

[8] Markarian 817 has become a notable target of the AGN STORM 2 project, in which a group of astronomers led by Edward M. Cackett from the Wayne State University in Detroit, monitored the galaxy with the Neil Gehrels Swift Observatory for 15 months, during which they obtained observations in X-rays and six ultraviolet/optical filters to shed more light on Markarian 817.

From the deep XMM Newton and NuSTAR observations, the spectra presents a complex X-ray wind which consists of neutral and ionized absorption zones.

[14] From the relationship of line widths and time lags, both galaxies showed that the broad-line regions (BLR) dynamics are consistent with the viral predication.