The investigation of emission line regions within active galaxies (AGNs) has a rich and
extensive history, now extending to the use of AGNs and quasars as “standardizable” …

This work focuses on active galactic nuclei (AGNs) and on the relation between the sizes of
the hot dust continuum and the broad-line region (BLR). We find that the continuum size …

Low-luminosity active galactic nuclei (LLAGN) are special among their kind due to the
profound structural changes that the central engine experiences at low accretion rates (≲ …

By using the GRAVITY instrument with the near-infrared (NIR) Very Large Telescope
Interferometer (VLTI), the structure of the broad (emission-) line region (BLR) in active …

We conduct the first systematic survey of a comprehensive set of the twenty optical coronal
lines in the spectra of nearly 1 million galaxies observed by the Sloan Digital Sky Survey …

Local low-metallicity dwarf galaxies are relics of the early universe and are thought to hold
clues into the origins of supermassive black holes. While recent studies are uncovering a …

Some galaxies show little to no sign of active galactic nucleus (AGN) activity, yet exhibit
strong coronal line (CL) emission relative to common narrow emission lines. Many of these …

Reverberation mapping accurately determines virial black hole masses only for redshifts z<
0.2 by utilizing the relationship between the Hβ broad-line region (BLR) size and the 5100 Å …

Forbidden collisionally excited optical atomic transitions from high-ionization-potential (IP≥
54.8 eV) ions, such as Ca 4+, Ne 4+, Fe 6+, Fe 10+, Fe 13+, Ar 9+, and S 11+, are known as …

ABSTRACT Coronal-Line Forest Active Galactic Nuclei (CLiF AGN) are characterized by
strong, high-ionization lines, which are in contrast to what is found in typical AGNs. Here, we …