Peter Hall

AGN STORM 2. I. First results: A Change in the Weather of Mrk 817

The Astrophysical Journal · 2021 · 112 citations

<jats:title>Abstract</jats:title>
\n <jats:p>We present the first results from the ongoing, intensive, multiwavelength monitoring program of the luminous Seyfert 1 galaxy Mrk 817. While this active galactic nucleus was, in part, selected for its historically unobscured nature, we discovered that the X-ray spectrum is highly absorbed, and there are new blueshifted, broad, and narrow UV absorption lines, which suggest that a dust-free, ionized obscurer located at the inner br…

Sloan Digital Sky Survey. V. Pioneering Panoptic Spectroscopy

The Astronomical Journal · 2025-12-23 · 24 citations

Abstract The Sloan Digital Sky Survey V (SDSS-V) is pioneering panoptic spectroscopy: it is the first all-sky, multiepoch, optical-to-infrared spectroscopic survey. SDSS-V is mapping the sky with multiobject spectroscopy (MOS) at telescopes in both hemispheres (the 2.5 m Sloan Foundation Telescope at Apache Point Observatory and the 100-inch du Pont Telescope at Las Campanas Observatory), where 500 zonal robotic fiber positioners feed light from a wide-field focal plane to an optical ( R ∼ 2000,…

Understanding the Broad-line Region of Active Galactic Nuclei with Photoionization. I. The Moderate-accretion Regime

The Astrophysical Journal · 2025-02-07 · 5 citations

Abstract Over three decades of reverberation mapping (RM) studies on local broad-line active galactic nuclei (AGNs) have measured reliable black hole (BH) masses for >100 AGNs. These RM measurements reveal a significant correlation between the Balmer broad-line region (BLR) size and AGN optical luminosity (the R – L relation). Recent RM studies for AGN samples with more diverse BH parameters (e.g., mass and Eddington ratio) reveal a substantial intrinsic dispersion around the average R – L re…

The SDSS-V Black Hole Mapper Reverberation Mapping Project: Multiline Dynamical Modeling of a Highly Variable Active Galactic Nucleus with Decade-long Light Curves

The Astrophysical Journal · 2025-09-30 · 4 citations

Abstract We present dynamical modeling of the broad-line region (BLR) of the highly variable active galactic nucleus (AGN) SDSS J141041.25+531849.0 ( z = 0.359) using photometric and spectroscopic monitoring data from the Sloan Digital Sky Survey (SDSS) Reverberation Mapping project and the current fifth-generation SDSS Black Hole Mapper program, spanning from early 2013 to early 2023. We model the geometry and kinematics of the BLR in the H β , H α , and Mg ii emission lines for three different…

The Nineteenth Data Release of the Sloan Digital Sky Survey

ArXiv.org · 2025-07-09 · 4 citations

Mapping the local and distant Universe is key to our understanding of it. For decades, the Sloan Digital Sky Survey (SDSS) has made a concerted effort to map millions of celestial objects to constrain the physical processes that govern our Universe. The most recent and fifth generation of SDSS (SDSS-V) is organized into three scientific ``mappers". Milky Way Mapper (MWM) that aims to chart the various components of the Milky Way and constrain its formation and assembly, Black Hole Mapper (BHM),…