The BAT AGN Spectroscopic Survey Data Release 2

Accreting supermassive black holes (SMBHs) or so called active galactic nuclei (AGN) are among the most luminous sources of radiation in the Universe and are thought to play an important role in the evolution of their host galaxies. The BAT AGN Spectroscopic Survey (BASS) uses an all-sky survey of the brightest and most powerful hard X-ray emission in the sky that can trace even highly obscured AGN, and then following them up with a multitude of observations carried out with large allocations of time on advanced facilities (including VLT, Keck, Gemini, Chandra, NuSTAR, VLA, ALMA, etc.). As such, BASS provides a crucial high-resolution, high-sensitivity, low-redshift benchmark for studying the cosmic evolution of SMBHs, anchoring narrow and deep surveys that focus on higher redshifts. The BASS data release 2 (DR2) focus issue provides an unprecedented spectroscopic AGN survey in spectral range, resolution, and sensitivity, including 1449 optical and 233 NIR spectra for the brightest 858 ultra-hard X-ray (14-195 keV) selected AGN across the entire sky and essentially all levels of obscuration. This BASS DR2 provides a highly complete set of key measurements (emission line measurements and central velocity dispersions), with 99.9% measured redshifts and 98% black hole masses estimated (for unbeamed AGN outside the Galactic plane). The BASS DR2 AGN sample represents a unique census of nearby powerful AGN, spanning over 5 orders of magnitude in AGN bolometric luminosity, black hole mass, Eddington ratio, and obscuration. In this poster, we provide an overview of the key BASS DR2 measurements, data sets and catalogs, and scientific highlights from a series of DR2-based works pursued by the BASS team.