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Creators/Authors contains: "Manzano-King, Christina"

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  1. ABSTRACT We present spatially resolved kinematic measurements of stellar and ionized gas components of dwarf galaxies in the stellar mass range $10^{8.5}\!-\!10^{10} \, \mathrm{M}_{\odot }$, selected from Sloan Digital Sky Survey DR7 and DR8 and followed up with Keck/Low-Resolution Imaging Spectrometer spectroscopy. We study the potential effects of active galactic nuclei (AGNs) on Galaxy-wide gas kinematics by comparing rotation curves of 26 Galaxies containing AGNs, and 19 control Galaxies with no optical or infrared signs of AGNs. We find a strong association between AGN activity and disturbed gas kinematics in the host Galaxies. While star-forming Galaxies in this sample tend to have orderly gas discs that co-rotate with the stars, 73 per cent of the AGNs have disturbed gas. We find that 5 out of 45 Galaxies have gaseous components in counter-rotation with their stars, and all Galaxies exhibiting counter-rotation contain AGNs. Six out of seven isolated Galaxies with disturbed ionized gas host AGNs. At least three AGNs fall clearly below the stellar–halo mass relation, which could be interpreted as evidence for ongoing star formation suppression. Taken together, these results provide new evidence supporting the ability of AGN to influence gas kinematics and suppress star formation in dwarf galaxies. This further demonstratesmore »the importance of including AGN as a feedback mechanism in galaxy formation models in the low-mass regime.« less
  2. Abstract We have modeled the velocity-resolved reverberation response of the H β broad emission line in nine Seyfert 1 galaxies from the Lick Active Galactic Nucleus (AGN) Monitoring Project 2016 sample, drawing inferences on the geometry and structure of the low-ionization broad-line region (BLR) and the mass of the central supermassive black hole. Overall, we find that the H β BLR is generally a thick disk viewed at low to moderate inclination angles. We combine our sample with prior studies and investigate line-profile shape dependence, such as log 10 ( FWHM / σ ) , on BLR structure and kinematics and search for any BLR luminosity-dependent trends. We find marginal evidence for an anticorrelation between the profile shape of the broad H β emission line and the Eddington ratio, when using the rms spectrum. However, we do not find any luminosity-dependent trends, and conclude that AGNs have diverse BLR structure and kinematics, consistent with the hypothesis of transient AGN/BLR conditions rather than systematic trends.
    Free, publicly-accessible full text available May 1, 2023
  3. Abstract

    We carried out spectroscopic monitoring of 21 low-redshift Seyfert 1 galaxies using the Kast double spectrograph on the 3 m Shane telescope at Lick Observatory from 2016 April to 2017 May. Targeting active galactic nuclei (AGNs) with luminosities ofλLλ(5100 Å) ≈ 1044erg s−1and predicted Hβlags of ∼20–30 days or black hole masses of 107–108.5M, our campaign probes luminosity-dependent trends in broad-line region (BLR) structure and dynamics as well as to improve calibrations for single-epoch estimates of quasar black hole masses. Here we present the first results from the campaign, including Hβemission-line light curves, integrated Hβlag times (8–30 days) measured againstV-band continuum light curves, velocity-resolved reverberation lags, line widths of the broad Hβcomponents, and virial black hole mass estimates (107.1–108.1M). Our results add significantly to the number of existing velocity-resolved lag measurements and reveal a diversity of BLR gas kinematics at moderately high AGN luminosities. AGN continuum luminosity appears not to be correlated with the type of kinematics that its BLR gas may exhibit. Follow-up direct modeling of this data set will elucidate the detailed kinematics and provide robust dynamical black hole masses for several objects in this sample.