Showing papers by "Vardha N. Bennert published in 2022"

The Lick AGN Monitoring Project 2016: Dynamical Modeling of Velocity-resolved Hβ Lags in Luminous Seyfert Galaxies

Abstract: We have modeled the velocity-resolved reverberation response of the Hβ 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 Hβ 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 log10(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 Hβ 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.

The Close AGN Reference Survey (CARS). Tracing the circumnuclear star formation in the super-Eddington NLS1 Mrk 1044

Abstract: Context. The host galaxy conditions for rapid supermassive black hole growth are poorly understood. Narrow-line Seyfert 1 (NLS1) galaxies often exhibit high accretion rates and are hypothesized to be prototypes of active galactic nuclei (AGN) at an early stage of their evolution. Aims. We present adaptive optics (AO) assisted VLT MUSE NFM observations of Mrk 1044, the nearest super-Eddington accreting NLS1. Together with archival MUSE WFM data, we aim to understand the host galaxy processes that drive Mrk 1044’s black hole accretion. Methods. We extracted the faint stellar continuum emission from the AGN-deblended host and performed spatially resolved emission line diagnostics with an unprecedented resolution. Combining both MUSE WFM and NFM-AO observations, we used a kinematic model of a thin rotating disk to trace the stellar and ionized gas motion from 10kpc galaxy scales down to ∼ 30pc around the nucleus. Results. Mrk 1044’s stellar kinematics follow circular rotation, whereas the ionized gas shows tenuous spiral features in the center. We resolve a compact star-forming circumnuclear ellipse (CNE) that has a semi-minor axis of 306pc. Within this CNE, the gas is metal-rich and its line ratios are entirely consistent with excitation by star formation. With an integrated star formation rate of 0 . 19 ± 0 . 05 M (cid:12) yr − 1 , the CNE contributes 27% of the galaxy-wide star formation. Conclusions. We conclude that Mrk 1044’s nuclear activity has not yet a ff ected the circumnuclear star formation. Thus, Mrk 1044 is consistent with the idea that NLS1s are young AGN. A simple mass budget consideration suggests that the circumnuclear star formation and AGN phase are connected and the patterns in the ionized gas velocity field are a signature of the ongoing AGN feeding.

The Close AGN Reference Survey (CARS)-IFU survey data and the BH mass dependence of long-term AGN variability

Abstract: Context. Active galactic nuclei (AGN) are thought to be intimately connected with their host galaxies through feeding and feedback processes. A strong coupling is predicted and supported by cosmological simulations of galaxy formation, but the details of the physical mechanisms are still observationally unconstrained. Aims. Galaxies are complex systems of stars and a multiphase interstellar medium (ISM). A spatially resolved multiwavelength survey is required to map the interaction of AGN with their host galaxies on different spatial scales and different phases of the ISM. The goal of the Close AGN Reference Survey (CARS) is to obtain the necessary spatially resolved multiwavelength observations for an unbiased sample of local unobscured luminous AGN. Methods. We present the overall CARS survey design and the associated wide-field optical integral-field unit (IFU) spectroscopy for all 41 CARS targets at z < 0.06 randomly selected from the Hamburg/ESO survey of luminous unobscured AGN. This data set provides the backbone of the CARS survey and allows us to characterize host galaxy morphologies, AGN parameters, precise systemic redshifts, and ionized gas distributions including excitation conditions, kinematics, and metallicities in unprecedented detail. Results. We focus our study on the size of the extended narrow-line region (ENLR) which has been traditionally connected to AGN luminosity. Given the large scatter in the ENLR size–luminosity relation, we performed a large parameter search to identify potentially more fundamental relations. Remarkably, we identified the strongest correlation between the maximum projected ENLR size and the black hole mass, consistent with an RENLR,max ∼ M0.5 BH relationship. We interpret the maximum ENLR size as a timescale indicator of a single black hole (BH) radiative-efficient accretion episode for which we inferred 〈 log(tAGN/[yr]) 〉 = (0.45± 0.08) log(MBH/[M ]) + 1.78+0.54 −0.67 using forward modeling. The extrapolation of our inferred relation toward higher BH masses is consistent with an independent lifetime estimate from the He ii proximity zones around luminous AGN at z ∼ 3. Conclusions. While our proposed link between the BH mass and AGN lifetime might be a secondary correlation itself or impacted by unknown biases, it has a few relevant implications if confirmed. For example, the famous AGN Eigenvector 1 parameter space may be partially explained by the range in AGN lifetimes. Also, the lack of observational evidence for negative AGN feedback on star formation can be explained by such timescale effects. Further observational tests are required to confirm or rule out our BH mass dependent AGN lifetime hypothesis.

The Close AGN Reference Survey (CARS). A parsec-scale multi-phase outflow in the super-Eddington NLS1 Mrk 1044

Abstract: Context. The interaction between Active Galactic Nuclei (AGN) and their host galaxies is scarcely resolved. Narrow-line Seyfert 1 (NLS1) galaxies are believed to represent AGN at early stages of their evolution and allow to observe AGN feeding and feedback processes at high accretion rates. the of outflow the outflow energetics and the timescales,

Signatures of Feedback in the Spectacular Extended Emission Region of NGC 5972

Abstract: We present Chandra X-ray Observatory observations and Space Telescope Imaging Spectrograph spectra of NGC 5972, one of the 19 "Voorwerpjes" galaxies. This galaxy contains an Extended Emission Line Region (EELR) and an arc-second scale nuclear bubble. NGC 5972 is a faded AGN, with EELR luminosity suggesting a 2.1 dex decrease in L bol in the last ∼ 5 × 10 4 yr. We investigate the role of AGN feedback in exciting the EELR and bubble given the long-term variability and potential accretion state changes. We detect broadband (0.3-8 keV) nuclear X-ray emission coincident with the [O iii] bubble, as well as diffuse soft X-ray emission coincident with the EELR. The soft nuclear (0.5-1.5 keV) emission is spatially extended and the spectra are consistent with two APEC thermal populations ( ∼ 0.80, ∼ 0.10 keV). We find a bubble age >2.2 Myr, suggesting formation before the current variability. We find evidence for efficient feedback with L kin / 𝐿 bol ∼ 0 . 8%, which may be overestimated given the recent L bol variation. Kinematics suggest an out-flowing 300 km s − 1 high-ionization [O iii]-emitting gas which may be the line of sight component of a ∼ 780 km s − 1 thermal X-ray outflow capable of driving strong shocks that could photoionize the precursor material. We explore possibilities to explain the overall jet, radio lobe and EELR misalignment including evidence for a double SMBH which could support a complex misaligned system. The mechanisms and effects of this feedback on the wider galaxy