Stronger Constraints on the Evolution of the M_BH− Relation up to z ∼ 0.6

Abstract

We revisit the possibility of redshift evolution in the M BH − σ * relation with a sample of 22 Seyfert 1 galaxies with black holes (BHs) in the mass range 10 6.3 − 10 8.3 M and redshift range 0.03 < z < 0.57 with spectra obtained from spatially resolved Keck/Low-Resolution Imaging Spectrometer observations. Stellar velocity dispersions were measured directly from the Mg Ib region, taking into consideration the effect of Fe II contamination, active galactic nucleus (AGN) dilution, and hostgalaxy morphology on our measurements. BH masses are estimated using the Hβ line width, and the luminosity at 5100Å is estimated from surface brightness decomposition of the AGN from the host galaxy using high-resolution imaging from the Hubble Space Telescope. Additionally, we investigate the use of the [O III]λ5007 emission line width as a surrogate for stellar velocity dispersion, finding better correlation once corrected for Fe II contamination and any possible blueshifted wing components. Our selection criteria allowed us to probe lower-luminosity AGNs and lower-mass BHs in the non-local universe than those measured in previous single-epoch studies. We find that any offset in the M BH −σ * relation up to z ∼ 0.6 is consistent with the scatter of local BH masses, and address the sources of biases and uncertainties that contribute to this scatter.

Dark Energy Survey identification of a low-mass active galactic nucleus at redshift 0.823 from optical variability

“…While based on only one data point, our result on DES J0218−0430 suggests no significant redshift evolution in the M • -M * scaling relation from redshift z ∼ 1 to z ∼ 0 (see also Ding et al 2020), which is consistent with previous results based on the M • -σ * relation (e.g. Shen et al 2015;Sexton et al 2019).…”

Spectral Classification and Ionized Gas Outflows in z ∼ 2 WISE-selected Hot Dust-obscured Galaxies

“…Here, we select the narrow line width from [O II]/Balmer lines instead of [O III] to minimize blending from outflows. Considering the dispersion of the M BH -σ * relation itself (a factor of 2-3; e.g., Kormendy & Ho 2013;Woo et al 2013), and the possibility of a systematic offset for various types of AGN compared to the local inactive galaxies on the BH-galaxy scaling relation (up to a factor of several, e.g., Kim et al 2008;Urrutia et al 2012;Sexton et al 2019), the M BH estimates for Hot DOGs could be inaccurate by up to an order of magnitude. Having in mind those uncertainties, we find most of the M BH values to be in the order of 10 9 M ⊙ while those associated with σ narrow > 400 km s −1 are given with upper limits and show values around ∼ 10 10 M ⊙ .…”

Multiwavelength Observations of SDSS J105621.45+313822.1, a Broad-line, Low-metallicity AGN

“…We analyzed this spectrum in order to compare broad-line fluxes and widths to our near-IR observations. Optical spectral decomposition was performed on the SDSS spectrum using emcee (Foreman-Mackey et al 2013) as done by Sexton et al (2019). For the Hβ/[O III] region, we fit the region from restframe 4400-5800 Å, which includes the bMg I region used to estimate stellar velocity dispersion.…”