First author: M. Laurenti
The bulk of X-ray spectroscopic studies of active galactic nuclei (AGN) are focused on local ($z < 0.1$) sources with low-to-moderate ($< 0.3$) Eddington ratio ($\lambda_\mathrm{Edd}$). It is then mandatory to overcome this limitation and improve our understanding of highly accreting AGN. In this work we present the preliminary results from the analysis of a sample of $\sim70$ high-$\lambda_\mathrm{Edd}$ radio-quiet AGN at $0.06 \leq z \leq 3.
First author: Rogemar A. Riffel
We use optical Integral Field Spectroscopy (IFU) to study the gas emission structure and kinematics in the inner 3.4$\times$4.9 kpc$^2$ region of the galaxy UGC 8782 (3C 293), host of a radio loud Active Galactic Nucleus (AGN). The observations were performed with the GMOS-IFU on the Gemini North telescope, resulting in a spatial resolution of $\sim725$ pc at the distance of the galaxy. While the stars present ordered rotation following the orientation of the large scale disc, the gas shows a disturbed kinematics.
First author: B. A. Nizamov
Positron annihilation line at 511~keV is a known component of the gamma-ray diffuse emission. It is believed to be produced in the Galaxy, but there could be possible extragalactic contribution as well. E.g., positrons can be produced in jets of active galactic nuclei (AGN) and after that accumulate and gradually annihilate in hot gaseous halos around galaxies. In this work we test this hypothesis in application to an individual object – the Andromeda galaxy (M31) which is close and has a supermassive black hole in its center, which powered an AGN before.
First author: Z. N. Osmanov
In the paper we study the process of excitation of Langmuir waves in the magnetospheres of active galactic nuclei (AGN), by taking a general-relativistic expression of the Goldreich-Julian density into account. We considered the linearised set of equations which describe dynamics of the studied mechanism: the Euler equation, the continuity equation and the Poisson equation. After solving the dispersion relation and obtaining the instability growth rate, we explored it versus several physical parameters: electron’s and proton’s relativistic factors and the mass and luminosity of AGN, which are supposed to be Kerr black holes.
Avi Vajpeyi
Active galactic nuclei (AGN) are promising environments for the assembly of merging binary black hole (BBH) systems. Interest in AGNs as nurseries for merging BBH is rising following the detection of gravitational waves from a BBH system from the purported pair-instability mass gap, most notably, GW190521. Active galactic nuclei have also been invoked to explain the formation of the high-mass-ratio system, GW190814. We draw on simulations of BBH systems in AGN to propose a phenomenological model for the distribution of black hole spins of merging binaries in AGN disks.
First author: Ivan Almeida
We present a simple model for low-luminosity active galactic nucleus (LLAGN) feedback through thermal winds produced by a hot accretion flow. The wind carries considerable energy and deposits it on the host galaxy at kiloparsec scales and beyond, heating the galactic gas thereby quenching star formation. Our model predicts that the typical LLAGN can quench more than $10%$ of star formation in its host galaxy. We find that long-lived LLAGN winds from supermassive black holes (SMBH) with masses $\geq 10^8 M_{\odot}$ and mass accretion rates $\dot{M} > 10^{-3}\dot{M}{\rm Edd}$ can prevent gas collapse and significantly quench galactic star formation compared to a scenario without AGN, if the wind persists over 1 Myr.
First author: Ethan R. Partington
The AGN STORM 2 collaboration targeted the Seyfert 1 galaxy Mrk 817 for a year-long multiwavelength, coordinated reverberation mapping campaign including HST, Swift, XMM-Newton, NICER, and ground-based observatories. Early observations with NICER and XMM revealed an X-ray state ten times fainter than historical observations, consistent with the presence of a new dust-free, ionized obscurer. The following analysis of NICER spectra attributes variability in the observed X-ray flux to changes in both the column density of the obscurer by at least one order of magnitude ($N_\mathrm{H}$ ranges from $2.
First author: Enrique Pérez-Montero
We present an adapted version of the code HII-CHI-Mistry-UV (P'erez-Montero & Amor'in 2017) to derive chemical abundances from emission lines in the ultraviolet, for use in narrow line regions (NLR) of Active Galactic Nuclei (AGN). We evaluate different ultraviolet emission line ratios and how different assumptions about the models, including the presence of dust grains, the shape of the incident spectral energy distribution, or the thickness of the gas envelope around the central source, may affect the final estimates as a function of the set of emission lines used.
First author: Junyao Li
We propose a new method to constrain the size of the dusty torus in broad-line active galactic nuclei (AGNs) using optical and mid-infrared (MIR) ensemble structure functions (SFs). Because of the geometric dilution of the torus, the mid-infrared response to optical continuum variations has suppressed variability with respect to the optical that depends on the geometry (e.g., size, orientation and opening angle) of the torus. More extended tori have steeper MIR SFs with respect to the optical SF.
First author: Francoise Combes
Since the 1990s, we have known that there is a super-massive black hole in every galaxy, and that its mass is proportional to the mass of the bulge. To better understand how these black holes were formed, in symbiosis with their galaxies, we will look at their demography, the scaling relations between properties of black holes and host galaxies, and their evolution in a Hubble time.
