English

z~2 dual AGN host galaxies are disky: stellar kinematics in the ASTRID Simulation

Astrophysics of Galaxies 2024-10-10 v2

Abstract

We study dual AGN host galaxy morphologies at z=2z=2 using the ASTRID simulation, selecting black hole (BH) pairs with small separation (Δr<30kpc\Delta r<30\rm{kpc}), high mass (MBH,12>107MM_{\text{BH,12}}>10^7M_\odot), and luminosity (Lbol,12>1043erg/sL_{\text{bol,12}}>10^{43}\rm{erg/s}). We kinematically decompose (using MORDOR) 1000\sim1000 dual AGN hosts into standard components - a `disk' (thin and thick disk, pseudo-bulge) and 'bulge' (bulge and halo) and define disk-dominated galaxies by the disk-to-total D/T0.5D/T\geq0.5. In ASTRID, 60.9±2.1%60.9\pm2.1\% of dual AGN hosts (independent of separation) are disk-dominated, with the D/TD/T distribution peaking at 0.7\sim0.7. Notably, hosts of BH pairs have similar morphologies (most either both disk or bulge-dominated). In dual-AGN hosts, the D/TD/T increases from 17%\sim17\% at M109MM_{\rm *}\sim 10^{9} M_{\odot} to 64% 64\% for M1011.5MM_{\rm *} \sim 10^{11.5} M_{\odot}, and the pseudo-bulge is the dominant component of the disk fraction at the high mass end. Moreover, dual AGN hosts exhibit a higher fraction of disk/large pseudo-bulge than single-AGN hosts. The Disk-to-Total ratio is approximately constant with BH mass or AGN luminosity. We also create mock images of dual AGN host galaxies, employing morphological fitting software Statmorph to calculate morphological parameters and compare them with our kinematic decomposition results. Around 83.3±2.4%83.3\pm2.4\% of galaxies display disk-like profiles, of which 60.7±2.2%\sim60.7\pm2.2\% are kinematically confirmed as disks. Se\'rsic indices and half-mass radii of dual AGN host galaxies align with observational measurements from HST at z2z\sim2. Around 34%34\% are identified as mergers from the GiniM20\text{Gini}-M_{20} relation. We find two dual AGN hosted by galaxies that exhibit disk-like se\'rsic index n12<1n_{12}<1 and (D/T)12>0.5(D/T)_{12}>0.5, which are in remarkable agreement with properties of recently discovered dual quasars in disk galaxies at z2z\sim 2.

Keywords

Cite

@article{arxiv.2312.14263,
  title  = {z~2 dual AGN host galaxies are disky: stellar kinematics in the ASTRID Simulation},
  author = {Ekaterine Dadiani and Tiziana Di Matteo and Nianyi Chen and Patrick Lachance and Yue Shen and Yu-Ching Chen and Rupert Croft and Yueying Ni and Simeon Bird},
  journal= {arXiv preprint arXiv:2312.14263},
  year   = {2024}
}

Comments

17 pages, 14 figures, submitted to the Open Journal of Astrophysics