Galaxy formation and evolution

Abstract:

Context. Feedback processes play a fundamental role in the regulation of the star formation (SF) activity in galaxies and, in particular, in the quenching of early-type galaxies (ETGs) as has been inferred by observational and numerical studies of Λ-CDM models. At z = 0, ETGs exhibit well-known fundamental scaling relations, but the connection between scaling relations and the physical processes shaping ETG evolution remains unknown.

Aims. This work aims to study the impact of the energetic feedback due to active galactic nuclei (AGN) on the formation and evolution of ETGs. We focus on assessing the impact of AGN feedback on the evolution of the mass–plane and the fundamental plane (FP; defined using mass surface density) as well as on morphology, kinematics, and stellar age across the FP.

Methods. The Horizon-AGN and Horizon-noAGN cosmological hydrodynamical simulations were performed with identical initial conditions, including the same physical processes except for the activation of the AGN feedback in the former. We selected a sample of central ETGs from both simulations using the same criteria and exhaustively studied their SF activity, kinematics, and scaling relations for z ≤ 3.

Results. We find that Horizon-AGN ETGs identified at z = 0 follow the observed fundamental scaling relations (mass–plane, FP, and mass–size relation) and qualitatively reproduce kinematic features albeit conserving a rotational inner component with a mass fraction regulated by the AGN feedback. We discover that AGN feedback seems to be required to reproduce the bimodality in the spin parameter distribution reported by observational works and the mass–size relation; more massive galaxies have older stellar populations, larger sizes, and are slower rotators. We study the evolution of the fundamental relations with redshift, finding a mild evolution of the mass–plane of Horizon-AGN ETGs for z <  1, whereas a stronger change is detected for z >  1. The ETGs in Horizon-noAGN show a strong systematic redshift evolution of the mass–plane. The FP of Horizon-AGN ETGs agrees with observations at z = 0. When AGN feedback is switched off, a fraction of galaxies depart from the expected FP at all analysed redshifts owing to the presence of a few extended galaxies with an excess of stellar surface density. We find that AGN feedback regulates the SF activity as a function of stellar mass and redshift being able to reproduce the observed relations. Our results show the impact of AGN feedback on the mass-to-light ratio (M/L) and its relation with the tilt of the luminosity FP (L-FP; defined using the averaged surface brightness). Overall, AGN feedback has an impact on the regulation of the SF activity, size, stellar surface density, stellar ages, rotation, and masses of ETGs that is reflected on the fundamental relations, particularly on the FP. We detect a dependence of the FP on stellar age and galaxy morphology that evolves with redshfit. The characteristics of the galaxy distribution on the FP according to these properties change drastically by z ∼ 1 in Horizon-AGN and hence this feature could provide further insight into the action of AGN feedback.

Abstract:

We construct a dynamical model of the Milky Way disk from a data set that combines Gaia EDR3 and APOGEE data throughout galactocentric radii in the range 5.0 kpc ≤ R ≤ 19.5 kpc. We make use of the spherically aligned Jeans anisotropic method to model the stellar velocities and their velocity dispersions. Building upon our previous work, our model is now fitted to kinematic maps that have been extended to larger galactocentric radii due to the expansion of our data set, probing the outer regions of the Galactic disk. Our best-fitting dynamical model suggests a logarithmic density slope of αDM = −1.602 ± 0.079syst for the dark matter halo and a dark matter density of ρDM(R⊙) = (8.92 ± 0.56syst) × 10−3 M⊙ pc−3 (0.339 ± 0.022syst GeV cm3). We estimate a circular velocity at the solar radius of vcirc = (234.7 ± 1.7syst) km s−1 with a decline toward larger radii. The total mass density is ρtot(R⊙) = (0.0672 ± 0.0015syst) M⊙ pc−3 with a slope of αtot = −2.367 ± 0.047syst for 5 kpc ≤ R ≤ 19.5 kpc, and the total surface density is Σ(R⊙, ∣z∣ ≤ 1.1 kpc) = (55.5 ± 1.7syst) M⊙ pc−2. While the statistical errors are small, the error budget of the derived quantities is dominated by the three to seven times larger systematic uncertainties. These values are consistent with our previous determination, but the systematic uncertainties are reduced due to the extended data set covering a larger spatial extent of the Milky Way disk. Furthermore, we test the influence of nonaxisymmetric features on our resulting model and analyze how a flaring disk model would change our findings.

Abstract:

This is an erratum to the paper 'Dark matter-deficient dwarf galaxies form via tidal stripping of dark matter in interactions with massive companions', which was published in MNRAS, 502, 1785 (Jackson et al. 2021). In the original version of the paper S. K. Yi's affiliation was incorrectly listed as 'School of Physics, Korea Institute for Advanced Study (KIAS), 85 Hoegiro, Dongdaemun-gu, Seoul 02455, Republic of Korea', whereas the correct affiliation is 'Department of Astronomy and Yonsei University Observatory, Yonsei University, Seoul 03722, Republic of Korea'. In addition S. K. Yi would also like to add the following acknowledgement: SKY acknowledges support from the Korean National Research Foundation (NRF-2020R1A2C3003769). The supercomputing time for numerical simulation was kindly provided by KISTI (KSC-2017-G2-003), and large data transfer was supported by KREONET.