Star–Gas Misalignment in Galaxies. I. The Properties of Galaxies from the Horizon-AGN Simulation and Comparisons to SAMI

Khim, Donghyeon J.; Yi, Sukyoung K.; Dubois, Yohan; Bryant, Julia J.; Croom, S. M.; Bland-Hawthorn, Joss; Brough, Sarah; Choi, Hoseung; Devriendt, Julien; Groves, Brent; Owers, Matt S.; Richards, Samuel N.; Sande, Jesse van de; Sweet, Sarah M.

doi:10.3847/1538-4357/ab88a9

Cited by 26 publications

(36 citation statements)

References 92 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We find that ∼ 24% of EAGLE ETGs are misaligned, consistent with the Khim et al (2020b) Horizon-AGN results (23.7±0.2%) but quite different from the SAMI observations (32.7±6.6%). This discrepancy could be explained by the fact that SAMI galaxies are classified as ETGs and LTGs by visual inspection and not through the kinematic thresholds calculated in simulations.…”

Section: Aligned and Misaligned Galaxy Populationssupporting

confidence: 67%

“…They identified the importance of gas loss through black hole feedback and gas stripping during a fly-by passage across a more massive group environment in driving misalignments between stars and SF gas. More recently, Khim et al (2020b) using the Horizon-AGN simulation (Dubois et al 2014) also found that ETGs are substantially more frequently misaligned than LTGs and that misalignment increases with decreasing gas fraction. They compared Horizon-AGN with SAMI, finding a significant discrepancy in the misalignment fraction for galaxies in dense environments.…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

The origin of star-gas misalignments in simulated galaxies

Casanueva,

Lagos,

Padilla

et al. 2021

Preprint

View full text Add to dashboard Cite

We study the origin of misalignments between the stellar and star-forming gas components of simulated galaxies in the EAGLE simulations. We focus on galaxies with stellar masses ≥ 10 9 M at 0≤z≤1. We compare the frequency of misalignments with observational results from the SAMI survey and find that overall, EAGLE can reproduce the incidence of misalignments in the field and clusters, as well as the dependence on stellar mass and optical colour within the uncertainties. We study the dependence on kinematic misalignments with internal galaxy properties and different processes related to galaxy mergers and sudden changes in stellar and star-forming gas mass. We found that despite the environment being relevant in setting the conditions to misalign the star-forming gas, the internal galaxy properties play a crucial role in determining whether the gas quickly aligns with the stellar component or not. Hence, galaxies that are more triaxial and more dispersion dominated display more misalignments because they are inefficient at realigning the star-forming gas towards the stellar angular momentum vector.

show abstract

Section: Aligned and Misaligned Galaxy Populationssupporting

confidence: 67%

Section: Introductionmentioning

confidence: 97%

The origin of star-gas misalignments in simulated galaxies

Casanueva,

Lagos,

Padilla

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…For this reason, we choose to use only the spin at the central region within r h determined in Section 2.3. We measure the spin vector (S) separately for each particle type (gas, star, and DM) with the same size of aperture, considering the misalignment between them (e.g., Chisari et al 2017;Duckworth et al 2020;Khim et al 2020). The orbital angular momentum vector, L, is calculated by taking the cross product of the position vector (d nei ) and the velocity vector (v nei ) of the nearest neighbor in the reference frame of the target, namely…”

Section: Spin-orbit Anglementioning

confidence: 99%

Living with Neighbors. III. The Origin of the Spin$-$Orbit Alignment of Galaxy Pairs: A Neighbor versus the Large-scale Structure

Moon,

An,

Yoon

2021

Preprint

View full text Add to dashboard Cite

Recent observations revealed a coherence between the spin vector of a galaxy and the orbital motion of its neighbors. We refer to the phenomenon as "the spin-orbit alignment (SOA)" and explore its physical origin via the IllustrisTNG simulation. This is the first study to utilize a cosmological hydrodynamic simulation to investigate the SOA of galaxy pairs. In particular, we identify paired galaxies at z = 0 having the nearest neighbor with mass ratios from 1/10 to 10 and calculate the spin-orbit angle for each pair. Our results are as follows. (a) There exists a clear preference for prograde orientations (i.e., SOA) for galaxy pairs, qualitatively consistent with observations. (b) The SOA is significant for both baryonic and dark matter spins, being the strongest for gas and the weakest for dark matter. (c) The SOA is stronger for less massive targets and for targets having closer neighbors. (d) The SOA strengthens for galaxies in low-density regions, and the signal is dominated by central-satellite pairs in low-mass halos. (e) There is an explicit dependence of the SOA on the duration of interaction with its current neighbor. Taken together, we propose that the SOA witnessed at z = 0 has been developed mainly by interactions with a neighbor for an extended period of time, rather than tidal torque from the ambient large-scale structure.

show abstract

“…In the previous paper (Khim et al 2020, Paper I), we investigated the properties of misaligned galaxies using the Horizon-AGN simulation and the observational data from SAMI (Bryant et al 2019). We hereby summarize the main results of Paper I.…”

Section: Introductionmentioning

confidence: 97%

Star-Gas Misalignment in Galaxies: II. Origins Found from the Horizon-AGN Simulation

Khim,

Yi,

Pichon

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

There have been many studies aiming to reveal the origins of the star-gas misalignment found in galaxies, but there still is a lack of understanding of the contribution from each formation channel candidate. We aim to answer the question by investigating the misaligned galaxies in Horizon-AGN, a cosmological large-volume simulation of galaxy formation. There are 27,903 galaxies of stellar mass M * > 10 10 M in our sample, of which 5,984 are in a group of the halo mass of M 200 > 10 12 M . We have identified four main formation channels of misalignment and quantified their level of contribution: mergers (35%), interaction with nearby galaxies (23%), interaction with dense environments or their central galaxies (21%), and secular evolution including smooth accretion from neighboring filaments (21%). We found in the simulation that the gas, rather than stars, is typically more vulnerable to dynamical disturbances; hence, misalignment formation is mainly due to the change in the rotational axis of the gas rather than stars, regardless of the origin. We have also inspected the lifetime (duration) of the misalignment. The decay timescale of the misalignment shows a strong anti-correlation with the kinematic morphology (V /σ) and the cold gas fraction of the galaxy. The misalignment has a longer lifetime in denser regions, which is linked with the environmental impact on the host galaxy. There is a substantial difference in the length of the misalignment lifetime depending on the origin, and it can be explained by the magnitude of the initial position angle offset and the physical properties of the galaxies.

show abstract

Star–Gas Misalignment in Galaxies. I. The Properties of Galaxies from the Horizon-AGN Simulation and Comparisons to SAMI

Cited by 26 publications

References 92 publications

The origin of star-gas misalignments in simulated galaxies

The origin of star-gas misalignments in simulated galaxies

Living with Neighbors. III. The Origin of the Spin$-$Orbit Alignment of Galaxy Pairs: A Neighbor versus the Large-scale Structure

Star-Gas Misalignment in Galaxies: II. Origins Found from the Horizon-AGN Simulation

Contact Info

Product

Resources

About