Testing the robustness of DYNAMITE triaxial Schwarzschild modelling: The effects of correcting the orbit mirroring

Thater, Sabine; Jethwa, Prashin; Tahmasebzadeh, Behzad; Zhu, Ling; Brok, Mark den; Santucci, Giulia; Ding, Yu-Chen; Poci, Adriano; Lilley, Edward J.; Zeeuw, Tim de; Zocchi, Alice; Maindl, Thomas I.; Rigamonti, Fabio; Ven, Glenn van de; Yang, Meng; Fahrion, Katja

doi:10.1051/0004-6361/202243926

Cited by 13 publications

(7 citation statements)

References 70 publications

(81 reference statements)

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“…Our choice for the symmetry of long-axis tube orbits should be feasible for modeling of barred galaxies. In these four mirrors, short-axis tube orbits also flip the signs in the same way as box orbits (Thater et al 2022b). Hence, the symmetrization pattern is identical for all orbit families in a barred galaxy model with figure rotation.…”

Section: Orbit Integration and Storagementioning

confidence: 91%

“…The stationary, nonrotating galaxies are symmetric in the three principal planes. In VdB08, all orbit properties were calculated in only one octant; the properties in the other octants were symmetrized by an eight-fold symmetry, as described in VdB08 and with a bug recently reported by Quenneville et al (2022) and corrected in the latest version of publicly released DYNAMITE code (Thater et al 2022b).…”

Section: Orbit Integration and Storagementioning

confidence: 99%

“…In modeling a barred galaxy with figure rotation, the symmetry in the x−y plane is broken and thus restricted to a four-fold symmetrization. For each orbit that we only sample the initial starting point in one octant, we obtain the other three mirror orbits by flipping the signs of positions and velocities following Table 1, which is revised from Thater et al (2022b). We combine four mirror orbits together and treat it as one single orbit in the model fitting.…”

Section: Orbit Integration and Storagementioning

confidence: 99%

“…In particular, the van den Bosch et al (2008) triaxial orbitsuperposition code (hereafter VdB08) has been widely used in measuring the central supermassive BH mass (e.g., van den Bosch & de Zeeuw 2010; Walsh et al 2012;Seth et al 2014;Walsh et al 2015;Feldmeier-Krause et al 2017;Ahn et al 2018;Quenneville et al 2022), probing the underlying luminous and dark mass distribution and stellar orbit distribution for large sample of galaxies across the Hubble types from CALIFA (Zhu et al 2018), MaNGA (Jin et al 2020), and SAMI (Santucci et al 2022), and studying formation history of galaxies by tagging orbits with stellar population properties (Poci et al 2019;Zhu et al 2020;Poci et al 2021;Zhu et al 2022). A new implementation of VdB08 code named DYNAMITE has been publicly released with some new features (Jethwa et al 2020;Thater et al 2022b). However, rotating barred structures are not included explicitly in most of the existing Schwarzschild models for external galaxies.…”

Section: Introductionmentioning

confidence: 99%

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Orbit-superposition Dynamical Modeling of Barred Galaxies

Tahmasebzadeh

Zhu

Shen³

et al. 2022

ApJ

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Barred structures are important in understanding galaxy evolution, but they were not included explicitly in most dynamical models for nearby galaxies due to their complicated morphological and kinematic properties. We modify the triaxial orbit-superposition Schwarzschild implementation by van den Bosch et al. to include barred structures explicitly. The gravitational potential is a combination of a spherical dark matter halo and stellar mass; with the 3D stellar density distribution deprojected from the observed 2D image using a two-component deprojection method, including an axisymmetric disk and a triaxial barred bulge. We consider figure rotation of the galaxy with the bar pattern speed as a free parameter. We validate the method by applying it to a mock galaxy with integral field unit (IFU) data created from an N-body simulation with a boxy/peanut or X-shaped bar. Our model fits the observed 2D surface density and all kinematic features well. The bar pattern speed is recovered well with a relative uncertainty smaller than 10%. Based on the internal stellar orbit distribution of the model, we decompose the galaxy into an X-shaped bar, a boxy bulge, a vertically extended structure and a disk, and demonstrate that our model recovers these structures generally well, similar to the true structures in the N-body simulation. Our method provides a realistic way of modeling the bar structure explicitly for nearby barred galaxies with IFU observations.

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Section: Orbit Integration and Storagementioning

confidence: 91%

Section: Orbit Integration and Storagementioning

confidence: 99%

Section: Orbit Integration and Storagementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Orbit-superposition Dynamical Modeling of Barred Galaxies

Tahmasebzadeh

Zhu

Shen³

et al. 2022

ApJ

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“…Recent findings tentatively suggest that the dynamical properties of stars of different ages in nearby galaxies may mirror that of the ionised gas across cosmic time. Using Schwarzschild orbital modelling (e.g., Schwarzschild 1979;van den Bosch et al 2008;Zhu et al 2020;Thater et al 2022) of the lenticular galaxy NGC 3115, Poci et al (2019) found that the stellar velocity dispersion as a function of population age steadily increases, mirroring that of the ionised gas in populations of galaxies across a broad range of redshifts (Kassin et al 2012;Wisnioski et al 2015;Übler et al 2019). Older stars, like the ionised gas in high redshift galaxies, exhibit hotter dynamics (i.e., more turbulence or random motions) than their younger/local counterparts.…”

Section: Introductionmentioning

confidence: 99%

The SAMI Survey: Evidence for dynamical coupling of ionised gas and young stellar populations

Foster¹,

Vaughan²,

Fraser-McKelvie³

et al. 2023

Preprint

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We explore local and global dynamical differences between the kinematics of ionised gas and stars in a sample of galaxies from Data Release 3 of the SAMI Galaxy Survey. We find better agreement between local (i.e., comparing on a spaxel-to-spaxel basis) velocities and dispersion of gas and stars in younger systems as with previous work on the asymmetric drift in galaxies, suggesting that the dynamics of stars and ionised gas are initially coupled. The intrinsic scatter around the velocity and dispersion relations increases with increasing stellar age and mass, suggesting that subsequent mechanisms such as internal processes, divergent star formation and assembly histories also play a role in setting and altering the dynamics of galaxies. The global (flux-weighted) dynamical support of older galaxies is hotter than in younger systems. We find that the ionised gas in galaxies is almost always dynamically colder than the stars with a steeper velocity gradient. In absolute terms, the local difference in velocity dispersion is more pronounced than the local difference in velocity, possibly reflecting inherent differences in the impact of turbulence, inflow and/or feedback on gas compared to stars. We suggest how these findings may be taken into account when comparing high and low redshift galaxy samples to infer dynamical evolution.

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The Fornax3D project: Environmental effects on the assembly of dynamically cold disks in Fornax cluster galaxies

Ding

Zhu

Ven

et al. 2023

A&A

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We apply a population-orbit superposition metho1d to 16 galaxies in the Fornax cluster observed with MUSE/VLT in the context of the Fornax3D project. By fitting the luminosity distribution, stellar kinematics, and age and metallicity maps simultaneously, we obtained the internal stellar orbit distribution, as well as the age and metallicity distribution of stars on different orbits for each galaxy. Based on the model, we decompose each galaxy into a dynamically cold disk (orbital circularity λz ≥ 0.8) and a dynamically hot non-disk component (orbital circularity λz < 0.8), and obtain the surface-brightness, age, and metallicity radial profiles of each component. The galaxy infall time into the cluster is strongly correlated with galaxy cold-disk age with older cold disks in ancient infallers. We quantify the infall time tinfall of each galaxy with its cold-disk age using a correlation calibrated with TNG50 cosmological simulations. For galaxies in the Fornax cluster, we found that the luminosity fraction of cold disk in galaxies with tinfall > 8 Gyr are a factor of ∼4 lower than in more recent infallers while controlling for total stellar mass. Nine of the 16 galaxies have spatially extended cold disks, and most of them show positive or zero age gradients; stars in the inner disk are ∼2 − 5 Gyr younger than that in the outer disk, in contrast to the expectation of inside-out growth. Our results indicate that the assembly of cold disks in galaxies is strongly affected by their infall into clusters, by either removal of gas in outer regions or even tidally stripping or heating part of the pre-existing disks. Star formation in outer disks can stop quickly after the galaxy falls into the cluster, while star formation in the inner disks can last for a few Gyrs more, building the positive age gradient measured in cold disks.

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Testing the robustness of DYNAMITE triaxial Schwarzschild modelling: The effects of correcting the orbit mirroring

Cited by 13 publications

References 70 publications

Orbit-superposition Dynamical Modeling of Barred Galaxies

Orbit-superposition Dynamical Modeling of Barred Galaxies

The SAMI Survey: Evidence for dynamical coupling of ionised gas and young stellar populations

The Fornax3D project: Environmental effects on the assembly of dynamically cold disks in Fornax cluster galaxies

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