Vertical stellar density distribution in a non-isothermal galactic disc

Sarkar, S.; Jog, Chanda J.

doi:10.1093/mnras/staa2924

Cited by 3 publications

(1 citation statement)

References 51 publications

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“…Observations of edge-on galaxies show that the vertical density distribution of stellar disks can be approximated by functions ρ * (z) ∝ exp(−z/h e ), ∝ sech(z/h 1 ), ∝ sech 2 (z/h * ) or their combinations [43][44][45], where h e , h 1 , and h * are the vertical scale heights. The vertical scale height of a stellar disk often depends on radial coordinate, which complicates the situation.…”

Section: Density Distribution Of Starsmentioning

confidence: 99%

Modeling of Spiral Structure in a Multi-Component Milky Way-Like Galaxy

2021

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Using recent observational data, we construct a set of multi-component equilibrium models of the disk of a Milky Way-like galaxy. The disk dynamics are studied using collisionless-gaseous numerical simulations, based on the joined integration of the equations of motion for the collision-less particles using direct integration of gravitational interaction and the gaseous SPH-particles. We find that after approximately one Gyr, a prominent central bar is formed having a semi-axis length of about three kpc, together with a multi-armed spiral pattern represented by a superposition of m= 2-, 3-, and 4-armed spirals. The spiral structure and the bar exist for at least 3 Gyr in our simulations. The existence of the Milky Way bar imposes limitations on the density distributions in the subsystems of the Milky Way galaxy. We find that a bar does not form if the radial scale length of the density distribution in the disk exceeds 2.6 kpc. As expected, the bar formation is also suppressed by a compact massive stellar bulge. We also demonstrate that the maximum value in the rotation curve of the disk of the Milky Way galaxy, as found in its central regions, is explained by non-circular motion due to the presence of a bar and its orientation relative to an observer.

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Section: Density Distribution Of Starsmentioning

confidence: 99%

Modeling of Spiral Structure in a Multi-Component Milky Way-Like Galaxy

2021

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Dissecting the Gaia HR diagram – II. The vertical structure of the star formation history across the solar cylinder

Mazzi,

Girardi,

Trabucchi

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Starting from the Gaia DR3 HR diagram, we derive the star formation history (SFH) as a function of distance from the Galactic Plane within a cylinder centred on the Sun with a 200 pc radius and spanning 1.3 kpc above and below the Galaxy’s midplane. We quantify both the concentration of the more recent star formation in the Galactic Plane, and the age-related increase in the scale height of the Galactic Disc stellar component, which is well-described by power-laws with indices ranging from 1/2 to 2/3. The vertically-integrated star formation rate falls from (1.147 ± 0.039) × 10−8 M⊙yr−1pc−2 at earlier times down to (6.2 ± 3.0) × 10−9 M⊙yr−1pc−2 at present times, but we find a significant peak of star formation in the 2 to 3 Gyr age bin. The total mass of stars formed per unit area over time is 118.7 ± 6.2 M⊙pc−2, which is nearly twice the present stellar mass derived from kinematics within 1 kpc from the Galactic Plane, implying a high degree of matter recycling in successive generations of stars. The method is then modified by adopting an age-dependent correlation between the SFH across the different slices, which results in less noisy and more symmetrical results without significantly changing the previously mentioned quantities. This appears to be a promising way to improve SFH recovery in external galaxies.

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Pressure-regulated, Feedback-modulated Star Formation in Disk Galaxies

Ostriker

Kim

2022

ApJ

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The star formation rate (SFR) in galactic disks depends on both the quantity of the available interstellar medium (ISM) gas and its physical state. Conversely, the ISM’s physical state depends on the SFR, because the “feedback” energy and momentum injected by recently formed massive stars is crucial to offsetting losses from turbulent dissipation and radiative cooling. The ISM’s physical state also responds to the gravitational field that confines it, with increased weight driving higher pressure. In a quasi-steady state, it is expected that the mean total pressure of different thermal phases will match each other, that the component pressures and total pressure will satisfy thermal and dynamical equilibrium requirements, and that the SFR will adjust as needed to provide the requisite stellar radiation and supernova feedback. The pressure-regulated, feedback-modulated (PRFM) theory of the star-forming ISM formalizes these ideas, leading to a prediction that the SFR per unit area, ΣSFR, will scale nearly linearly with ISM weight  . In terms of the large-scale gas surface density Σgas, stellar plus dark matter density ρ sd, and effective ISM velocity dispersion σ eff, an observable weight estimator is  ≈ P DE = π G Σ gas 2 / 2 + Σ gas ( 2 G ρ sd ) 1 / 2 σ eff , and this is predicted to match the total midplane pressure P tot. Using a suite of multiphase magnetohydrodynamic simulations run with the TIGRESS computational framework, we test the principles of the PRFM model and calibrate the total feedback yield ϒtot = P tot/ΣSFR ∼ 1000 km s−1, as well as its components. We compare the results from TIGRESS to theory, previous numerical simulations, and observations, finding excellent agreement.

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Vertical stellar density distribution in a non-isothermal galactic disc

Cited by 3 publications

References 51 publications

Modeling of Spiral Structure in a Multi-Component Milky Way-Like Galaxy

Modeling of Spiral Structure in a Multi-Component Milky Way-Like Galaxy

Dissecting the Gaia HR diagram – II. The vertical structure of the star formation history across the solar cylinder

Pressure-regulated, Feedback-modulated Star Formation in Disk Galaxies

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