What can simulated molecular clouds tell us about real molecular clouds?

Duarte-Cabral, A.; Dobbs, Clare

doi:10.1093/mnras/stw469

Cited by 78 publications

(81 citation statements)

References 81 publications

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“…Theory-wise, numerical simulations, including self-gravity and feedback, showed how easy it is to reproduce giant molecular filaments (40-250 pc in length) in the interarm regions through galactic shear, and these GMF appear to be situated either in the interarm or else in the process of joining an arm -see [64].…”

Section: Filamentsmentioning

confidence: 99%

A guided map to the spiral arms in the galactic disk of the Milky Way

Vallée

2017

Astronomical Review

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An up-to-date overview of the recent history is given, aiming is to present a helpful working guide to the literature and at the same time introduce key systems and observational results, starting from the Sun and going toward the Galactic Center and parts of the Zona Galactica Incognita, and beyond. We start by presenting an observational view of the Milky Way's disk plane (cartographic, dynamical, chemical crosscut, magnetic). This included the four long spiral arms in the disk of the Milky Way galaxy, their geometry, components, velocity, their widths and internal layers as well as onion-like ordered offsets, the central galactic bars, arm tangents, arm pitch and arm shape, arm origins near the Galactic Center, and other possible players in the spiral arm, such as the magnetic field and the dark matter content. After, we present a basic analysis of some theoretical predictions from galactic arm formation: numerical simulations or analytical theories, and observations are checked against predictions from various numerical simulations and analytical (theoretical) models.

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Section: Filamentsmentioning

confidence: 99%

A guided map to the spiral arms in the galactic disk of the Milky Way

Vallée

2017

Astronomical Review

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“…While both the Smith et al (2014) and Duarte-Cabral & Dobbs (2016); Duarte-Cabral & Dobbs (2017) simulations suggest that the physical properties of synthetic large-scale filaments may change due to galactic environment 1 , comparatively little work has been done to systematically analyze these properties and contextualize them in light of the growing sample of (very diverse) filaments observed in our own Galaxy ). The Smith et al (2014) simulations provide the opportunity to analyze the response of these dense molecular filaments to an external spiral potential at high resolution over a large fraction of the disc.…”

Section: Introductionmentioning

confidence: 99%

Synthetic Large-scale Galactic Filaments: On Their Formation, Physical Properties, and Resemblance to Observations

Zucker

Smith

Goodman

2019

ApJ

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Using a population of large-scale filaments extracted from an AREPO simulation of a Milky Waylike galaxy, we seek to understand the extent to which observed large-scale filament properties (with lengths 100 pc) can be explained by galactic dynamics alone. From an observer's perspective in the disk of the galaxy, we identify filaments forming purely due to galactic dynamics, without the effects of feedback or local self-gravity. We find that large-scale Galactic filaments are intrinsically rare, and we estimate that at maximum approximately one filament per kpc 2 should be identified in projection, when viewed from the direction of our Sun in the Milky Way. In this idealized scenario, we find filaments in both the arm and interarm regions, and hypothesize that the former may be due to gas compression in the spiral-potential wells, with the latter due to differential rotation. Using the same analysis pipeline applied previously to observations, we analyze the physical properties of large-scale Galactic filaments, and quantify their sensitivity to projection effects and galactic environment (i.e. whether they lie in the arm or interarm regions). We find that observed "Giant Molecular Filaments" are consistent with being non-self-gravitating structures dominated by galactic dynamics. Straighter, narrower, and denser "Bone-like" filaments, like the paradigmatic Nessie filament, have similar column densities, velocity gradients, and Galactic plane heights (z ≈ 0 pc) to those in our simple model, but additional physical effects (such as feedback and self-gravity) must be invoked to explain their lengths and widths.

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“…For example, the velocity structures of synthetic spectral lines provide important diagnostics of interstellar turbulence (e.g., Falgarone et al 1994), and the nature of CNM dynamics (Hennebelle et al 2007;Saury et al 2014). Furthermore, synthetic observations have been used extensively to investigate molecule formation (Shetty et al 2011;Smith et al 2014;Duarte-Cabral et al 2015;Duarte-Cabral & Dobbs 2016) and Galactic morphology (Douglas et al 2010;Acreman et al 2012;Pettitt et al 2014). Important observational biases can be directly quantified using these comparisons.…”

Section: Introductionmentioning

confidence: 99%

Recovering Interstellar Gas Properties with Hi Spectral Lines: A Comparison between Synthetic Spectra and 21-SPONGE

Murray

Stanimirović

Kim

et al. 2017

ApJ

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We analyze synthetic neutral hydrogen (H I) absorption and emission spectral lines from a high-resolution, threedimensional hydrodynamical simulation to quantify how well observational methods recover the physical properties of interstellar gas. We present a new method for uniformly decomposing H I spectral lines and estimating the properties of associated gas using the Autonomous Gaussian Decomposition (AGD) algorithm. We find that H I spectral lines recover physical structures in the simulation with excellent completeness at high Galactic latitude, and this completeness declines with decreasing latitude due to strong velocity-blending of spectral lines. The temperature and column density inferred from our decomposition and radiative transfer method agree with the simulated values within a factor of <2 for the majority of gas structures. We next compare synthetic spectra with observations from the 21-SPONGE survey at the Karl G. Jansky Very Large Array using AGD. We find more components per line of sight in 21-SPONGE than in synthetic spectra, which reflects insufficient simulated gas scale heights and the limitations of local box simulations. In addition, we find a significant population of lowoptical depth, broad absorption components in the synthetic data which are not seen in 21-SPONGE. This population is not obvious in integrated or per-channel diagnostics, and reflects the benefit of studying velocityresolved components. The discrepant components correspond to the highest spin temperatures ( < < T 1000 4000 K s ), which are not seen in 21-SPONGE despite sufficient observational sensitivity. We demonstrate that our analysis method is a powerful tool for diagnosing neutral interstellar medium conditions, and future work is needed to improve observational statistics and implementation of simulated physics.

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What can simulated molecular clouds tell us about real molecular clouds?

Cited by 78 publications

References 81 publications

A guided map to the spiral arms in the galactic disk of the Milky Way

A guided map to the spiral arms in the galactic disk of the Milky Way

Synthetic Large-scale Galactic Filaments: On Their Formation, Physical Properties, and Resemblance to Observations

Recovering Interstellar Gas Properties with Hi Spectral Lines: A Comparison between Synthetic Spectra and 21-SPONGE

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