Galactic cold cores

Rivera-Ingraham, A.; Ristorcelli, I.; Juvela, M.; Montillaud, J.; Malinen, J.; Pelkonen, V. M.; Marston, A. P.; Martín, P. G.; Pagani, L.; Paladini, R.; Paradis, D.; Ysard, N.; Ward-Thompson, Derek; Bernard, J.-P.; Marshall, D. J.; Montier, L.; Tóth, L. V.

doi:10.1051/0004-6361/201628552

Cited by 22 publications

(7 citation statements)

References 57 publications

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“…We also note that filaments embedded in high column density environments tend to have higher column densities. The same behavior was observed in Herschel data at smaller scales (Rivera-Ingraham et al 2017), where dense filaments tend to be embedded in dense environments.…”

Section: Column Density Subsamplessupporting

confidence: 82%

Statistical analysis of the interplay between interstellar magnetic fields and filaments hostingPlanckGalactic cold clumps

Alina

Ristorcelli

Montier

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present a statistical study of the relative orientation in the plane of the sky between interstellar magnetic fields and filaments hosting cold clumps. For the first time, we consider both the density of the environment and the density contrast between the filaments and their environment. Moreover, we geometrically distinguish between the clumps and the remaining portions of the filaments. We infer the magnetic field orientations in the filaments and in their environment from the Stokes parameters †, assuming optically thin conditions. Thus, we analyze the relative orientations between filaments, embedded clumps, and internal and background magnetic fields, depending on the filament environment and evolutionary stages. We recover the previously observed trend for filaments in low column density environments to be aligned parallel to the background magnetic field; however, we find that this trend is significant only for low contrast filaments, whereas high contrast filaments tend to be randomly orientated with respect to the background magnetic field. Filaments in high column density environments do not globally show any preferential orientation, although low contrast filaments alone tend to have perpendicular relative orientation with respect to the background magnetic field. For a subsample of nearby filaments, for which volume densities can be derived, we find a clear transition in the relative orientation with increasing density, at n H ∼ 10 3 cm −3 , changing from mostly parallel to mostly perpendicular in the off-clump portions of filaments and from even to bimodal in the clumps. Our results confirm a strong interplay between interstellar magnetic fields and filaments during their formation and evolution.

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Section: Column Density Subsamplessupporting

confidence: 82%

Statistical analysis of the interplay between interstellar magnetic fields and filaments hostingPlanckGalactic cold clumps

Alina

Ristorcelli

Montier

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…WR 18 would then be the result of a large clump that was triggered into star formation by a passing wave of material. There are numerous examples of triggered clumps of this kind in Herschel observations (Hill et al 2011;Rivera-Ingraham et al 2015;Zavagno et al 2010).…”

Section: Discussionmentioning

confidence: 99%

Hot Gas in the Wolf–Rayet Nebula NGC 3199

Toalá

Marston²,

Guerrero

et al. 2017

ApJ

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The Wolf-Rayet (WR) nebula NGC 3199 has been suggested to be a bow shock around its central star WR 18, presumably a runaway star, because optical images of the nebula show a dominating arc of emission south-west of the star. We present the XMM-Newton detection of extended X-ray emission from NGC 3199, unveiling the powerful effect of the fast wind from WR 18. The X-ray emission is brighter in the region south-east of the star and analysis of the spectral properties of the X-ray emission reveals abundance variations: i) regions close to the optical arc present nitrogen-rich gas enhanced by the stellar wind from WR 18 and ii) gas at the eastern region exhibits abundances close to those reported for nebular abundances derived from optical studies, signature of an efficient mixing of the nebular material with the stellar wind. The dominant plasma temperature and electron density are estimated to be T ≈ 1.2×10 6 K and n e =0.3 cm −3 with an X-ray luminosity in the 0.3-3.0 keV energy range of L X =2.6×10 34 erg s −1 . Combined with information derived from Herschel and the recent Gaia first data release, we conclude that WR 18 is not a runaway star and the formation, chemical variations, and shape of NGC 3199 depend on the initial configuration of the interstellar medium.1 The post-shock temperature in a hot bubble can be expressed as k B T = 3µm H v 2 ∞ /16, where µm H and k B are the mean mass per particle and the Boltzmann's constant, respectively.

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“…Filaments appear to be highly dynamic entities. Rivera-Ingraham et al (2017) have shown evidence that the filaments evolve from a subcritical (i.e., stable; Inutsuka & Miyama 1992) to a supercritical (i.e., unstable) regime by accretion of material from their environment according to recent observations of nearby (d < 500 pc) filaments (Rivera-Ingraham et al 2016). They found that self-gravitating filaments in dense environments (Av ∼ 3, N H2 ∼ 2.9 × 10 20 cm −2 ) can become supercritical on timescales of ∼ 1 Myr, and suggested that filaments evolve in tandem with their environment.…”

Section: Molecular Cloud Substructure and Star Formationmentioning

confidence: 99%

Filamentary collapse flow in molecular clouds

Naranjo-Romero¹,

Vázquez-Semadeni²,

Loughnane³

2020

Preprint

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We present idealized numerical simulations of prestellar gravitational collapse of a moderate initial filamentary perturbation with an additional central ellipsoidal enhancement (a core) considering a uniform, and a stratified background, the latter representing flattened clouds. Both simulations maintain the filamentary structure during the collapse, developing a hierarchical accretion flow from the cloud to the plane; from there to the filament, and from the filament to the core. The flow changes direction smoothly at every step of the hierarchy, with no density divergence nor a shock developing at the filament's axis during the studied prestellar evolution. The flow drives accretion onto the central core and drains material from the filament, slowing down the growth of the latter. As a consequence, the ratio of the central density of the core to the filament density increases in time, diverging at the time of singularity formation in the core. The stratified simulation produces the best match for observed Plummer-like radial column density profiles of filaments, while the uniform simulation does not produce a flat central density profile. This result supports recent suggestions that MCs may be preferentially flattened structures. We examine the possibility that the filamentary flow might approach a quasi-stationary regime in which the radial accretion onto the filament is balanced by the longitudinal accretion onto the core. A simple argument suggests that such a stationary state may be an attractor for the system. Our simulations, do not attain this stationary stage, but appear to be approaching it during the prestellar stage.

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Galactic cold cores

Cited by 22 publications

References 57 publications

Statistical analysis of the interplay between interstellar magnetic fields and filaments hostingPlanckGalactic cold clumps

Statistical analysis of the interplay between interstellar magnetic fields and filaments hostingPlanckGalactic cold clumps

Hot Gas in the Wolf–Rayet Nebula NGC 3199

Filamentary collapse flow in molecular clouds

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