The dynamical properties of dense filaments in the infrared dark cloud G035.39−00.33★

Henshaw, Jonathan D.; Caselli, P.; Fontani, F.; Jiménez-Serra, I.; Tan, Jonathan C.

doi:10.1093/mnras/stu446

Cited by 132 publications

(212 citation statements)

References 59 publications

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“…In this work we showed that this could have its origin in different masses per unit length compared to the critical value (M/L)crit (equation 2). However, there are also a number of observations which report the collapse of filaments towards a central massive clump (Myers 2009;Schneider et al 2012;Kirk et al 2013a;Henshaw et al 2014;Peretto et al 2014), which we do not see in the simulations presented so far. A possible mechanism to obtain such a centralised collapse mode, is to impose different initial conditions in our simulations.…”

Section: Edge-on Vs Centralised Collapsecontrasting

confidence: 85%

“…Observations of star-forming filaments reveal nonthermal line widths, which indicate an additional turbulent velocity field with typical Mach numbers between 1 and 3 (Arzoumanian et al 2013;Hacar et al 2013;Furuya et al 2014;Henshaw et al 2014;Jiménez-Serra et al 2014;Li et al 2014). For this reason, we apply a transonic or supersonic turbulent velocity field.…”

Section: Initial Conditionsmentioning

confidence: 99%

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The impact of turbulence and magnetic field orientation on star-forming filaments

Seifried

Walch

2015

Mon. Not. R. Astron. Soc.

117

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We present simulations of collapsing filaments studying the impact of turbulence and magnetic field morphologies on their evolution and star formation properties. We vary the mass per unit length of the filaments as well as the orientation of the magnetic field with respect to the major axis. We find that the filaments, which have no or a perpendicular magnetic field, typically reveal a smaller width than the universal width of 0.1 pc proposed by e.g. Arzoumanian et al. (2011). We show that this also holds in the presence of supersonic turbulence and that accretion driven turbulence is too weak to stabilize the filaments along their radial direction. On the other hand, we find that a magnetic field that is parallel to the major axis can stabilize the filament against radial collapse resulting in widths of 0.1 pc. Furthermore, depending on the filament mass and magnetic field configuration, gravitational collapse and fragmentation in filaments occurs either in an edge-on way, uniformly distributed across the entire length, or in a mixed way. In the presence of initially moderate density perturbations, a centralized collapse towards a common gravitational centre occurs. Our simulations can thus reproduce different modes of fragmentation observed recently in star forming filaments. Moreover, we find that turbulent motions influence the distance between individual fragments along the filament, which does not always match the results of a Jeans analysis.

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Section: Edge-on Vs Centralised Collapsecontrasting

confidence: 85%

Section: Initial Conditionsmentioning

confidence: 99%

The impact of turbulence and magnetic field orientation on star-forming filaments

Seifried

Walch

2015

Mon. Not. R. Astron. Soc.

117

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“…The signal-to-noise ratio of the CH 3 OH(2 0,2 −1 0,1 )A+ is not good enough to perform the multicomponent fit, so we performed one velocity Gaussian fitting. We found that the C 2 H(N = 1-0) spectrum shows strong double velocity peaks in some positions, so we followed the routine described by Henshaw et al (2014) and Hacar et al (2013) by performing a multiple-component Gaussian fit.…”

Section: Kinematicsmentioning

confidence: 99%

“…The fit results from the average spectrum are used as the initial guesses for all the spectra inside the square area. If one spectrum is fitted with two velocity components, we apply the following quality check: the separation of the two components must be larger than the half-width at half-maximum of the stronger component, and the peak intensity of each component must be larger than 3σ (with σ = 0.45 Jy beam −1 ), otherwise, the spectrum is fitted with one velocity component (see Henshaw et al 2014;Hacar et al 2013 for the details of the fitting routine). While most of the C 2 H emission can be fitted with one single velocity component, emission in the north and southwest requires of two velocity components.…”

Section: Kinematicsmentioning

confidence: 99%

Ongoing star formation in the protocluster IRAS 22134+5834

Wang

Audard

Fontani

et al. 2016

A&A

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Aims. Massive stars form in clusters, and their influence on nearby starless cores is still poorly understood. The protocluster associated with IRAS 22134+5834 represents an excellent laboratory for studying the influence of massive YSOs on nearby starless cores and the possible implications in the clustered star formation process. Methods. IRAS 22134+5834 was observed in the cm range with (E)VLA, 3 mm with CARMA, 2 mm with PdBI, and 1.3 mm with SMA, to study both the continuum emission and the molecular lines that trace different physical conditions of the gas. Results. The multiwavelength centimeter continuum observations revealed two radio sources within the cluster, VLA1 and VLA2. VLA1 is considered to be an optically thin UCH region with a size of 0.01 pc that sits at the edge of the near-infrared (NIR) cluster. The flux of ionizing photons of the VLA1 corresponds to a B1 ZAMS star. VLA2 is associated with an infrared point source and has a negative spectral index. We resolved six millimeter continuum cores at 2 mm, MM2 is associated with the UCH region VLA1, and other dense cores are distributed around the UCH region. Two high-mass starless clumps (HMSC), HMSC-E (east) and HMSC-W (west), are detected around the NIR cluster with N 2 H + (1-0) and NH 3 emission, and they show different physical and chemical properties. Two N 2 D + cores are detected on an NH 3 filament close to the UCH region with a projected separation of ∼8000 AU at the assumed distance of 2.6 kpc. The kinematic properties of the molecular line emission confirm that the UCH region is expanding and that the molecular cloud around the NIR cluster is also expanding. Conclusions. Our multiwavelength study has revealed different generations of star formation in IRAS 22134+5834. The formed intermediate-to-massive stars show a strong impact on nearby starless clumps. We propose that the starless clumps and HMPOs formed at the edge of the cluster while the stellar wind from the UCH region and the NIR cluster drives the large scale bubble.

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“…Caselli et al 2002;Tafalla et al 2004;Tobin et al 2013;Miettinen & Offner 2013) and more massive IRDC regions (e.g. Ragan et al 2006;Beuther & Henning 2009;Vasyunina et al 2011;Sanhueza et al 2013;Gerner et al 2014;Henshaw et al 2014). …”

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Fragmentation and kinematics of dense molecular cores in the filamentary infrared-dark cloud G011.11–0.12

Ragan¹,

Henning²,

Beuther³

et al. 2015

A&A

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We present new Plateau de Bure Interferometer observations of a region in the filamentary infrared-dark cloud (IRDC) G011.11-0.12 containing young, star-forming cores. In addition to the 3.2 mm continuum emission from cold dust, we map this region in the N 2 H + (1−0) line to trace the core kinematics with an angular resolution of 2 and velocity resolution of 0.2 km s −1 . These data are presented in concert with recent Herschel results, single-dish N 2 H + (1−0) data, SABOCA 350 µm continuum data, and maps of the C 18 O (2−1) transition obtained with the IRAM 30 m telescope. We recover the star-forming cores at 3.2 mm continuum, while in N 2 H + they appear at the peaks of extended structures. The mean projected spacing between N 2 H + emission peaks is 0.18 pc, consistent with simple isothermal Jeans fragmentation. The 0.1 pc-sized cores have low virial parameters on the criticality borderline, while on the scale of the whole region, we infer that it is undergoing large-scale collapse. The N 2 H + linewidth increases with evolutionary stage, while CO isotopologues show no linewidth variation with core evolution. Centroid velocities of all tracers are in excellent agreement, except in the starless region where two N 2 H + velocity components are detected, one of which has no counterpart in C 18 O. We suggest that gas along this line of sight may be falling into the quiescent core, giving rise to the second velocity component, possibly connected to the global collapse of the region.

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The dynamical properties of dense filaments in the infrared dark cloud G035.39−00.33★

Cited by 132 publications

References 59 publications

The impact of turbulence and magnetic field orientation on star-forming filaments

The impact of turbulence and magnetic field orientation on star-forming filaments

Ongoing star formation in the protocluster IRAS 22134+5834

Fragmentation and kinematics of dense molecular cores in the filamentary infrared-dark cloud G011.11–0.12

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