scholarly journals Hydrodynamic simulations of mechanical stellar feedback in a molecular cloud formed by thermal instability

2017 ◽  
Vol 470 (2) ◽  
pp. 2283-2313 ◽  
Author(s):  
C. J. Wareing ◽  
J. M. Pittard ◽  
S. A. E. G. Falle
Keyword(s):  
Molecular Cloud ◽  
Thermal Instability ◽  
Hydrodynamic Simulations ◽  
Stellar Feedback

The Perseus OB2 Superbubble and the Taurus-Auriga-California-Perseus Molecular Cloud Loop

2021 ◽  
Author(s):  
Xuepeng Chen ◽  
Weihua Guo ◽  
Jiangcheng Feng ◽  
Yang Su ◽  
Yan Sun ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Cloud ◽  
Three Dimensional ◽  
Solar Neighborhood ◽  
Dimensional Structure ◽  
Wide Field ◽  
Star Forming ◽  
Stellar Feedback ◽  
History Of ◽  
Cloud Complex

Abstract Located at a distance of about 300 pc, Perseus OB2 (or Per~OB2 for short) is one of the major OB associations in the solar vicinity\cite{Zeeuw99,Belikov2002}, which has blown a supershell with a diameter of about 15 degree seen in the atomic hydrogen line surveys\cite{Sancisi1974,Heiles1984,Hartmann1997}. It was long considered that stellar feedback from the Per~OB2 association had formed a superbubble that swept up the surrounding interstellar medium into the observed supershell\cite{Bally2008}. Here we report the three-dimensional structure of the Per~OB2 superbubble, based on wide-field atomic hydrogen and molecular gas (traced by CO) surveys. The measured diameter of the superbubble is roughly 330 pc. Multiple atomic hydrogen shells/loops with expansion velocities of about 10 km/s are revealed in the superbubble, suggesting a complicated evolution history of the superbubble. Furthermore, the inspections of the morphology, kinematics and timescale of the Taurus-Auriga, California, and Perseus molecular clouds shows that the cloud complex is a super molecular cloud loop circling around and co-expanding with the Per~OB2 superbubble. We conclude that the Taurus-Auriga-California-Perseus loop, the largest star-forming molecular cloud complex in the solar neighborhood, is formed from the feedback of the Per~OB2 superbubble.

scholarly journals Efficacy of early stellar feedback in low gas surface density environments

2019 ◽  
Vol 491 (2) ◽  
pp. 2088-2103 ◽  
Author(s):  
Rahul Kannan ◽  
Federico Marinacci ◽  
Christine M Simpson ◽  
Simon C O Glover ◽  
Lars Hernquist
Keyword(s):  
Star Formation ◽  
Radiation Pressure ◽  
Surface Density ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Medium Density ◽  
Hydrodynamic Simulations ◽  
Radiative Feedback ◽  
Stellar Feedback ◽  
Radiation Feedback

ABSTRACT We present a suite of high-resolution radiation hydrodynamic simulations of a small patch (1 kpc2) of the interstellar medium (ISM) performed with arepo-rt, with the aim to quantify the efficacy of various feedback processes like supernova (SN) explosions, photoheating, and radiation pressure in low gas surface density galaxies (Σgas ≃ 10 M⊙ pc−2). We show that radiative feedback decrease the star formation rate and therefore the total stellar mass formed by a factor of approximately two. This increases the gas depletion time-scale and brings the simulated Kennicutt–Schmidt relation closer to the observational estimates. Radiation feedback coupled with SN is more efficient at driving outflows with the mass and energy loading increasing by a factor of ∼10. This increase is mainly driven by the additional entrainment of medium-density (10−2  cm−3 ≤ n < 1 cm−3) warm (300 K ≤ T < 8000 K) material. Therefore, including radiative feedback tends to launch colder, denser, and more mass- and energy-loaded outflows. This is because photoheating of the high-density gas around a newly formed star overpressurizes the region, causing it to expand. This reduces the ambient density in which the SN explode by a factor of 10–100 which in turn increases their momentum output by a factor of ∼1.5–2.5. Finally, we note that in these low gas surface density environments, radiative feedback primarily impact the ISM via photoheating and radiation pressure has only a minimal role in regulating star formation.

scholarly journals High-resolution three-dimensional simulations of gas removal from ultrafaint dwarf galaxies

2019 ◽  
Vol 630 ◽  
pp. A140 ◽  
Author(s):  
Donatella Romano ◽  
Francesco Calura ◽  
Annibale D’Ercole ◽  
C. Gareth Few
Keyword(s):  
High Resolution ◽  
Milky Way ◽  
Dwarf Galaxies ◽  
Three Dimensional ◽  
Energy Output ◽  
Potential Well ◽  
Hydrodynamic Simulations ◽  
Stellar Feedback ◽  
Gas Removal ◽  
Cold Gas

Context. The faintest Local Group galaxies found lurking in and around the Milky Way halo provide a unique test bed for theories of structure formation and evolution on small scales. Deep Subaru and Hubble Space Telescope photometry demonstrates that the stellar populations of these galaxies are old and that the star formation activity did not last longer than 2 Gyr in these systems. A few mechanisms that may lead to such a rapid quenching have been investigated by means of hydrodynamic simulations, but these have not provided any final assessment so far. Aims. This is the first in a series of papers aimed at analyzing the roles of stellar feedback, ram pressure stripping, host-satellite tidal interactions, and reionization in cleaning the lowest mass Milky Way companions of their cold gas using high-resolution, three-dimensional hydrodynamic simulations. Methods. We simulated an isolated ultrafaint dwarf galaxy loosely modeled after Boötes I, and examined whether or not stellar feedback alone could drive a substantial fraction of the ambient gas out from the shallow potential well. Results. In contrast to simple analytical estimates, but in agreement with previous hydrodynamical studies, we find that most of the cold gas reservoir is retained. Conversely, a significant amount of the metal-enriched stellar ejecta crosses the boundaries of the computational box with velocities exceeding the local escape velocity and is, thus, likely lost from the system. Conclusions. Although the total energy output from multiple supernova explosions exceeds the binding energy of the gas, no galactic-scale outflow develops in our simulations and as such, most of the ambient medium remains trapped within the weak potential well of the model galaxy. It seems thus unavoidable that to explain the dearth of gas in ultrafaint dwarf galaxies, we will have to resort to environmental effects. This will be the subject of a forthcoming paper.

scholarly journals The Supershell-Molecular Cloud Connection in the Milky Way and Beyond

2012 ◽  
Vol 8 (S292) ◽  
pp. 83-86
Author(s):  
J. R. Dawson ◽  
N. M. McClure-Griffiths ◽  
Y. Fukui ◽  
J. Dickey ◽  
T. Wong ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Molecular Clouds ◽  
Large Scale ◽  
Milky Way ◽  
Observational Evidence ◽  
Cloud Formation ◽  
Stellar Feedback ◽  
The Relationship ◽  
Global Contribution

AbstractThe role of large-scale stellar feedback in the formation of molecular clouds has been investigated observationally by examining the relationship between Hi and 12CO(J = 1−0) in supershells. Detailed parsec-resolution case studies of two Milky Way supershells demonstrate an enhanced level of molecularisation over both objects, and hence provide the first quantitative observational evidence of increased molecular cloud production in volumes of space affected by supershell activity. Recent results on supergiant shells in the LMC suggest that while they do indeed help to organise the ISM into over-dense structures, their global contribution to molecular cloud formation is of the order of only ∼ 10%.

scholarly journals Cooling and instabilities in colliding flows

2021 ◽  
Author(s):  
R N Markwick ◽  
A Frank ◽  
J Carroll-Nellenback ◽  
B Liu ◽  
E G Blackman ◽  
...  
Keyword(s):  
Thermal Instability ◽  
Three Dimensional ◽  
Oscillation Period ◽  
Three Dimensions ◽  
Temperature Dependent ◽  
Radiative Shock ◽  
Hydrodynamic Simulations ◽  
Protostellar Jets ◽  
The One ◽  
Cooling Function

Abstract Collisional self-interactions occurring in protostellar jets give rise to strong shocks, the structure of which can be affected by radiative cooling within the flow. To study such colliding flows, we use the AstroBEAR AMR code to conduct hydrodynamic simulations in both one and three dimensions with a power law cooling function. The characteristic length and time scales for cooling are temperature dependent and thus may vary as shocked gas cools. When the cooling length decreases sufficiently rapidly the system becomes unstable to the radiative shock instability, which produces oscillations in the position of the shock front; these oscillations can be seen in both the one and three dimensional cases. Our simulations show no evidence of the density clumping characteristic of a thermal instability, even when the cooling function meets the expected criteria. In the three-dimensional case, the nonlinear thin shell instability (NTSI) is found to dominate when the cooling length is sufficiently small. When the flows are subjected to the radiative shock instability, oscillations in the size of the cooling region allow NTSI to occur at larger cooling lengths, though larger cooling lengths delay the onset of NTSI by increasing the oscillation period.

scholarly journals MOLECULAR CLOUD EVOLUTION. III. ACCRETION VERSUS STELLAR FEEDBACK

2010 ◽  
Vol 715 (2) ◽  
pp. 1302-1317 ◽  
Author(s):  
Enrique Vázquez-Semadeni ◽  
Pedro Colín ◽  
Gilberto C. Gómez ◽  
Javier Ballesteros-Paredes ◽  
Alan W. Watson
Keyword(s):  
Molecular Cloud ◽  
Stellar Feedback ◽  
Cloud Evolution

scholarly journals Is multiphase gas cloudy or misty?

2020 ◽  
Vol 494 (1) ◽  
pp. L27-L31 ◽  
Author(s):  
Max Gronke ◽  
S Peng Oh
Keyword(s):  
Radiative Transfer ◽  
Thermal Instability ◽  
Weak Dependence ◽  
Multistage Process ◽  
Pressure Balance ◽  
Hydrodynamic Simulations ◽  
Contraction Phase ◽  
Gas Cloud ◽  
Resolution Requirements ◽  
Cold Gas

ABSTRACT Cold T ∼ 104 K gas morphology could span a spectrum ranging from large discrete clouds to a fine ‘mist’ in a hot medium. This has myriad implications, including dynamics and survival, radiative transfer, and resolution requirements for cosmological simulations. Here, we use 3D hydrodynamic simulations to study the pressure-driven fragmentation of cooling gas. This is a complex, multistage process, with an initial Rayleigh–Taylor unstable contraction phase that seeds perturbations, followed by a rapid, violent expansion leading to the dispersion of small cold gas ‘droplets’ in the vicinity of the gas cloud. Finally, due to turbulent motions, and cooling, these droplets may coagulate. Our results show that a gas cloud ‘shatters’ if it is sufficiently perturbed out of pressure balance (δP/P ∼ 1) and has a large final overdensity χf ≳ 300, with only a weak dependence on the cloud size. Otherwise, the droplets reassemble back into larger pieces. We discuss our results in the context of thermal instability and clouds embedded in a shock-heated environment.

scholarly journals Global Protoplanetary Disk Simulations: Dead Zone Formation and FUor Outbursts

2018 ◽  
Vol 14 (S345) ◽  
pp. 324-325
Author(s):  
Kundan Kadam ◽  
E. Vorobyov ◽  
Zs. Regály ◽  
Á. Kóspál ◽  
P. Ábráham
Keyword(s):  
Molecular Cloud ◽  
Dead Zone ◽  
Protoplanetary Disk ◽  
Model Parameters ◽  
Zone Formation ◽  
Hydrodynamic Simulations ◽  
Disk Structure ◽  
Self Consistent ◽  
Disk Evolution ◽  
Collapse Phase

AbstractWe conducted global hydrodynamic simulations of protoplanetary disk evolution with an adaptive Shakura-Sunyaev α prescription to represent the layered disk structure, and starting with the collapse phase of the molecular cloud. With the canonical values of model parameters, self-consistent dead zones formed at the scale of a few au. The instabilities associated with the dead zone and corresponding outbursts, similar to FUor eruptions, were also observed in the simulations.

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