scholarly journals Dust entrainment in galactic winds

2021 ◽  
Vol 503 (1) ◽  
pp. 336-343
Author(s):  
R Kannan ◽  
M Vogelsberger ◽  
F Marinacci ◽  
L V Sales ◽  
P Torrey ◽  
...  

ABSTRACT Winds driven by stellar feedback are an essential part of the galactic ecosystem and are the main mechanism through which low-mass galaxies regulate their star formation. These winds are generally observed to be multiphase with detections of entrained neutral and molecular gas. They are also thought to enrich the circumgalactic medium around galaxies with metals and dust. This ejected dust encodes information about the integrated star formation and outflow history of the galaxy. Therefore it is important to understand how much dust is entrained and driven out of the disc by galactic winds. Here, we demonstrate that stellar feedback is efficient in driving dust-enriched winds and eject enough material to account for the amount of extraplanar dust observed in nearby galaxies. The amount of ejected dust depends on the sites from where they are launched, with dustier galaxies launching more dust-enriched outflows. Moreover, the outflowing cold and dense gas is significantly more dust enriched than the volume filling hot and tenuous material. These results provide an important new insight into the dynamics, structure, and composition of galactic winds and their role in determining the dust content of the extragalactic gas in galaxies.

2019 ◽  
Vol 488 (3) ◽  
pp. 3904-3928 ◽  
Author(s):  
Ryan Leaman ◽  
Francesca Fragkoudi ◽  
Miguel Querejeta ◽  
Gigi Y C Leung ◽  
Dimitri A Gadotti ◽  
...  

ABSTRACT Stellar feedback plays a significant role in modulating star formation, redistributing metals, and shaping the baryonic and dark structure of galaxies – however, the efficiency of its energy deposition to the interstellar medium is challenging to constrain observationally. Here we leverage HST and ALMA imaging of a molecular gas and dust shell ($M_{\mathrm{ H}_2} \sim 2\times 10^{5}\, {\rm M}_{\odot }$) in an outflow from the nuclear star-forming ring of the galaxy NGC 3351, to serve as a boundary condition for a dynamical and energetic analysis of the outflowing ionized gas seen in our MUSE TIMER survey. We use starburst99 models and prescriptions for feedback from simulations to demonstrate that the observed star formation energetics can reproduce the ionized and molecular gas dynamics – provided a dominant component of the momentum injection comes from direct photon pressure from young stars, on top of supernovae, photoionization heating, and stellar winds. The mechanical energy budget from these sources is comparable to low luminosity active galactic neuclei, suggesting that stellar feedback can be a relevant driver of bulk gas motions in galaxy centres – although here ≲10−3 of the ionized gas mass is escaping the galaxy. We test several scenarios for the survival/formation of the cold gas in the outflow, including in situ condensation and cooling. Interestingly, the geometry of the molecular gas shell, observed magnetic field strengths and emission line diagnostics are consistent with a scenario where magnetic field lines aided survival of the dusty ISM as it was initially launched (with mass-loading factor ≲1) from the ring by stellar feedback. This system’s unique feedback-driven morphology can hopefully serve as a useful litmus test for feedback prescriptions in magnetohydrodynamical galaxy simulations.


1983 ◽  
Vol 103 ◽  
pp. 463-472 ◽  
Author(s):  
Alfonso Serrano

Tinsley (1978) has done an excellent review that illustrates the methods and concepts that can be developed to assess the effects of planetary nebulae (PN) on the long-term history of the galaxy. Tinsley concluded that research in PN could put constraints on the past rate of star formation and provide information on chemical enrichment by low mass stars.


2020 ◽  
Vol 494 (3) ◽  
pp. 3971-3997 ◽  
Author(s):  
Peter D Mitchell ◽  
Joop Schaye ◽  
Richard G Bower ◽  
Robert A Crain

ABSTRACT We present measurements of galactic outflow rates from the eagle suite of cosmological simulations. We find that gas is removed from the interstellar medium (ISM) of central galaxies with a dimensionless mass loading factor that scales approximately with circular velocity as $V_{\mathrm{c}}^{-3/2}$ in the low-mass regime where stellar feedback dominates. Feedback from active galactic nuclei causes an upturn in the mass loading for halo masses ${\gt}10^{12} \, \mathrm{M_\odot }$. We find that more gas outflows through the halo virial radius than is removed from the ISM of galaxies, particularly at low redshifts, implying substantial mass loading within the circumgalactic medium. Outflow velocities span a wide range at a given halo mass/redshift, and on average increase positively with redshift and halo mass up to $M_{200} \sim 10^{12} \, \mathrm{M_\odot }$. Outflows exhibit a bimodal flow pattern on circumgalactic scales, aligned with the galactic minor axis. We present a number of like-for-like comparisons to outflow rates from other recent cosmological hydrodynamical simulations, and show that comparing the propagation of galactic winds as a function of radius reveals substantial discrepancies between different models. Relative to some other simulations, eagle favours a scenario for stellar feedback where agreement with the galaxy stellar mass function is achieved by removing smaller amounts of gas from the ISM, but with galactic winds that then propagate and entrain ambient gas out to larger radii.


1985 ◽  
Vol 106 ◽  
pp. 561-566
Author(s):  
Frank H. Shu

We examine how star formation occurs in the Galaxy and come to the following conclusions. (1) The distribution of newly-born stars in the Galaxy depends on the origin of giant-molecular-cloud complexes. For individual complexes, we favor the mechanism of Parker's instability behind galactic shocks. The production of “supercomplexes” may require the mediation of Jeans instability in the interstellar gas. (2) Magnetic fields help to support the clumps of molecular gas making up a complex against gravitational collapse. On a timescale of 107 years, these fields slip by ambipolar diffusion relative to the neutral gas, leading to the formation of dense cloud cores. This timescale is the expected spread in ages of stars born in any clump. (3) When the cores undergo gravitational collapse, they usually give rise to low-mass stars on a timescale of 105 years. (4) What shuts off the accretion flow and determines the mass of a new star is the onset of a powerful stellar wind. The ultimate source of energy for driving this wind in low-mass stars is the release of the energy of differential rotation acquired during the protostellar phase of evolution. The release is triggered by the entire protostar being driven convectively unstable when deuterium burning turns on.


2018 ◽  
Vol 14 (S344) ◽  
pp. 301-304
Author(s):  
Kristen B. W. McQuinn ◽  
Liese van Zee ◽  
Evan D. Skillman

AbstractMass-loss via stellar-feedback driven outflows is predicted to play a critical role in the baryon cycle of low-mass galaxies. However, observational constraints on warm winds are limited as outflows are transient, intrinsically low-surface brightness events and, thus, difficult to detect. Here, we search for outflows in a sample of eleven nearby starburst dwarf galaxies which are strong candidates for outflows. Despite deep H? imaging on galaxies, only a fraction of the sample show evidence of winds. The spatial extent of all detected ionized gas is limited and would still be considered part of the ISM by simulations. These new observations indicate that the physical extent of warm phase outflows is modest and most of the mass will be recycled to the galaxy. The sample is part of the panchromatic STARBurst IRegular Dwarf Survey (STARBIRDS) designed to characterize the starburst phenomenon and its impact on the evolution of low-mass galaxies.


2015 ◽  
Vol 11 (S315) ◽  
pp. 258-261
Author(s):  
D. Utomo ◽  
L. Blitz ◽  
A. Bolatto ◽  
T. Wong ◽  
A. Leroy ◽  
...  

AbstractWe present an updated status of the EDGE project, which is a survey of 125 local galaxies in the 12CO(1−0) and 13CO(1−0) lines. We combine the molecular data of the EDGE survey with the stellar and ionized gas maps of the CALIFA survey to give a comprehensive view of the dependence of the star formation efficiency, or equivalently, the molecular gas depletion time, on various local environments, such as the stellar surface density, metallicity, and radius from the galaxy center. This study will provide insight into the parameters that drive the star formation efficiency in galaxies at z ~ 0.


2019 ◽  
Vol 15 (S359) ◽  
pp. 386-390
Author(s):  
Lucimara P. Martins

AbstractWith the exception of some nearby galaxies, we cannot resolve stars individually. To recover the galaxies star formation history (SFH), the challenge is to extract information from their integrated spectrum. A widely used tool is the full spectral fitting technique. This consists of combining simple stellar populations (SSPs) of different ages and metallicities to match the integrated spectrum. This technique works well for optical spectra, for metallicities near solar and chemical histories not much different from our Galaxy. For everything else there is room for improvement. With telescopes being able to explore further and further away, and beyond the optical, the improvement of this type of tool is crucial. SSPs use as ingredients isochrones, an initial mass function, and a library of stellar spectra. My focus are the stellar libraries, key ingredient for SSPs. Here I talk about the latest developments of stellar libraries, how they influence the SSPs and how to improve them.


2010 ◽  
Vol 6 (S270) ◽  
pp. 503-506
Author(s):  
Pedro Colín ◽  
Vladimir Avila-Reese ◽  
Octavio Valenzuela

AbstractCosmological Adaptive Mesh Refinement simulations are used to study the specific star formation rate (sSFR=SSF/Ms) history and the stellar mass fraction, fs=Ms/MT, of small galaxies, total masses MT between few × 1010 M⊙ to few ×1011 M⊙. Our results are compared with recent observational inferences that show the so-called “downsizing in sSFR” phenomenon: the less massive the galaxy, the higher on average is its sSFR, a trend seen at least since z ~ 1. The simulations are not able to reproduce this phenomenon, in particular the high inferred values of sSFR, as well as the low values of fs constrained from observations. The effects of resolution and sub-grid physics on the SFR and fs of galaxies are discussed.


2006 ◽  
Vol 2 (S237) ◽  
pp. 331-335
Author(s):  
Yu Gao

AbstractActive star formation (SF) is tightly related to the dense molecular gas in the giant molecular clouds' dense cores. Our HCN (measure of the dense molecular gas) survey in 65 galaxies (including 10 ultraluminous galaxies) reveals a tight linear correlation between HCN and IR (SF rate) luminosities, whereas the correlation between IR and CO (measure of the total molecular gas) luminosities is nonlinear. This suggests that the global SF rate depends more intimately upon the amount of dense molecular gas than the total molecular gas content. This linear relationship extends to both the dense cores in the Galaxy and the hyperluminous extreme starbursts at high-redshift. Therefore, the global SF law in dense gas appears to be linear all the way from dense cores to extreme starbursts, spanning over nine orders of magnitude in IR luminosity.


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