Instability of supersonic cold streams feeding galaxies–II. Non-linear evolution of surface and body modes of Kelvin–Helmholtz instability

Padnos, Dan; Mandelker, Nir; Birnboim, Yuval; Krumholz, Mark R.; Steinberg, Elad

doi:10.1093/mnras/sty789

Cited by 36 publications

(39 citation statements)

References 85 publications

(168 reference statements)

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“…This has motivated idealized studies of cold streams, such as the ones by Mandelker et al (2016), Padnos et al (2018) and Mandelker et al (2019), where instability mechanisms can be more easily understood and the streams can be properly resolved. These studies considered the cold streams using ideal hydrodynamics.…”

Section: Resultsmentioning

confidence: 99%

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The impact of magnetic fields on cold streams feeding galaxies

Berlok

Pfrommer

2019

Monthly Notices of the Royal Astronomical Society

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High redshift, massive halos are observed to have sustained, high star formation rates, which require that the amount of cold gas in the halo is continuously replenished. The cooling time scale for the hot virialized halo gas is too long to provide the source of cold gas. Supersonic, cold streams have been invoked as a mechanism for feeding massive halos at high redshift and deliver the cold gas required for continued star formation at the rates observed. This mechanism for replenishing the cold gas reservoir is motivated by some cosmological simulations. However, the cold streams are likely to be subject to the supersonic version of the Kelvin-Helmholtz instability (KHI), which eventually leads to stream disruption. Cosmological simulations have yet to obtain the spatial resolution required for understanding the detailed stability properties of cold streams. In this paper, we consider instead an idealized model of magnetized cold streams that we spatially resolve. Using linear theory we show how magnetic fields with dynamically important field strengths do not inhibit the KHI but rather enhance its growth rate. We perform nonlinear simulations of magnetized stream disruption and find that magnetic fields can nevertheless increase stream survival times by suppressing the mixing rate of cold gas with the circumgalactic medium. We find that magnetic fields can allow streams to survive ∼ 2 − 8 times longer and, consequently, that streams ∼ 2 − 8 times thinner can reach the central galaxy if the magnetic field strength is ∼ 0.3 − 0.8µG.

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Section: Resultsmentioning

confidence: 99%

“…The key difference between our models of cold streams and the ones studied by Mandelker et al (2016), Padnos et al (2018) and Mandelker et al (2019) is that we include a magnetic field and treat the system with ideal MHD (see e.g. Freidberg 2014).…”

Section: Idealized Magnetized Cold Stream Modelmentioning

confidence: 99%

The impact of magnetic fields on cold streams feeding galaxies

Berlok

Pfrommer

2019

Monthly Notices of the Royal Astronomical Society

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“…Examples of large-scale perturbation may be caused by gravitational accretion combined with hydrodynamical (e.g., Kelvin-Helmholtz) or thermal instabilities as we will discuss elsewhere (Vossberg, Cantalupo & Pezzulli, in prep. ; see also Mandelker et al 2016;Padnos et al 2018;Ji et al 2018). Because these density perturbations will be either highly over-pressured or under-pressured for large σ we expect that they would dissipate quickly.…”

Section: Log-normal Density Distributionmentioning

confidence: 97%

The large- and small-scale properties of the intergalactic gas in the Slug Ly α nebula revealed by MUSE Heiiemission observations

Cantalupo

Pezzulli

Lilly

et al. 2018

Monthly Notices of the Royal Astronomical Society

108

126

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With a projected size of about 450 kpc at z 2.3, the Slug Lyα nebula is a rare laboratory to study, in emission, the properties of the intergalactic gas in the Cosmic Web. Since its discovery, the Slug has been the subject of several spectroscopic follow-ups to constrain the properties of the emitting gas. Here we report the results of a deep MUSE integral-field spectroscopic search for non-resonant, extended He λ1640 and metal emission. Extended He radiation is detected on scales of about 100 kpc, but only in some regions associated with the bright Lyα emission and a continuum-detected source, implying large and abrupt variations in the line ratios across adjacent regions in projected space. The recent detection of associated Hα emission and similar abrupt variations in the Lyα kinematics, strongly suggest that the He /Lyα gradient is due to large variations in the physical distances between the associated quasar and these regions. This implies that the overall length of the emitting structure could extend to physical Mpc scales and be mostly oriented along our line of sight. At the same time, the relatively low He /Lyα values suggest that the emitting gas has a broad density distribution that -if expressed in terms of a lognormal -implies dispersions as high as those expected in the interstellar medium of galaxies. These results strengthen the possibility that the density distribution of intergalactic gas at high-redshift is extremely clumpy and multiphase on scales below our current observational spatial resolution of a few physical kpc.

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“…In such a scenario, the angular momentum segregation between DM and gas could be construed as an artefact of poor numerical resolution in filaments. Several authors (Freundlich et al 2014;Mandelker et al 2016;Padnos et al 2018;Mandelker et al 2019;Berlok & Pfrommer 2019) carried out idealised simulations of filaments entering a halo, and concluded that they should be stable, given their width and velocity. Cornuault et al (2018) used a phenomenological model of a gas stream to explore the possibility of a turbulent, multi-phase filament.…”

Section: Introductionmentioning

confidence: 99%

Rivers of gas – I. Unveiling the properties of high redshift filaments

Ramsøy

Slyz

Devriendt

et al. 2021

Monthly Notices of the Royal Astronomical Society

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At high redshift, the cosmic web is widely expected to have a significant impact on the morphologies, dynamics, and star formation rates of the galaxies embedded within it, underscoring the need for a comprehensive study of the properties of such a filamentary network. With this goal in mind, we perform an analysis of high-z gas and dark matter (DM) filaments around a Milky Way-like progenitor simulated with the ramses adaptive mesh refinement (AMR) code from cosmic scales (∼1 Mpc) down to the virial radius of its DM halo host (∼20 kpc at z = 4). Radial density profiles of both gas and DM filaments are found to have the same functional form, namely a plummer-like profile modified to take into account the wall within which these filaments are embedded. Measurements of the typical filament core radius r0 from the simulation are consistent with that of isothermal cylinders in hydrostatic equilibrium. Such an analytic model also predicts a redshift evolution for the core radius of filaments in fair agreement with the measured value for DM [r0∝ (1 + z)−3.18 ± 0.28]. Gas filament cores grow as [r0∝ (1 + z)−2.72 ± 0.26]. In both gas and DM, temperature and vorticity sharply drop at the edge of filaments, providing an excellent way to constrain the outer filament radius. When feedback is included, the gas temperature and vorticity fields are strongly perturbed, hindering such a measurement in the vicinity of the galaxy. However, the core radius of the filaments as measured from the gas density field is largely unaffected by feedback; and the median central density is only reduced by about 20 per cent.

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Instability of supersonic cold streams feeding galaxies–II. Non-linear evolution of surface and body modes of Kelvin–Helmholtz instability

Cited by 36 publications

References 85 publications

The impact of magnetic fields on cold streams feeding galaxies

The impact of magnetic fields on cold streams feeding galaxies

The large- and small-scale properties of the intergalactic gas in the Slug Ly α nebula revealed by MUSE Heiiemission observations

Rivers of gas – I. Unveiling the properties of high redshift filaments

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