Radiative magnetized thermal conduction fronts

Borkowski, Kazimierz J.; Balbus, Steven A.; Fristrom, C. C.

doi:10.1086/168784

Cited by 164 publications

(206 citation statements)

References 0 publications

Supporting

Mentioning

193

Contrasting

Order By: Relevance

“…We find that the observed high ion ratios can be explained by subsolar abundance models of shock ionization (Dopita & Sutherland 1996) or turbulent mixing layers (Slavin et al 1993). The conductive interface model (Borkowski et al 1990) produces lower ratios of [Si iv/O vi] than observed. However Si iii is more easily photoionized (ionization potential ¼ 33:5 eV) than the other high ions.…”

Section: High Ions In Complex Cmentioning

confidence: 82%

Metallicity and Ionization in High‐Velocity Cloud Complex C

Collins

Shull²,

Giroux

2007

ApJ

140

View full text Add to dashboard Cite

We analyze HST and FUSE ultraviolet spectroscopic data for 11 sight lines passing through the infalling highvelocity cloud (HVC) Complex C. These sight lines pass through regions with H i column densities in the range N H i ¼ 10 18:1 Y10 20:1 cm À2 . From [O i/H i] abundances, we find that Complex C metallicities range from 0.09 to 0.29 Z , with a column density weighted mean of 0.13 Z . Nitrogen (N i) is underabundant by factors of (0.01Y0.07)(N/H) , significantly less than oxygen relative to solar abundances. This pattern suggests nucleosynthetic enrichment by Type II SNe, consistent with an origin in the Galactic fountain or infalling gas produced in winds from Local Group galaxies. The range of metallicity and its possible (2 ) dependence on N H i could indicate some mixing of primordial material with enriched gas from the Milky Way, but the mixing mechanism is unclear. We also investigate the significant highly ionized component of Complex C, detected in C iv, Si iv, and O vi, but not in N v. High-ion column density ratios show little variance and are consistent with shock ionization or ionization at interfaces between Complex C and a hotter surrounding medium. Evidence for the former mechanism is seen in the Mrk 876 line profiles, where the offset in line centroids between low and high ions suggests a decelerating bow shock.

show abstract

Section: High Ions In Complex Cmentioning

confidence: 82%

Metallicity and Ionization in High‐Velocity Cloud Complex C

Collins

Shull²,

Giroux

2007

ApJ

140

View full text Add to dashboard Cite

show abstract

“…A hot plasma may cool at lower rates (Sutherland & Dopita 1993) or at higher rates (e.g. Borkowski et al 1990) relative to the condition of ionization equilibrium, depending on its thermal history.…”

Section: Discussionmentioning

confidence: 99%

Galactic fountains and outflows in star-forming dwarf galaxies: interstellar medium expulsion and chemical enrichment

Melioli¹,

Brighenti²,

D’Ercole³

2014

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We investigated the impact of supernova feedback in gas-rich dwarf galaxies experiencing a low-to-moderate star formation rate, typical of relatively quiescent phases between starbursts. We calculated the long term evolution of the ISM and the metalrich SN ejecta using 3D hydrodynamic simulations, in which the feedback energy is deposited by SNeII exploding in distinct OB associations. We found that a circulation flow similar to galactic fountains is generally established, with some ISM lifted at heights of one to few kpc above the galactic plane. This gas forms an extra-planar layer, which falls back to the plane in ≈ 10 8 yr, once the star formation stops. Very little or no ISM is expelled outside the galaxy system for the considered SFRs, even though in the most powerful model the SN energy is comparable to the gas binding energy. The metal-rich SN ejecta is instead more vulnerable to the feedback and we found that a significant fraction (25 − 80%) is vented in the intergalactic medium, even for low SN rate (7 × 10 −5 − 7 × 10 −4 yr −1 ). About half of the metals retained by the galaxy are located far (z > 500 pc) from the galactic plane. Moreover, our models indicate that the circulation of the metal-rich gas out from and back to the galactic disk is not able to erase the chemical gradients imprinted by the (centrally concentrated) SN explosions.

show abstract

“…Zhekov & Myasnikov (1998) showed that conduction also significantly alters the structure of spherically symmetric SWBs around static stars. Spectral signatures of a conduction front at the edge of the SWB around the Wolf-Rayet star HD 50896 were detected by Boroson et al (1997), although further work is required to constrain the strength of the conduction, which can be affected by e.g., magnetic fields (Borkowski et al 1990). Our simulations do not include thermal conduction, so the mixing layer is mediated by turbulent mixing, which we found to be very efficient at removing energy from the SWB.…”

Section: The Wind-ism Boundarymentioning

confidence: 99%

Detecting stellar-wind bubbles through infrared arcs in H ii regions

Mackey

Haworth

Gvaramadze

et al. 2016

A&A

View full text Add to dashboard Cite

Mid-infrared arcs of dust emission are often seen near ionizing stars within H  regions. A possible explanations for these arcs is that they could show the outer edges of asymmetric stellar wind bubbles. We use two-dimensional, radiation-hydrodynamics simulations of wind bubbles within H  regions around individual stars to predict the infrared emission properties of the dust within the H  region.We assume that dust and gas are dynamically well-coupled and that dust properties (composition, size distribution) are the same in the H  region as outside it, and that the wind bubble contains no dust. We post-process the simulations to make synthetic intensity maps at infrared wavebands using the  code. We find that the outer edge of a wind bubble emits brightly at 24 µm through starlight absorbed by dust grains and re-radiated thermally in the infrared. This produces a bright arc of emission for slowly moving stars that have asymmetric wind bubbles, even for cases where there is no bow shock or any corresponding feature in tracers of gas emission. The 24 µm intensity decreases exponentially from the arc with increasing distance from the star because the dust temperature decreases with distance. The size distribution and composition of the dust grains has quantitative but not qualitative effects on our results. Despite the simplifications of our model, we find good qualitative agreement with observations of the H  region RCW 120, and can provide physical explanations for any quantitative differences. Our model produces an infrared arc with the same shape and size as the arc around CD −38• 11636 in RCW 120, and with comparable brightness. This suggests that infrared arcs around O stars in H  regions may be revealing the extent of stellar wind bubbles, although we have not excluded other explanations.

show abstract

Radiative magnetized thermal conduction fronts

Cited by 164 publications

References 0 publications

Metallicity and Ionization in High‐Velocity Cloud Complex C

Metallicity and Ionization in High‐Velocity Cloud Complex C

Galactic fountains and outflows in star-forming dwarf galaxies: interstellar medium expulsion and chemical enrichment

Detecting stellar-wind bubbles through infrared arcs in H ii regions

Contact Info

Product

Resources

About