Hot Gas in the Wolf–Rayet Nebula NGC 3199

Toalá, J. A.; Marston, A. P.; Guerrero, M. A.; Chu, You‐Hua; Gruendl, R. A.

doi:10.3847/1538-4357/aa8554

Cited by 26 publications

(16 citation statements)

References 49 publications

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“…Similar to wind-blown bubbles around massive stars, the X-ray temperatures obtained by means of spectral fitting from hot bubbles in PNe are in the T X = (1 − 3) × 10 6 K range [5,6], which is not in accordance to what is expected from analytical predictions. The temperature of an adiabatically-shocked wind-blown bubble is a function of the terminal wind velocity (V ∞ ) from the central star and can be estimated to be…”

Section: Introductioncontrasting

confidence: 64%

Simulations of the Formation and X-ray Emission from Hot Bubbles in Planetary Nebulae

Toalá¹,

Arthur²

2018

Galaxies

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High-quality X-ray observations of planetary nebulae (PNe) have demonstrated that the X-ray-emitting gas in their hot bubbles have temperatures in the small range T X = (1 − 3) × 10 6 K. However, according to theoretical expectations, adiabatically-shocked wind-blown bubbles should have temperatures up to two orders of magnitude higher. Numerical simulations show that instabilities at the interface between the hot bubble and the nebular material form clumps and filaments that generate an intermediate-temperature turbulent mixing layer. We describe the X-ray properties resulting from simulations of PNe in our Galaxy and the Magellanic Clouds.

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Section: Introductioncontrasting

confidence: 64%

Simulations of the Formation and X-ray Emission from Hot Bubbles in Planetary Nebulae

Toalá¹,

Arthur²

2018

Galaxies

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“…Accordingly a physical association between WR 18, NGC 3199 and #0708 at ∼2 kpc appears to be the better bet. In addition, recent work by Toalá et al (2017) challenges an older view that WR 18 is a runaway from Wd2: they do this on grounds of proper motion data on the WR star and stars near it, and also the far-infrared morphology of NGC 3199.…”

Section: A Distinct Ob Grouping and Other 'Unrelated' Objectsmentioning

confidence: 99%

Massive stars in the hinterland of the young cluster, Westerlund 2

Drew

Herrero

Mohr-Smith

et al. 2018

Monthly Notices of the Royal Astronomical Society

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An unsettled question concerning the formation and distribution of massive stars is whether they must be born in massive clusters and, if found in less dense environments, whether they must have migrated there. With the advent of wide-area digital photometric surveys, it is now possible to identify massive stars away from prominent Galactic clusters without bias. In this study we consider 40 candidate OB stars found in the field around the young massive cluster, Westerlund 2, by Mohr-Smith et al (2017): these are located inside a box of 1.5×1.5 square degrees and are selected on the basis of their extinctions and K magnitudes. We present VLT/X-shooter spectra of two of the hottest O stars, respectively 11 and 22 arcmin from the centre of Westerlund 2. They are confirmed as O4V stars, with stellar masses likely to be in excess of 40 M . Their radial velocities relative to the non-binary reference object, MSP 182, in Westerlund 2 are −29.4±1.7 and −14.4±2.2 km s −1 , respectively. Using Gaia DR2 proper motions we find that between 8 and 11 early O/WR stars in the studied region (including the two VLT targets, plus WR 20c and WR 20aa) could have been ejected from Westerlund 2 in the last one million years. This represents an efficiency of massive-star ejection of up to ∼ 25%. On sky, the positions of these stars and their proper motions show a near N-S alignment. We discuss the possibility that these results are a consequence of prior sub-cluster merging combining with dynamical ejection.

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“…It is this Fe abundance that is responsible for the plateau seen in the emission coefficient curve around log10(T ) ∼ 6.7. The stellar surface abundances of WR136, as determined from stellar atmosphere model fits to optical and UV spectra ( Diffuse X-ray emission has been detected in four WR nebulae: S 308, NGC 2359, NGC 3199 and NGC6888 around WR 6, WR 7, WR 18 and WR 136, respectively (Toalá et al 2012, 2015b, 2016a, 2017. The spectral type of the central star of NGC 6888, WR136, is WN6, while the other three central stars are all WN4.…”

Section: Wolf-rayet Nebulaementioning

confidence: 99%

On the X-ray temperature of hot gas in diffuse nebulae

Toalá¹,

Arthur²

2018

Monthly Notices of the Royal Astronomical Society

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X-ray emitting diffuse nebulae around hot stars are observed to have soft-band temperatures in the narrow range [1-3]×10 6 K, independent of the stellar wind parameters and the evolutionary stage of the central star. We discuss the origin of this X-ray temperature for planetary nebulae (PNe), Wolf-Rayet nebulae (WR) and interstellar wind bubbles around hot young stars in our Galaxy and the Magellanic Clouds. We calculate the differential emission measure (DEM) distributions as a function of temperature from previously published simulations and combine these with the X-ray emission coefficient for the 0.3-2.0 keV band to estimate the X-ray temperatures. We find that all simulated nebulae have DEM distributions with steep negative slopes, which is due to turbulent mixing at the interface between the hot shocked stellar wind and the warm photoionized gas. Sharply peaked emission coefficients act as temperature filters and emphasize the contribution of gas with temperatures close to the peak position, which coincides with the observed X-ray temperatures for the chemical abundance sets we consider. Higher metallicity nebulae have lower temperature and higher luminosity X-ray emission. We show that the second temperature component found from spectral fitting to X-ray observations of WR nebulae is due to a significant contribution from the hot shocked stellar wind, while the lower temperature principal component is dominated by nebular gas. We suggest that turbulent mixing layers are the origin of the soft X-ray emission in the majority of diffuse nebulae.

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Hot Gas in the Wolf–Rayet Nebula NGC 3199

Cited by 26 publications

References 49 publications

Simulations of the Formation and X-ray Emission from Hot Bubbles in Planetary Nebulae

Simulations of the Formation and X-ray Emission from Hot Bubbles in Planetary Nebulae

Massive stars in the hinterland of the young cluster, Westerlund 2

On the X-ray temperature of hot gas in diffuse nebulae

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