Aqueous Lithium–Air Systems

Crowther, Owen; Salomon, Mark

doi:10.1002/9781118615515.ch9

Cited by 8 publications

(10 citation statements)

References 54 publications

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“…The strength of winds from WR stars in particular, the features of which we have observed in the candidate sample, is dependent strongly on metallicity (Vink & de Koter 2005), with wind velocity and mass loss (and therefore momentum) increasing with increasing metallicity (e.g. Leitherer et al 1992;Kudritzki & Puls 2000;Crowther 2000;Nugis & Lamers 2000;Crowther & Hadfield 2006;Crowther 2007;Mokiem et al 2007). Over time, therefore, as more metal enriched young stars produce stellar winds, the energy deposition to the surrounding dense ISM is expected to increase.…”

Section: Evidence For Differences In Metallicitymentioning

confidence: 77%

THE INTERSTELLAR MEDIUM AND FEEDBACK IN THE PROGENITORS OF THE COMPACT PASSIVE GALAXIES ATz∼ 2

Williams

Giavalisco

Lee

et al. 2015

ApJ

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Quenched galaxies at z>2 are nearly all very compact relative to z∼0, suggesting a physical connection between high stellar density and efficient, rapid cessation of star-formation. We present rest-frame UV spectra of Lyman-break galaxies (LBGs) at z ∼ 3 selected to be candidate progenitors of the quenched galaxies at z ∼ 2 based on their compact restframe-optical sizes and high Σ SF R . We compare their UV properties to those of more extended LBGs of similar mass and star-formation rate (non-candidates). We find that candidate progenitors have faster bulk ISM gas velocities and higher equivalent widths of interstellar absorption lines, implying larger velocity spread among absorbing clouds. Candidates deviate from the relationship between equivalent widths of Lyα and interstellar absorption lines in that their Lyα emission remains strong despite high interstellar absorption, possibly indicating that the neutral HI fraction is patchy, such that Lyα photons can escape. We detect stronger C IV P-Cygni features (emission and absorption) and He II emission in candidates, indicative of larger populations of metal-rich Wolf-Rayet stars compared to non-candidates. The faster bulk motions, broader spread of gas velocity, and Lyα properties of candidates are consistent with their ISM being subject to more energetic feedback than non-candidates. Together with their larger metallicity (implying more evolved star-formation activity) this leads us to propose, if speculatively, that they are likely to quench sooner than non-candidates, supporting the validity of selection criteria used to identify them as progenitors of z ∼ 2 passive galaxies. We propose that massive, compact galaxies undergo more rapid growth of their stellar mass content, perhaps because the gas accretion mechanisms are different, and quench sooner than normally-sized LBGs at these (early) epochs.

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Section: Evidence For Differences In Metallicitymentioning

confidence: 77%

THE INTERSTELLAR MEDIUM AND FEEDBACK IN THE PROGENITORS OF THE COMPACT PASSIVE GALAXIES ATz∼ 2

Williams

Giavalisco

Lee

et al. 2015

ApJ

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“…1, with a subtype dependence apparent in the reddening-free Q1 vs Q2 diagram. Table 1 provides basic observational properties for the new Wolf-Rayet stars, for which we obtained NTT/SOFI spectroscopy, while Table B1 (available online) provides a list of all candidates for which we ob- a: (Bohannan & Crowther 1999), b: (Vreux et al 1983); c: (Howarth & Schmutz 1992), d: ), e: (Hillier et al 1983), f: (Crowther 2000), g: (Homeier et al 2003); h: , i: This study; j: (Vreux et al 1990), k: ), l: Crowther et al (1995, m: : n: tained spectroscopy, together with a brief note describing the nature of each source. In addition to the candidate WR stars, we have also obtained NTT/SOFI spectroscopy of 14 Wolf-Rayet stars for which optical classifications have been undertaken, in order to refine near-IR based classification criteria (see Sect.…”

Section: Ntt/sofi Spectroscopy Of Wolf-rayet Candidatesmentioning

confidence: 99%

A deep near-infrared spectroscopic survey of the Scutum-Crux arm for Wolf-Rayet stars★

Rosslowe¹,

Crowther²

2017

Monthly Notices of the Royal Astronomical Society

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We present an NTT/SOFI spectroscopic survey of infrared selected Wolf-Rayet candidates in the Scutum-Crux spiral arm (298 • ≤ l ≤ 340 • , |b| ≤ 0.5 • ). We obtained near-IR spectra of 127 candidates, revealing 17 Wolf-Rayet stars -a ∼ 13% success rate -of which 16 are newly identified here. The majority of the new Wolf-Rayet stars are classified as narrow-lined WN5-7 stars, with 2 broad-lined WN4-6 stars and 3 WC6-8 stars. The new stars, with distances estimated from previous absolute magnitude calibrations, have no obvious association with the Scutum-Crux arm. Refined near-infrared (YHJK) classification criteria based on over a hundred Galactic and Magellanic Cloud WR stars, providing diagnostics for hydrogen in WN stars, plus the identification of WO stars and intermediate WN/C stars. Finally, we find that only a quarter of WR stars in the survey region are associated with star clusters and/or H ii regions, with similar statistics found for Luminous Blue Variables in the Milky Way. The relative isolation of evolved massive stars is discussed, together with the significance of the co-location of LBVs and WR stars in young star clusters.

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“…Their mass loss is line driven, and the mass-loss rate decreases with metallicity (Kudritzki 2002;Crowther & Hadfield 2006). Assuming each WR star ejects approximately 1 × 10 −5 M ⊙ yr −1 of gas (Crowther 2000), WR stars eject is about 1 × 10 −4 M ⊙ yr −1 of gas into the ISM in the SMC. The LMC WR catalog lists 134 stars (Breysacher et al 1999) and about 1 × 10 −3 M ⊙ yr −1 of gas is ejected from WR stars into the ISM in the LMC.…”

Section: Other Dust and Gas Sourcesmentioning

confidence: 99%

The global gas and dust budget of the Small Magellanic Cloud

Matsuura

Woods

Owen

2012

Monthly Notices of the Royal Astronomical Society

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In order to understand the evolution of the interstellar medium (ISM) of a galaxy, we have analysed the gas and dust budget of the Small Magellanic Cloud (SMC). Using the Spitzer Space Telescope, we measured the integrated gas mass-loss rate across asymptotic giant branch (AGB) stars and red supergiants (RSGs) in the SMC, and obtained a rate of 1.4×10 −3 M ⊙ yr −1 . This is much smaller than the estimated gas ejection rate from type II supernovae (SNe) (2-4×10 −2 M ⊙ yr −1 ). The SMC underwent a an increase in starformation rate in the last 12 Myrs, and consequently the galaxy has a relatively high SN rate at present. Thus, SNe are more important gas sources than AGB stars in the SMC. The total gas input from stellar sources into the ISM is 2-4×10 −2 M ⊙ yr −1 . This is slightly smaller than the ISM gas consumed by starformation (∼8×10 −2 M ⊙ yr −1 ). Starformation in the SMC relies on a gas reservoir in the ISM, but eventually the starformation rate will decline in this galaxy, unless gas infalls into the ISM from an external source. The dust injection rate from AGB and RSG candidates is 1×10 −5 M ⊙ yr −1 . Dust injection from SNe is in the range of 0.2-11×10 −4 M ⊙ yr −1 , although the SN contribution is rather uncertain. Stellar sources could be important for ISM dust (3×10 5 M ⊙ ) in the SMC, if the dust lifetime is about 1.4 Gyrs. We found that the presence of poly-aromatic hydrocarbons (PAHs) in the ISM cannot be explained entirely by carbon-rich AGB stars. Carbon-rich AGB stars could inject only 7×10 −9 M ⊙ yr −1 of PAHs at most, which could contribute up to 100 M ⊙ of PAHs in the lifetime of a PAH. The estimated PAH mass of 1800 M ⊙ in the SMC can not be explained. Additional PAH sources, or ISM reprocessing should be needed.

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Aqueous Lithium–Air Systems

Cited by 8 publications

References 54 publications

THE INTERSTELLAR MEDIUM AND FEEDBACK IN THE PROGENITORS OF THE COMPACT PASSIVE GALAXIES ATz∼ 2

THE INTERSTELLAR MEDIUM AND FEEDBACK IN THE PROGENITORS OF THE COMPACT PASSIVE GALAXIES ATz∼ 2

A deep near-infrared spectroscopic survey of the Scutum-Crux arm for Wolf-Rayet stars★

The global gas and dust budget of the Small Magellanic Cloud

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