Cosmological evolution of the nitrogen abundance

Vangioni, Elisabeth; Dvorkin, Irina; Olive, Keith A.; Dubois, Yohan; Molaro, P.; Petitjean, P.; Silk, Joseph; Kimm, Taysun

doi:10.1093/mnras/sty559

Cited by 18 publications

(9 citation statements)

References 96 publications

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“…The third diatomic biosignature is molecular nitrogen. This is a key species in cosmology and has been observed in various galactic environments (Vangioni et al 2018). Although direct observation of N 2 is often difficult, as it lacks strong pure rotational or vibrational lines (Li et al 2013).…”

Section: Molecular Nitrogenmentioning

confidence: 99%

A large-scale approach to modelling Biosignatures: First Steps

Cross¹,

Pignatari²,

Benoit³

et al. 2024

Preprint

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<p>For this poster I will be presenting the approaches taken to produce synthetic spectra for molecules believed to be biosignatures. In astrochemistry, biosignatures describe a group of molecules which could be produced by life and therefore act as an indication of it. Naturally, by being able to identify these molecules it will be possible to screen exoplanets for the possibility of harbouring life.&#160;</p> <p>Recently, Seager, Bains and Petkowski (2016) produced a catalogue of possible biosignatures, which totalled above 14,000 molecules. There are groups such as the ExoMol group which model these molecules at extremely high precision. However, due to the large number of molecules, a high precision method would take an unreasonable amount of time and therefore a faster means of producing spectra is required. The work shown within is designed to be quick and produce data for the full rovibronic spectrum rather than selected bands. I will show that anharmonic corrections are needed to be able to simulate qualitatively correct ro-vibrational transitions. In my method, this is done by implementing TOSH, transition optimised shifted hermites, which was first detailed by Lin, Gilbert and Gill (2007). Finally I will be presenting my latest results using this analytical anharmonic approach.&#160;</p>

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Section: Molecular Nitrogenmentioning

confidence: 99%

A large-scale approach to modelling Biosignatures: First Steps

Cross¹,

Pignatari²,

Benoit³

et al. 2024

Preprint

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“…Nevertheless, super-AGB stars do not provide a significant contribution to the global chemical enrichment of galaxies (see, e.g. Vangioni et al 2018;Prantzos et al 2018;Kobayashi et al, in prep. ).…”

Section: Production Rate Of He From Simple Stellar Populations Of Different Metallicity In Our Cosmological Simulationmentioning

confidence: 99%

He abundances in disc galaxies

Vincenzo

Miglio

Mackereth

et al. 2019

A&A

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We investigate how the stellar and gas-phase He abundances evolve as a function of time within simulated star-forming disc galaxies with different star formation histories. We make use of a cosmological chemodynamical simulation for galaxy formation and evolution, which includes star formation as well as energy and chemical enrichment feedback from asymptotic giant branch stars, core-collapse supernovae, and Type Ia supernovae. The predicted relations between the He mass fraction, Y, and the metallicity, Z, in the interstellar medium of our simulated disc galaxies depend on the galaxy star formation history. In particular, dY/dZ is not constant and evolves as a function of time, depending on the specific chemical element that we choose to trace Z; in particular, dY/dXO and dY/dXC increase as a function of time, whereas dY/dXN decreases. In the gas-phase, we find negative radial gradients of Y, due to the inside-out growth of our simulated galaxy discs as a function of time; this gives rise to longer chemical enrichment timescales in the outer galaxy regions, where we find lower average values for Y and Z. Finally, by means of chemical-evolution models, in the galactic bulge and inner disc, we predict steeper Y vs. age relations at high Z than in the outer galaxy regions. We conclude that for calibrating the assumed Y − Z relation in stellar models, C, N, and C+N are better proxies for the metallicity than O because they show steeper and less scattered relations.

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“…Numerous cosmological simulations can predict the metallicity distribution and evolution in the CGM (e.g. Nelson et al 2018;Crain et al 2013;Vangioni et al 2018). However, these predictions are subject to various uncertainties, such as the supernova and AGN feedback efficiency, the metal loading and advection in the outflows, and mixing with the gas inflowing from the IGM.…”

Section: Introductionmentioning

confidence: 99%

Metal enrichment in the circumgalactic medium and Lyα haloes around quasars at z $\sim$3

Guo,

Maiolino,

Jiang

et al. 2020

Preprint

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Deep observations have detected extended Lyα emission nebulae surrounding tens of QSOs at redshift 2 to 6. However, the metallicity of such extended haloes is still poorly understood. We perform a detailed analysis on a large sample of 80 quasars at z ∼ 3 based on MUSE-VLT data. We find clear evidence of extended emission of the UV nebular lines C IV λ1549 and He II λ1640 for about 18% of the sample, while C III] λ1909 is only marginally detected in a few objects. By stacking the cubes we detect emission of C IV, He II and C III] out to a radius of about 45 kpc. C IV and He II show a radial decline much steeper than Lyα, while C III] shows a shallower profile similar to Lyα in the inner 45 kpc. We infer that the average metallicity of the circumgalactic gas within the central 30-50 kpc is ∼0.5 solar, or even higher. However, we also find evidence of a component of the Lyα haloes, which has much weaker metal emission lines relative to Lyα. We suggest that the high metallicity of the circumgalactic medium within the central 30-50 kpc is associated with chemical pre-enrichment by past quasar-driven outflows and that there is a more extended component of the CGM that has much lower metallicity and likely associated with near-pristine gas accreted from the intergalactic medium. We show that our observational results are in good quantitative agreement with the expectations of the FABLE cosmological simulations.

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Cosmological evolution of the nitrogen abundance

Cited by 18 publications

References 96 publications

A large-scale approach to modelling Biosignatures: First Steps

A large-scale approach to modelling Biosignatures: First Steps

He abundances in disc galaxies

Metal enrichment in the circumgalactic medium and Lyα haloes around quasars at z $\sim$3

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