Chemical diversity of gas in distant galaxies

Ramburuth-Hurt, Tanita; De, A.; Krogager, Jens-Kristian; Ledoux, C.; Petitjean, P.; Péroux, Céline; Dessauges‐Zavadsky, M.; Fynbo, J. P. U.; Wendt, Martin; Bouché, Nicolas; Konstantopoulou, C.; Jermann, I.

doi:10.1051/0004-6361/202244609

Cited by 5 publications

(4 citation statements)

References 76 publications

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“…The neutral ISM is likely complex and possibly chemically inhomogeneous (e.g. Welty et al 2020;De Cia et al 2021;Ramburuth-Hurt et al 2023). Our understanding of its chemical properties through the study of the abundance patterns is hindered by the several processes that shape them.…”

Section: Resultsmentioning

confidence: 99%

“…Sk 108) within the SMC (Welty et al 1997), a target which is also in our sample, and SN 1987A within the LMC (Welty et al 1999). Variations in depletion within absorbing systems have been observed for distant galaxies by Ramburuth-Hurt et al (2023). Figure 14 shows our analysis of the metal patterns of the groups of individual component using the measurements of Welty et al (1997), and with the same technique of Ramburuth-Hurt et al (2023).…”

Section: A Mixture Of Different Ism Gas Typesmentioning

confidence: 89%

“…The ISM in the Milky Way has regions with different metallicities (De Cia et al 2021) and strengths of dust depletion (Jenkins 2009;Welty et al 2020). Variations in metallicities (Sánchez Almeida et al 2015;Kreckel et al 2019;Wang et al 2022;Chartab et al 2022) and dust depletion (Prochaska 2003;Dessauges-Zavadsky et al 2006;Rodríguez et al 2006;Wiseman et al 2017;de Ugarte Postigo et al 2018;Noterdaeme et al 2017;Guber et al 2018;Ramburuth-Hurt et al 2023) have been observed within external galaxies as well. It is well possible that the total line of sight towards a star intercepts gases with different chemical properties.…”

Section: A Mixture Of Different Ism Gas Typesmentioning

confidence: 97%

“…Variations in depletion within absorbing systems have been observed for distant galaxies by Ramburuth-Hurt et al (2023). Figure 14 shows our analysis of the metal patterns of the groups of individual component using the measurements of Welty et al (1997), and with the same technique of Ramburuth-Hurt et al (2023). This technique analyses the metal patterns in a very similar way we analyse the abundance patterns, but without including H, so that it cannot give information on metallicities, but it characterizes the dust depletion and any deviations due to nucleosynthesis, in particular for individual components.…”

Section: A Mixture Of Different Ism Gas Typesmentioning

confidence: 99%

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α-element enhancements in the ISM of the LMC and SMC: Evidence of recent star formation

De Cia,

Roman-Duval,

Konstantopoulou

et al. 2024

A&A

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Important questions regarding the chemical composition of the neutral interstellar medium (ISM) in the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) are still open. It is usually assumed that their metallicity is uniform and equal to that measured in hot stars and regions, but direct measurements of the neutral ISM metallicity had not been performed until now. Deriving the metallicity from the observed metal abundances is not straightforward because the abundances depend on the depletion of metals into dust and on nucleosynthesis effects such as alpha -element enhancement. Our aim is to measure the metallicity of the neutral ISM in the LMC and SMC, dust depletion, and any nucleosynthesis effects. We collected literature column densities of and in the neutral ISM towards 32 hot stars in the LMC and $22$ in the SMC. We determined dust depletion from the relative abundances of different metals because they deplete with different strengths. This includes a `golden sample' of sightlines where Ti and other alpha -elements are available. We fit linear relations to the observed abundance patterns so that the slopes determined the strengths of dust depletion and the normalizations determined the metallicities. We investigated alpha -element enhancements in the gas from the deviations from the linear fits and compared them with stars. In our golden sample we find alpha -element enhancement in the neutral ISM in most systems, on average 0.26 dex (0.35 dex) for the LMC (SMC), and an Mn underabundance in the SMC (on average $-0.35$ dex). Measurements of are not available for the LMC. These are higher than for stars at similar metallicities. We find total neutral ISM metallicities that are mostly consistent with hot star metallicity values, on average $M$/H tot =-0.33$ ($-0.83$), with standard deviations of 0.30 (0.30), in the LMC (the SMC). In six systems, however, we find significantly lower metallicities, 2 out of 32 in the LMC (with $ solar) and 4 out of 22 in the SMC (3<!PCT!>\ and 10<!PCT!> solar), two of which are in the outskirts of the SMC near the Magellanic Bridge, a region known for having a lower metallicity. The observed alpha -element enhancements and Mn underabundance are likely due to bursts of star formation, more recently than $ Gyr ago, that enriched the ISM from core-collapse supernovae. With the exception of lines of sight towards the Magellanic Bridge, the neutral gas in the LMC and SMC appears fairly well mixed in terms of metallicity.

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Section: Resultsmentioning

confidence: 99%

Section: A Mixture Of Different Ism Gas Typesmentioning

confidence: 89%

Section: A Mixture Of Different Ism Gas Typesmentioning

confidence: 97%

Section: A Mixture Of Different Ism Gas Typesmentioning

confidence: 99%

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α-element enhancements in the ISM of the LMC and SMC: Evidence of recent star formation

De Cia,

Roman-Duval,

Konstantopoulou

et al. 2024

A&A

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The α-element enrichment of gas in distant galaxies

Velichko,

De Cia,

Konstantopoulou

et al. 2024

A&A

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The chemical evolution of distant galaxies cannot be assessed from observations of individual stars, in contrast to the case of nearby galaxies. On the other hand, the study of the interstellar medium (ISM) offers an alternative way to reveal important properties of the chemical evolution of distant galaxies. The chemical enrichment of the ISM is produced by all the previous generations of stars and it is possible to precisely determine the metal abundances in the neutral ISM in galaxies. The chemical abundance patterns in the neutral ISM are determined by the gas metallicity, presence of dust (the depletion of metals into dust grains), and possible deviations due to specific nucleosynthesis, for example, alpha -element enhancements. We aim to derive the metallicities, dust depletion, and alpha -element enhancements in the neutral ISM of gas-rich mostly-metal-poor distant galaxies (Damped Lyman-alpha absorbers, DLAs). Furthermore, we aim to constrain the distribution of alpha -element enhancements with metallicity in these galaxies. We collected a literature sample of column density measurements of O, Mg, Si, S, Ti, Cr, Fe, Ni, Zn, P, and Mn in the neutral ISM of DLAs at redshifts of $0.60 < z < 3.40$. We used this sample to define a golden sample of DLAs with constrained observations of Ti and at least one other alpha -element. By studying the abundance patterns, we determined the amount of dust depletion, solely based on the observed relative abundances of the alpha -elements. We then used the abundances of Fe-peak elements to determine the overall metallicity of each system, after correcting for dust depletion. In addition, we studied the deviations from the basic (linear) abundance patterns. We divided our sample into two groups of galaxies based on the widths of their absorption lines ($ $ above or below 100 which may be considered as a proxy for their dynamical mass. We characterised the distribution of the alpha -element enhancements as a function of metallicity for the galaxy population as a whole, by fitting a piecewise function (plateau, decline, plateau) to the data. We observed systematic deviations from the basic abundance patterns for O, Mg, Si, S, Ti, and Mn, which we interpreted as alpha -element enhancements and a Mn underabundance. The distribution of the alpha -element enhancements with metallicity is different in the high-$ $ and low-$ $ groups of galaxies. We constrained the metallicity of the alpha -element knee for the high-$ $ and low-$ $ groups of galaxies to be $-$1.02pm 0.15 dex and $-$1.84pm 0.11 dex, respectively. The average alpha -element enhancement at the high-plateau is alpha /Fe =0.38pm 0.07 dex. On the other hand, Mn shows an underabundance in all DLAs in the golden sample of $-$0.36pm 0.07 dex, on average. We have constrained, for the first time, the distribution of the alpha -element enhancement with metallicity in the neutral ISM in distant galaxies. Less massive galaxies show an alpha -element knee at lower metallicities than more massive galaxies. This can be explained by a lower star formation rate in less massive galaxies. If this collective behaviour can be interpreted in the same way as it is for individual systems, this would suggest that more massive and metal-rich systems evolve to higher metallicities before the contribution of SN-Ia to alpha /Fe levels out that of core-collapse SNe. This finding may plausibly be supported by different SFRs in galaxies of different masses. Overall, our results offer important clues to the study of chemical evolution in distant galaxies.

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DUNE: Dust depletion UNified method across cosmic time and Environments

Konstantopoulou,

De Cia,

Krogager

et al. 2024

A&A

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We present a novel method to characterize dust depletion, namely, the depletion of metals into dust grains. We used observed correlations among relative abundances combining a total of 17 metals in diverse galactic environments, including the Milky Way (MW), Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and damped Lyman-alpha absorbers (DLAs) towards quasars and gamma-ray bursts (GRBs). We only considered the relative abundances of metals that qualify as tracers of dust and we used all available dust tracers. We find linear correlations among all studied dust tracers in a multidimensional space, where each dimension corresponds to an individual dust tracer. The fit to the linear correlations among the dust tracers describes the tendencies of different elements when depleting into dust grains. We determined the overall strength of dust depletion, Delta , along individual lines of sight, based on the correlations among different dust tracers. We avoided any preference for specific dust tracers or any other assumptions by including all available dust tracers in this multidimensional space. We also determined the dust depletion of Kr, C, O, Cl, P, Zn, Ge, Mg, Cu, Si, Fe, Ni, and Ti. Finally, we offer simple guidelines for the application of the method to the study of the observed patterns of abundances and relative abundances. This has allowed for a straightforward determination of the overall strength of depletion and the dust depletion of individual elements. We also obtained an estimate for the gas-phase metallicity and identified any additional deviations due to the nucleosynthesis of specific stellar populations. Thus, we have established a unified methodology for characterizing dust depletion across cosmic time and diverse galactic environments, offering a valuable new approach to the study of dust depletion in studies of the chemical evolution of galaxies.

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Chemical diversity of gas in distant galaxies

Cited by 5 publications

References 76 publications

α-element enhancements in the ISM of the LMC and SMC: Evidence of recent star formation

α-element enhancements in the ISM of the LMC and SMC: Evidence of recent star formation

The α-element enrichment of gas in distant galaxies

DUNE: Dust depletion UNified method across cosmic time and Environments

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