The properties and environment of very young galaxies in the local Universe
| Autor: | Fabricio Ferrari, Marina Trevisan, A. Ranjan, Gary A. Mamon, Trinh X. Thuan, Leonid S. Pilyugin |
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| Přispěvatelé: | Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2021 |
| Předmět: |
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Stellar mass media_common.quotation_subject FOS: Physical sciences Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics 01 natural sciences Spectral line 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Surface brightness Control sample 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics media_common Physics 010308 nuclear & particles physics Star formation Astronomy and Astrophysics galaxies: dwarf Astrophysics - Astrophysics of Galaxies Universe Galaxy Large sample Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) galaxies: stellar content galaxies: evolution [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Astrophysics - Cosmology and Nongalactic Astrophysics |
| Zdroj: | Mon.Not.Roy.Astron.Soc. Mon.Not.Roy.Astron.Soc., 2021, 502 (4), pp.4815-4841. ⟨10.1093/mnras/staa4008⟩ |
| ISSN: | 1365-2966 0035-8711 |
| DOI: | 10.1093/mnras/staa4008 |
| Popis: | In the local Universe, there is a handful of dwarf compact star-forming galaxies with extremely low oxygen abundances. It has been proposed that they are young, having formed a large fraction of their stellar mass during their last few hundred Myr. However, little is known about the fraction of young stellar populations in more massive galaxies. In a previous article, we analyzed 280 000 SDSS spectra to identify a surprisingly large sample of more massive Very Young Galaxies (VYGs), defined to have formed at least $50\%$ of their stellar mass within the last 1 Gyr. Here, we investigate in detail the properties of a subsample of 207 galaxies that are VYGs according to all three of our spectral models. We compare their properties with those of control sample galaxies (CSGs). We find that VYGs tend to have higher surface brightness and to be more compact, dusty, asymmetric, and clumpy than CSGs. Analysis of a subsample with HI detections reveals that VYGs are more gas-rich than CSGs. VYGs tend to reside more in the inner parts of low-mass groups and are twice as likely to be interacting with a neighbour galaxy than CSGs. On the other hand, VYGs and CSGs have similar gas metallicities and large scale environments (relative to filaments and voids). These results suggest that gas-rich interactions and mergers are the main mechanisms responsible for the recent triggering of star formation in low-redshift VYGs, except for the lowest mass VYGs, where the starbursts may arise from a mixture of mergers and gas infall. 33 pages, 24 figures, to be published in MNRAS |
| Databáze: | OpenAIRE |
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