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http://hdl.handle.net/20.500.12386/28929
Title: | Galaxies in the act of quenching star formation | Authors: | Quai, Salvatore POZZETTI, Lucia Citro, Annalisa Moresco, Michele CIMATTI, ANDREA |
Issue Date: | 2018 | Journal: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Number: | 478 | Issue: | 3 | First Page: | 3335 | Abstract: | Detecting galaxies when their star formation is being quenched is crucial to understand the mechanisms driving their evolution. We identify for the first time a sample of quenching galaxies selected just after the interruption of their star formation by exploiting the [O III] λ5007/H α ratio and searching for galaxies with undetected [O III]. Using a sample of ∼174000 star-forming galaxies extracted from the SDSS-DR8 at 0.04 ≤ z< 0.21, weidentify the ∼300 quenching galaxy best candidates with low [O III]/H α, out of ∼26000 galaxies without [O III] emission. They have masses between 10^{9.7} and 10^{10.8} M_{☉}, consistently with the corresponding growth of the quiescent population at these redshifts. Their main properties (i.e. star-formation rate, colours, and metallicities) are comparable to those of the star-forming population, coherently with the hypothesis of recent quenching, but preferably reside in higher-density environments. Most candidates have morphologies similar to star-forming galaxies, suggesting that no morphological transformation has occurred yet. From a survival analysis we find a low fraction of candidates (∼0.58 per cent of the star-forming population), leading to a short quenching time-scale of t<SUB>Q</SUB> ∼ 50 Myr and an e-folding time for the quenching history of τ<SUB>Q</SUB> ∼ 90 Myr, and their upper limits of t<SUB>Q</SUB> < 0.76 Gyr and τ<SUB>Q</SUB> <1.5 Gyr, assuming as quenching galaxies 50 per cent of objects without [O III] (∼ 7.5 per cent). Ourresults are compatible with a 'rapid' quenching scenario of satellites galaxies due to the final phase of strangulation or ram-pressure stripping. This approach represents a robust alternative to methods used so far to select quenched galaxies (e.g. colours, specific star-formation rate, or post-starburst spectra). | URI: | http://hdl.handle.net/20.500.12386/28929 | URL: | https://academic.oup.com/mnras/article-abstract/478/3/3335/4989931?redirectedFrom=fulltext | ISSN: | 0035-8711 | DOI: | 10.1093/mnras/sty1045 | Bibcode ADS: | 2018MNRAS.478.3335Q | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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