A methodology to select galaxies just after the quenching of star formation

Abstract

We propose a new methodology aimed at finding star-forming galaxies in the phase which immediately follows the star-formation (SF) quenching, based on the use of high- to low-ionization emission line ratios. These ratios rapidly disappear after the SF halt, due to the softening of the UV ionizing radiation. We focus on [O III] $\lambda$5007/H$\alpha$ and [Ne III] $\lambda$3869/[O II] $\lambda$3727, studying them with simulations obtained with the CLOUDY photoionization code. If a sharp quenching is assumed, we find that the two ratios are very sensitive tracers as they drop by a factor $\sim$ 10 within $\sim$ 10 Myr from the interruption of the SF; instead, if a smoother and slower SF decline is assumed (i.e. an exponentially declining star-formation history with $e$-folding time $\tau =$ 200 Myr), they decrease by a factor $\sim$ 2 within $\sim$ 80 Myr. We mitigate the ionization -- metallicity degeneracy affecting our methodology using pairs of emission line ratios separately related to metallicity and ionization, adopting the [N II] $\lambda$6584/[O II] $\lambda$3727 ratio as metallicity diagnostic. Using a Sloan Digital Sky Survey galaxy sample, we identify 10 examples among the most extreme quenching candidates within the [O III] $\lambda$5007/H$\alpha$ vs. [N II] $\lambda$6584/[O II] $\lambda$3727 plane, characterized by low [O III] $\lambda$5007/H$\alpha$, faint [Ne III] $\lambda$3869, and by blue dust-corrected spectra and $(u-r)$ colours, as expected if the SF quenching has occurred in the very recent past. Our results also suggest that the observed fractions of quenching candidates can be used to constrain the quenching mechanism at work and its time-scales.

Accepted for publication in MNRAS; 19 pages, 21 figures, 1 table

References in corpus (23)

• Cosmic Star Formation History
• The James Webb Space Telescope
• Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample
• Constraining the Low-Mass Slope of the Star Formation Sequence at 0.5<z<2.5
• The 2013 Release of Cloudy
• Multiple minor mergers: formation of elliptical galaxies and constraints for the growth of spiral disks
• Post-starburst galaxies: more than just an interesting curiosity
• The relation between star formation, morphology and local density in high redshift clusters and groups
• The metallicity of the most distant quasars
• ISM excitation and metallicity of star-forming galaxies at z~3.3 from near-IR spectroscopy
• The UV properties of E+A galaxies: constraints on feedback-driven quenching of star formation
• Dynamical properties of Ultraluminous Infrared Galaxies. II. Traces of dynamical evolution and end products of local ultraluminous mergers
• High-Velocity Outflows Without AGN Feedback: Eddington-Limited Star Formation in Compact Massive Galaxies
• A Population of Massive and Evolved Galaxies at z$\ga$5
• Modelling the number density of Halpha emitters for future spectroscopic near-IR space missions
• The imprint of rapid star formation quenching on the spectral energy distributions of galaxies
• The SAMI Galaxy Survey: Spatially resolving the environmental quenching of star formation in GAMA galaxies
• GMASS Ultradeep Spectroscopy of Galaxies at z~2. III: The emergence of the color bimodality at z~2
• Photoionization models of the CALIFA HII regions. I. Hybrid models
• Inferring the star formation histories of the most massive and passive early-type galaxies at z<0.3
• Spectroscopic Confirmation of an Ultra Massive and Compact Galaxy at z=3.35: A Detailed Look at an Early Progenitor of Local Most Massive Ellipticals
• A Photometrically and Spectroscopically Confirmed Population of Passive Spiral Galaxies
• Physical Properties of Local Star-Forming Analogues to z~5 Lyman Break Galaxies

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• A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE).IX. The effects of ram pressure stripping down to the scale of individual HII regions in the dwarf galaxy IC 3476
• The interconnection between galaxy mergers, AGN activity and rapid quenching of star formation in simulated post-merger galaxies
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• Spatially resolved signature of quenching in star-forming galaxies
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