The colors and sizes of recently quenched galaxies: a result of compact starburst before quenching
| Autor: | Rachel Bezanson, Marijn Franx, Ivana Barišić, Adam Muzzin, Po-Feng Wu, Francesco D'Eugenio, Arjen van der Wel, Anna Gallazzi, David Sobral, Priscilla Chauke, Josha van Houdt, Caroline M. S. Straatman, Camilla Pacifici, Eric F. Bell |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Galaxy structure
010504 meteorology & atmospheric sciences Galaxy mergers Population FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Galaxy colors Galaxy merger 01 natural sciences Gravitation POST-STARBURST symbols.namesake BLUE Galaxy evolution 0103 physical sciences Galaxy formation and evolution GIANT BRANCH STARS RED-SEQUENCE education BLACK-HOLES 010303 astronomy & astrophysics POPULATION Astrophysics::Galaxy Astrophysics STAR-FORMATION HISTORIES 0105 earth and related environmental sciences Physics Galaxy formation education.field_of_study TIME-SCALES Star formation Balmer series Astronomy and Astrophysics Radius Astrophysics - Astrophysics of Galaxies EVOLUTION Galaxy Galaxy stellar content Physics and Astronomy Galaxy quenching Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) symbols CLUSTERS |
| Zdroj: | The Astrophysical Journal The Astrophysical Journal, 888(2), 77 ASTROPHYSICAL JOURNAL |
| ISSN: | 0004-637X 1538-4357 1538-3873 0067-0049 1538-3881 |
| DOI: | 10.3847/1538-4357/ab5fd9 |
| Popis: | We analyze the colors and sizes of 32 quiescent (UVJ-selected) galaxies with strong Balmer absorption ($\mbox{EW}(H\delta) \geq 4$\AA) at $z\sim0.8$ drawn from DR2 of the LEGA-C survey to test the hypothesis that these galaxies experienced compact, central starbursts before quenching. These recently quenched galaxies, usually referred to as post-starburst galaxies, span a wide range of colors and we find a clear correlation between color and half-light radius, such that bluer galaxies are smaller. We build simple toy models to explain this correlation: a normal star-forming disk plus a central, compact starburst component. Bursts with exponential decay timescale of $\sim$~100 Myr that produce $\sim10\%$ to more than 100\% of the pre-existing masses can reproduce the observed correlation. More significant bursts also produce bluer and smaller descendants. Our findings imply that when galaxies shut down star formation rapidly, they generally had experienced compact, starburst events and that the large, observed spread in sizes and colors mostly reflects a variety of burst strengths. Recently quenched galaxies should have younger stellar ages in the centers; multi-wavelength data with high spatial resolution are required to reveal the age gradient. Highly dissipative processes should be responsible for this type of formation history. While determining the mechanisms for individual galaxies is challenging, some recently quenched galaxies show signs of gravitational interactions, suggesting that mergers are likely an important mechanism in triggering the rapid shut-down of star-formation activities at $z\sim0.8$. Comment: 16 pages, 8 figures, 1 table, accepted by ApJ |
| Databáze: | OpenAIRE |
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