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Pérez González, Pablo Guillermo and Cardiel López, Nicolás and Eliche Moral, María del Carmen and otros, ... (2016) Caught in the act: gas and stellar velocity dispersions in a fast Quenching compact star-forming galaxy at z ~ 1.7. Astrophysical journal, 820 (2). ISSN 0004-637X
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Official URL: http://dx.doi.org/10.3847/0004-637X/820/2/120
Abstract
We present Keck I MOSFIRE spectroscopy in the Y and H bands of GDN-8231, a massive, compact, star-forming galaxy at a redshift of z ~ 1.7. Its spectrum reveals both Hα and [Nii] emission lines and strong Balmer absorption lines. The Hα and Spitzer MIPS 24 μm fluxes are both weak, thus indicating a low star-formation rate of SFR≲5-10 M_⨀ yr−1. This, added to a relatively young age of ~700 Myr measured from the absorption lines, provides the first direct evidence for a distant galaxy being caught in the act of rapidly shutting down its star formation. Such quenching allows GDN-8231 to become a compact, quiescent galaxy, similar to three other galaxies in our sample, by z ~ 1.5. Moreover, the color profile of GDN-8231 shows a bluer center, consistent with the predictions of recent simulations for an early phase of inside-out quenching. Its line-of-sight velocity dispersion for the gas, σ_LOG^gas = 127 ± 32 km s^−1, is nearly 40% smaller than that of its stars, σ_LOG^* = 215 ± 35 km s^−1. High-resolution hydro-simulations of galaxies explain such apparently colder gas kinematics of up to a factor of ~1.5 with rotating disks being viewed at different inclinations and/or centrally concentrated star-forming regions. A clear prediction is that their compact, quiescent descendants preserve some remnant rotation from their star-forming progenitors.
Item Type: | Article |
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Additional Information: | © 2016 The American Astronomical Society. |
Uncontrolled Keywords: | Greater-than 1; Post-starburst galaxies; Hubble-space-telescope; Absorption-line spectroscopy; Passively evolving galaxies; Extragalactic legacy survey; Near-infrared spectroscopy; K-selected galaxies; Inside-out growth; Quiescent galaxies |
Subjects: | Sciences > Physics > Astrophysics Sciences > Physics > Astronomy |
ID Code: | 38002 |
Deposited On: | 06 Jun 2016 14:38 |
Last Modified: | 10 Dec 2018 15:04 |
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