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Sub-kiloparsec alma imaging of compact star-forming galaxies at z ~ 2.5: revealing the formation of dense galactic cores in the progenitors of compact quiescent galaxies



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Pérez González, Pablo Guillermo and otros, ... (2016) Sub-kiloparsec alma imaging of compact star-forming galaxies at z ~ 2.5: revealing the formation of dense galactic cores in the progenitors of compact quiescent galaxies. Astrophysical journal letters, 827 (2). ISSN 2041-8205

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Official URL: http://dx.doi.org/10.3847/2041-8205/827/2/L32


We present spatially resolved Atacama Large Millimeter/submillimeter Array (ALMA) 870 μm dust continuum maps of six massive, compact, dusty star-forming galaxies at z ~ 2.5. These galaxies are selected for their small rest-frame optical sizes (r_e,F160W ~ 1.6 kpc) and high stellar mass densities that suggest that they are direct progenitors of compact quiescent galaxies at z ~ 2. The deep observations yield high far-infrared (FIR) luminosities of L_IR = 10^12.3-12.8 L_⨀ and star formation rates (SFRs) of SFR = 200–700 M_⊙ yr^−1, consistent with those of typical star-forming "main sequence" galaxies. The high spatial resolution (FWHM ~ 0 12–0 18) ALMA and Hubble Space Telescope photometry are combined to construct deconvolved, mean radial profiles of their stellar mass and (UV+IR) SFR. We find that the dusty, nuclear IR–SFR overwhelmingly dominates the bolometric SFR up to r ~ 5 kpc, by a factor of over 100× from the unobscured UV–SFR. Furthermore, the effective radius of the mean SFR profile (r_e,SFR ~ 1 kpc) is ~30% smaller than that of the stellar mass profile. The implied structural evolution, if such nuclear starburst last for the estimated gas depletion time of Δt = ±100 Myr, is a 4×increase of the stellar mass density within the central 1 kpc and a 1.6× decrease of the half-mass–radius. This structural evolution fully supports dissipation-driven, formation scenarios in which strong nuclear starbursts transform larger, star-forming progenitors into compact quiescent galaxies.

Item Type:Article
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© 2016. The American Astronomical Society. All rights reserved. Artículo firmado por 13 autores. G.B. and M.K. acknowledge support from HST-AR-12847 and the Hellman Fellows Fund. P.G.P.-G. acknowledges support from grant AYA2015-70815-ERC. W.R. is supported by a CUniverse Grant (CUAASC) from Chulalongkorn University. This paper makes use of the following ALMA data: ADS/JAO. ALMA#2013.1.00576. S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

Uncontrolled Keywords:Massive galaxies; Formation rates; Number counts; Legacy survey; Red nuggets; Goods-south; Inside-out; Candels; Stellar; Dust
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:39992
Deposited On:10 Nov 2016 15:58
Last Modified:10 Dec 2018 15:04

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