Structural Evolution in Massive Galaxies at z ∼ 2

Ken Ichi Tadaki, Sirio Belli, Andreas Burkert, Avishai Dekel, Natascha M. Förster Schreiber, Reinhard Genzel, Masao Hayashi, Rodrigo Herrera-Camus, Tadayuki Kodama, Kotaro Kohno, Yusei Koyama, Minju M. Lee, Dieter Lutz, Lamiya Mowla, Erica J. Nelson, Alvio Renzini, Tomoko L. Suzuki, Linda J. Tacconi, Hannah Ubler, Emily WisnioskiStijn Wuyts

    Research output: Contribution to journalArticlepeer-review

    58 Citations (Scopus)


    We present 0.″2 resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations at 870 μm in a stellar mass-selected sample of 85 massive (M* > 1011 M⊙) star-forming galaxies (SFGs) at z = 1.9-2.6 in the CANDELS/3D-Hubble Space Telescope fields of UDS and GOODS-S. We measure the effective radius of the rest-frame far-infrared (FIR) emission for 62 massive SFGs. They are distributed over wide ranges of FIR size from Re,FIR = 0.4 kpc to Re,FIR = 6 kpc. The effective radius of the FIR emission is smaller by a factor of 2.3-1.0+1.9 than the effective radius of the optical emission and is smaller by a factor of 1.9-1.0+1.9 than the half-mass radius. Taking into account potential extended components, the FIR size would change only by ∼10%. By combining the spatial distributions of the FIR and optical emission, we investigate how galaxies change the effective radius of the optical emission and the stellar mass within a radius of 1 kpc, M1kpc. The compact starburst puts most of the massive SFGs on the mass-size relation for quiescent galaxies (QGs) at z ∼ 2 within 300 Myr if the current star formation activity and its spatial distribution are maintained. We also find that within 300 Myr, ∼38% of massive SFGs can reach the central mass of M1kpc = 1010.5 M ⊙, which is around the boundary between massive SFGs and QGs. These results suggest an outside-in transformation scenario in which a dense core is formed at the center of a more extended disk, likely via dissipative in-disk inflows. Synchronized observations at ALMA 870 μm and James Webb Space Telescope 3-4 μm will explicitly verify this scenario.

    Original languageEnglish
    Article number74
    JournalAstrophysical Journal
    Issue number1
    Publication statusPublished - 20 Sept 2020


    Dive into the research topics of 'Structural Evolution in Massive Galaxies at z ∼ 2'. Together they form a unique fingerprint.

    Cite this