GOODS-ALMA: The slow downfall of star formation in z = 2-3 massive galaxies
Abstract
We investigate the properties of a sample of 35 galaxies, detected with the Atacama Large Millimeter/Submillimeter Array (ALMA) at 1.1 mm in the GOODS-ALMA field (area of 69 arcmin2, resolution = 0.60″, rms ≃ 0.18 mJy beam-1). Using the ultraviolet-to-radio deep multiwavelength coverage of the GOODS-South field, we fit the spectral energy distributions of these galaxies to derive their key physical properties. The galaxies detected by ALMA are among the most massive at z = 2-4 (M⋆, med = 8.5 × 1010 M⊙) and they are either starburst or located in the upper part of the galaxy star-forming main sequence. A significant portion of our galaxy population (∼40%), located at z ∼ 2.5 - 3, exhibits abnormally low gas fractions. The sizes of these galaxies, measured with ALMA, are compatible with the trend between the rest-frame 5000 Å size and stellar mass observed for z ∼ 2 elliptical galaxies, suggesting that they are building compact bulges. We show that there is a strong link between star formation surface density (at 1.1 mm) and gas depletion time: The more compact a galaxy's star-forming region is, the shorter its lifetime will be (without gas replenishment). The identified compact sources associated with relatively short depletion timescales (∼100 Myr) are the ideal candidates to be the progenitors of compact elliptical galaxies at z ∼ 2.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 2020
- DOI:
- 10.1051/0004-6361/202038312
- arXiv:
- arXiv:2005.03043
- Bibcode:
- 2020A&A...643A..30F
- Keywords:
-
- galaxies: high-redshift;
- galaxies: evolution;
- galaxies: star formation;
- galaxies: active;
- galaxies: fundamental parameters;
- submillimeter: galaxies;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 18 pages, 8 figures, Accepted for publication in A&