We present CO J = 4–3 line and 3 mm dust continuum observations of a 100 kpc-scale filamentary Lyα nebula (SSA22 LAB18) at z = 3.1 using the Atacama Large Millimeter/submillimeter Array (ALMA). We detected the CO J = 4–3 line at a systemic zCO = 3.093 ± 0.001 at 11 σ from one of the ALMA continuum sources associated with the Lyα filament. We estimated the CO J = 4–3 luminosity of $L^{\prime }_{\rm {CO(4-3)}}=(2.3 \pm 0.2)\times 10^{9}\:$K km s−1 pc2 for this CO source, which is one order of magnitude smaller than those of typical z > 1 dusty star-forming galaxies (DSFGs) of similar far-infrared luminosity LIR ∼ 1012 L⊙. We derived a molecular gas mass of $M_{\rm {gas}} = (4.4^{+0.9}_{-0.6}) \times 10^{9}\, M_{{\odot }}$ and a star-formation rate of SFR =270 ± 160 M⊙ yr−1. We also estimated a gas depletion time of τdep = 17 ± 10 Myr, which is shorter than those of typical DSFGs. It is suggested that this source is in the transition phase from DSFG to a gas-poor, early-type galaxy. From ALMA to Herschel multi-band dust continuum observations, we measured a dust emissivity index β = 2.3 ± 0.2, which is similar to those of local gas-poor, early-type galaxies. From recent laboratory experiments, the specific chemical compositions needed to reproduce such a high β for interstellar dust at the submillimeter wavelengths. ALMA CO and multi-band dust continuum observations can constrain the evolutionary stage of high-redshift galaxies through τdep and β, and thus we can investigate the chemical composition of dust even in the early Universe.
The Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme Starbursts project aims to identify a population of extremely luminous galaxies using the Planck all-sky survey and to explore the nature of their gas fuelling, induced starburst, and the resulting feedback that shape their evolution. Here, we report the identification of 22 high-redshift luminous dusty star-forming galaxies (DSFGs) at z = 1.1–3.3 drawn from a candidate list constructed using the Planck Catalogue of Compact Sources and Wide-field Infrared Survey Explorer all-sky survey. They are confirmed through follow-up dust continuum imaging and CO spectroscopy using AzTEC and the Redshift Search Receiver on the Large Millimeter Telescope Alfonso Serrano. Their apparent infrared luminosities span (0.1–3.1) × 1014 L⊙ (median of 1.2 × 1014 L⊙), making them some of the most luminous galaxies found so far. They are also some of the rarest objects in the sky with a source density of ≲0.01 deg−2. Our Atacama Large Millimeter/submillimeter Array 1.1 mm continuum observations with θ ≈ 0.4 arcsec resolution show clear ring or arc morphologies characteristic of strong lensing. Their lensing-corrected luminosity of LIR ≳ 1013 L⊙ (star-formation rate ≳ 103 M⊙ yr−1) indicates that they are the magnified versions of the most intrinsically luminous DSFGs found at these redshifts. Our spectral energy distribution analysis finds little detectable active galactic nucleus (AGN) activity despite their enormous luminosity, and any AGN activity present must be extremely heavily obscured.
more » « less- NSF-PAR ID:
- 10369287
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 515
- Issue:
- 3
- ISSN:
- 0035-8711
- Page Range / eLocation ID:
- p. 3911-3937
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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