2025/04/08 by Nicholas Foo, Foo, Nicholas, Kevin C. Harrington +47 · 1 voice · 1 citation
#astro-ph.GA
paper · pdf · doi:10.48550/arxiv.2504.05617
Investigating the processes by which galaxies rapidly build up their stellar mass during the peak of their star formation (z=2--3) is crucial to advancing our understanding of the assembly of large-scale structures. We report the discovery of one of the most gas- and dust-rich protocluster core candidates, PJ0846+15 (J0846), from the Planck All-Sky Survey to Analyze Gravitationally lensed Extreme Starbursts (PASSAGES) sample. The exceedingly high total apparent star formation rate of up to (μSFR) ∼ 93600 M_\odot yr-1 is a result of a foreground cluster lens magnifying at least 11 dusty star-forming galaxies between z=2.660--2.669. Atacama Large Millimeter Array (ALMA) observations revealed 18 CO(3--2) emission-line detections, some of which are multiply-imaged systems, lensed by a foreground cluster at z=0.77. We present the first multi-wavelength characterization of this field, constructing a lens model that predicts that these 11 systems (magnification factor, μ≃1.5--25) are contained within a projected physical extent of 280×150 kpc, with a velocity dispersion of σv=246±72 km s-1 and a total intrinsic star formation rate of up to (SFR) ∼10400 M_\odot yr-1. J0846 is one of the most unique, lensed, protocluster core candidates ever reported, and offers a magnified glimpse into the rapid buildup of massive local galaxy clusters.