The Astrophysical Journal (Jan 2024)

Birds of a Feather: Resolving Stellar Mass Assembly with JWST/NIRCam in a Pair of Kindred z ∼ 2 Dusty Star-forming Galaxies Lensed by the PLCK G165.7+67.0 Cluster

  • Patrick S. Kamieneski,
  • Brenda L. Frye,
  • Rogier A. Windhorst,
  • Kevin C. Harrington,
  • Min S. Yun,
  • Allison Noble,
  • Massimo Pascale,
  • Nicholas Foo,
  • Seth H. Cohen,
  • Rolf A. Jansen,
  • Timothy Carleton,
  • Anton M. Koekemoer,
  • Christopher N. A. Willmer,
  • Jake S. Summers,
  • Nikhil Garuda,
  • Reagen Leimbach,
  • Benne W. Holwerda,
  • Justin D. R. Pierel,
  • Eric F. Jiménez-Andrade,
  • S. P. Willner,
  • Belén Alcalde Pampliega,
  • Amit Vishwas,
  • William C. Keel,
  • Q. Daniel Wang,
  • Cheng Cheng,
  • Dan Coe,
  • Christopher J. Conselice,
  • Jordan C. J. D’Silva,
  • Simon P. Driver,
  • Norman A. Grogin,
  • Tyler Hinrichs,
  • James D. Lowenthal,
  • Madeline A. Marshall,
  • Mario Nonino,
  • Rafael Ortiz III,
  • Alex Pigarelli,
  • Nor Pirzkal,
  • Maria del Carmen Polletta,
  • Aaron S. G. Robotham,
  • Russell E. Ryan Jr.,
  • Haojing Yan

DOI
https://doi.org/10.3847/1538-4357/ad5d59
Journal volume & issue
Vol. 973, no. 1
p. 25

Abstract

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We present a new parametric lens model for the G165.7+67.0 galaxy cluster, which was discovered with Planck through its bright submillimeter flux, originating from a pair of extraordinary dusty star-forming galaxies (DSFGs) at z ≈ 2.2. Using JWST and interferometric mm/radio observations, we characterize the intrinsic physical properties of the DSFGs, which are separated by only ∼1″ (8 kpc) and a velocity difference Δ V ≲ 600 km s ^−1 in the source plane, and thus are likely undergoing a major merger. Boasting intrinsic star formation rates SFR _IR = 320 ± 70 and 400 ± 80 M _⊙ yr ^−1 , stellar masses of $\mathrm{log}[{M}_{\star }/{M}_{\odot }]=10.2\pm 0.1$ and 10.3 ± 0.1, and dust attenuations of A _V = 1.5 ± 0.3 and 1.2 ± 0.3, they are remarkably similar objects. We perform spatially resolved pixel-by-pixel spectral energy distribution (SED) fitting using rest-frame near-UV to near-IR imaging from JWST/NIRCam for both galaxies, resolving some stellar structures down to 100 pc scales. Based on their resolved specific star formation rates (SFRs) and UVJ colors, both DSFGs are experiencing significant galaxy-scale star formation events. If they are indeed interacting gravitationally, this strong starburst could be the hallmark of gas that has been disrupted by an initial close passage. In contrast, the host galaxy of SN H0pe has a much lower SFR than the DSFGs, and we present evidence for the onset of inside-out quenching and large column densities of dust even in regions of low specific SFR. Based on the intrinsic SFRs of the DSFGs inferred from UV through far-infrared SED modeling, this pair of objects alone is predicted to yield an observable 1.1 ± 0.2 core-collapse supernovae per year, making this cluster field ripe for continued monitoring.

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