GOALS-JWST: Hidden Star Formation and Extended PAH Emission in the Luminous Infrared Galaxy VV 114
Journal article, 2022
James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) images of the luminous infrared (IR) galaxy VV 114 are presented. This redshift ∼0.020 merger has a western component (VV 114W) rich in optical star clusters and an eastern component (VV 114E) hosting a luminous mid-IR nucleus hidden at UV and optical wavelengths by dust lanes. With MIRI, the VV 114E nucleus resolves primarily into bright NE and SW cores separated by 630 pc. This nucleus comprises 45% of the 15 μm light of VV 114, with the NE and SW cores having IR luminosities, L IR(8 − 1000 μm) ∼ 8 ± 0.8 × 1010 L ⊙ and ∼ 5 ± 0.5 × 1010 L ⊙, respectively, and IR densities, ΣIR ≳ 2 ± 0.2 × 1013 L ⊙ kpc−2 and ≳ 7 ± 0.7 × 1012 L ⊙ kpc−2, respectively—in the range of ΣIR for the Orion star-forming core and the nuclei of Arp 220. The NE core, previously speculated to have an active galactic nucleus (AGN), has starburst-like mid-IR colors. In contrast, the VV 114E SW core has AGN-like colors. Approximately 40 star-forming knots with L IR ∼ 0.02-5 × 1010 L ⊙ are identified, 28% of which have no optical counterpart. Finally, diffuse emission accounts for 40%-60% of the mid-IR emission. Mostly notably, filamentary polycyclic aromatic hydrocarbon (PAH) emission stochastically excited by UV and optical photons accounts for half of the 7.7 μm light of VV 114. This study illustrates the ability of JWST to detect obscured compact activity and distributed PAH emission in the most extreme starburst galaxies in the local universe.
Author
Aaron S. Evans
University of Virginia
National Radio Astronomy Observatory
D. Frayer
Green Bank Observatory
V. Charmandaris
University of Crete
European University Cyprus
Foundation for Research and Technology Hellas (FORTH)
Lee Armus
California Institute of Technology (Caltech)
H. Inami
Hiroshima University
J. A. Surace
California Institute of Technology (Caltech)
S. T. Linden
University of Massachusetts
B. T. Soifer
Spitzer Science Center
T. Diaz-Santos
Foundation for Research and Technology Hellas (FORTH)
European University Cyprus
K. Larson
Space Telescope Science Institute (STScI)
Jeff Rich
Carnegie Observatories
Y. Song
National Radio Astronomy Observatory
University of Virginia
Loreto Barcos-Munoz
University of Virginia
National Radio Astronomy Observatory
J. Mazzarella
California Institute of Technology (Caltech)
G. Privon
National Radio Astronomy Observatory
University of Florida
U. Vivian
University of California at Irvine (UCI)
Anne M. Medling
ARC Centre of Excellence for All-sky Astrophysics
University of Toledo
T. Boker
European Space Agency (ESA)
Susanne Aalto
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
K. Iwasawa
University of Barcelona
Catalan Institution for Research and Advanced Studies
Justin Howell
California Institute of Technology (Caltech)
P. van der Werf
Leiden University
P. Appleton
California Institute of Technology (Caltech)
Thomas Bohn
Hiroshima University
Michael J.I. Brown
Monash University
Christopher C. Hayward
Flatiron Institute
Shunshi Hoshioka
Hiroshima University
F. Kemper
Catalan Institution for Research and Advanced Studies
Thomas Lai
California Institute of Technology (Caltech)
David Law
Space Telescope Science Institute (STScI)
M. A. Malkan
University of California
Jason Marshall
Glendale Community College
E. J. Murphy
National Radio Astronomy Observatory
D. B. Sanders
University of Hawaii
S. Stierwalt
Occidental College
Astrophysical Journal Letters
2041-8205 (ISSN) 2041-8213 (eISSN)
Vol. 940 1 L8Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Other Physics Topics
DOI
10.3847/2041-8213/ac9971