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GOALS-JWST: Hidden Star Formation and Extended PAH Emission in the Luminous Infrared Galaxy VV 114

Authors :
A. S. Evans
D. T. Frayer
Vassilis Charmandaris
Lee Armus
Hanae Inami
Jason Surace
Sean Linden
B. T. Soifer
Tanio Diaz-Santos
Kirsten L. Larson
Jeffrey A. Rich
Yiqing Song
Loreto Barcos-Munoz
Joseph M. Mazzarella
George C. Privon
Vivian U
Anne M. Medling
Torsten Böker
Susanne Aalto
Kazushi Iwasawa
Justin H. Howell
Paul van der Werf
Philip Appleton
Thomas Bohn
Michael J. I. Brown
Christopher C. Hayward
Shunshi Hoshioka
Francisca Kemper
Thomas Lai
David Law
Matthew A. Malkan
Jason Marshall
Eric J. Murphy
David Sanders
Sabrina Stierwalt
Source :
The Astrophysical Journal Letters, Vol 940, Iss 1, p L8 (2022)
Publication Year :
2022
Publisher :
IOP Publishing, 2022.

Abstract

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 μ m light of VV 114, with the NE and SW cores having IR luminosities, L _IR (8 − 1000 μ m) ∼ 8 ± 0.8 × 10 ^10 L _⊙ and ∼ 5 ± 0.5 × 10 ^10 L _⊙ , respectively, and IR densities, Σ _IR ≳ 2 ± 0.2 × 10 ^13 L _⊙ kpc ^−2 and ≳ 7 ± 0.7 × 10 ^12 L _⊙ kpc ^−2 , respectively—in the range of Σ _IR 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 × 10 ^10 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 μ m 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.

Details

Language :
English
ISSN :
20418213 and 20418205
Volume :
940
Issue :
1
Database :
Directory of Open Access Journals
Journal :
The Astrophysical Journal Letters
Publication Type :
Academic Journal
Accession number :
edsdoj.2807c0d92654fdabed4582a359b4f67
Document Type :
article
Full Text :
https://doi.org/10.3847/2041-8213/ac9971