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arXiv · 2208.14507

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

Aaron S. Evans·David Frayer·Vassilis Charmandaris·Lee Armus·Hanae Inami·Jason Surace·Sean Linden·Baruch Soifer·Tanio Diaz-Santos·Kirsten Larson·Jeffrey Rich·Yiqing Song·Loreto Barcos-Munoz·Joseph Mazzarella·George Privon·Vivian U·Anne Medling·Torsten Boeker·Susanne Aalto·Kazushi Iwasawa·Justin Howell·Paul van der Werf·Philip N. Appleton·Thomas Bohn·Michael Brown·Christopher Hayward·Shunshi Hoshioka·Francisca Kemper·Thomas Lai·David Law·Matthew Malkan·Jason Marshall·Eric Murphy·David Sanders·Sabrina Stierwalt
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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 15um light of VV 114, with the NE and SW cores having IR luminosities, L_ IR (8-1000um) ~ 8+/-0.8x10^10 L_sun and ~ 5+/-0.5x10^10 L_sun, respectively, and IR densities, Sigma_IR >~ 2+/-0.2x10^13 L_sun / kpc^2 and >~ 7+/-0.7x10^12 L_sun / kpc^2, respectively -- in the range of Sigma_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 has AGN-like colors. Approximately 40 star-forming knots with L_IR ~ 0.02-5x10^10 L_sun are identified, 25% of which have no optical counterpart. Finally, diffuse emission accounts for 40-60% of the mid-IR emission. Mostly notably, filamentary Poly-cyclic Aromatic Hydrocarbon (PAH) emission stochastically excited by UV and optical photons accounts for half of the 7.7um 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.

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Aaron S. Evans, David Frayer, Vassilis Charmandaris, Lee Armus, Hanae Inami, Jason Surace, Sean Linden, Baruch Soifer, Tanio Diaz-Santos, Kirsten Larson, Jeffrey Rich, Yiqing Song, Loreto Barcos-Munoz, Joseph Mazzarella, George Privon, Vivian U, Anne Medling, Torsten Boeker, Susanne Aalto, Kazushi Iwasawa, Justin Howell, Paul van der Werf, Philip N. Appleton, Thomas Bohn, Michael Brown, Christopher Hayward, Shunshi Hoshioka, Francisca Kemper, Thomas Lai, David Law, Matthew Malkan, Jason Marshall, Eric Murphy, David Sanders, Sabrina Stierwalt. 2022-08-30. GOALS-JWST: Hidden Star Formation and Extended PAH Emission in the Luminous Infrared Galaxy VV 114. https://doi.org/10.3847/2041-8213%2Fac9971

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