GOALS-JWST: Pulling Back the Curtain on the AGN and Star Formation in VV 114

Abstract

We present results from the James Webb Space Telescope Director’s Discretionary Time Early Release Science program 1328 targeting the nearby, luminous infrared galaxy, VV 114. We use the MIRI and NIRSpec instruments to obtain integral-field spectroscopy of the heavily obscured eastern nucleus (V114E) and surrounding regions. The spatially resolved, high-resolution spectra reveal the physical conditions in the gas and dust over a projected area of 2–3 kpc that includes the two brightest IR sources, the NE and SW cores. Our observations show for the first time spectroscopic evidence that the SW core hosts an active galactic nucleus as evidenced by its very low 6.2 μm and 3.3 μm polycyclic aromatic hydrocarbon equivalent widths (0.12 and 0.017 μm, respectively) and mid- and near-IR colors. Our observations of the NE core show signs of deeply embedded star formation including absorption features due to aliphatic hydrocarbons, large quantities of amorphous silicates, as well as HCN due to cool gas along the line of sight. We detect elevated [Fe ii]/Pfα consistent with extended shocks coincident with enhanced emission from warm H2, far from the IR-bright cores and clumps. We also identify broadening and multiple kinematic components in both H2 and fine structure lines caused by outflows and previously identified tidal features.

GOALS-JWST: Mid-infrared Molecular Gas Excitation Probes the Local Conditions of Nuclear Star Clusters and the Active Galactic Nucleus in the LIRG VV 114

“…The Q-branches of C 2 H 2 , HCN, and CO 2 , blends of closely spaced pure vibrational lines, have been detected by Spitzer toward a handful of local U/LIRGs (Lahuis et al 2007), but at lower spatial and spectral resolution. Rich et al (2023) previously reported the detection of the ν 2 14.0 μm band of HCN and the ν 5 13.7 μm band of C 2 H 2 in absorption toward the NE core in VV 114E. The fundamental band of CO at 4.67 μm, tracing transitions between the ground state and the first vibrationally excited state, has been observed in absorption toward several heavily obscured U/LIRGs from the ground (e.g., Spoon et al 2003;Geballe et al 2006;Shirahata et al 2013;Baba et al 2022;Ohyama et al 2023).…”

“…We reduced the data using JWST Science Calibration Pipeline version 1.11.1.dev1+g9975346 and calibration reference data system (CRDS) reference file jwst_1097.pmap. This is an updated version of the pipeline with respect to the one applied by Rich et al (2023).…”

“…Evans et al (2022) found mid-IR colors that are consistent with a starburst toward the NE core, while those toward the SW core are in line with an AGN. Moreover, the extremely low equivalent widths of 3.3 and 6.2 μm polycyclic aromatic hydrocarbon (PAH) features found by Rich et al (2023) are strong evidence for the presence of an AGN in the SW core. These JWST observations indicate that the IR-bright point source in the SW core harbors an AGN, while the other nuclear continuum peaks are starburst regions.…”

[O iv]- and [Ne v]-weak Active Galactic Nuclei Hidden by Compton-thick Material in Late Mergers

“…A combination of deep X-ray and mid-IR spectroscopy would be crucial to reveal the fraction and structure of buried AGNs in U/LIRGs, which are the key population in the study of SMBH growth in obscured AGNs at z ∼ 1 and beyond (see Section 1). The James Webb Space Telescope (JWST), endowed with a supreme mid-IR spectroscopic capability and unprecedentedly high sensitivity, can identify rapidly growing SMBHs in U/LIRGs (e.g., Inami et al 2022;Rich et al 2023). JWST observations combined with high-quality X-ray observations would enable us to identify buried AGNs almost fully covered by dense circumnuclear material with high ( ) f CT spec at cosmic noon, the population of which is predicted to increase significantly toward higher redshifts (e.g., Ueda et al 2014;Gilli et al 2022), and would help us reveal the entire picture of growth of both obscured and unobscured SMBHs.…”

Halfway to the Peak: Spatially Resolved Star Formation and Kinematics in a z = 0.54 Dusty Galaxy with JWST/MIRI

“…Spatial variations in PAH emission have even been resolved in a lensed galaxy at z = 4.2 (Spilker et al 2023). The high spectral resolution has also enabled kinematic studies of shocks and outflows (e.g., Vivian et al 2022;Goold et al 2023;Rich et al 2023). Lines such as [Ar II]6.99 μm are strong in nearby infrared-luminous galaxies (e.g., Vivian et al 2022), and have yet to be explored beyond the local Universe.…”