More Like this

1. PHANGS–JWST First Results: Variations in PAH Fraction as a Function of ISM Phase and Metallicity

   https://doi.org/10.3847/2041-8213/acadd7  

   Chastenet, Jérémy ; Sutter, Jessica ; Sandstrom, Karin ; Belfiore, Francesco ; Egorov, Oleg V. ; Larson, Kirsten L. ; Leroy, Adam K. ; Liu, Daizhong ; Rosolowsky, Erik ; Thilker, David A. ; et al ( February 2023 , The Astrophysical Journal Letters)

   We present maps tracing the fraction of dust in the form of polycyclic aromatic hydrocarbons (PAHs) in IC 5332, NGC 628, NGC 1365, and NGC 7496 from JWST/MIRI observations. We trace the PAH fraction by combining the F770W (7.7μm) and F1130W (11.3μm) filters to track ionized and neutral PAH emission, respectively, and comparing the PAH emission to F2100W, which traces small, hot dust grains. We find the averageR_PAH= (F770W + F1130W)/F2100W values of 3.3, 4.7, 5.1, and 3.6 in IC 5332, NGC 628, NGC 1365, and NGC 7496, respectively. We find that Hiiregions traced by MUSE Hαshow a systematically low PAH fraction. The PAH fraction remains relatively constant across other galactic environments, with slight variations. We use CO+Hi+Hαto trace the interstellar gas phase and find that the PAH fraction decreases above a value of${\mathrm{I}}_{\mathrm{H}\alpha }/{\mathrm{\Sigma }}_{\mathrm{H}\mathrm{I}+{\mathrm{H}}_2}\sim {10}^{37.5}\mathrm{erg}{\mathrm{s}}^{-1}{\mathrm{kpc}}^{-2}{(M_{\odot }{\mathrm{pc}}^{-2})}^{-1}$in all four galaxies. Radial profiles also show a decreasing PAH fraction with increasing radius, correlated with lower metallicity, in line with previous results showing a strong metallicity dependence to the PAH fraction. Our results suggest that the process of PAH destruction in ionized gas operates similarly across the four targets.

    

   more » « less
2. GOALS-JWST: Resolving the Circumnuclear Gas Dynamics in NGC 7469 in the Mid-infrared

   https://doi.org/10.3847/2041-8213/ac961c  

   U, Vivian ; Lai, Thomas ; Bianchin, Marina ; Remigio, Raymond P. ; Armus, Lee ; Larson, Kirsten L. ; Díaz-Santos, Tanio ; Evans, Aaron ; Stierwalt, Sabrina ; Law, David R. ; et al ( November 2022 , The Astrophysical Journal Letters)

   The nearby, luminous infrared galaxy NGC 7469 hosts a Seyfert nucleus with a circumnuclear star-forming ring and is thus the ideal local laboratory for investigating the starburst–AGN (active galactic nucleus) connection in detail. We present integral-field observations of the central 1.3 kpc region in NGC 7469 obtained with the JWST Mid-InfraRed Instrument. Molecular and ionized gas distributions and kinematics at a resolution of ∼100 pc over the 4.9–7.6μm region are examined to study the gas dynamics influenced by the central AGN. The low-ionization [Feii]λ5.34μm and [Arii]λ6.99μm lines are bright on the nucleus and in the starburst ring, as opposed to H₂S(5)λ6.91μm, which is strongly peaked at the center and surrounding ISM. The high-ionization [Mgv] line is resolved and shows a broad, blueshifted component associated with the outflow. It has a nearly face-on geometry that is strongly peaked on the nucleus, where it reaches a maximum velocity of −650 km s⁻¹, and extends about 400 pc to the east. Regions of enhanced velocity dispersion in H₂and [Feii] ∼ 180 pc from the AGN that also show highL(H₂)/L(PAH) andL([Feii])/L(Pfα) ratios to the W and N of the nucleus pinpoint regions where the ionized outflow is depositing energy, via shocks, into the dense interstellar medium between the nucleus and the starburst ring. These resolved mid-infrared observations of the nuclear gas dynamics demonstrate the power of JWST and its high-sensitivity integral-field spectroscopic capability to resolve feedback processes around supermassive black holes in the dusty cores of nearby luminous infrared galaxies.

    

   more » « less
3. GOALS-JWST: Gas Dynamics and Excitation in NGC 7469 Revealed by NIRSpec

   https://doi.org/10.3847/1538-4357/ad2a50  

   Bianchin, Marina ; U, Vivian ; Song, Yiqing ; Lai 賴, Thomas S. -Y. 劭愉 ; Remigio, Raymond P. ; Barcos-Muñoz, Loreto ; Díaz-Santos, Tanio ; Armus, Lee ; Inami, Hanae ; Larson, Kirsten L. ; et al ( April 2024 , The Astrophysical Journal)

   We present new JWST NIRSpec integral field spectroscopy (IFS) data for the luminous infrared galaxy NGC 7469, a nearby (70.6 Mpc) active galaxy with a Seyfert 1.5 nucleus that drives a highly ionized gas outflow and a prominent nuclear star-forming ring. Using the superb sensitivity and high spatial resolution of the JWST instrument NIRSpec IFS, we investigate the role of the Seyfert nucleus in the excitation and dynamics of the circumnuclear gas. Our analysis focuses on the [Feii], H₂, and hydrogen recombination lines that trace the radiation/shocked-excited molecular and ionized interstellar medium around the active galactic nucleus (AGN). We investigate gas excitation through H₂/Brγand [Feii]/Paβemission line ratios and find that photoionization by the AGN dominates within the central 300 pc of the galaxy except in a small region that shows signatures of shock-heated gas; these shock-heated regions are likely associated with a compact radio jet. In addition, the velocity field and velocity dispersion maps reveal complex gas kinematics. Rotation is the dominant feature, but we also identify noncircular motions consistent with gas inflows as traced by the velocity residuals and the spiral pattern in the Paαvelocity dispersion map. The inflow is 2 orders of magnitude higher than the AGN accretion rate. The compact nuclear radio jet has enough power to drive the highly ionized outflow. This scenario suggests that the inflow and outflow are in a self-regulating feeding–feedback process, with a contribution from the radio jet helping to drive the outflow.

    

   more » « less
4. GOALS-JWST: Tracing AGN Feedback on the Star-forming Interstellar Medium in NGC 7469

   https://doi.org/10.3847/2041-8213/ac9ebf  

   Lai, Thomas S.-Y. ; Armus, Lee ; U, Vivian ; Díaz-Santos, Tanio ; Larson, Kirsten L. ; Evans, Aaron ; Malkan, Matthew A. ; Appleton, Philip ; Rich, Jeff ; Müller-Sánchez, Francisco ; et al ( December 2022 , The Astrophysical Journal Letters)

   Abstract We present James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) integral-field spectroscopy of the nearby merging, luminous infrared galaxy, NGC 7469. This galaxy hosts a Seyfert type-1.5 nucleus, a highly ionized outflow, and a bright, circumnuclear star-forming ring, making it an ideal target to study active galactic nucleus (AGN) feedback in the local universe. We take advantage of the high spatial/spectral resolution of JWST/MIRI to isolate the star-forming regions surrounding the central active nucleus and study the properties of the dust and warm molecular gas on ∼100 pc scales. The starburst ring exhibits prominent polycyclic aromatic hydrocarbon (PAH) emission, with grain sizes and ionization states varying by only ∼30%, and a total star formation rate of 10–30 M ⊙ yr −1 derived from fine structure and recombination emission lines. Using pure rotational lines of H 2 we detect 1.2 × 10 7 M ⊙ of warm molecular gas at a temperature higher than 200 K in the ring. All PAH bands get significantly weaker toward the central source, where larger and possibly more ionized grains dominate the emission, likely the result of the ionizing radiation and/or the fast wind emerging from the AGN. The small grains and warm molecular gas in the bright regions of the ring however display properties consistent with normal star-forming regions. These observations highlight the power of JWST to probe the inner regions of dusty, rapidly evolving galaxies for signatures of feedback and inform models that seek to explain the coevolution of supermassive black holes and their hosts. 

   more » « less
5. PHANGS–JWST First Results: Multiwavelength View of Feedback-driven Bubbles (the Phantom Voids) across NGC 628

   https://doi.org/10.3847/2041-8213/aca7b9  

   Barnes, Ashley. T. ; Watkins, Elizabeth J. ; Meidt, Sharon E. ; Kreckel, Kathryn ; Sormani, Mattia C. ; Treß, Robin G. ; Glover, Simon C. O. ; Bigiel, Frank ; Chandar, Rupali ; Emsellem, Eric ; et al ( February 2023 , The Astrophysical Journal Letters)

   We present a high-resolution view of bubbles within the Phantom Galaxy (NGC 628), a nearby (∼10 Mpc), star-forming (∼2M_⊙yr⁻¹), face-on (i∼ 9°) grand-design spiral galaxy. With new data obtained as part of the Physics at High Angular resolution in Nearby GalaxieS (PHANGS)-JWST treasury program, we perform a detailed case study of two regions of interest, one of which contains the largest and most prominent bubble in the galaxy (the Phantom Void, over 1 kpc in diameter), and the other being a smaller region that may be the precursor to such a large bubble (the Precursor Phantom Void). When comparing to matched-resolution Hαobservations from the Hubble Space Telescope, we see that the ionized gas is brightest in the shells of both bubbles, and is coincident with the youngest (∼1 Myr) and most massive (∼10⁵M_⊙) stellar associations. We also find an older generation (∼20 Myr) of stellar associations is present within the bubble of the Phantom Void. From our kinematic analysis of the HI, H₂(CO), and Hiigas across the Phantom Void, we infer a high expansion speed of around 15 to 50 km s⁻¹. The large size and high expansion speed of the Phantom Void suggest that the driving mechanism is sustained stellar feedback due to multiple mechanisms, where early feedback first cleared a bubble (as we observe now in the Precursor Phantom Void), and since then supernovae have been exploding within the cavity and have accelerated the shell. Finally, comparison to simulations shows a striking resemblance to our JWST observations, and suggests that such large-scale, stellar-feedback-driven bubbles should be common within other galaxies.

    

   more » « less