@article{e1f5d431f67d46b79cdac703c62b0a4c,
title = "PHANGS-JWST First Results: Destruction of the PAH Molecules in H ii Regions Probed by JWST and MUSE",
abstract = "Polycyclic aromatic hydrocarbons (PAHs) play a critical role in the reprocessing of stellar radiation and balancing the heating and cooling processes in the interstellar medium but appear to be destroyed in H ii regions. However, the mechanisms driving their destruction are still not completely understood. Using PHANGS-JWST and PHANGS-MUSE observations, we investigate how the PAH fraction changes in about 1500 H ii regions across four nearby star-forming galaxies (NGC 628, NGC 1365, NGC 7496, and IC 5332). We find a strong anticorrelation between the PAH fraction and the ionization parameter (the ratio between the ionizing photon flux and the hydrogen density) of H ii regions. This relation becomes steeper for more luminous H ii regions. The metallicity of H ii regions has only a minor impact on these results in our galaxy sample. We find that the PAH fraction decreases with the Hα equivalent width—a proxy for the age of the H ii regions—although this trend is much weaker than the one identified using the ionization parameter. Our results are consistent with a scenario where hydrogen-ionizing UV radiation is the dominant source of PAH destruction in star-forming regions.",
author = "Egorov, {Oleg V.} and Kathryn Kreckel and Sandstrom, {Karin M.} and Leroy, {Adam K.} and Glover, {Simon C.O.} and Brent Groves and Kruijssen, {J. M.Diederik} and Barnes, {Ashley T.} and Francesco Belfiore and F. Bigiel and Blanc, {Guillermo A.} and M{\'e}d{\'e}ric Boquien and Yixian Cao and J{\'e}r{\'e}my Chastenet and M{\'e}lanie Chevance and Enrico Congiu and Dale, {Daniel A.} and Eric Emsellem and Kathryn Grasha and Klessen, {Ralf S.} and Larson, {Kirsten L.} and Daizhong Liu and Murphy, {Eric J.} and Pan, {Hsi An} and Ismael Pessa and J{\'e}r{\^o}me Pety and Erik Rosolowsky and Fabian Scheuermann and Eva Schinnerer and Jessica Sutter and Thilker, {David A.} and Watkins, {Elizabeth J.} and Williams, {Thomas G.}",
note = "Funding Information: K.K., O.E., and F.S. gratefully acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) in the form of an Emmy Noether Research Group (grant No. KR4598/2-1; PI: Kreckel). E.J.W., R.S.K., and S.C.O.G. acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) project ID 138713538—SFB 881 (“The Milky Way System,” subprojects A1, B1, B2, B8, P1). H.A.P. acknowledges support by the National Science and Technology Council of Taiwan under grant 110-2112-M-032-020-MY3. T.G.W. and E.S. acknowledge funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 694343). M.B. acknowledges support from FONDECYT regular grant 1211000 and by ANID BASAL project FB210003. J.M.D.K. gratefully acknowledges funding from the European Research Council (ERC) under the European Union{\textquoteright}s Horizon 2020 research and innovation program via the ERC Starting Grant MUSTANG (grant agreement No. 714907). COOL Research DAO is a Decentralized Autonomous Organization supporting research in astrophysics aimed at uncovering our cosmic origins. E.C. acknowledges support from ANID Basal projects ACE210002 and FB210003. F.B. would like to acknowledge funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 726384/Empire). M.C. gratefully acknowledges funding from the DFG through an Emmy Noether Research Group (grant No. CH2137/1-1). R.S.K. and S.C.O.G. acknowledge support from the European Research Council via the ERC Synergy Grant “ECOGAL” (project ID 855130), the Heidelberg Cluster of Excellence (EXC 2181-390900948) “STRUCTURES,” funded by the German Excellence Strategy, and the German Ministry for Economic Affairs and Climate Action for funding in project “MAINN” (funding ID 50OO2206). E.R. acknowledges the support of the Natural Sciences and Engineering Research Council of Canada (NSERC), funding reference No. RGPIN-2022-03499. K.G. is supported by the Australian Research Council through Discovery Early Career Researcher Award (DECRA) Fellowship DE220100766 funded by the Australian Government. K.G. is supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) through project No. CE170100013. G.A.B. acknowledges the support from ANID Basal project FB210003. J.C. acknowledges support from ERC starting grant No. 851622 DustOrigin. A.K.L. gratefully acknowledges support by grants 1653300 and 2205628 from the National Science Foundation, award JWST-GO-02107.009-A, and a Humboldt Research Award from the Alexander von Humboldt Foundation. J.P. acknowledges support by DAOISM grant ANR-21-CE31-0010 and the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, cofunded by CEA and CNES. Funding Information: This work is based on observations made with the NASA/ESA/CSA JWST. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. The observations are associated with JWST program 2107. The specific observations analyzed can be accessed via 10.17909/9bdf-jn24. Based on observations collected at the European Southern Observatory under ESO programs 094.C-0623 (PI: Kreckel), 095.C-0473, 098.C-0484 (PI: Blanc), and 1100.B-0651 (PHANGS-MUSE; PI: Schinnerer), as well as 094.B-0321 (MAGNUM; PI: Marconi), 099.B-0242, 0100.B-0116, 098.B-0551 (MAD; PI: Carollo), and 097.B-0640 (TIMER; PI: Gadotti). Publisher Copyright: {\textcopyright} 2023. The Author(s). Published by the American Astronomical Society.",
year = "2023",
month = feb,
day = "1",
doi = "10.3847/2041-8213/acac92",
language = "English",
volume = "944",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "IOP Publishing",
number = "2",
}