PHANGS-JWST First Results: Destruction of the PAH Molecules in H ii Regions Probed by JWST and MUSE

Oleg V. Egorov; Kathryn Kreckel; Karin M. Sandstrom; Adam K. Leroy; Simon C.O. Glover; Brent Groves; J. M.Diederik Kruijssen; Ashley T. Barnes; Francesco Belfiore; F. Bigiel; Guillermo A. Blanc; Médéric Boquien; Yixian Cao; Jérémy Chastenet; Mélanie Chevance; Enrico Congiu; Daniel A. Dale; Eric Emsellem; Kathryn Grasha; Ralf S. Klessen; Kirsten L. Larson; Daizhong Liu; Eric J. Murphy; Hsi An Pan; Ismael Pessa; Jérôme Pety; Erik Rosolowsky; Fabian Scheuermann; Eva Schinnerer; Jessica Sutter; David A. Thilker; Elizabeth J. Watkins; Thomas G. Williams

doi:10.3847/2041-8213/acac92

PHANGS-JWST First Results: Destruction of the PAH Molecules in H ii Regions Probed by JWST and MUSE

Oleg V. Egorov^*, Kathryn Kreckel, Karin M. Sandstrom, Adam K. Leroy, Simon C.O. Glover, Brent Groves, J. M.Diederik Kruijssen, Ashley T. Barnes, Francesco Belfiore, F. Bigiel, Guillermo A. Blanc, Médéric Boquien, Yixian Cao, Jérémy Chastenet, Mélanie Chevance, Enrico Congiu, Daniel A. Dale, Eric Emsellem, Kathryn Grasha, Ralf S. KlessenKirsten L. Larson, Daizhong Liu, Eric J. Murphy, Hsi An Pan, Ismael Pessa, Jérôme Pety, Erik Rosolowsky, Fabian Scheuermann, Eva Schinnerer, Jessica Sutter, David A. Thilker, Elizabeth J. Watkins, Thomas G. Williams

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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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.

Original language	English
Article number	L16
Journal	Astrophysical Journal Letters
Volume	944
Issue number	2
DOIs	https://doi.org/10.3847/2041-8213/acac92
Publication status	Published - 1 Feb 2023

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Egorov, O. V., Kreckel, K., Sandstrom, K. M., Leroy, A. K., Glover, S. C. O., Groves, B., Kruijssen, J. M. D., Barnes, A. T., Belfiore, F., Bigiel, F., Blanc, G. A., Boquien, M., Cao, Y., Chastenet, J., Chevance, M., Congiu, E., Dale, D. A., Emsellem, E., Grasha, K., ... Williams, T. G. (2023). PHANGS-JWST First Results: Destruction of the PAH Molecules in H ii Regions Probed by JWST and MUSE. Astrophysical Journal Letters, 944(2), Article L16. https://doi.org/10.3847/2041-8213/acac92

@article{6aa3d23fae69465ea2414d00fa857f85,

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 = "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 = "American Astronomical Society",

number = "2",

}

Egorov, OV, Kreckel, K, Sandstrom, KM, Leroy, AK, Glover, SCO, Groves, B, Kruijssen, JMD, Barnes, AT, Belfiore, F, Bigiel, F, Blanc, GA, Boquien, M, Cao, Y, Chastenet, J, Chevance, M, Congiu, E, Dale, DA, Emsellem, E, Grasha, K, Klessen, RS, Larson, KL, Liu, D, Murphy, EJ, Pan, HA, Pessa, I, Pety, J, Rosolowsky, E, Scheuermann, F, Schinnerer, E, Sutter, J, Thilker, DA, Watkins, EJ & Williams, TG 2023, 'PHANGS-JWST First Results: Destruction of the PAH Molecules in H ii Regions Probed by JWST and MUSE', Astrophysical Journal Letters, vol. 944, no. 2, L16. https://doi.org/10.3847/2041-8213/acac92

TY - JOUR

T1 - PHANGS-JWST First Results

T2 - Destruction of the PAH Molecules in H ii Regions Probed by JWST and MUSE

AU - Egorov, Oleg V.

AU - Kreckel, Kathryn

AU - Sandstrom, Karin M.

AU - Leroy, Adam K.

AU - Glover, Simon C.O.

AU - Groves, Brent

AU - Kruijssen, J. M.Diederik

AU - Barnes, Ashley T.

AU - Belfiore, Francesco

AU - Bigiel, F.

AU - Blanc, Guillermo A.

AU - Boquien, Médéric

AU - Cao, Yixian

AU - Chastenet, Jérémy

AU - Chevance, Mélanie

AU - Congiu, Enrico

AU - Dale, Daniel A.

AU - Emsellem, Eric

AU - Grasha, Kathryn

AU - Klessen, Ralf S.

AU - Larson, Kirsten L.

AU - Liu, Daizhong

AU - Murphy, Eric J.

AU - Pan, Hsi An

AU - Pessa, Ismael

AU - Pety, Jérôme

AU - Rosolowsky, Erik

AU - Scheuermann, Fabian

AU - Schinnerer, Eva

AU - Sutter, Jessica

AU - Thilker, David A.

AU - Watkins, Elizabeth J.

AU - Williams, Thomas G.

PY - 2023/2/1

Y1 - 2023/2/1

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85148723687&partnerID=8YFLogxK

U2 - 10.3847/2041-8213/acac92

DO - 10.3847/2041-8213/acac92

M3 - Article

SN - 2041-8205

VL - 944

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 2

M1 - L16

ER -

PHANGS-JWST First Results: Destruction of the PAH Molecules in H ii Regions Probed by JWST and MUSE

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