Spatial variations in aromatic hydrocarbon emission in a dust-rich galaxy
Abstract
Dust grains absorb half of the radiation emitted by stars throughout the history of the universe, re-emitting this energy at infrared wavelengths. Polycyclic aromatic hydrocarbons (PAHs) are large organic molecules that trace millimeter-size dust grains and regulate the cooling of the interstellar gas within galaxies. Observations of PAH features in very distant galaxies have been difficult due to the limited sensitivity and wavelength coverage of previous infrared telescopes. Here we present JWST observations that detect the 3.3um PAH feature in a galaxy observed less than 1.5 billion years after the Big Bang. The high equivalent width of the PAH feature indicates that star formation, rather than black hole accretion, dominates the infrared emission throughout the galaxy. The light from PAH molecules, large dust grains, and stars and hot dust are spatially distinct from one another, leading to order-of-magnitude variations in the PAH equivalent width and the ratio of PAH to total infrared luminosity across the galaxy. The spatial variations we observe suggest either a physical offset between the PAHs and large dust grains or wide variations in the local ultraviolet radiation field. Our observations demonstrate that differences in the emission from PAH molecules and large dust grains are a complex result of localized processes within early galaxies.
Cite
@article{arxiv.2306.03152,
title = {Spatial variations in aromatic hydrocarbon emission in a dust-rich galaxy},
author = {Justin S. Spilker and Kedar A. Phadke and Manuel Aravena and Melanie Archipley and Matthew B. Bayliss and Jack E. Birkin and Matthieu Bethermin and James Burgoyne and Jared Cathey and Scott C. Chapman and Hakon Dahle and Anthony H. Gonzalez and Gayathri Gururajan and Christopher C. Hayward and Yashar D. Hezaveh and Ryley Hill and Taylor A. Hutchison and Keunho J. Kim and Seonwoo Kim and David Law and Ronan Legin and Matthew A. Malkan and Daniel P. Marrone and Eric J. Murphy and Desika Narayanan and Alex Navarre and Grace M. Olivier and Jeffrey A. Rich and Jane R. Rigby and Cassie Reuter and James E. Rhoads and Keren Sharon and J. D. T. Smith and Manuel Solimano and Nikolaus Sulzenauer and Joaquin D. Vieira and Axel Weiss and Katherine E. Whitaker},
journal= {arXiv preprint arXiv:2306.03152},
year = {2023}
}
Comments
Published in Nature 5 June 2023 at https://www.nature.com/articles/s41586-023-05998-6. MIRI MRS reduction notebook is available at https://github.com/jwst-templates