Rotational Spectrum and First Interstellar Detection of 2-Methoxyethanol Using ALMA Observations of NGC 6334I
We use both chirped-pulse Fourier transform and frequency modulated absorption spectroscopy to study the rotational spectrum of 2-methoxyethanol in several frequency regions ranging from 8.7-500 GHz.
The resulting rotational parameters permitted a search for this molecule in Atacama Large Millimeter/submillimeter Array (ALMA) observations toward the massive protocluster NGC 6334I as well as source B of the low-mass protostellar system IRAS 16293-2422. 25 rotational transitions are observed in the ALMA Band 4 data toward NGC 6334I, resulting in the first interstellar detection of 2-methoxyethanol.
A column density of 1.3+1.4−0.9×1017 cm−2 is derived at an excitation temperature of 143+31−39 K. However, molecular signal is not observed in the Band 7 data toward IRAS 16293-2422B and an upper limit column density of 2.5×1015 cm−2 is determined. Various possible formation pathways–including radical recombination and insertion reactions–are discussed. We also investigate physical differences between the two interstellar sources that could result in the observed abundance variations.
Zachary T.P. Fried, Samer J. El-Abd, Brian M. Hays, Gabi Wenzel, Alex N. Byrne, Laurent Margulès, Roman A. Motiyenko, Steven T. Shipman, Maria P. Horne, Jes K. Jørgensen, Crystal L. Brogan, Todd R. Hunter, Anthony J. Remijan, Andrew Lipnicky, Ryan A. Loomis, Brett A. McGuire
Comments: Accepted for publication in The Astrophysical Journal Letters
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2403.17341 [astro-ph.GA] (or arXiv:2403.17341v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2403.17341
Submission history
From: Zachary Fried
[v1] Tue, 26 Mar 2024 03:01:44 UTC (4,940 KB)
https://arxiv.org/abs/2403.17341
Astrobiology, Astrochemistry,
