High Spectral Resolution Observations of Propynal (HCCCHO) toward TMC-1 from the GOTHAM Large Program on the GBT
Name
Remijan_2024_ApJ_976_105.pdf
Description
Published version
Size
1.21 MB
Format
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Checksum (MD5)
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Author(s)
Remijan, Anthony J
Fried, Zachary TP
Cooke, Ilsa R
Wenzel, Gabi
Loomis, Ryan
Shingledecker, Christopher N
Lipnicky, Andrew
Xue, Ci
McCarthy, Michael C
McGuire, Brett A
Date Issued
November 15, 2024
Journal
The Astrophysical Journal
Publisher
American Astronomical Society
Citation
Anthony J. Remijan et al 2024 ApJ 976 105
Version
Final published version
Abstract
\We used new high spectral resolution observations of propynal (HCCCHO) toward TMC-1 and in the laboratory to update the spectral line catalog available for transitions of HCCCHO—specifically at frequencies lower than 30 GHz, which were previously discrepant in a publicly available catalog. The observed astronomical frequencies provided a high enough spectral resolution that, when combined with high-resolution (∼2 kHz) measurements taken in the laboratory, a new, consistent fit to both the laboratory and astronomical data was achieved. Now with a nearly exact (<1 kHz) frequency match to the J = 2–1 and 3–2 transitions in the astronomical data, using a Markov Chain Monte Carlo analysis, a best fit to the total HCCCHO column density of 7.28+ 10 -1.94
x 10 12 cm−2 was found with a surprisingly low excitation temperature of just over 3 K. This column density is around a factor of 5 times larger than reported in previous studies. Finally, this work highlights that care is needed when using publicly available spectral catalogs to characterize astronomical spectra. The availability of these catalogs is essential to the success of modern astronomical facilities and will only become more important as the next generation of facilities comes online.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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DOI of Published Version
https://doi.org/10.3847/1538-4357/ad856e
