arXiv Analytics

Sign in

arXiv:1706.09766 [astro-ph.GA]AbstractReferencesReviewsResources

Detection of Interstellar HC$_5$O in TMC-1 with the Green Bank Telescope

Brett A. McGuire, Andrew M. Burkhardt, Christopher N. Shingledecker, Sergei V. Kalenskii, Eric Herbst, Anthony J. Remijan, Michael C. McCarthy

Published 2017-06-29Version 1

We report the detection of the carbon-chain radical HC$_5$O for the first time in the interstellar medium toward the dark cloud TMC-1 using the 100 m Green Bank Telescope. We observe four hyperfine components of this radical in the $J = 17/2 \rightarrow 15/2$ rotational transition that originates from the $^2\Pi_{1/2}$ fine structure level of its ground state, and calculate an abundance of $n/n_{H_2}$ = $1.7\times 10^{-10}$, assuming an excitation temperature of $T_{ex} = 7$~K. No indication of HC$_3$O, HC$_4$O, HC$_6$O, is found in these or archival observations of the source, while we report tentative evidence for HC$_7$O. We compare calculated upper limits, and the abundance of HC$_5$O to predictions based on (1) the abundance trend of the analogous HC$_n$N family in TMC-1 and (2) a gas-grain chemical model. We find that the gas-grain chemical model well reproduces the observed abundance of HC$_5$O, as well as the upper limits of HC$_3$O, HC$_6$O, and HC$_7$O, but HC$_4$O is over produced. The prospects for astronomical detection of both shorter and longer HC$_n$O chains are discussed.

Comments: Accepted in The Astrophysical Journal Letters
Categories: astro-ph.GA
Related articles: Most relevant | Search more
arXiv:1411.0691 [astro-ph.GA] (Published 2014-11-03)
Search for PAHs in the Perseus molecular cloud with the Green Bank Telescope
arXiv:1806.07395 [astro-ph.GA] (Published 2018-06-19)
A Detection of Sgr A* in the far infrared
arXiv:1709.06496 [astro-ph.GA] (Published 2017-09-19)
Upper Limits to Magnetic Fields in the Outskirts of Galaxies