Detection of FeO towards SgrB2

Abstract

We have observed the J=5-4 ground state transition of FeO at a frequency of 153 GHz towards a selection of galactic sources. Towards the galactic center source SgrB2, we see weak absorption at approximately the velocity of other features towards this source (62 km s${}^{-1}$ LSR). Towards other sources, the results were negative as they were also for MgOH(3-2) and FeC(6-5). We tentatively conclude that the absorption seen toward SgrB2 is due to FeO in the hot ($\sim$ 500 K) relatively low density absorbing gas known to be present in this line of sight. This is the first (albeit tentative) detection of FeO or any iron--containing molecule in the interstellar gas. Assuming the observed absorption to be due to FeO, we estimate [FeO]/[SiO] to be of order or less than 0.002 and [FeO]/[H${}_2$] of order $310^{-11}$. This is compatible with our negative results in other sources. Our results suggest that the iron liberated from grains in the shocks associated with SgrB2 remains atomic and is not processed into molecular form.

1 postscrit figure,10 pages

Cited by in corpus (13)

• 2021 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules
• 2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules
• The chemistry of interstellar molecules containing the halogen elements
• Discovery of Interstellar CF+
• Deuterated molecules as a probe of ionization fraction in dense interstellar clouds
• The line-of-sight distribution of water in the SgrB2 complex
• Cold condensation of dust in the ISM
• Constraints on metal oxide and metal hydroxide abundances in the winds of AGB stars - Potential detection of FeO in R Dor
• Missing Fe: hydrogenated iron nanoparticles
• UV spectra of iron-doped carbon clusters FeC_n n = 3-6
• Conformational isomerism of methyl formate: new detections of the higher-energy trans conformer and theoretical insights
• Perspective from a Younger Generation -- The Astro-Spectroscopy of Gisbert Winnewisser
• Metallic species in interstellar medium: Astrochemical modeling