3-mm spectral line survey of two lines of sight towards two typical cloud complexes in the Galactic Centre

Armijos-Abendaño, Jairo, Martin-Pintado, J., Requena-Torres, M.A., Martin, S. and Rodriguez-Franco, A. 2014. 3-mm spectral line survey of two lines of sight towards two typical cloud complexes in the Galactic Centre. Monthly Notices of the Royal Astronomical Society: Letters 446 (4) , pp. 3842-3862. 10.1093/mnras/stu2271

Full text not available from this repository.

Abstract

We present the results of two Mopra 3-mm spectral line surveys of the lines of sight (LOS) towards the Galactic Centre (GC) molecular complexes Sgr B2 (LOS+0.693) and Sgr A (LOS−0.11). The spectra covered the frequency ranges of ∼77–93 GHz and ∼105–113 GHz. We have detected 38 molecular species and 25 isotopologues. The isotopic ratios derived from column density ratios are consistent with the canonical values, indicating that chemical isotopic fractionation and/or selective photodissociation can be considered negligible (<10 per cent) for the GC physical conditions. The derived abundances and rotational temperatures are very similar for both LOSs, indicating very similar chemical and excitation conditions for the molecular gas in the GC. The excitation conditions are also very similar to those found for the nucleus of the starburst galaxy NGC 253. We report for the first time the detection of HCO and HOC+ emission in LOS+0.693. Our comparison of the abundance ratios between CS, HCO, HOC+ and HCO+ found in the two LOSs with those in typical Galactic photodissociation regions (PDRs) and starbursts galaxies does not show any clear trend to distinguish between ultraviolet- and X-ray-induced chemistries. We propose that the CS/HOC+ ratio could be used as a tracer of the PDR components in the molecular clouds in the nuclei of galaxies.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Publisher:	Wiley
ISSN:	1745-3925
Date of Acceptance:	23 October 2014
Last Modified:	11 Jul 2023 16:01
URI:	https://orca.cardiff.ac.uk/id/eprint/159158

Actions (repository staff only)

Edit Item