Spectral Line Survey toward a Molecular Cloud in IC10

Abstract

We have conducted a spectral line survey observation in the 3 mm band toward the low-metallicity dwarf galaxy IC10 with the 45 m radio telescope of Nobeyama Radio Observatory to explore its chemical composition at a molecular-cloud scale (~80 pc). The CS, SO, CCH, HCN, HCO+, and HNC lines are detected for the first time in this galaxy in addition to the CO and 13CO lines, while c-C3H2, CH3OH, CN, C18O, and N2H+ lines are not detected. The spectral intensity pattern is found to be similar to those observed toward molecular clouds in the Large Magellanic Cloud, whose metallicity is as low as IC10. Nitrogen-bearing species are deficient in comparison with the Galactic molecular clouds due to a lower elemental abundance of nitrogen. CCH is abundant in comparison with Galactic translucent clouds, whereas CH3OH may be deficient. These characteristic trends for CCH and CH3OH are also seen in the LMC, and seem to originate from photodissociation regions more extended in peripheries of molecular clouds due to the lower metallicity condition.

13pages, 3 figures, 3 tables, accepted for publication in ApJ

References in corpus (10)

• An eclipsing binary distance to the Large Magellanic Cloud accurate to 2 per cent
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• A 2 mm spectral line survey of the starburst galaxy NGC 253
• Molecular Gas in the Low Metallicity, Star Forming Dwarf IC 10
• Lambda = 3 mm line survey of nearby active galaxies
• Abundances and Isotope Ratios in the Magellanic Clouds: The Star Forming Environment of N113
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• Spectral Line Survey toward Spiral Arm of M51 in the 3 mm and 2 mm Bands
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• The Detection of Hot Cores and Complex Organic Molecules in the Large Magellanic Cloud
• Molecular-Cloud-Scale Chemical Composition II: Mapping Spectral Line Survey toward W3(OH) in the 3 mm Band
• Dense gas in low-metallicity galaxies
• A molecular line survey toward the nearby galaxies NGC 1068, NGC 253, and IC 342 at 3 mm with the Nobeyama 45 m radio telescope: The data
• A 3 mm Spectral Line Survey toward the Barred Spiral Galaxy NGC 3627