Dense molecular gas in the nearby low-metallicity dwarf starburst galaxy IC 10
Dense molecular gas and star formation are correlated in galaxies. The effect of low metallicity on this relationship is crucial for interpreting observations of high-redshift galaxies, which have lower metallicities than galaxies today. However, it remains relatively unexplored because dense molecu...
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| Main Authors: | , , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2018 July 30
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| In: |
The astrophysical journal
Year: 2018, Volume: 862, Issue: 2 |
| ISSN: | 1538-4357 |
| DOI: | 10.3847/1538-4357/aacaf4 |
| Online Access: | Verlag, Volltext: https://doi.org/10.3847/1538-4357/aacaf4
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| Author Notes: | Amanda A. Kepley, Lauren Bittle, Adam K. Leroy, María J. Jiménez-Donaire, Andreas Schruba, Frank Bigiel, Molly Gallagher, Kelsey Johnson, and Antonio Usero |
| Summary: | Dense molecular gas and star formation are correlated in galaxies. The effect of low metallicity on this relationship is crucial for interpreting observations of high-redshift galaxies, which have lower metallicities than galaxies today. However, it remains relatively unexplored because dense molecular gas tracers like HCN and HCO+ are faint in low-metallicity systems. We present Green Bank Telescope observations of HCN(1-0) and HCO+(1-0) on giant molecular cloud (34 pc) scales in the nearby low-metallicity () starburst IC 10 and compare them to those in other galaxies. We detect HCN and HCO+ in one and three of five pointings, respectively. The values are within the range seen in other galaxies, but are most similar to those seen in other low-metallicity sources and in starbursts. The detections follow the fiducial - and - relationships. These trends suggest that HCN and HCO+ can be used to trace dense molecular gas at metallicities of 1/4 Z ⊙, to first order. The dense gas fraction is similar to that in spiral galaxies, but lower than that in U/LIRGs. The dense molecular gas star formation efficiency, however, is on the upper end of those in normal galaxies and consistent with those in U/LIRGs. These results suggest that the CO and HCN/HCO+ emission occupy the same relative volumes as they do at higher metallicity, but that the entire emitting structure is reduced in size. Dense gas mass estimates for high-redshift galaxies may need to be corrected for this effect. |
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| Item Description: | Gesehen am 24.10.2019 |
| Physical Description: | Online Resource |
| ISSN: | 1538-4357 |
| DOI: | 10.3847/1538-4357/aacaf4 |