Journal
ASTROPHYSICAL JOURNAL LETTERS
Volume 836, Issue 2, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.3847/2041-8213/836/2/L29
Keywords
galaxies: ISM; ISM: molecules; radio lines: galaxies
Categories
Funding
- DFG [BI 1546/1-1]
- Centre National d'Etudes Spatiales (CNES)
- Spanish MINECO [FIS2012-32096, ESP2015-68964]
- National Science Foundation [1615105, 1615109]
- ARC [DP160100695]
- Division Of Astronomical Sciences
- Direct For Mathematical & Physical Scien [1615109] Funding Source: National Science Foundation
Ask authors/readers for more resources
We use the IRAM Large Program EMPIRE and new high-resolution ALMA data to measure (CO)-C-13(1-0)/(CO)-O-18(1-0) intensity ratios across nine nearby spiral galaxies. These isotopologues of (CO)-C-12 are typically optically thin across most of the area in galaxy disks, and this ratio allows us to gauge their relative abundance due to chemistry or stellar nucleosynthesis effects. Resolved (CO)-C-13/(CO)-O-18 gradients across normal galaxies have been rare due to the faintness of these lines. We find a mean (CO)-C-13/(CO)-O-18 ratio of 6.0 +/- 0.9 for the central regions of our galaxies. This agrees well with results in the Milky Way, but differs from results for starburst galaxies (3.4 +/- 0.9) and ultraluminous infrared galaxies (1.1 +/- 0.4). In our sample, the (CO)-C-13/(CO)-O-18 ratio consistently increases with increasing galactocentric radius and decreases with increasing star formation rate surface density. These trends could be explained if the isotopic abundances are altered by fractionation; the sense of the trends also agrees with those expected for carbon and oxygen isotopic abundance variations due to selective enrichment by massive stars.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available