<sup>13</sup>CO/C<sup>18</sup>O Gradients across the Disks of Nearby Spiral Galaxies
<sup>13</sup>CO/C<sup>18</sup>O Gradients across the Disks of Nearby Spiral Galaxies
We use the IRAM Large Program EMPIRE and new high-resolution ALMA data to measure 13CO(1-0)/C18O(1-0) intensity ratios across nine nearby spiral galaxies. These isotopologues of CO are typically optically thin across most of the area in galaxy disks, and this ratio allows us to gauge their relative abundance due to …