Table 7
Abundance ratios.
| Measured values (LTE) | Galactic values | |||||||
|
|
||||||||
| I(3) | Red Stacking | |||||||
|
|
||||||||
| Transition | XObs | 13CO | XObs | 13CO | XGISM | 13CO | ||
| (2–1) | /Mol | /Mol | /Mol | |||||
| (MR) | (GC) | (MR) | (GC) | |||||
|
|
||||||||
| 13CO | 10.8 ± 2.7 ×10-8 | 1 | 8.0 ± 1.5 × 10-8 | 1 | 5.3 ×10-7 | 1.4 ×10-6 | 1 | 1 |
| C18O | 7.3 ± 2.4 ×10-8 | 1.48 ± 0.51 | 4.6 ± 1.4 × 10-8 | 1.73 ± 0.58 | 8.6 ×10-8 | 1.1 ×10-7 | 6.2 | 12.7 |
|
|
||||||||
| Measured values (LTE) | Galactic values | |||||||
|
|
||||||||
| I(2) | SE red Stacking | |||||||
|
|
||||||||
| Transition | X Obs | Mol | X Obs | Mol | X GISM | Mol | ||
| (1–0) | /HCO+ | /HCO+ | /HCO+ | |||||
|
|
||||||||
| HCN | 1.8 ±0.3 × 10-10 | 1.11 ± 0.22 | 2.6 ± 0.5 × 10-10 | 1.96 ± 0.64 | 1.9 ×10-9 | 4.0 | ||
| HCO+ | 1.6 ±0.2 × 10-10 | 1 | 1.3 ± 0.3 × 10-10 | 1 | 4.7 ×10-10 | 1 | ||
|
|
||||||||
| I-B(1) | ||||||||
|
|
||||||||
| Transition | XObs | Mol | ||||||
| (1–0) | /HCO+ | |||||||
|
|
||||||||
| HCN | 1.3 ± 0.2 × 10-10 | 1.01 ± 0.14 | ||||||
| HCO+ | 1.3 ± 0.1 × 10-10 | 1 | ||||||
Notes. For each molecule, we provide the expected abundances, assuming LTE and optically thin conditions, to compare them with Galactic values. We provide abundances and abundance ratios for two positions M31-I(3) and M31-I(2) (Cols. 2–3) and the stacking detections (Cols. 4–5), and then compare these values with those expected for the Galactic interstellar medium, at 4 kpc (MR) and at the Galactic centre (GC), derived from Bergin et al. (1995) and Wilson & Rood (1994) (Cols. 6–9). When 12CO(1–0) is not measured directly, the numbers are in italics.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.