EDP Sciences logo
Subscriber Authentication Point
Search
Menu
Home All issues Volume 549 (January 2013) A&A, 549 (2013) A5 Full HTML
Free Access

Table 2

Molecular lines and frequencies.

Molecule J + 1 → J Eu/kB Frequency n crit a Bandwidth Resolution Beam B eff F eff 1σ rms
(K) (GHz) (cm-3) (MHz) (km s-1) (′′) (K)
IRAM 30 m telescope
H13CO+ 1–0 4.16   86.754   1.7 × 105 160 0.16 29 0.78 0.98 0.06
SiO 2–1 6.25   86.847   7.3 × 105 160 0.16 29 0.78 0.98 0.07
HCO+ 1–0 4.28   89.189   1.8 × 105 40 0.08 28 0.78 0.98 0.10
CH3CN 5–4, K = 0, 1, 2, 3, 4 13.24b 91.987b 4.7 × 105 120 0.16 27 0.78 0.98 0.09
N2H+ 1–0 4.47   93.174   1.6 × 105 40 0.08 27 0.78 0.98 0.11
C18O 2–1 15.81   219.560   9.2 × 103 512 1.5 12 0.62 0.94 0.12
CO 2–1 16.60   230.538   1.1 × 104 512 1.5 11 0.58 0.92 1.3
APEX telescope
N2H+ 3–2 26.83   279.512   3.0 × 106 1000 0.15 22 0.73 0.97 0.23
H2CO 404–303c 34.90   290.623   9.2 × 106 1000 0.15 22 0.73 0.97 0.20
HCO+ 4–3 42.80   356.734   9.1 × 106 1000 0.12 18 0.73 0.97 0.47
CO 3–2 33.19   345.796   3.5 × 104 1000 0.12 18 0.73 0.97 1.1

Notes. Columns are (from left to right) the molecule, its transition, its upper energy level, its frequency, its critical column density, the bandwidth used in the observation, the velocity resolution of the observation, the telescope beam, the main beam and forward beam efficiency of the observation, and the mean 1σ noise value. .

(a)

Calculated from the collision rates at T = 20 K from the LAMBDA molecular database (Schöier et al. 2005).

(b)

Frequency and Eu/kB for the K = 0 level. Observed were K = 0, 1, 2, 3, 4

(c)

The observed K level is given in subscript.

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.