Data · dataset · 2026
A 1.3cm spectral line study of the W33 region
Listed in ScienceDB
At a distance of 2.4 kpc, W33 is one of the most prolific sources of molecular line emission, and it is an excellent research target for a centimeter spectral line search.
Description
We carried out a 1.3 cm spectral line survey in the frequency range 18–26GHz. The lines we identified include 44 radio recombination lines (RRLs) and 24 molecular lines, excluding transitions from the main isotopolog of NH3.
The RRLs are associated with the ionized gas from W33 Main. Intensity ratios between RRL pairs with varying differences in the principal quantum number n (i.e., Δn) from the same element at adjacent frequencies agree with ratios expected under conditions of local thermodynamical equilibrium. In spite of a resulting helium-to-hydrogen abundance ratio (equal emitting volumes assumed) of (10.7±1.8)%, which is consistent with expectations, helium shows broader turbulent line widths than hydrogen.
Read the rest (3 more)
The difference amounts to a few kilometers per second, hinting that the spatial distributions are slightly different. The molecular lines are attributed to nine different species (CH3OH, HC3N, SiS, c-C3H2, CH3CN, NH2D, HNCO, H2O and CCS). Rotation temperatures and column densities were derived from CH3OH transitions using rotational temperature diagram analysis.
Maser emission produced by water vapor and methanol have been observed in W33 Main, W33A, and W33 B. Our survey discovered a CH3OH(102,8–101,9 E) maser in W33 Main. Toward W33 B1, the fractionated deuterium-to-hydrogen ratio (D/H) deduced from para-NH2D/NH3 is estimated to be ≲(1.0 ± 0.2)×10−3. For the other molecular W33-hotspots, 3σ upper limits are (5.0 ± 0.4)×10−3.
At linear scales of (0.5 pc), fractional abundances and excitation temperatures do not reach values close to those in well-established hot cores, but higher-resolution measurements may alter this picture.
Links
Where it is published
- DOI doi.org/10.57760/sciencedb.43534 ↗
DOI / persistent id · from scidb cn
Catalogue records · 1
- OAI-PMH record scidb.cn/oai?verb=GetRecord&metadataPrefix=oai_dc&identifier=10.57760%2… ↗
metadata API · from scidb cn
Topics
- From keywords
- Earth & Environmental Science · Engineering · Humanities · Life Sciences · Social Science
Provenance · 1 source records, 9 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| ScienceDB | 10.57760/sciencedb.43534 | 12 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| concepts[field].local:field:earth-environmental | mapping · scidb cn | connector:scidb_cn@1.0.0 | |
| concepts[field].local:field:engineering | mapping · scidb cn | connector:scidb_cn@1.0.0 | |
| concepts[field].local:field:humanities | mapping · scidb cn | connector:scidb_cn@1.0.0 | |
| concepts[field].local:field:life-sciences | mapping · scidb cn | connector:scidb_cn@1.0.0 | |
| concepts[field].local:field:social-science | mapping · scidb cn | connector:scidb_cn@1.0.0 | |
| description | source · scidb cn | connector:scidb_cn@1.0.0 | /metadata/dc/description |
| license_text | source · scidb cn | connector:scidb_cn@1.0.0 | |
| publication_date | source · scidb cn | connector:scidb_cn@1.0.0 | |
| title | source · scidb cn | connector:scidb_cn@1.0.0 | /metadata/dc/title |