Publ. Astron. Soc. Jap., 57, 917-931 (2005/December-0)
An unbiased search for molecular clouds in the southern galactic warp.
NAKAGAWA M., ONISHI T., MIZUNO A. and FUKUI Y.
Abstract (from CDS):
We made an unbiased search for molecular clouds in the Galactic Warp. This survey, covering an area of 56 square degrees at l = 252° to 266° and b = -5° to -1°, revealed 70 molecular clouds, while only 6 clouds were previously known in this sector at R ≫ 14.5 kpc. The mass of the clouds is in a range from 7.8 x 102M☉ to 8.4 x 104M☉, significantly less than the most massive giant molecular clouds in the inner disk, ∼ 106M_☉, while the cloud mass spectrum characterized by a power law is basically similar to other parts of the Galaxy. The X factor, N(H2)/[?]T(12CO)dV, derived from the molecular clouds in the Warp, is estimated to be 3.5(±1.8)-times larger than that in the inner disk. The total molecular mass in the Warp is estimated to be 7.3 x 105M☉, and the total mass in the far-outer Galaxy (R ≫ 14.5 kpc) can be estimated to be 2 x 107M☉. The spatial correlation between the CO and HI distribution appears to be fairly good, and the mass of the molecular gas is about 1% of that of the atomic gas in the far-outer Galaxy. This ratio is similar to that in the interarm, but is ten-times smaller than those of the spiral arms. Only 6 of the 70 Warp clouds show signs of star formation at the IRAS sensitivity, and the star-formation efficiency for high-mass stars in the Warp is found to be smaller than those in other molecular clouds in the Galaxy.
Galaxy: warp - ISM: abundances - ISM: clouds - radio lines: ISM
VizieR on-line data:
<Available at CDS (J/PASJ/57/917): table1.dat>
Table 1: [NOM2005] NN (Nos 1-71).
Status at CDS:
could be processed
// All or part of tables of objects could be ingested in SIMBAD with priority 2.
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