CO2 and non-CO2 radiative forcings in climate projections for twenty-first century mitigation scenarios

Climate is simulated for reference and mitigation emissions scenarios from Integrated Assessment Models using the Bern2.5CC carbon cycle-climate model. Mitigation options encompass all major radiative forcing agents. Temperature change is attributed to forcings using an impulse-response substitute of Bern2.5CC. The contribution of CO2 to global warming increases over the century in all scenarios. Non-CO2 mitigation measures add to the abatement of global warming. The share of mitigation carried by CO2, however, increases when radiative forcing targets are lowered, and increases after 2000 in all mitigation scenarios. Thus, non-CO2 mitigation is limited and net CO2 emissions must eventually subside. Mitigation rapidly reduces the sulfate aerosol loading and associated cooling, partly masking Greenhouse Gas mitigation over the coming decades. A profound effect of mitigation on CO2 concentration, radiative forcing, temperatures and the rate of climate change emerges in the second half of the centur

Arc-like distribution of high CO(J=3-2)/CO(J=1-0) ratio gas surrounding the central star cluster of the supergiant HII region NGC 604

We report the discovery of a high CO(J=3-2)/CO(J=1-0) ratio gas with an arc-like distribution (``high-ratio gas arc'') surrounding the central star cluster of the supergiant HII region NGC 604 in the nearby spiral galaxy M 33, based on multi-J CO observations of a 5' $\times$ 5' region of NGC 604 conducted using the ASTE 10-m and NRO 45-m telescopes. The discovered ``high-ratio gas arc'' extends to the south-east to north-west direction with a size of $\sim$ 200 pc. The western part of the high-ratio gas arc closely coincides well with the shells of the HII regions traced by H$\alpha$ and radio continuum peaks. The CO(J=3-2)/CO(J=1-0) ratio, R_{3-2/1-0}, ranges between 0.3 and 1.2 in the observed region, and the R_{3-2/1-0} values of the high-ratio gas arc are around or higher than unity, indicating very warm (T_kin > 60 K) and dense (n(H_2) > 10^{3-4} cm^{-3}) conditions of the high-ratio gas arc. We suggest that the dense gas formation and second-generation star formation occur in the surrounding gas compressed by the stellar wind and/or supernova of the first-generation stars of NGC 604, i.e., the central star cluster of NGC 604.Comment: 4 pages, 4 figures. The Astrophysical Journal Letters, in pres

Dense Molecular Gas in Lenticular Galaxies

We made CO and HCN simultaneous observations of lenticular galaxies, NGC 404, NGC 3593 and NGC 4293, and detected HCN emission in NGC 3593 and NGC 4293 as well as CO in all the galaxies. The I(HCN)/I(CO) ratios were 0.025+-0.006 and 0.066+-0.005 in NGC 3593 and NGC 4293, respectively, which are comparable to the late-type spiral galaxies. The average of the I(HCN)/I(CO) ratios at the center of 12 nearby spiral galaxies including late-type was 0.055+-0.028. The line profiles of CO and HCN emission showed different shape in both galaxies. The HCN peaks were not at the systemic velocity of these galaxies, while the CO peaks were near the systemic velocity. These results suggest that the fraction of the dense molecular gas is high around the center in these galaxies.Comment: 8 pages, 2 figures, to be published in PASJ (Publications of the Astronomical Society of Japan) Vol.54, No.

The mapping class group and the Meyer function for plane curves

For each d>=2, the mapping class group for plane curves of degree d will be defined and it is proved that there exists uniquely the Meyer function on this group. In the case of d=4, using our Meyer function, we can define the local signature for 4-dimensional fiber spaces whose general fibers are non-hyperelliptic compact Riemann surfaces of genus 3. Some computations of our local signature will be given.Comment: 24 pages, typo adde

Hyperfine Populations Prior to Muon Capture

It is shown that the 1S level hyperfine populations prior to muon capture will be statistical when either target or beam are unpolarised independent of the atomic level at which the hyperfine interaction becomes appreciable. This assertion holds in the absence of magnetic transitions during the cascade and is true because of minimal polarisation after atomic capture and selective feeding during the cascade.Comment: (revtex, 6 preprint pages, no figures