12^{12}C/13^{13}C ratio in planetary nebulae from the IUE archives

We investigated the abundance ratio of $^{12}$C/$^{13}$C in planetary nebulae by examining emission lines arising from \ion{C}{3} 2s2p ^3P_{2,1,0} \to 2s^2 ^1S_0. Spectra were retrieved from the International Ultraviolet Explorer archives, and multiple spectra of the same object were coadded to achieve improved signal-to-noise. The $^{13}$C hyperfine structure line at 1909.6 \AA was detected in NGC 2440. The $^{12}$C/$^{13}$C ratio was found to be $\sim4.4\pm$1.2. In all other objects, we provide an upper limit for the flux of the 1910 \AA line. For 23 of these sources, a lower limit for the $^{12}$C/$^{13}$C ratio was established. The impact on our current understanding of stellar evolution is discussed. The resulting high signal-to-noise \ion{C}{3} spectrum helps constrain the atomic physics of the line formation process. Some objects have the measured 1907/1909 flux ratio outside the low-electron density theoretical limit for $^{12}$C. A mixture of $^{13}$C with $^{12}$C helps to close the gap somewhat. Nevertheless, some observed 1907/1909 flux ratios still appear too high to conform to the presently predicted limits. It is shown that this limit, as well as the 1910/1909 flux ratio, are predominantly influenced by using the standard partitioning among the collision strengths for the multiplet $^1S_0$--$^3P_J$ according to the statistical weights. A detailed calculation for the fine structure collision strengths between these individual levels would be valuable.Comment: ApJ accepted: 19 pages, 3 Figures, 2 Table

Bryn Mawr Alumnae Quarterly, 1907-1909

https://repository.brynmawr.edu/bmc_alumnae/1004/thumbnail.jp

Bryn Mawr Alumnae Quarterly, 1907-1909

https://repository.brynmawr.edu/bmc_alumnae/1004/thumbnail.jp

Nebular Line Emission During the Epoch of Reionization

Nebular emission lines associated with galactic HII regions carry information about both physical properties of the ionised gas and the source of ionising photons as well as providing the opportunity of measuring accurate redshifts and thus distances once a cosmological model is assumed. While nebular line emission has been extensively studied at lower redshift there are currently only few constraints within the epoch of reionisation (EoR, $z>6$), chiefly due to the lack of sensitive near-IR spectrographs. However, this will soon change with the arrival of the Webb Telescope providing sensitive near-IR spectroscopy covering the rest-frame UV and optical emission of galaxies in the EoR. In anticipation of Webb we combine the large cosmological hydrodynamical simulation Bluetides with photoionisation modelling to predict the nebular emission line properties of galaxies at $z=8\to 13$. We find good agreement with the, albeit limited, existing direct and indirect observational constraints on equivalent widths though poorer agreement with luminosity function constraints.Comment: 17 pages, accepted to MNRAS, significant modification from v1.0 data available at https://stephenmwilkins.github.io/BluetidesEmissionLines_Public

On the lack of correlation between Mg II 2796, 2803 Angstrom and Lyman alpha emission in lensed star-forming galaxies

We examine the Mg II 2796, 2803 Angstrom, Lyman alpha, and nebular line emission in five bright star-forming galaxies at 1.66<z<1.91 that have been gravitationally lensed by foreground galaxy clusters. All five galaxies show prominent Mg II emission and absorption in a P Cygni profile. We find no correlation between the equivalent widths of Mg II and Lyman alpha emission. The Mg II emission has a broader range of velocities than do the nebular emission line profiles; the Mg II emission is redshifted with respect to systemic by 100 to 200 km/s. When present, Lyman alpha is even more redshifted. The reddest components of Mg II and Lyman alpha emission have tails to 500-600 km/s, implying a strong outflow. The lack of correlation in the Mg II and Lyman alpha equivalent widths, the differing velocity profiles, and the high ratios of Mg II to nebular line fluxes together suggest that the bulk of Mg II emission does not ultimately arise as nebular line emission, but may instead be reprocessed stellar continuum emission.Comment: The Astrophysical Journal, in press. 6 pages, 2 figure

Is Deflation depressing? Evidence from the Classical Gold Standard

We distinguish between good and bad deflations. In the former case, falling prices may be caused by aggregate supply (possibly driven by technology advances) increasing more rapidly than aggregate demand. In the latter case, declines in aggregate demand outpace any expansion in aggregate supply. This was the experience in the Great Depression (1929-33), the recession of 1919-21, and may be the case in Japan today. In this paper we focus on the price level and growth experience of the United States and Canada, 1870-1913. Both countries adhered to the international gold standard. This meant that the domestic price level was largely determined by international (exogenous) forces. In addition, neither country had a central bank which could intervene in the gold market to shield the domestic economy from external conditions. We proceed by identifying separate supply' shocks, money supply shocks and demand shocks using a Blanchard-Quah methodology. We model the economy as a small open economy on the gold standard and identify the shocks by imposing long run restrictions on the impact of the shocks and on output prices. We then do a historical decomposition to examine the impact of each shock on output. The results for the U.S. are clear: the different rates of change in the price levels before and after 1890 are attributed to different monetary shocks, but these shocks explain very little of output growth or volatility, which is almost entirely a response to supply' shocks. For Canada the results are murkier. As in the U.S., the money supply shocks before 1896 are predominantly negative and after that are largely positive. However, they are non-neutral, and relative to the U.S., money supply shocks play a larger role in determining output behavior in Canada. The key conclusion of our analysis is that the simple demarcation of good vs. bad deflation, where either prices fall because of a positive supply shock, or prices fall because of a negative demand (money) shock does not capture the complexity of the historical experience of the pre-1896 period. Indeed, we find that prices fell as a result of a combination of negative money supply shocks and positive supply shocks.

\u3csup\u3e12\u3c/sup\u3eC/\u3csup\u3e13\u3c/sup\u3eC Ratio in Planetary Nebulae from the \u3cem\u3eIUE\u3c/em\u3e Archives

We investigated the abundance ratio of 12C/13C in planetary nebulae by examining emission lines arising from C III 2s2p3Po2,1,0 → 2s21S0. Spectra were retrieved from the International Ultraviolet Explorer archives, and multiple spectra of the same object were co-added to achieve improved signal-to-noise ratio. The 13C hyperfine structure line at 1909.6 Å was detected in NGC 2440. The 12C/13C ratio was found to be ~4.4+/-1.2. In all other objects, we provide an upper limit for the flux of the 1910 Å line. For 23 of these sources, a lower limit for the 12C/13C ratio was established. The impact on our current understanding of stellar evolution is discussed. The resulting high-signal-to-noise ratio C III spectrum helps constrain the atomic physics of the line formation process. Some objects have the measured 1907/1909 Å flux ratio outside the low-electron density theoretical limit for 12C. A mixture of 13C with 12C helps to close the gap somewhat. Nevertheless, some observed 1907/1909 Å flux ratios still appear too high to conform to the currently predicted limits. It is shown that this limit, as well as the 1910/1909 Å flux ratio, are predominantly influenced by using the standard partitioning among the collision strengths for the multiplet 1S0-3PoJ according to the statistical weights. A detailed calculation for the fine-structure collision strengths between these individual levels would be valuable

New insights into the physical state of gaseous nebulae

The impact of knowledge of H II regions, planetary nebulae and supernova remnants due to International Ultraviolet Explorer is examined. The more relevant aspects related to the physical conditions of gaseous nebulae are reviewed. The following properties of gaseous nebulae are discussed: (1) density and temperature distribution; (2) ionization structure; (3) chemical composition; (4) internal dust; and (5) shock velocity for supernova remnants. The CNO abundances of planetary nebulae are compared with stellar evolution models

The Situation of Chinese Migrants Abroad in the Newspaper of Singapore

Migrants abroad Fujian southern coast especially southern coast of China, from Hiroshi east northeastern coastal area is famous, but not been studied in detail immigrants or were conducted in any area specifically from these areas. But it is the time of，1907-1909 years you look at the newspaper articles that were published in Singapore，one end of passengers number of arrival of ships to Singapore from Shantou (Swatow) and Xiamen (Amoy) can be seen.So I made it clear specifically referring to the newspaper article about the number of Chinese who arrived from Singapore to Shantou and Xiamen 1907-1909 year in this paper文部科学省グローバルCOEプログラム 関西大学文化交渉学教育研究拠点東アジアの歴史と動