arXiv subjects

L. Ji

Publications and source records attributed to L. Ji.

77 records · Page 5Linked to original sources

arXiv2000

The FIR-Radio Correlation of Wolf-Rayet Galaxies and the Role of Star Formation in LINERs

We find that a preliminary classification of LINERs' energetics may be made in terms of the FIR-radio correlation of Wolf-Rayet galaxies. The AGN- or starburst-supported LINERs can be distinguished by their FIR-to-radio ratio, $Q\equiv L(1.4{\rm GHz})/$ $L(60μ{\rm m})>$ or $<0.01$. It is interesting to note that almost all the LINERs with inner rings might be starburst- supported, indicating reduced AGN activities compared with those of the AGN-supported ones. We also find that a shock-heating phase for the warm dust component might be important for some starbursts at the burst age of $\ge 10^{7}$ yr, with $Q<0.001$.

astro-ph↗

arXiv1998

Role of Starbursts in LINERs

We report our preliminary results on the role of starbursts in LINERs by use of WR galaxies as a tool. The essence of this approach lies in the different FIR-radio relation of WR galaxies from the pure AGN's.

astro-ph↗

arXiv1998

Enhanced Star Formation in Seyfert 2 Galaxies

In this paper, we report our preliminary results on enhanced star formation activity in Seyfert 2 galaxies. By re-analysing the Tully-Fisher relation for Whittle(1992)'s sample and for a Seyfert 2s' sample selecting from Veron-Cetty & Veron (1996), we find that (1) almost all Seyfert 2 galaxies with circumnuclear star formation have a ratio of far infrared (FIR) to blue luminosities ($L_{FIR}/L_{B}$) to be larger than 1/3; (2) for Seyfert 2 galaxies with $L_{FIR}/L_{B} < 1/3$, the Tully-Fisher relation is similar to that of the normal spiral galaxies; while for those with $\rm L_{FIR}/L_{B} \geq 1/3 $, they are significantly different from the normal ones, which confirms Whittle's suggestion of enhanced star formation activities in the circumnuclear regions of these Seyfert 2 galaxies.

astro-ph↗

arXiv1998

New Wolf-Rayet Galaxies with Detection of WC Stars

We report the discovery of two new Wolf-Rayet (WR) galaxies: Mrk~1039, and F08208$+$2816. Two broad WR bumps at 5808Å~ and 4650Å~ indicate the presence of WCE and WNL star population in all two sources. We also confirm the presenceof WR features in Mrk~35, previously detected in a different position. The observed equivalent width of the WR bump at 4650Å~ and the derived number ratios of WR/(WR$+$O) imply that star formation in these sources takes place inshort burst duration. Comparisons with the recent models of WR populations in young starbursts with the observed EW(\HeII)/EW(\CIV)/EW(WRbump) and their relative intensitie provide an indication that the stellar initial mass function in some WR galaxies might not be Salpeter-like. It is interesting to find that the luminous IRAS source, F08208$+$2816, has little dust reddening, probably because of the existence of a powerful superwind. By comparisons with other starbursts observed with the Hopkins Ultraviolet Telescope, F08208$+$2816 as a merging system renders a chance to study the contribution from young starbursts to the UV background radiation in universe.

astro-ph↗

arXiv1996

Single-Electron Traps: A Quantitative Comparison of Theory and Experiment

We have carried out a coordinated experimental and theoretical study of single-electron traps based on submicron aluminum islands and aluminum oxide tunnel junctions. The results of geometrical modeling using a modified version of MIT's FastCap were used as input data for the general-purpose single-electron circuit simulator MOSES. The analysis indicates reasonable quantitative agreement between theory and experiment for those trap characteristics which are not affected by random offset charges. The observed differences between theory and experiment (ranging from a few to fifty percent) can be readily explained by the uncertainty in the exact geometry of the experimental nanostructures.

cond-mat↗