http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Miocchi, P.,Pasquato, M.,Lanzoni, B.,Ferraro, F. R.,Dalessandro, E.,Vesperini, E.,Alessandrini, E.,Lee, Y.-W. IOP Publishing 2015 The Astrophysical journal Vol.799 No.1
<P>We present semi-analytical models and simplified N-body simulations with 10(4) particles aimed at probing the role of dynamical friction (DF) in determining the radial distribution of blue straggler stars (BSSs) in globular clusters. The semi-analytical models show that DF (which is the only evolutionary mechanism at work) is responsible for the formation of a bimodal distribution with a dip progressively moving toward the external regions of the cluster. However, these models fail to reproduce the formation of the long-lived central peak observed in all dynamically evolved clusters. The results of N-body simulations confirm the formation of a sharp central peak, which remains as a stable feature over time regardless of the initial concentration of the system. In spite of noisy behavior, a bimodal distribution forms in many cases, with the size of the dip increasing as a function of time. In the most advanced stages, the distribution becomes monotonic. These results are in agreement with the observations. Also, the shape of the peak and the location of the minimum (which, in most of cases, is within 10 core radii) turn out to be consistent with observational results. For a more detailed and close comparison with observations, including a proper calibration of the timescales of the dynamical processes driving the evolution of the BSS spatial distribution, more realistic simulations will be necessary.</P>
ULTRAVIOLET PROPERTIES OF GALACTIC GLOBULAR CLUSTERS WITH GALEX. I. THE COLOR-MAGNITUDE DIAGRAMS
Schiavon, Ricardo P.,Dalessandro, Emanuele,Sohn, Sangmo T.,Rood, Robert T.,O'Connell, Robert W.,Ferraro, Francesco R.,Lanzoni, Barbara,Beccari, Giacomo,Rey, Soo-Chang,Rhee, Jaehyon,Rich, R. Michael,Yo American Institute of Physics 2012 The Astronomical journal Vol.143 No.5
<P>We present Galaxy Evolution Explorer (GALEX) data for 44 Galactic globular clusters (GCs) obtained during three GALEX observing cycles between 2004 and 2008. This is the largest homogeneous data set on the UV photometric properties of Galactic GCs ever collected. The sample selection and photometric analysis are discussed, and color-magnitude diagrams (CMDs) are presented. The blue and intermediate-blue horizontal branch is the dominant feature of the UV CMDs of old Galactic GCs. Our sample is large enough to display the remarkable variety of horizontal branch shapes found in old stellar populations. Other stellar types that are obviously detected are blue stragglers and post-core-He burning stars. The main features of UV CMDs of Galactic GCs are briefly discussed. We establish the locus of post-core-He burning stars in the UV CMD and present a catalog of candidate asymptotic giant branch (AGB), AGB-manqué, post early-AGB, and post-AGB stars within our cluster sample.</P>