31,285 research outputs found
Probing baryonic processes and gastrophysics in the formation of the Milky Way dwarf satellites: I. metallicity distribution properties
In this paper, we study the chemical properties of the stars in the dwarf
satellites around the MW-like host galaxies, and explore the possible effects
of several baryonic processes, including supernova (SN) feedback, the
reionization of the universe and H cooling, on them and how current and
future observations may put some constraints on these processes. We use a
semi-analytical model to generate MW-like galaxies, for which a fiducial model
can reproduce the luminosity function and the stellar metallicity--stellar mass
correlation of the MW dwarfs. Using the simulated MW-like galaxies, we focus on
investigating three metallicity properties of their dwarfs: the stellar
metallicity--stellar mass correlation of the dwarf population, and the
metal-poor and metal-rich tails of the stellar metallicity distribution in
individual dwarfs. We find that (1) the slope of the stellar
metallicity--stellar mass correlation is sensitive to the SN feedback strength
and the reionization epoch; (2) the extension of the metal-rich tails is mainly
sensitive to the SN feedback strength; (3) the extension of the metal-poor
tails is mainly sensitive to the reionization epoch; (4) none of the three
chemical properties are sensitive to the H cooling process; and (5)
comparison of our model results with the current observational slope of the
stellar metallicity--stellar mass relation suggests that the local universe is
reionized earlier than the cosmic average and local sources may have a
significant contribution to the reionization in the local region, and an
intermediate to strong SN feedback strength is preferred. Future observations
of metal-rich and metal-poor tails of stellar metallicity distributions will
put further constraints on the SN feedback and the reionization processes.Comment: 22 pages, 16 figures, accepted for publication in the Astrophysical
Journa
Heat conduction in 2D strongly-coupled dusty plasmas
We perform non-equilibrium simulations to study heat conduction in
two-dimensional strongly coupled dusty plasmas. Temperature gradients are
established by heating one part of the otherwise equilibrium system to a higher
temperature. Heat conductivity is measured directly from the stationary
temperature profile and heat flux. Particular attention is paid to the
influence of damping effect on the heat conduction. It is found that the heat
conductivity increases with the decrease of the damping rate, while its
magnitude agrees with previous experimental measurement.Comment: 4 pages, 2 figures, presented in SCCS2008 conferenc
Soft-Defined Heterogeneous Vehicular Network: Architecture and Challenges
Heterogeneous Vehicular NETworks (HetVNETs) can meet various
quality-of-service (QoS) requirements for intelligent transport system (ITS)
services by integrating different access networks coherently. However, the
current network architecture for HetVNET cannot efficiently deal with the
increasing demands of rapidly changing network landscape. Thanks to the
centralization and flexibility of the cloud radio access network (Cloud-RAN),
soft-defined networking (SDN) can conveniently be applied to support the
dynamic nature of future HetVNET functions and various applications while
reducing the operating costs. In this paper, we first propose the multi-layer
Cloud RAN architecture for implementing the new network, where the multi-domain
resources can be exploited as needed for vehicle users. Then, the high-level
design of soft-defined HetVNET is presented in detail. Finally, we briefly
discuss key challenges and solutions for this new network, corroborating its
feasibility in the emerging fifth-generation (5G) era
Marriage, Cohabitation and Women’s Response to Changes in the Male Wage Structure
Using micro data and grouped data that cover the period 1996-2006, we assess the extent to which cohabiting women adjust their labour supply to a lesser extent, if any, than married women in response to changes in male wages. Both micro data regressions and grouping estimators unambiguously indicate that cohabiting women respond less to variation in male wages than married women. However, the magnitude of the difference is not sizeable. Combined with the fact that married men’s and cohabiting men’s own-wage elasticities do not differ much, this explains why the impact of changes in male wages on family earnings ends up being very similar for married couples and cohabiting couples.marriage, cohabitation, women’s labour supply
- …