Au Scale Structures in Extra-planar Gas
نویسنده
چکیده
Recent spectroscopic observations of intermediate-and high-velocity clouds (IVCs and HVCs) in the Milky Way halo have unveiled the presence of diffuse interstellar molecular hydrogen (H 2) several kpc away from the Galactic disk. Most of this H 2 gas appears to reside in relatively small (∼ 0.1 pc), dense (n H ≈ 30 cm −3) gaseous filaments that probably are part of the cold neutral medium (CNM) in IVCs and HVCs. Also much smaller structures at AU scale and very high densities (n H ≈ 800 cm −3) have been observed, suggesting the presence of tiny-scale atomic structures (TSAS) in the Milky Way's extra-planar gas. It is not yet understood how such objects can form and exist in the Milky Way halo, but the high detection rate of H 2 absorption in IVCs implies that the CNM represents a gas phase that is characteristic for neutral clouds in the lower halo.
منابع مشابه
Planar Molecular Dynamics Simulation of Au Clusters in Pushing Process
Based on the fact the manipulation of fine nanoclusters calls for more precise modeling, the aim of this paper is to conduct an atomistic investigation for interaction analysis of particle-substrate system for pushing and positioning purposes. In the present research, 2D molecular dynamics simulations have been used to investigate such behaviors. Performing the planar simulations can provide a ...
متن کاملThe structure of Au(6)Y(+) in the gas phase.
The geometric and electronic structure of the Au(6)Y(+) cation is studied by gas phase vibrational spectroscopy combined with density functional theory calculations. The infrared photodissociation spectrum of Au(6)Y(+)·Ne is measured in the 95-225 cm(-1) energy range and exhibits two characteristic absorption bands at 181 cm(-1) and 121 cm(-1). Based on DFT/BP86 quantum chemical calculations, t...
متن کاملStructural Evolution of Doped Gold Clusters: MAu
We report a joint experimental and theoretical study on the structures of a series of gold clusters doped with a group-14 atom: MAux (M ) Si, Ge, Sn; x ) 5-8). Well-resolved photoelectron spectra were obtained and compared to calculations at several levels of theory to identify the low-lying structures of MAu5-8. We found that the structure of SiAu5 is dominated by the tetrahedrally coordinated...
متن کاملStarbursts and Extra-planar Hα from SINGG
The NOAO Survey for Ionization in Neutral Gas Galaxies (SINGG) is the largest star formation survey of an H i selected sample. Since the selection is made without regard to optical morphology, it is not biased toward or against “interesting” types of galaxies; thus SINGG is an ideal sample for studying galaxy demographics. Of a sample of 90 extra-galactic sources observed in photometric conditi...
متن کاملA dynamical model for the extra-planar gas in spiral galaxies
Recent H I observations reveal that the discs of spiral galaxies are surrounded by extended gaseous haloes. This extra-planar gas reaches large distances (several kpc) from the disc and shows peculiar kinematics (low rotation and inflow). We have modelled the extra-planar gas as a continuous flow of material from the disc of a spiral galaxy into its halo region. The output of our models are pse...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2004