ﻻ يوجد ملخص باللغة العربية
The gas distribution and dynamics in the inner Galaxy present many unknowns as the origin of the asymmetry of the longitude-velocity (lv) diagram of the Central Molecular Zone (CMZ). On the other hand, there are recent evidences in the stellar component of the presence of a nuclear bar that could be slightly lopsided. Our goal is to characterize the nuclear bar observed in 2MASS maps and to study the gas dynamics in the inner Milky Way taking into account this secondary bar. We have derived a realistic mass distribution by fitting 2MASS star counts maps with three components (disk, bulge and nuclear bar) and we have simulated the gas dynamics, in the deduced gravitational potential, using a sticky-particles code. Our simulations of the gas dynamics reproduce successfully the main characteristics of the Milky Way for a bulge orientation of 20-35 deg with respect to the Sun-Galactic Center (GC) line and a pattern speed of 30-40 km/s/kpc. In our models the Galactic Molecular Ring (GMR) is not an actual ring but the inner parts of the spiral arms, while the 3-kpc arm and its far side counterpart are lateral arms that contour the bar. Our simulations reproduce, for the first time, the parallelogram shape of the lv-diagram of the CMZ as the gas response to the nuclear bar. This bar should be oriented by an angle of ~60-75 deg with respect to the Sun-GC line and its mass amounts to (2-5.5)10e9 Msun. We show that the observed asymmetry of the CMZ cannot be due to lopsidedness of the nuclear bar as suggested by the 2MASS maps. We do not find clear evidences of lopsidedness in the stellar potential. We propose that the observed asymmetry of the central gas layer can be due to the infalling of gas into the CMZ in the l=1.3-complex
We use a model of the Galactic fountain to simulate the neutral-hydrogen emission of the Milky Way Galaxy. The model was developed to account for data on external galaxies with sensitive HI data. For appropriate parameter values, the model reproduces
We investigate data from the Galactic Effelsberg--Bonn HI Survey (EBHIS), supplemented with data from the third release of the Galactic All Sky Survey (GASS III) observed at Parkes. We explore the all sky distribution of the local Galactic HI gas wit
Using the Tuorla-Heidelberg model for the mass distribution of the Milky Way, I determine the rotation curve predicted by MOND. The result is in good agreement with the observed terminal velocities interior to the solar radius and with estimates of t
We present a new joint analysis of pulsar dispersion measures and diffuse H-alpha emission in the Milky Way, which we use to derive the density, pressure and filling factor of the thick disk component of the warm ionised medium (WIM) as a function of
We address the spatial scale, ionization structure, mass and metal content of gas at the Milky Way disk-halo interface detected as absorption in the foreground of seven closely-spaced, high-latitude halo blue horizontal branch stars (BHBs) with heigh