2008A&A...489..115R


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.04CET20:53:23

2008A&A...489..115R - Astronomy and Astrophysics, volume 489, 115-133 (2008/10-1)

Gas flow models in the Milky Way embedded bars.

RODRIGUEZ-FERNANDEZ N.J. and COMBES F.

Abstract (from CDS):

The gas distribution and dynamics in the inner Galaxy present many unknowns, such as the origin of the asymmetry of the lv-diagram of the Central Molecular Zone (CMZ). On the other hand, there is recent evidence in the stellar component of the presence of a nuclear bar that may 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 the 2MASS star count map with a model including 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 successfully reproduce the main characteristics of the Milky Way for a bulge orientation of 20°-35° with respect to the Sun-Galactic Center (GC) line and a pattern speed of 30-40km/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 extend around 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° with respect to the Sun-GC line and its mass amounts to (2-5.5)109M. 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 evidence 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.

Abstract Copyright:

Journal keyword(s): Galaxy: structure - Galaxy: center - Galaxy: kinematics and dynamics - ISM: kinematics and dynamics - methods: numerical

Simbad objects: 20

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Number of rows : 20

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME Per Arm PoG 03 30 +45.0           ~ 1290 0
2 NAME Gal Anticenter reg 05 46 +28.9           ~ 748 0
3 NAME Car Arm PoG 10 00 -60.0           ~ 385 1
4 M 100 AGN 12 22 54.9318850854 +15 49 20.294302163 10.04 10.05 9.35     ~ 1683 2
5 NAME Crux-Scutum Spiral Arm reg 12 30 -60.0           ~ 283 0
6 M 94 SyG 12 50 53.148 +41 07 12.55 9.15 8.96 8.24 7.78   ~ 1247 3
7 NAME Car-Sgr Arm PoG 15 00 -40.0           ~ 440 1
8 NAME Nor Arm PoG 16 00 -50.0           ~ 354 0
9 NAME Sgr C MoC 17 44 36.3 -29 28 13           ~ 318 0
10 NAME Sgr A Region reg 17 45 12 -28 48.3           ~ 920 0
11 GAL 000.0+00.0 gam 17 45 39.60213 -29 00 22.0000           ~ 12009 0
12 NAME Sgr B MoC 17 47 02 -28 25.4           ~ 195 0
13 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 1981 1
14 Bania Clump 2 MoC 17 51 42.6 -26 17 18           ~ 33 1
15 NAME Sgr Arm PoG 19 00 -30.0           ~ 542 1
16 NAME Outer Arm PoG 21 48 +69.4           ~ 230 0
17 NAME Centaurus Arm PoG ~ ~           ~ 74 0
18 NAME Local Arm reg ~ ~           ~ 395 0
19 NAME Scutum Spiral Arm PoG ~ ~           ~ 290 0
20 NAME Galactic Molecular Ring PoG ~ ~           ~ 39 0

    Equat.    Gal    SGal    Ecl

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