scholarly journals Simulation of the gas density distribution in the accelerator of the ELISE test facility

2020 ◽  
Vol 91 (1) ◽  
pp. 013511
Author(s):  
M. Siragusa ◽  
E. Sartori ◽  
F. Bonomo ◽  
B. Heinemann ◽  
G. Orozco ◽  
...  
Keyword(s):  
Density Distribution ◽  
Test Facility ◽  
Gas Density

scholarly journals A new concept of transonic galactic outflows and its application to the Sombrero galaxy

2016 ◽  
Vol 11 (S321) ◽  
pp. 125-125
Author(s):  
Asuka Igarashi ◽  
Masao Mori ◽  
Shin-ya Nitta
Keyword(s):  
Star Formation ◽  
Density Distribution ◽  
Cold Dark Matter ◽  
Star Formation History ◽  
Dark Matter Halo ◽  
Polytropic Model ◽  
Gas Density ◽  
Galactic Outflows ◽  
Distant Region ◽  
Subsonic Region

AbstractWe study fundamental properties of transonic galactic outflows in the gravitational potential of a cold dark matter halo (DMH) with a central super-massive black hole (SMBH) assuming a polytropic, steady and spherically symmetric state. We have classified the transonic solutions with respect to their topology in the phase space. As a result, we have found two types of transonic solutions characterized by a magnitude relationship between the gravity of DMH and that of SMBH. These two types of solutions have different loci of the transonic points; one transonic point is formed at a central region (< 0.01kpc) and another is at a distant region (> 100kpc). Also, mass fluxes and outflow velocities are different between the two solutions. These two transonic solutions may play different roles on the star formation history of galaxies and the metal contamination of intergalactic space. Furthermore, we have applied our model to the Sombrero galaxy. In this galaxy, the wide-spread hot gas is detected as an apparent trace of galactic outflows while the star-formation rate is disproportionately low, and the observed gas density distribution is quite similar to the hydrostatic state (Li et al. 2011). To solve this discrepancy, we propose a slowly accelerating outflow in which the transonic point forms in a distant region (~ 120 kpc) and the subsonic region spreads across the stellar distribution. In the subsonic region, the gas density distribution is similar to that of the hydrostatic state. Our model predicts the possibility of the slowly accelerating outflow in the Sombrero galaxy. Igarashi et al. 2014 used the isothermal model and well reproduced the observed gas density distribution, but the estimated mass flux (1.8M⊙/yr) is lager than the mass of the gas supplied by stars (0.3-0.4M⊙/yr). Then, we expect that the polytropic model may reproduce the observational mass of the supplied gas (Igarashi et al. 2015). Such slowly accelerating outflows should be distinguished from the conventional supersonic outflows frequently argued in star-forming galaxies.

Observation of excitation discharge on an excimer laser in nonuniform gas density distribution

1997 ◽  
Author(s):  
Go Imada ◽  
Yasuo Sato ◽  
Hiroyuki Yoshida ◽  
Wataru Masuda ◽  
Kiyoshi Yatsui
Keyword(s):  
Density Distribution ◽  
Excimer Laser ◽  
Gas Density ◽  
Nonuniform Gas

scholarly journals Dynamical Effects in the Central Region of the Galaxy

1977 ◽  
Vol 45 ◽  
pp. 103-113 ◽  
Author(s):  
Robert H. Sanders
Keyword(s):  
Density Distribution ◽  
Central Region ◽  
Molecular Clouds ◽  
Rotation Curve ◽  
Disk Model ◽  
Gas Density ◽  
Spherical Component ◽  
The Galaxy

For the purpose of this Paper, I will define the central region of the galaxy as being the inner four kiloparsecs. I make this definition for three reasons:1) Outside of four kiloparsecs, the rotation curve for the galaxy is well-defined by the Schmidt disk model; whereas, inside four kiloparsecs, the effects of a central spherical component on the rotation curve become conspicuous. This inner spheroid is a dynamical component of the galaxy which is distinct from the disk and may be distinct from the extended halo component as well.2) There is a conspicuous hole in the total gas density distribution inside 4 kpc.3) High peculiar or non-circular gas velocities are observed within the inner 4 kpc; velocities ranging from the 53 km s-1of the so-called 3 kpc arm, to 165 km s-1in the molecular clouds within 300 pc of the center.I will now discuss these points in some greater detail.

scholarly journals Transonic galactic outflows in a dark matter halo with a central black hole

2015 ◽  
Vol 11 (A29B) ◽  
pp. 741-741
Author(s):  
Asuka Igarashi ◽  
Masao Mori ◽  
Shin-ya Nitta
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Density Distribution ◽  
Mass Flux ◽  
Dark Matter Halo ◽  
Polytropic Model ◽  
Gas Density ◽  
Topological Features ◽  
Galactic Outflows ◽  
Distant Region

AbstractWe study fundamental properties of transonic galactic outflows in the gravitational potential of a cold dark matter halo (DMH) with a central super-massive black hole (SMBH) assuming an isothermal, steady and spherically symmetric state. Transonic solutions of galactic outflows are classified according to their topological features. As result, we find two types of transonic solutions distinguished by a magnitude relationship between the gravity of DMH and that of SMBH. The loci of transonic points for two types are different; one transonic point is formed at a central region (< 0.01kpc) and another is at a very distant region (> 100kpc). Also, mass fluxes and outflow velocities are different for two solutions. Thus, these solutions may differently influence the evolution of galaxies and the release of metals into the intergalactic space.Furthermore, we apply our model to the Sombrero galaxy. In this galaxy, the wide-spread hot gas is detected as the trace of galactic outflows while the star-formation rate is low, and the observed gas density distribution is similar to the hydrostatic state (Li et al. 2011). To solve this discrepancy, we propose a solution that this galaxy has a slowly accelerating outflow; the transonic point forms in a very distant region (~ 120 kpc) and the wide subsonic region spreads across the stellar distribution. Thus, the gas density distribution in the observed region is similar to the hydrostatic state. Such slowly accelerating outflows are different from high-velocity outflows conventionally studied (Igarashi et al. 2014).However, this isothermal model requires an unrealistically large mass flux. Then, we apply the polytropic model to this galaxy incorporating mass flux supplied by stellar components. We find that it can reproduce the observed gas density and the temperature distributions with the realistic mass flux. Thus, our polytropic model successfully demonstrates the existence of the slowly accelerating outflow in the Sombrero galaxy (Igarashi et al. 2015).

Visualization of 3D gas density distribution using optical tomography

2002 ◽  
Vol 86 (3) ◽  
pp. 243-250 ◽  
Author(s):  
J. Feng ◽  
K. Okamoto ◽  
D. Tsuru ◽  
H. Madarame ◽  
M. Fumizawa
Keyword(s):  
Density Distribution ◽  
Optical Tomography ◽  
Gas Density

scholarly journals Evolution of Planetary Nebulae Envelopes: An Empirical Approach

1993 ◽  
Vol 155 ◽  
pp. 370-370
Author(s):  
V.V. Golovaty ◽  
Yu. F. Malkov
Keyword(s):  
Integral Equation ◽  
Density Distribution ◽  
Radial Distribution ◽  
Empirical Investigation ◽  
Planetary Nebulae ◽  
Symmetric Case ◽  
Radio Continuum ◽  
Spherically Symmetric ◽  
Gas Density ◽  
Approximative Expression

We carried out the empirical investigation of the evolution of gas density distribution in the envelopes of planetary nebulae (PN). For this purpose we analysed the isophotal maps of 10 PN in the lines H alpha, H beta or in the optically thin radio continuum. To obtain the spatial radial distribution of gas density n(r) (where n = n(H)+n(He)) we used Abell's integral equation in the simplest, spherically-symmetric case. We found that n(r) for all PN envelopes in our sample can be described by an approximative expression:

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