|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'506'133
Articles rated: 2609
27 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
X-ray Emission of Baryonic Gas in the Universe: Luminosity-Temperature Relationship and Soft-Band Background | | Tong-Jie Zhang
; Jiren Liu
; Long-long Feng
; Ping He
; Li-Zhi Fang
; | | Date: |
9 Jan 2006 | | Abstract: | We study the X-ray emission of baryon fluid in the universe using the WIGEON cosmological hydrodynamic simulations. It has been revealed that cosmic baryon fluid in the nonlinear regime behaves like Burgers turbulence, i.e. the fluid field consists of shocks. Like turbulence in incompressible fluid, the Burgers turbulence plays an important role in converting the kinetic energy of fluid to thermal energy, and heats the gas. We show that the simulation sample of the LCDM model without adding extra heating sources can fit well the observed distributions of X-ray luminosity vs. temperature ($L_x - T$) of galaxy groups, and also consistent with the distributions of X-ray luminosity vs. velocity dispersion ($L_{
m x} - sigma$). Because the baryonic gas is multiphase, the $L_{
m x}-T$ and $L_{
m x}-sigma$ distributions are significantly scattered. If we describe the relationships by power laws $L_{
m x}propto T^{alpha_{LT}}$ and $L_{
m x}propto sigma^{alpha_{LV}}$, we find $alpha_{LT}>2.5$ and $alpha_{LV}>2.1$. The X-ray background in soft-band $0.5-2$ keV emitted by the baryonic gas in the temperature range $10^5<T<10^7$ K has also been calculated. We show that, among the total background, (1) no more than 2% comes from the region with the temperature less than $10^{6.5}$ K, and (2) no more than 7% is from the region of dark matter with mass density $
ho_{
m dm}<50 ar{
ho}_{
m dm}$. The region of $
ho_{
m dm}>50ar{
ho}_{
m dm}$ is generally clustered and discretely distributed. Therefore, almost all of the soft X-ray background comes from clustered sources, and the contribution from truly diffused gas is probably negligible. This point agrees with current X-ray observations. | | Source: | arXiv, astro-ph/0601192 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER