| | |
| | |
Stat |
Members: 3645 Articles: 2'501'711 Articles rated: 2609
20 April 2024 |
|
| | | |
|
Article overview
| |
|
Evidence for Radiation Pressure Compression in the X-ray Narrow Line Region of Seyfert galaxies | Stefano Bianchi
; Matteo Guainazzi
; Ari Laor
; Jonathan Stern
; Ehud Behar
; | Date: |
8 Feb 2019 | Abstract: | The observed spatial and kinematic overlap between soft X-ray emission and
the Narrow Line Region (NLR) in obscured Active Galactic Nuclei (AGN) yields
compelling evidence that relatively low-density gas co-exists with higher
density gas on scales as large as 100s of pc. This is commonly interpreted as
evidence for a constant gas pressure multiphase medium, likely produced by
thermal instability. Alternatively, Radiation Pressure Compression (RPC) also
leads to a density distribution, since a gas pressure (and hence density)
gradient must arise within each cloud to counteract the incident ionising
radiation pressure. RPC leads to a well-defined ionization distribution, and a
Differential Emission Measure (DEM) distribution with a universal slope of
$sim-0.9$, weakly dependent on the gas properties and the illuminating
radiation field. In contrast, a multiphase medium does not predict the form of
the DEM. The observed DEMs of obscured AGN with XMM-Newton RGS spectra (the
CHRESOS sample) are in striking agreement with the predicted RPC DEM, providing
a clear signature that RPC is the dominant mechanism for the observed range of
densities in the X-ray NLR. In contrast with the constant gas pressure
multiphase medium, RPC further predicts an increasing gas pressure with
decreasing ionization, which can be tested with future X-ray missions using
density diagnostics. | Source: | arXiv, 1902.3076 | 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:
| |