On the Observability of Optically Thin Coronal Hyperfine Structure Lines
arXiv:1406.0868 · doi:10.1088/0004-637X/787/2/96
Abstract
We present Cloudy calculations for the intensity of coronal hyperfine lines in various environments. We model indirect collisional and radiative transitions, and quantify the collisionally-excited line emissivity in the density-temperature phase-space. As an observational aid, we also express the emissivity in units of the continuum in the 0.4--0.7 keV band. For most hyperfine lines, knowledge of the X-ray surface brightness and the plasma temperature is sufficient for rough estimates. We find that the radiation fields of both Perseus A and Virgo A can enhance the populations of highly ionized species within 1 kpc. They can also enhance line emissivity within the cluster core. This could have implications for the interpretation of spectra around bright AGN. We find the intensity of the Fe XXIV λ3.068 mm to be about two orders of magnitude fainter than previously thought, at about 20 μK. Comparably bright lines may be found in the infrared. Finally, we find the intensity of hyperfine lines in the Extended Orion Nebula to be low, due to the shallow sightline. Observations of coronal hyperfine lines will likely be feasible with the next generation of radio and sub-mm telescopes.
arXiv comment48 pages; 13 figures; 9 tables; additional images available at the online journal
References in corpus (28)
- The chemical composition of the Sun
- Correcting for the Effects of Interstellar Extinction
- Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
- A very deep Chandra observation of the Perseus cluster: shocks, ripples and conduction
- X-ray Spectroscopy of Cooling Clusters
- Filaments, Bubbles, and Weak Shocks in the Gaseous Atmosphere of M87
- An Integrated Spectrophotometric Survey of Nearby Star-Forming Galaxies
- A Compendium of Far-Infrared Line and Continuum Emission for 227 Galaxies Observed by the Infrared Space Observatory
- Fermi Discovery of Gamma-Ray Emission from NGC 1275
- Mid-Infrared Spectra of Classical AGN Observed with the Spitzer Space Telescope
- A 0.8-2.4 microns spectral atlas of Active Galactic Nuclei
- A New Measurement of the Primordial Abundance of Deuterium: Toward Convergence with the Baryon Density from the CMB?
- Measuring the non-thermal pressure in early type galaxy atmospheres: A comparison of X-ray and optical potential profiles in M87 and NGC1399
- XMM-Newton Observations of the Perseus Cluster II: Evidence for Gas Motions in the Core
- Million-Degree Plasma Pervading the Extended Orion Nebula
- An optical spectroscopic survey of the 3CR sample of radio galaxies with z<0.3. I. Presentation of the data
- On the Detectability of Turbulence and Bulk Flows in X-ray Clusters
- Feedback under the microscope II: heating, gas uplift, and mixing in the nearest cluster core
- OP data on CD for mean opacities and radiative accelerations
- Galaxy Clusters in the Swift/BAT era II: 10 more Clusters detected above 15 keV
- Core-collapse supernova enrichment in the core of the Virgo Cluster
- The long-term millimeter activity of active galactic nuclei
- Exploring the relation between (sub-)millimeter radiation and gamma-ray emission in blazars with Planck and Fermi
- ROSAT PSPC observations of the outer regions of the Perseus cluster of galaxies
- Hydrogen-like nitrogen radio line from hot interstellar and warm-hot intergalactic gas
- 3-He in the Milky Way Interstellar Medium: Ionization Structure
- Excitation of the 3.071mm Hyperfine Line in Li-Like 57-Fe in Astrophysical Plasmas
- Effects of External Radiation Fields on Line Emission - Application to Star-forming Regions