scholarly journals Atomic Data Needs for X-ray Astronomy

2002 ◽  
Vol 12 ◽  
pp. 82-83
Author(s):  
Nancy S. Brickhouse
Keyword(s):  
High Resolution ◽  
Atomic Data ◽  
Ionization Mechanism ◽  
Ionization State ◽  
Astrophysical Plasmas ◽  
X Ray ◽  
Physical Conditions ◽  
Elemental Abundances ◽  
The Status ◽  
Collisional Ionization

AbstractWith the launches of the Chandra X-ray Observatory and XMM-Newton, high resolution X-ray spectra of cosmic sources are broadening our understanding of the physical conditions, such as temperature, density, ionization state, and elemental abundances. X-ray emitting astrophysical plasmas can be generally classified by their dominant ionization mechanism, either collisional ionization or X-ray photoionization. The atomic data needs are significantly different for these two cases; however, for both cases it is important that we identify robust and accurate diagnostics and that we verify completeness of the broadband models. We discuss the status of the atomic data currently used in atomic databases for X-ray astronomy, in view of theoretical and experimental atomic physics considerations.

scholarly journals Atomic Data Needed for X-ray and EUV Astronomy

1992 ◽  
Vol 9 ◽  
pp. 573-574
Author(s):  
John C. Raymond
Keyword(s):  
Spectral Resolution ◽  
Atomic Data ◽  
Ionization State ◽  
Crystal Spectrometer ◽  
X Ray ◽  
Transmission Grating ◽  
Elemental Abundances ◽  
The Past ◽  
Accurate Temperature

AbstractThe astronomical X-ray and EUV satellites of the past generally had low enough spectral resolution that atomic data of modest quality was sufficient for most interpretation of the data. Typical proportional counter resolution Δ E/E ~ 1 permits a determination of the spectral shape sufficient for an estimate of the temperature of the emitting gas, but only the Fe K feature at 6.7 keV stands out as a distinct emission line. The higher spectral resolution Einstein Transmission Grating, Solid State Spectrometer, and Focal Plane Crystal Spectrometer instruments measured a score of emission lines or line blends, permitting determinations of the elemental abundances, temperature, and ionization state of the emitting gas. The higher spectral resolution and throughput of the BBXRT aboard the ASTRO mission and the instruments planned for EUVE, ASTRO-D, AXAF, and XMM will make possible a far more detailed analysis of the data. It should be possible to derive better abundances for more elements, accurate temperature distributions, electron densities, and accurate ionization states.

Atomic physics calculations relevant to solar flare spectra

1991 ◽  
Vol 336 (1643) ◽  
pp. 471-484 ◽  
Keyword(s):  
Solar Flare ◽  
Atomic Physics ◽  
Solar Flares ◽  
Solar Maximum ◽  
Emission Lines ◽  
Atomic Data ◽  
Solar Maximum Mission ◽  
X Ray ◽  
Physical Conditions ◽  
Recombination Processes

Solar flare spectra in the ultraviolet and X-ray wavelength regions are rich in emission lines from highly ionized ions, formed at temperatures around 10 7 K. These lines can be used as valuable diagnostics for probing the physical conditions in solar flares. Such analyses require accurate atomic data for excitation, ionization and recombination processes. In this paper, we present a review of work which has already been carried out, in particular for the Solar Maximum Mission observations, and we look to future requirements for Solar-A .

scholarly journals NIFS Atomic Numerical Databases

2005 ◽  
Vol 13 ◽  
pp. 672-673
Author(s):  
Izumi Murakami ◽  
Takako Kato
Keyword(s):  
Cross Sections ◽  
Atomic Data ◽  
Astrophysical Plasmas ◽  
Excitation Cross Sections ◽  
Collisional Ionization

AbstractWe have compiled the atomic and molecular numerical databases which are available through internet. The databases provide basic atomic data, such as collisional ionization and excitation cross sections, which are important for modeling and diagnosing astrophysical plasmas.

scholarly journals Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi*

2018 ◽  
Vol 70 (2) ◽  
Author(s):  
Hitomi Collaboration, Felix Aharonian ◽  
Hiroki Akamatsu ◽  
Fumie Akimoto ◽  
Steven W Allen ◽  
Lorella Angelini ◽  
...  
Keyword(s):  
High Resolution ◽  
Atomic Data ◽  
Spectral Modeling ◽  
X Ray ◽  
Perseus Cluster

scholarly journals Non-Equilibrium Ionization X-ray Emission from Supernova Remnants

1983 ◽  
Vol 101 ◽  
pp. 99-107
Author(s):  
J. Michael Shull
Keyword(s):  
Supernova Remnants ◽  
Heavy Element ◽  
Plasma Temperature ◽  
Supernova Explosion ◽  
Theoretical Models ◽  
Astrophysical Plasmas ◽  
Ionization Equilibrium ◽  
X Ray ◽  
Elemental Abundances ◽  
Stellar Nucleosynthesis

X-ray spectra of young supernova remnants (SNR's) are perhaps the most spectacular examples of hot, line-emitting astrophysical plasmas. Heated to temperatures of 1 to 10 keV and enriched with the heavy element products of stellar nucleosynthesis, the plasma inside these SNR's emits prodigiously in lines of 0, Ne, Mg, Si, S, Ar, Ca, and Fe. Theoretical models of this emission provide measures of the plasma temperature and density, elemental abundances, and the degree of approach to ionization equilibrium. Thus, astrophysicists are offered the opportunity to test their understanding of the supernova explosion, its interaction with the interstellar medium, and the nucleo-synthetic processes which enrich our galaxy with heavy elements.

scholarly journals Probing X-ray Emitting Plasma with High Resolution Chandra and XMM-Newton Spectra

2005 ◽  
Vol 13 ◽  
pp. 618-621
Author(s):  
Julia C. Lee
Keyword(s):  
High Resolution ◽  
Atomic Physics ◽  
Theoretical Calculations ◽  
Atomic Data ◽  
Experimental Measurements ◽  
Edge Structure ◽  
X Ray

AbstractHighlights of interesting astrophysical discoveries are reviewed in the context of high resolution X-ray spectroscopy made possible with Chandra and XMM-Newton, and its relevance to atomic physics calculations and measurements is discussed. These spectra have shown that the overlap between astrophysics and atomic physics is stronger than ever, as discoveries of new X-ray lines and edge structure is matching the need for increasingly detailed theoretical calculations and experimental measurements of atomic data.

scholarly journals X-Ray Spectroscopic Measurements of Non-Equilibrium Ionization in Supernova Remnants

1984 ◽  
Vol 86 ◽  
pp. 76-79
Author(s):  
T.H. Markert ◽  
C.R. Canizares ◽  
T. Pfafman ◽  
P. Vedder ◽  
P.F. Winkler ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
X Rays ◽  
Ionization Equilibrium ◽  
X Ray ◽  
Elemental Abundances ◽  
Ion Collisions ◽  
Ionization Structure ◽  
Cool Plasma ◽  
Collisional Ionization ◽  
Time Required

When a cool plasma is shock-heated to X-ray temperatures, the ionization structure does not attain its final, equilibrium value immmediately, but proceeds toward it through electron-ion collisions with a timescale τ ≡ net of order 1012 cm−3 sec. For supernova remnants (SNRs), where 0.1 ≤ ne ≤ 10 cm−3 typically, the time required to achieve collisional ionization equilibrium (CIE) can be greater than the age of the remnant. Even if the SNR is quite old, that part of the remnant which is emitting most of the X-rays may have been shocked relatively recently, so that the assumption of CIE may be inappropriate (see below).The question of ionization equilibrium is of great astrophysical importance in the study of SNRs because it affects the deduced values of their masses and elemental abundances (e.g. Shull 1982). Mass determinations are affected because underionized plasma generally has a much higher emissivity in soft X-rays than equilibrium plasma. Unless this is accounted for, the deduced value of the density and therefore of the mass, will be considerably overestimated.

scholarly journals New Chandra/HST-STIS Results on Seyfert I AGN: Photoionized Outflows

2003 ◽  
Vol 214 ◽  
pp. 259-264
Author(s):  
Barry McKernan ◽  
Tahir Yaqoob
Keyword(s):  
High Resolution ◽  
Column Density ◽  
Emission Lines ◽  
High Resolution Spectroscopy ◽  
Type I ◽  
Ionization State ◽  
X Ray ◽  
Spectral Signatures

We present soft X-ray results from observations with Chandra (HETGS) of the Seyfert I AGN NGC 4593 and Mrk 509. We discuss the photoionized outflows associated with Seyfert I AGN in terms of their absorption spectral signatures and discuss their kinematics, column density and ionization state. We discuss the link between UV and X-ray absorbers in Mrk 509 (which was simultaneously observed with Chandra and HST-STIS). We also briefly discuss the possibility of absorption due to neutral Fe embedded in the warm absorber of NGC 4593 versus an interpretation of the data in terms of soft X-ray relativistic emission lines. We conclude with a summary of what is being learnt about warm absorbers in type I AGN from high resolution spectroscopy.

scholarly journals The Astrophysical Plasma Emission Database: Progress and Plans

2005 ◽  
Vol 13 ◽  
pp. 666-667
Author(s):  
Randall K. Smith ◽  
Nancy S. Brickhouse ◽  
Duane A. Liedahl
Keyword(s):  
High Resolution ◽  
Transition Rate ◽  
Atomic Data ◽  
Plasma Emission ◽  
Current Version ◽  
Astrophysical Plasma ◽  
Bibliographic Reference ◽  
High Resolution Data ◽  
X Ray ◽  
Resolution Data

AbstractThe Astrophysical Plasma Emission Database (APED) contains atomic data for the 14 most abundant astrophysical elements, collected from the literature. Although APED was originally designed for use in calculating a collisional-equilibrium X-ray spectrum suitable for analysis of high-resolution data, it is in a general format which can be efficiently used to calculate absorption spectra, photoionization models, and non-equilibrium collisional models. We emphasize original sources; each transition, rate, and energy level in APED contains a bibliographic reference. The APED can be downloaded from http://cxc.harvard.edu/atomdb/, or our website WebGUIDE (http://obsvis.harvard.edu/WebGUIDE/) can be used to search for individual lines or transitions. We are continually working to expand APED (current version 1.3.1) and regularly issue updated collections.

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