scholarly journals Charge exchange in galaxy clusters

2018 ◽  
Vol 611 ◽  
pp. A26 ◽  
Author(s):  
Liyi Gu ◽  
Junjie Mao ◽  
Jelle de Plaa ◽  
A. J. J. Raassen ◽  
Chintan Shah ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Charge Exchange ◽  
Sample Selection ◽  
Selection Criterion ◽  
Line Emission ◽  
Abundance Pattern ◽  
Systematic Uncertainties ◽  
Characteristic Wavelength ◽  
New Research ◽  
Marginal Detection

Context. Though theoretically expected, the charge exchange emission from galaxy clusters has never been confidently detected. Accumulating hints were reported recently, including a rather marginal detection with the Hitomi data of the Perseus cluster. As previously suggested, a detection of charge exchange line emission from galaxy clusters would not only impact the interpretation of the newly discovered 3.5 keV line, but also open up a new research topic on the interaction between hot and cold matter in clusters.Aim. We aim to perform the most systematic search for the O VIII charge exchange line in cluster spectra using the RGS on board XMM-Newton.Methods. We introduce a sample of 21 clusters observed with the RGS. In order to search for O VIII charge exchange, the sample selection criterion is a >35σ detection of the O VIII Lyα line in the archival RGS spectra. The dominating thermal plasma emission is modeled and subtracted with a two-temperature thermal component, and the residuals are stacked for the line search. The systematic uncertainties in the fits are quantified by refitting the spectra with a varying continuum and line broadening.Results. By the residual stacking, we do find a hint of a line-like feature at 14.82 Å, the characteristic wavelength expected for oxygen charge exchange. This feature has a marginal significance of 2.8σ, and the average equivalent width is 2.5 × 10−4 keV. We further demonstrate that the putative feature can be barely affected by the systematic errors from continuum modeling and instrumental effects, or the atomic uncertainties of the neighboring thermal lines.Conclusions. Assuming a realistic temperature and abundance pattern, the physical model implied by the possible oxygen line agrees well with the theoretical model proposed previously to explain the reported 3.5 keV line. If the charge exchange source indeed exists, we expect that the oxygen abundance could have been overestimated by 8−22% in previous X-ray measurements that assumed pure thermal lines. These new RGS results bring us one step forward to understanding the charge exchange phenomenon in galaxy clusters.

scholarly journals Simulation of Spectra Code (SOS) for ITER Active Beam Spectroscopy

Atoms ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 30 ◽  
Author(s):  
Manfred von Hellermann ◽  
Maarten de Bock ◽  
Oleksandr Marchuk ◽  
Detlev Reiter ◽  
Stanislav Serov ◽  
...  
Keyword(s):  
Charge Exchange ◽  
Stark Effect ◽  
Fusion Reaction ◽  
Line Emission ◽  
High Energy ◽  
Fusion Reactions ◽  
General Applicability ◽  
Generic Structure ◽  
Nuclear Fusion Reactions ◽  
Simulation Of Spectra

The concept and structure of the Simulation of Spectra (SOS) code is described starting with an introduction to the physics background of the project and the development of a simulation tool enabling the modeling of charge-exchange recombination spectroscopy (CXRS) and associated passive background spectra observed in hot fusion plasmas. The generic structure of the code implies its general applicability to any fusion device, the development is indeed based on over two decades of spectroscopic observations and validation of derived plasma data. Four main types of active spectra are addressed in SOS. The first type represents thermal low-Z impurity ions and the associated spectral background. The second type of spectra represent slowing-down high energy ions created from either thermo-nuclear fusion reactions or ions from injected high energy neutral beams. Two other modules are dedicated to CXRS spectra representing bulk plasma ions (H+, D+, or T+) and beam emission spectroscopy (BES) or Motional Stark Effect (MSE) spectrum appearing in the same spectral range. The main part of the paper describes the physics background for the underlying emission processes: active and passive CXRS emission, continuum radiation, edge line emission, halo and plume effect, or finally the charge exchange (CX) cross-section effects on line shapes. The description is summarized by modeling the fast ions emissions, e.g., either of the α particles of the fusion reaction or of the beam ions itself.

scholarly journals On the impact of baryons on the halo mass function, bias, and cluster cosmology

2020 ◽  
Vol 500 (2) ◽  
pp. 2316-2335
Author(s):  
Tiago Castro ◽  
Stefano Borgani ◽  
Klaus Dolag ◽  
Valerio Marra ◽  
Miguel Quartin ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Cosmological Parameters ◽  
High Sensitivity ◽  
Mass Function ◽  
Quality Data ◽  
Systematic Uncertainties ◽  
Statistical Precision ◽  
Supernova Explosions ◽  
Hydrodynamical Simulations ◽  
The Impact

ABSTRACT Luminous matter produces very energetic events, such as active galactic nuclei and supernova explosions, that significantly affect the internal regions of galaxy clusters. Although the current uncertainty in the effect of baryonic physics on cluster statistics is subdominant as compared to other systematics, the picture is likely to change soon as the amount of high-quality data is growing fast, urging the community to keep theoretical systematic uncertainties below the ever-growing statistical precision. In this paper, we study the effect of baryons on galaxy clusters, and their impact on the cosmological applications of clusters, using the magneticum suite of cosmological hydrodynamical simulations. We show that the impact of baryons on the halo mass function can be recast in terms on a variation of the mass of the haloes simulated with pure N-body, when baryonic effects are included. The halo mass function and halo bias are only indirectly affected. Finally, we demonstrate that neglecting baryonic effects on haloes mass function and bias would significantly alter the inference of cosmological parameters from high-sensitivity next-generations surveys of galaxy clusters.

scholarly journals LOW X-RAY LUMINOSITY GALAXY CLUSTERS: MAIN GOALS, SAMPLE SELECTION, PHOTOMETRIC AND SPECTROSCOPIC OBSERVATIONS

2016 ◽  
Vol 151 (6) ◽  
pp. 151
Author(s):  
José Luis Nilo Castellón ◽  
M. Victoria Alonso ◽  
Diego García Lambas ◽  
Carlos Valotto ◽  
Ana Laura O’ Mill ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Sample Selection ◽  
X Ray ◽  
Spectroscopic Observations ◽  
Photometric And Spectroscopic Observations ◽  
Low X

scholarly journals NIR Line Observations of Starburst Galaxies

1999 ◽  
Vol 186 ◽  
pp. 286-286
Author(s):  
H. Sugai ◽  
M.A. Malkan ◽  
M.J. Ward ◽  
R.I. Davies ◽  
I.S. McLean
Keyword(s):  
Line Emission ◽  
Starburst Galaxies ◽  
Emission Lines ◽  
Ionized Gas ◽  
The Galaxy ◽  
Component C ◽  
Band Spectra ◽  
Marginal Detection ◽  
The Continuum ◽  
K Band

We have obtained images of the H2and Brγ emission lines in the galaxy interacting system NGC 3690 + IC 694. We have also obtained simultaneous H- and K-band spectra for three of its 2μm continuum peaks. The most detectable line emission is concentrated at the continuum peaks. Therefore, the emission lines as well as stellar absorption lines can be used as tracers of the activity in the nuclei themselves. From the strong Brγ and marginal detection of Br10 at the nucleus of IC 694, we derive a large extinction for the fully ionized gas in this nucleus. If we adopt this extinction also for the [Fe II]1.64μm emission, the extinction-corrected [Fe II]1.64μm/Brγ ratio will lie at the higher end of starburst galaxies, and is typical for AGNs or AGN/starburst composites. This might imply that many SNRs are involved in the starburst at this nucleus, unless it includes an AGN. All of our results for Component C, including very little CO absorption in the K band, a largeEW(Brγ), a small H2/Brγ ratio, the effective temperature (Teff≃ 40,000K) derived from HeI 1.70μm/Br10 and HeI 2.06μm/Brγ, are consistent with a very young starburst.

scholarly journals Cool gas in brightest cluster galaxies

2009 ◽  
Vol 5 (H15) ◽  
pp. 279-279
Author(s):  
J. B. R. Oonk ◽  
W. Jaffe ◽  
M. N. Bremer ◽  
N. Hatch
Keyword(s):  
Galaxy Clusters ◽  
Line Emission ◽  
Young Stars ◽  
Molecular Gas ◽  
Strongly Coupled ◽  
Cluster Galaxies ◽  
Gas Phases ◽  
Brightest Cluster Galaxies ◽  
Cool Gas

AbstractGas in galaxy clusters requires re-heating. We study the re-heating of the cool gas phases. Ionized and molecular gas is traced out to 20 kpc and found to be strongly coupled. The observed line emission may in part be explained by excitation due to hot, young stars.

scholarly journals Measuring bulk flows of the intracluster medium in the Perseus and Coma galaxy clusters using XMM-Newton

2020 ◽  
Vol 633 ◽  
pp. A42 ◽  
Author(s):  
J. S. Sanders ◽  
K. Dennerl ◽  
H. R. Russell ◽  
D. Eckert ◽  
C. Pinto ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Temporal Variations ◽  
Energy Scale ◽  
Line Of Sight ◽  
Intracluster Medium ◽  
Link Type ◽  
The North ◽  
Systematic Uncertainties ◽  
The Difference ◽  
Width Measurements

We demonstrate a novel technique for calibrating the energy scale of the EPIC-pn detector on XMM-Newton, which allows us to measure bulk flows in the intracluster medium (ICM) of the Perseus and Coma galaxy clusters. The procedure uses the fluorescent instrumental background lines present in all observations, in particular, Cu-Kα. By studying their spatial and temporal variations, in addition to incorporating calibration observations, we refined the absolute energy scale of the detector to better than 150 km s−1 at the Fe-K line, a large improvement over the nominal calibration accuracy of 550 km s−1. With our calibration, we mapped the bulk motions over much of the central 1200 and 800 kpc of Perseus and Coma, respectively, in spatial regions down to 65 and 140 kpc size. We cross-checked our procedure by comparing our measurements with those found in Perseus by Hitomi for an overlapping 65 kpc square region, finding consistent results. For Perseus, there is a relative line-of-sight velocity increase of 480 ± 210 km s−1 (1σ) at a radius of 250 kpc east of the nucleus. This region is associated with a cold front, providing direct evidence of the ICM sloshing in the cluster potential well. Assuming the intrinsic distribution of bulk motions is Gaussian, its width is 214 ± 85 km s−1, excluding systematic uncertainties. Removing the sloshing region, this is reduced to 20–150 km s−1, which is similar in magnitude to the Hitomi line width measurements in undisturbed regions. In Coma, the line-of-sight velocity of the ICM varies between the velocities of the two central galaxies. Maps of the gas velocity and metallicity provide clues about the merger history of the Coma, with material to the north and east of the cluster core having a velocity similar to NGC 4874, while that to the south and west has velocities close to NGC 4889. Our results highlight the difference between a merging system, such as Coma, where we observe a ∼1000 km s−1 range in velocity, and a relatively relaxed system, such as Perseus, with much weaker bulk motions.

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