helium sedimentation effect

[1102.5363v2] The Effect of Helium Sedimentation on …

Recent theoretical studies predict that the inner regions of galaxy clusters may have an enhanced helium abundance due to sedimentation over the cluster lifetime. If sedimentation is not suppressed (e.g., by tangled magnetic fields), this may significantly affect the cluster mass estimates. We use Chandra X-ray observations of eight relaxed …

Astronomy c ESO 2011 Astrophysics

distribution from numerical simulations of helium sedimentation on a timescale of 11 Gyr. Results.The assumed helium sedimentation model, on average, produces a negligible increase in the gas mass inferred within large radii (r

Table 7 from The effect of helium sedimentation on galaxy …

Measured Average Temperature (TX) and the Mass Proxy (YX) - "The effect of helium sedimentation on galaxy cluster masses and scaling relations" Skip to search form Skip to main content Skip to account menu. Semantic Scholar's Logo. Search 217,422,128 papers from all fields of science. Search ...

The Effect of Helium Sedimentation on Chandra X-ray …

In this talk we will present observational measurements of the effect of He sedimentation on X-ray derived galaxy cluster masses using high signal-to-noise Chandra X-ray observations of galaxy ...

Figure 1 from The effect of helium sedimentation on galaxy …

Fig. 1. The band-averaged X-ray cooling function, Λee(r), for two different helium distributions in the ICM: a uniform helium abundance (blue dashed line) and a helium sedimentation distribution provided by Peng & Nagai (2009) (red line). The overdensity radius r500 is the radius within which the mean cluster density is a factor of 500 times …

[PDF] HELIUM SEDIMENTATION AND THE ULTRAVIOLET …

Recent observations with the Galaxy Evolution Explorer (GALEX) show strong unexpected ultraviolet (UV) excess in the spectrum of brightest cluster galaxies (BCGs). It is believed that the excess UV signal is produced by old and evolved core-He burning stars, and the UV flux strength could be greatly enhanced if the progenitor stars have a high value of …

Effect of Helium Sedimentation on X-ray Measurements of …

The uniformity of the helium-to-hydrogen abundance ratio in X-ray emitting intracluster medium is one of the commonly adopted assumptions in X-ray analyses of galaxy clusters and cosmological constraints derived from these measurements. In this work, we investigate the effect of He sedimentation on X-ray measurements of galaxy clusters in …

Effects of sedimented helium on the X–ray properties of …

helium and proton density of 0.2 cm−3 at ∼1keV. and the age of the Universe for the assumed cosmology, 1.3×1010 years. 2 SEDIMENTATION OF HELIUM Spitzer (1956) presents the physics of fully ionized gases that we adopt in the following discussion. In general, the time of equipar-tition between H and He (Fe) ions is low when it is compared

Effect of Helium Sedimentation in X-ray Clusters | Request …

Request PDF | Effect of Helium Sedimentation in X-ray Clusters | Helium nuclei in the intracluster plasma can sediment in the gravitational potential well of hot X-ray luminous, dynamically ...

Plasma Instabilities in the Context of Current Helium Sedimentation

Understanding whether Helium can sediment to the core of galaxy clusters is important for a number of problems in cosmology and astrophysics. All current models addressing this question are one-dimensional and do not account for the fact that magnetic fields can effectively channel ions and electrons, leading to anisotropic transport of momentum, …

[PDF] The effect of helium sedimentation on galaxy …

Context. Recent theoretical studies predict that the inner regions of galaxy clusters may have an enhanced helium abundance due to sedimentation over the …

HELIUM SEDIMENTATION AND THE ULTRAVIOLET …

HELIUM SEDIMENTATION AND THE ULTRAVIOLET UPTURN IN BRIGHTEST CLUSTER GALAXIES - IOPscience. The American Astronomical Society …

Evaluation of the effect of the helium-neon laser (632.8 nm) …

Microscopic examination, packed cell volume and erythrocyte sedimentation rate methods was used during the period of examination the red blood cells and exposure of them to laser radiation for two different periods of time, recording the results after all period of time and comparing them with the control group.

The effect of helium sedimentation on galaxy cluster masses …

Context. Recent theoretical studies predict that the inner regions of galaxy clusters may have an enhanced helium abundance due to sedimentation over the cluster lifetime. If …

(PDF) Effects of sedimented helium on the X-ray properties …

4 DISCUSSION AND CONCLUSIONS As expected, higher helium abundance induces larger emission and shorter cooling time of the emitting plasma, with a cooling func- We have studied the effects of the sedimentation of helium nuclei tion that raises for, e.g., a gas at 2 keV and proton density of 0.2 on the X-ray properties of galaxy clusters.

Effect of helium sedimentation on X-ray measurements of …

Effect of helium sedimentation on X-ray measurements of galaxy clusters ... ... Article

Effects of sedimented helium on the X-ray properties of

The assumed helium sedimentation model, on average, produces a negligible increase in the gas mass inferred within large radii (r < r500) (1.3 +/- 1.2 per cent) and a (10.2 +/- 5.5) per cent mean ...

helium sedimentation effect- 08083769 Effect of Helium Sedimentation …

The helium is taken as Figure 15 gives more background to the calculated condensation sedimentation effect that causes the earlier arrival of helium at the General Chemistry/Properties of Matter/Classification of Matter Centrifugation and Sedimentation Helium can be separated from a mixture with hydrogen by

EFFECT OF HELIUM SEDIMENTATION ON X-RAY …

By solving a set of flow equations for a H–He plasma, we show that the He-to-H mass ratio is significantly enhanced in the inner regions of clusters. The effect of He sedimentation, if not accounted for, introduces systematic biases in observable …

(PDF) Helium Sedimentation and the Ultraviolet Upturn in …

In this work, we propose that the sedimentation process can greatly enhance the He abundance in BCGs. Our model predicts that the UV flux strength is stronger in more massive, low-redshift, and ...

Figure 4 from The effect of helium sedimentation on galaxy …

Fig. 4. The fractional change in gas mass and total mass with radius as a result of an extreme helium sedimentation with respect to masses produced by a uniform Anders & Grevesse (1989) helium abundance for a sample of eight relaxed clusters. The black lines correspond to the mean fractional change and the shaded are indicates the standard …

[0808.3769] Effect of Helium Sedimentation on X-ray …

By solving a set of flow equations for a H-He plasma, we show that the helium-to-hydrogen mass ratio is significantly enhanced in the inner regions of …

EFFECT OF HELIUM SEDIMENTATION ON X-RAY …

The uniformity of the helium-to-hydrogen (He-to-H) abundance ratio in the X-ray emitting intracluster medium (ICM) is one of the commonly adopted assumptions in X-ray analyses of galaxy clusters and cosmological constraints derived from these measurements. In this paper, we investigate the effect of He sedimentation

The effect of helium sedimentation on galaxy cluster …

Recent theoretical studies predict that the inner regions of galaxy clusters may have an enhanced helium abundance due to sedimentation over the cluster lifetime. If …

The effect of helium sedimentation on galaxy cluster …

Significantly stronger effects in the gas mass (10.5 ± 0.8%) and total mass (25.1 ± 1.1%) are seen at small radii owing to a larger variance in helium abundance in the inner region, r ≤ 0.1 r 500. Conclusions. We find that the slope of the YX - M 500 scaling relation is not significantly affected by helium sedimentation.

The Effect of Helium Sedimentation on Chandra X-ray …

Corpus ID: 116138561; The Effect of Helium Sedimentation on Chandra X-ray Observations of Galaxy Clusters Abell 1835 and Abell 2204 @inproceedings{Bulbul2010TheEO, title={The Effect of Helium Sedimentation on Chandra X-ray Observations of Galaxy Clusters Abell 1835 and Abell 2204}, author={G. …

Helium abundance in galaxy clusters and Sunyaev-Zeldovich effect

The assumed helium sedimentation model, on average, produces a negligible increase in the gas mass inferred within large radii (r < r500) (1.3 +/- 1.2 per cent) and a (10.2 +/- 5.5) per cent mean ...

The diffusion of helium through sedimentary rocks

Helium is produced by the radioactive decay of the nuclides of certain minerals and it is commonly assumed that a portion of this helium migrates from its source through overlying rocks to the atmosphere. ... The process of sedimentation effects the diffusivity of the sediments in that at 110 The diffusion of helium through sedimentary rocks ...

(PDF) Effect of Helium Sedimentation on X-Ray …

Effect of Helium Sedimentation on X-Ray Measurements of Galaxy Clusters

The Effect of Helium Sedimentation on Chandra X-ray …

Recent theoretical studies predict that the inner regions of galaxy clusters are enriched by the sedimentation of Helium (He) ions into the cluster core. However, since He produces no lines at X-ray emitting temperatures, cluster masses are generally derived under the assumption that the He abundance is fixed at the Solar abundance value. In this talk we …