scholarly journals A first determination of the surface density of galaxy clusters at very low x-ray fluxes

1995 ◽  
Vol 445 ◽  
pp. L11 ◽  
Author(s):  
Piero Rosati ◽  
Roberta della Ceca ◽  
Richard Burg ◽  
Colin Norman ◽  
Riccardo Giacconi
Keyword(s):  
Galaxy Clusters ◽  
Surface Density ◽  
X Ray ◽  
Low X

X-Ray Absorption-Edge Determination of Cobalt in Complex Mixtures*

1961 ◽  
Vol 5 ◽  
pp. 379-388
Author(s):  
E.A. Hakkila ◽  
G.R. Waterbury
Keyword(s):  
Nitric Acid ◽  
Absorption Edge ◽  
Path Length ◽  
Construction Materials ◽  
X Ray ◽  
Relative Standard ◽  
Standard Deviations ◽  
Low X ◽  
X Ray Absorption

AbstractThe application of the X-ray absorption-edge technique was extended to the determination of cobalt in aqueous and alcoholic solutions containing a wide variety of impurity elements. In the procedure developed, secondary radiation from a 50% copper-nickel alloy is passed through an absorption cell filled alternately with the solvent and the sample solution. The transmitted Intensities of the Kα lines for copper and nickel are measured, and the concentration of cobalt is determined using accepted absorption principles. The K absorption edge for cobalt occurs at 1.604 A, restricting cell construction materials and solvents to those containing light elements with low X-ray absorption characteristics and also limiting the path length of the cell.Cells of 0.16- and 0.34-cm path length were used in the analysis of aqueous and alcoholic solutions, respectively. With the 0.16-cm path-length cell, relative standard deviations of 4.6 to 0.5% were obtained for cobalt concentrations ranging from 1.00 to 10.00 mg/ml for known aqueous solutions that contain various known concentrations of nitric acid. With the longer path-length cell, relative standard deviations from 1.8 to 0.46% were obtained for cobalt concentrations in the same range in known alcoholic solutions containing various known concentrations of nitric acid. The standard deviation of determining the blank is 0.043 mg of cobalt per milliliter for the 0.16-cm cell and 0.016 mg of cobalt per milliliter for the longer cell.A Norelco X-ray spectrograph with a three-position head was used in these analyses. Less than 5 min is required to convert this instrument from normal fluorescence operation to absorption-edge analysis. Approximately 15 to 20 analyses can be performed daily.

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

XMM-NEWTONOBSERVATIONS OF THREE LOW X-RAY LUMINOSITY GALAXY CLUSTERS

2010 ◽  
Vol 724 (1) ◽  
pp. 608-617 ◽  
Author(s):  
Seth Bruch ◽  
Megan Donahue ◽  
G. Mark Voit ◽  
Ming Sun ◽  
Christopher J. Conselice
Keyword(s):  
Galaxy Clusters ◽  
X Ray ◽  
Low X

scholarly journals Mass determination of 5 relaxed galaxy clusters with Chandra X-ray data

2019 ◽  
Vol 1354 ◽  
pp. 012014
Author(s):  
H Wulandari ◽  
A H Fikri ◽  
K Vierdayanti ◽  
A N I Putri ◽  
D G Ramadhan
Keyword(s):  
Galaxy Clusters ◽  
Mass Determination ◽  
X Ray

scholarly journals Why are some galaxy clusters underluminous?

2019 ◽  
Vol 630 ◽  
pp. A78 ◽  
Author(s):  
S. Andreon ◽  
A. Moretti ◽  
G. Trinchieri ◽  
C. H. Ishwara-Chandra
Keyword(s):  
Electron Density ◽  
Galaxy Clusters ◽  
Stellar Mass ◽  
Electron Density Profile ◽  
Sloan Digital Sky Survey ◽  
Radial Dependence ◽  
X Ray ◽  
Low Concentration ◽  
Electron Density Profiles ◽  
Low X

Our knowledge of the variety of galaxy clusters has been increasing in the last few years thanks to our progress in understanding the severity of selection effects on samples. To understand the reason for the observed variety, we study CL2015, a cluster (log M500/M⊙ = 14.39) easily missed in X-ray selected observational samples. Its core-excised X-ray luminosity is low for its mass M500, well below the mean relation for an X-ray selected sample, but only ∼1.5σ below that derived for an X-ray unbiased sample. We derived thermodynamic profiles and hydrostatic masses with the acquired deep Swift X-ray data, and we used archival Einstein, Planck, and Sloan Digital Sky Survey data to derive additional measurements, such as integrated Compton parameter, total mass, and stellar mass. The pressure and the electron density profiles of CL2015 are systematically outside the ±2σ range of the universal profiles; in particular the electron density profile is even lower than the one derived from Planck-selected clusters. CL2015 also turns out to be fairly different in the X-ray luminosity vs. integrated pressure scaling compared to an X-ray selected sample, but it is a normal object in terms of stellar mass fraction. CL2015’s hydrostatic mass profile, by itself or when is considered together with dynamical masses, shows that the cluster has an unusual low concentration and an unusual sparsity compared to clusters in X-ray selected samples. The different behavior of CL2015 is caused by its low concentration. When concentration differences are accounted for, the properties of CL2015 become consistent with comparison samples. CL2015 is perhaps the first known cluster with a remarkably low mass concentration for which high quality X-ray data exist. Objects similar to CL2015 fail to enter observational X-ray selected samples because of their low X-ray luminosity relative to their mass. The different radial dependence of various observables is a promising way to collect other examples of low concentration clusters.

CHARACTERISATION OF TLDS-200 AND OSLDS AT LOW X-RAY ENERGIES AND DETERMINATION OF EYE LENS DOSE, THYROID DOSE AND MEAN GLANDULAR DOSE DURING STANDARD MAMMOGRAPHY AND TOMOSYNTHESIS

2019 ◽  
Vol 186 (4) ◽  
pp. 469-478
Author(s):  
R Pirchio ◽  
A Stefanic ◽  
R R Rojas
Keyword(s):  
Limit Of Detection ◽  
Digital Breast Tomosynthesis ◽  
Eye Lens ◽  
Breast Tomosynthesis ◽  
Full Field ◽  
X Ray ◽  
Full Field Digital Mammography ◽  
Low X ◽  
Optically Stimulated Luminescent Dosimeters

Abstract The objective of this study was to characterise thermoluminescent (TLDs) and optically stimulated luminescent dosimeters (OSLDs) at low X-ray energies and estimate the eye lens (DL), thyroid (DT) and mean glandular (DG) doses received during Full-Field Digital Mammography (FFDM) and Digital Breast Tomosynthesis (DBT). The dosimeters were characterised in mammography energies. DL, DT and DG were estimated in FFDM and DBT mode taping dosimeters on the skin of the thyroid gland and on the left eye lens of an Alderson phantom. Dosimeters were also placed on the top of a NORMI PAS phantom simulating a compressed breast. The accuracy, precision and lower limit of detection (LLD) for TLDs and OSLDs were 5 and 8%, 6 and 3%, and 38 and 11 μSv, respectively. The linearity of the kerma response had an R2 > 0.99 and energy dependence was lower than 40%. DT ranged from 0.40 to 2.87 μGy for FFDM and 1.27 to 5.99 μGy for DBT. DG was between 0.50 and 1.27 mGy for FFDM and 1.07 and 1.60 mGy for DBT. DL was below the LLD. Dosimeters showed good performance. DG values were lower than those found in the literature, whereas DT value agreed with references. Differences between DG and DT determined with OSLDs and TLDs were lower than 10% and 200%.

Interelement effects in X-ray fluorescence determination of the surface density of vanadium nanofilms on various substrates

2013 ◽  
Vol 49 (12) ◽  
pp. 1194-1198 ◽  
Author(s):  
N. I. Mashin ◽  
E. A. Chernyaeva ◽  
A. N. Tumanova ◽  
A. A. Ershov
Keyword(s):  
Surface Density ◽  
X Ray ◽  
Fluorescence Determination

scholarly journals 3D-MiXD: 3D-printed X-ray-compatible microfluidic devices for rapid, low-consumption serial synchrotron crystallography data collection in flow

IUCrJ ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 207-219 ◽  
Author(s):  
Diana C. F. Monteiro ◽  
David von Stetten ◽  
Claudia Stohrer ◽  
Marta Sans ◽  
Arwen R. Pearson ◽  
...  
Keyword(s):  
Data Collection ◽  
Room Temperature ◽  
Time Resolved ◽  
X Ray ◽  
Biologically Relevant ◽  
3D Printed ◽  
Serial Crystallography ◽  
Low X ◽  
Very High

Serial crystallography has enabled the study of complex biological questions through the determination of biomolecular structures at room temperature using low X-ray doses. Furthermore, it has enabled the study of protein dynamics by the capture of atomically resolved and time-resolved molecular movies. However, the study of many biologically relevant targets is still severely hindered by high sample consumption and lengthy data-collection times. By combining serial synchrotron crystallography (SSX) with 3D printing, a new experimental platform has been created that tackles these challenges. An affordable 3D-printed, X-ray-compatible microfluidic device (3D-MiXD) is reported that allows data to be collected from protein microcrystals in a 3D flow with very high hit and indexing rates, while keeping the sample consumption low. The miniaturized 3D-MiXD can be rapidly installed into virtually any synchrotron beamline with only minimal adjustments. This efficient collection scheme in combination with its mixing geometry paves the way for recording molecular movies at synchrotrons by mixing-triggered millisecond time-resolved SSX.

scholarly journals Diffuse galaxy cluster emission at 168 MHz within the Murchison Widefield Array Epoch of Reionization 0-h field

2021 ◽  
Vol 38 ◽  
Author(s):  
S. W. Duchesne ◽  
M. Johnston-Hollitt ◽  
A. R. Offringa ◽  
G. W. Pratt ◽  
Q. Zheng ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Galaxy Cluster ◽  
Scaling Relations ◽  
Cluster Emission ◽  
X Ray ◽  
Diffuse Sources ◽  
Radio Halo ◽  
The Galaxy ◽  
Murchison Widefield Array

Abstract We detect and characterise extended, diffuse radio emission from galaxy clusters at 168 MHz within the Epoch of Reionization 0-h field: a $45^{\circ} \times 45^{\circ}$ region of the southern sky centred on R. A. ${}= 0^{\circ}$ , decl. ${}=-27^{\circ}$ . We detect 29 sources of interest; a newly detected halo in Abell 0141; a newly detected relic in Abell 2751; 4 new halo candidates and a further 4 new relic candidates; and a new phoenix candidate in Abell 2556. Additionally, we find nine clusters with unclassifiable, diffuse steep-spectrum emission as well as a candidate double relic system associated with RXC J2351.0-1934. We present measured source properties such as their integrated flux densities, spectral indices ( $\alpha$ , where $S_\nu \propto \nu^\alpha$ ), and sizes where possible. We find several of the diffuse sources to have ultra-steep spectra including the halo in Abell 0141, if confirmed, showing $\alpha \leq -2.1 \pm 0.1$ with the present data making it one of the steepest-spectrum haloes known. Finally, we compare our sample of haloes with previously detected haloes and revisit established scaling relations of the radio halo power ( $P_{1.4}$ ) with the cluster X-ray luminosity ( $L_{\textrm{X}}$ ) and mass ( $M_{500}$ ). We find that the newly detected haloes and candidate haloes are consistent with the $P_{1.4}$ – $L_{\textrm{X}}$ and $P_{1.4}$ – $M_{500}$ relations and see an increase in scatter in the previously found relations with increasing sample size likely caused by inhomogeneous determination of $P_{1.4}$ across the full halo sample. We show that the MWA is capable of detecting haloes and relics within most of the galaxy clusters within the Planck catalogue of Sunyaev–Zel’dovich sources depending on exact halo or relic properties.

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