scholarly journals Strong lensing models of eight CLASH clusters from extensive spectroscopy: Accurate total mass reconstructions in the cores

2019 ◽  
Vol 632 ◽  
pp. A36 ◽  
Author(s):  
G. B. Caminha ◽  
P. Rosati ◽  
C. Grillo ◽  
G. Rosani ◽  
K. I. Caputi ◽  
...  
Keyword(s):  
Total Mass ◽  
High Efficiency ◽  
Mass Density ◽  
Mean Value ◽  
Parametric Models ◽  
Large Field ◽  
Redshift Range ◽  
Multiple Images ◽  
Mass Distributions ◽  
Strong Lensing

We carried out a detailed strong lensing analysis of a sub-sample of eight galaxy clusters of the Cluster Lensing And Supernova survey with Hubble (CLASH) in the redshift range of zcluster = [0.23 − 0.59] using extensive spectroscopic information, primarily from the Multi Unit Spectroscopic Explorer (MUSE) archival data and complemented with CLASH-VLT redshift measurements. The observed positions of the multiple images of strongly lensed background sources were used to constrain parametric models describing the cluster total mass distributions. Different models were tested in each cluster depending on the complexity of its mass distribution and on the number of detected multiple images. Four clusters show more than five spectroscopically confirmed multiple image families. In this sample, we did not make use of families that are only photometrically identified in order to reduce model degeneracies between the values of the total mass of a cluster source redshifts, in addition to systematics due to the potential misidentifications of multiple images. For the remaining four clusters, we used additional families without any spectroscopic confirmation to increase the number of strong lensing constraints up to the number of free parameters in our parametric models. We present spectroscopic confirmation of 27 multiply lensed sources, with no previous spectroscopic measurements, spanning over the redshift range of zsrc = [0.7 − 6.1]. Moreover, we confirm an average of 48 galaxy members in the core of each cluster thanks to the high efficiency and large field of view of MUSE. We used this information to derive precise strong lensing models, projected total mass distributions, and magnification maps. We show that, despite having different properties (i.e. number of mass components, total mass, redshift, etc.), the projected total mass and mass density profiles of all clusters have very similar shapes when rescaled by independent measurements of M200c and R200c. Specifically, we measured the mean value of the projected total mass of our cluster sample within 10 (20)% of R200c to be 0.13 (0.32) of M200c, with a remarkably small scatter of 5 (6)%. Furthermore, the large number of high-z sources and the precise magnification maps derived in this work for four clusters add up to the sample of high-quality gravitational telescopes to be used to study the faint and distant Universe.

scholarly journals Strong-lensing measurement of the total-mass-density profile out to three effective radii for z ∼ 0.5 early-type galaxies

2018 ◽  
Vol 480 (1) ◽  
pp. 431-438 ◽  
Author(s):  
Rui Li ◽  
Yiping Shu ◽  
Jiancheng Wang
Keyword(s):  
Total Mass ◽  
Mass Density ◽  
Three Dimensional ◽  
Stellar Dynamics ◽  
Average Density ◽  
Joint Analysis ◽  
Gravitational Lenses ◽  
Early Type ◽  
Three Samples ◽  
Strong Lensing

ABSTRACT We measure the total-mass-density profiles out to three effective radii for a sample of 63$z$ ∼ 0.5, massive early-type galaxies (ETGs) acting as strong gravitational lenses through a joint analysis of lensing and stellar dynamics. The compilation is selected from three galaxy-scale strong-lens samples, namely the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey (BELLS), the BELLS for GALaxy-Lyα EmitteR sYstems Survey (BELLS GALLERY), and the Strong Lensing Legacy Survey (SL2S). Utilizing the wide source-redshift coverage (0.8–3.5) provided by these three samples, we build a statistically significant ensemble of massive ETGs for which robust mass measurements can be achieved within a broad range of Einstein radii up to three effective radii. Characterizing the three-dimensional total-mass-density distribution by a power-law profile as ρ ∝ r−γ, we find that the average logarithmic density slope for the entire sample is $\langle \gamma \rangle =2.000_{-0.032}^{+0.033}$ (68 per cent CL) with an intrinsic scatter of $\delta =0.180_{-0.028}^{+0.032}$. Further parametrizing 〈γ〉 as a function of redshift $z$ and the ratio of Einstein radius to effective radius Rein/Reff, we find that the average density distributions of these massive ETGs become steeper at later cosmic times and at larger radii, with magnitudes $\mathrm{d} \langle \gamma \rangle / \mathrm{d}z=-0.309_{-0.160}^{+0.166}$ and $\mathrm{d} \langle \gamma \rangle / \mathrm{d} \log _{10} ({R_{\rm ein}}/{R_{\rm eff}})=0.194_{-0.083}^{+0.092}$.

scholarly journals An accurate strong lensing model of the Abell 2163 core

2020 ◽  
Vol 635 ◽  
pp. A98
Author(s):  
U. Rescigno ◽  
C. Grillo ◽  
M. Lombardi ◽  
P. Rosati ◽  
G. B. Caminha ◽  
...  
Keyword(s):  
Total Mass ◽  
Large Scale ◽  
Statistical Error ◽  
Small Scale ◽  
Multiple Images ◽  
A Value ◽  
Very Large Telescope ◽  
Strong Lensing ◽  
Phase Data ◽  
Mass Profile

Abell 2163 at z ≃ 0.201 is one of the most massive galaxy clusters known, very likely in a post-merging phase. Data from several observational windows suggest a complex mass structure with interacting subsystems, which makes the reconstruction of a realistic merging scenario very difficult. A missing key element in this sense is unveiling the cluster mass distribution at high resolution. We perform such a reconstruction of the cluster inner total mass through a strong lensing model based on new spectroscopic redshift measurements. We use data from the Multi Unit Spectroscopic Explorer on the Very Large Telescope to confirm 12 multiple images of four sources with redshift values from 1.16 to 2.72. We also discover four new multiple images and identify 29 cluster members and 35 foreground and background sources. The resulting galaxy member and image catalogs are used to build five cluster total mass models. The fiducial model consists of 111 small-scale subhalos, plus a diffuse component, which is centered ∼2″ away from the BCG belonging to the east Abell 2163 subcluster. We confirm that the latter is well represented by a single, large-scale mass component. Its strong elongation towards a second (west) subcluster confirms the existence of a preferential axis, corresponding to the merging direction. From the fiducial model, we extrapolate the cumulative projected total mass profile and measure a value of M(<300 kpc) = 1.43−0.06+0.07 × 1014 M⊙, which has a significantly reduced statistical error compared with previous estimates, thanks to the inclusion of the spectroscopic redshifts. Our strong lensing results are very accurate: the model-predicted positions of the multiple images are, on average, only 0″​​.15 away from the observed ones.

scholarly journals hybrid-lenstool: a self-consistent algorithm to model galaxy clusters with strong- and weak-lensing simultaneously

2020 ◽  
Vol 493 (3) ◽  
pp. 3331-3340 ◽  
Author(s):  
Anna Niemiec ◽  
Mathilde Jauzac ◽  
Eric Jullo ◽  
Marceau Limousin ◽  
Keren Sharon ◽  
...  
Keyword(s):  
Density Profile ◽  
Mass Density ◽  
Galaxy Cluster ◽  
Parametric Models ◽  
Free Form ◽  
Weak Lensing ◽  
Mass Distributions ◽  
True Value ◽  
Self Consistent ◽  
Non Parametric

ABSTRACT We present a new galaxy cluster lens modelling approach, hybrid-lenstool, that is implemented in the publicly available modelling software lenstool. hybrid-lenstool combines a parametric approach to model the core of the cluster, and a non-parametric (free-form) approach to model the outskirts. hybrid-lenstool optimizes both strong- and weak-lensing constraints simultaneously (Joint-Fit), providing a self-consistent reconstruction of the cluster mass distribution on all scales. In order to demonstrate the capabilities of the new algorithm, we tested it on a simulated cluster. hybrid-lenstool yields more accurate reconstructed mass distributions than the former Sequential-Fit approach where the parametric and the non-parametric models are optimized successively. Indeed, we show with the simulated cluster that the mass density profile reconstructed with a Sequential-Fit deviates from the input by 2–3σ at all scales while the Joint-Fit gives a profile that is within 1–1.5σ of the true value. This gain in accuracy is consequential for recovering mass distributions exploiting cluster lensing and therefore for all applications of clusters as cosmological probes. Finally we found that the Joint-Fit approach yields shallower slope of the inner density profile than the Sequential-Fit approach, thus revealing possible biases in previous lensing studies.

scholarly journals MIFAL: fully automated Multiple-Image Finder ALgorithm for strong-lens modelling – proof of concept

2019 ◽  
Vol 491 (3) ◽  
pp. 3778-3792 ◽  
Author(s):  
Mauricio Carrasco ◽  
Adi Zitrin ◽  
Gregor Seidel
Keyword(s):  
Simple Procedure ◽  
Lens Model ◽  
Proof Of Concept ◽  
Photometric Redshifts ◽  
Multiple Images ◽  
Mass Distributions ◽  
Photometric Redshift ◽  
Multiple Image ◽  
Strong Lensing ◽  
Blind Manner

ABSTRACT We outline a simple procedure designed for automatically finding sets of multiple images in strong lensing (SL) clusters. We show that by combining (a) an arc-finding (or source extracting) program, (b) photometric redshift measurements, and (c) a preliminary light-traces-mass lens model, multiple-image systems can be identified in a fully automated (‘blind’) manner. The presented procedure yields an assessment of the likelihood of each arc to belong to one of the multiple-image systems, as well as the preferred redshift for the different systems. These could be then used to automatically constrain and refine the initial lens model for an accurate mass distribution. We apply this procedure to Cluster Lensing And Supernova with Hubble observations of three galaxy clusters, MACS J0329.6-0211, MACS J1720.2 + 3536, and MACS J1931.8-2635, comparing the results to published SL analyses where multiple images were verified by eye on a particular basis. In the first cluster all originally identified systems are recovered by the automated procedure, and in the second and third clusters about half are recovered. Other known systems are not picked up, in part due to a crude choice of parameters, ambiguous photometric redshifts, or inaccuracy of the initial lens model. On top of real systems recovered, some false images are also mistakenly identified by the procedure, depending on the thresholds used. While further improvements to the procedure and a more thorough scrutinization of its performance are warranted, the work constitutes another important step toward fully automatizing SL analyses for studying mass distributions of large cluster samples.

scholarly journals Accelerated method for the determination of freeze-thaw resistance of concrete

2015 ◽  
Vol 1 ◽  
pp. 170 ◽  
Author(s):  
Sergey Nikolskiy ◽  
Olga Pertseva
Keyword(s):  
High Efficiency ◽  
Reference Method ◽  
Mean Value ◽  
Nondestructive Method ◽  
National Standard ◽  
Labor Input ◽  
Standard Specification ◽  
Freeze Thaw ◽  
Mathematical Relation

<p class="R-AbstractKeywords"><span lang="EN-US">Main purpose of this research is to create the new reference method of determining the freeze-thaw resistance of concrete that is characterized by small labor input, high efficiency and a wide application scope. The offered method is based on measurement of long strength by nondestructive method. During this research, the theoretical analysis of concrete's specimen dependence on freeze-thaw resistance and energy, which is emitted by a specimen during destruction, has been carried out.  Freeze-thaw resistance of a specimen is calculated as the mathematical relation of these energies, and the freeze-thaw resistance of concrete is calculated as an arithmetic mean value across specimens. </span></p><p class="R-AbstractKeywords"><span lang="EN-US">To prove the method correctness it was realized on 10 concrete specimens. Age of specimens cosolidation is 88 days. Speciments of concrete mortar were prepared using a mix of portland cement 400 (12,3%), sand of dimentions 0.6-5 mm (24,7%), granite macadam of dimentions 5-20 mm (55,4%) and water (7,4%). Freeze-thaw resistance such mortar was determed earlier by method, approved national standard specification, it was equal 105 cycles. According dimentions by new offered method freeze-thaw resistance such mortar is equal 107 cycles and its confidence interval is equal 5,4 (probability P = 0,95). Therefore, spread of results could be casual and the offered method is correct.</span></p>

Waste Rice Seed in Conventional and Stripper-Head Harvested Fields in California: Implications for Wintering Waterfowl

2012 ◽  
Vol 3 (2) ◽  
pp. 266-275 ◽  
Author(s):  
Joseph P. Fleskes ◽  
Brian J. Halstead ◽  
Michael L. Casazza ◽  
Peter S. Coates ◽  
Jeffrey D. Kohl ◽  
...  
Keyword(s):  
Total Mass ◽  
Mass Density ◽  
Seed Mass ◽  
Credible Interval ◽  
Rice Fields ◽  
Rice Seed ◽  
Seed Loss ◽  
Wintering Waterfowl ◽  
Rice Area ◽  
Seed Eating

Abstract Waste rice seed is an important food for wintering waterfowl and current estimates of its availability are needed to determine the carrying capacity of rice fields and guide habitat conservation. We used a line-intercept method to estimate mass-density of rice seed remaining after harvest during 2010 in the Sacramento Valley (SACV) of California and compared results with estimates from previous studies in the SACV and Mississippi Alluvial Valley (MAV). Posterior mean (95% credible interval) estimates of total waste rice seed mass-density for the SACV in 2010 were 388 (336–449) kg/ha in conventionally harvested fields and 245 (198–307) kg/ha in stripper-head harvested fields; the 2010 mass-density is nearly identical to the mid-1980s estimate for conventionally harvested fields but 36% lower than the mid-1990s estimate for stripped fields. About 18% of SACV fields were stripper-head harvested in 2010 vs. 9–15% in the mid-1990s and 0% in the mid-1980s; but due to a 50% increase in planted rice area, total mass of waste rice seed in SACV remaining after harvest in 2010 was 43% greater than in the mid-1980s. However, total mass of seed-eating waterfowl also increased 82%, and the ratio of waste rice seed to seed-eating waterfowl mass was 21% smaller in 2010 than in the mid-1980s. Mass-densities of waste rice remaining after harvest in SACV fields are within the range reported for MAV fields. However, because there is a lag between harvest and waterfowl use in the MAV but not in the SACV, seed loss is greater in the MAV and estimated waste seed mass-density available to wintering waterfowl in SACV fields is about 5–30 times recent MAV estimates. Waste rice seed remains an abundant food source for waterfowl wintering in the SACV, but increased use of stripper-head harvesters would reduce this food. To provide accurate data on carrying capacities of rice fields necessary for conservation planning, trends in planted rice area, harvest method, and postharvest field treatment should be tracked and impacts of postharvest field treatment and other farming practices on waste rice seed availability should be investigated.

scholarly journals Strong Lensing Mass Reconstruction: from Frontier Fields to the Typical Lensing Clusters of Future Surveys

2015 ◽  
Vol 11 (A29B) ◽  
pp. 793-794
Author(s):  
Keren Sharon ◽  
Michael D. Gladders ◽  
Jane R. Rigby ◽  
Matthew B. Bayliss ◽  
Eva Wuyts ◽  
...  
Keyword(s):  
Mass Density ◽  
High Redshift ◽  
High Mass ◽  
Quality Data ◽  
High Quality Data ◽  
Strong Lensing ◽  
Modeling Techniques ◽  
Lens Modeling ◽  
High Redshift Universe ◽  
Mass Reconstruction

AbstractDriven by the unprecedented wealth of high quality data that is accumulating for the Frontier Fields, they are becoming some of the best-studied strong lensing clusters to date, and probably the next few years. As will be discussed intensively in this focus meeting, the FF prove transformative for many fields: from studies of the high redshift Universe, to the assembly and structure of the clusters themselves. The FF data and the extensive collaborative effort around this program will also allow us to examine and improve upon current lens modeling techniques. Strong lensing is a powerful tool for mass reconstruction of the cores of galaxy clusters of all scales, providing an estimate of the total (dark and seen) projected mass density distribution out to 0.5 Mpc. Though SL mass may be biased by contribution from structures along the line of sight, its strength is that it is relatively insensitive to assumptions on cluster baryon astrophysics and dynamical state. Like the Frontier Fields clusters, the most “famous” strong lensing clusters are at the high mass end; they lens dozens of background sources into multiple images, providing ample lensing constraints. In this talk, I will focus on how we can leverage what we learn from modeling the FF clusters in strong lensing studies of the hundreds of clusters that will be discovered in upcoming surveys. In typical clusters, unlike the Frontier Fields, the Bullet Cluster and A1689, we observe only one to a handful of background sources, and have limited lensing constraints. I will describe the limitations that such a configuration imposes on strong lens modeling, highlight measurements that are robust to the richness of lensing evidence, and address the sources of uncertainty and what sort of information can help reduce those uncertainties. This category of lensing clusters is most relevant to the wide cluster surveys of the future.

scholarly journals The rotation curve, mass, light, and velocity distribution of M31

1970 ◽  
Vol 38 ◽  
pp. 51-60
Author(s):  
J. Einasto ◽  
U. Rümmel
Keyword(s):  
Spectroscopic Data ◽  
Total Mass ◽  
Rotation Curve ◽  
Mass Density ◽  
Major Axis ◽  
Deviation Angle ◽  
Andromeda Galaxy ◽  
The Galaxy ◽  
M 31 ◽  
Central Concentration

A model for the Andromeda galaxy, M 31, has been derived from the available radio, photometric, and spectroscopic data. The model consists of four components – the nucleus, the bulge, the disc, and the flat component.For all components the following functions have been found: the mass density; the mass-to-light ratio; the velocity dispersions in three perpendicular directions (for the plane of symmetry and the axis of the galaxy); the deviation angle of the major axis of the velocity ellipsoid from the plane of symmetry; the centroid velocity (for the plane of symmetry).Our model differs in two points from the models obtained by other authors: the central concentration of mass is higher (in the nucleus the mass-to-light ratio is about 170), and the total mass of the galaxy (200 × 109 solar masses) is smaller. The differences can be explained by different rotation curves adopted, and by attributing more weight to photometric and spectroscopic data in the case of our model.

scholarly journals Investigating the Influence of Shaft Balance Point on Clubhead Speed: A Simulation Study

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 156
Author(s):  
William McNally ◽  
John McPhee
Keyword(s):  
Total Mass ◽  
Center Of Mass ◽  
Golf Club ◽  
Physical Interaction ◽  
Balance Point ◽  
Mass Distributions ◽  
Biomechanical Models ◽  
Significant Difference ◽  
The Mean ◽  
Simulation Results

In this study, a dynamic golfer model was used to investigate the influence of the golf shaft’s balance point (i.e., center of mass) on the generation of clubhead speed. Three hypothetical shaft designs having different mass distributions, but the same total mass and stiffness, were proposed. The golfer model was then stochastically optimized 100 times using each shaft. A statistically significant difference was found between the mean clubhead speeds at impact (p < 0.001), where the clubhead speed increased as the balance point moved closer to the grip. When comparing the two shafts with the largest difference in balance point, a 1.6% increase in mean clubhead speed was observed for a change in balance point of 18.8 cm. The simulation results have implications for shaft design and demonstrate the usefulness of biomechanical models for capturing the complex physical interaction between the golfer and golf club.

scholarly journals The dust mass function from z ∼0 to z ∼2.5

2019 ◽  
Vol 491 (4) ◽  
pp. 5073-5082 ◽  
Author(s):  
F Pozzi ◽  
F Calura ◽  
G Zamorani ◽  
I Delvecchio ◽  
C Gruppioni ◽  
...  
Keyword(s):  
Mass Density ◽  
Dust Emission ◽  
Black Body ◽  
Mass Function ◽  
Steep Slope ◽  
Number Density ◽  
Local Universe ◽  
Redshift Range ◽  
Dust Mass ◽  
First Time

ABSTRACT We derive for the first time the dust mass function (DMF) in a wide redshift range, from z ∼ 0.2 up to z ∼ 2.5. In order to trace the dust emission, we start from a far-IR (160-μm) Herschel selected catalogue in the COSMOS field. We estimate the dust masses by fitting the far-IR data (λrest$\,\, \buildrel\gt \over \sim \,\,$50 μm) with a modified black body function and we present a detailed analysis to take into account the incompleteness in dust masses from a far-IR perspective. By parametrizing the observed DMF with a Schechter function in the redshift range 0.1 &lt; z ≤ 0.25, where we are able to sample faint dust masses, we measure a steep slope (α ∼1.48), as found by the majority of works in the Local Universe. We detect a strong dust mass evolution, with $M_{\rm d}^{\star }$ at z ∼ 2.5 almost 1 dex larger than in the local Universe, combined with a decrease in their number density. Integrating our DMFs, we estimate the dust mass density (DMD), finding a broad peak at z ∼ 1, with a decrease by a factor of ∼ 3 towards z ∼ 0 and z ∼ 2.5. In general, the trend found for the DMD mostly agrees with the derivation of Driver et al., another DMD determination based also on far-IR detections, and with other measures based on indirect tracers.

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