scholarly journals LESSER: a catalogue of spectroscopically selected sample of Lyman-α emitters lensed by galaxies

2020 ◽  
Vol 499 (3) ◽  
pp. 3610-3619
Author(s):  
Xiaoyue Cao ◽  
Ran Li ◽  
Yiping Shu ◽  
Shude Mao ◽  
Jean-Paul Kneib ◽  
...  
Keyword(s):  
Dark Matter ◽  
Spectral Resolution ◽  
Spectroscopic Imaging ◽  
Line Profiles ◽  
Luminous Red Galaxies ◽  
Low Mass ◽  
Fine Structures ◽  
Red Galaxies ◽  
Shed Light

ABSTRACT We introduce the LEnSed laeS in the Eboss suRvey (LESSER) project, which aims to search for lensed Lyman-α emitters (LAEs) in the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). The final catalogue contains 361 candidate lensing systems. The lens galaxies are luminous red galaxies (LRGs) at redshift 0.4 < z < 0.8, and the source galaxies are LAEs at redshift 2 < z < 3. The spectral resolution of eBOSS (∼2000) allows us to further identify the fine structures of Lyman-α ($\rm Ly\alpha$) emissions. Among our lensed LAE candidates, 281 systems present single-peaked line profiles while 80 systems show double-peaked features. Future spectroscopic/imaging follow-up observations of the catalogue may shed light on the origin of diverse $\rm Ly\alpha$ line morphology, and provide promising labs for studying low-mass dark matter haloes/subhaloes.

scholarly journals Where are the Luminous Red Galaxies (LRGs)? Using correlation measurements and lensing to relate LRGs to dark matter haloes

2013 ◽  
Vol 435 (3) ◽  
pp. 2345-2370 ◽  
Author(s):  
Chiaki Hikage ◽  
Rachel Mandelbaum ◽  
Masahiro Takada ◽  
David N. Spergel
Keyword(s):  
Dark Matter ◽  
Luminous Red Galaxies ◽  
Red Galaxies

Tax evasion in the medical profession An Empirical Study in the General Tax Authority in Iraq

2019 ◽  
Vol 118 (11) ◽  
pp. 80-88
Author(s):  
Ramyar Rzgar Ahmed ◽  
Hawkar Qasim Birdawod ◽  
S. Rabiyathul Basariya
Keyword(s):  
Tax Evasion ◽  
Income Tax ◽  
Medical Profession ◽  
Great Influence ◽  
Tax Law ◽  
Degree Of Confidence ◽  
Medical Professions ◽  
Shed Light

The study dealt with tax evasion in the medical profession, where the problem was the existence of many cases of tax evasion, especially tax evasion in the income tax of medical professions. The aim of the study is to try to shed light on the phenomenon of tax evasion and the role of the tax authority in the development of controls and means that reduce the phenomenon of tax evasion. The most important results of the low level of tax awareness and lack of knowledge of the tax law and the unwillingness to read it and the sense of taxpayers unfairness of the tax all lead to an increase in cases of tax evasion and in suggested tightening control and follow-up on the offices of auditors, through the investigation and auditing The reports of certified accountants and the use of computers for this purpose in order to raise the degree of confidence in these reports and bring them closer to the required truth and coordination and cooperation with the Union of Accountants and Auditors and inform them about each case of violations of the auditors and accountants N because of its great influence in the rejection of the organization of the accounts and not to ratify fake accounts lead to show taxpayers accounts on a non-truth in order to tax evasion.

scholarly journals Exoplanet mass estimation for a sample of targets for the Ariel mission

2021 ◽  
Author(s):  
J. R. Barnes ◽  
C. A. Haswell
Keyword(s):  
Radial Velocity ◽  
Input Parameter ◽  
Noise Sources ◽  
Time Commitment ◽  
Low Mass ◽  
Time Required ◽  
Fixed Input ◽  
The Impact ◽  
Quadrature Sampling

AbstractAriel’s ambitious goal to survey a quarter of known exoplanets will transform our knowledge of planetary atmospheres. Masses measured directly with the radial velocity technique are essential for well determined planetary bulk properties. Radial velocity masses will provide important checks of masses derived from atmospheric fits or alternatively can be treated as a fixed input parameter to reduce possible degeneracies in atmospheric retrievals. We quantify the impact of stellar activity on planet mass recovery for the Ariel mission sample using Sun-like spot models scaled for active stars combined with other noise sources. Planets with necessarily well-determined ephemerides will be selected for characterisation with Ariel. With this prior requirement, we simulate the derived planet mass precision as a function of the number of observations for a prospective sample of Ariel targets. We find that quadrature sampling can significantly reduce the time commitment required for follow-up RVs, and is most effective when the planetary RV signature is larger than the RV noise. For a typical radial velocity instrument operating on a 4 m class telescope and achieving 1 m s−1 precision, between ~17% and ~ 37% of the time commitment is spent on the 7% of planets with mass Mp < 10 M⊕. In many low activity cases, the time required is limited by asteroseismic and photon noise. For low mass or faint systems, we can recover masses with the same precision up to ~3 times more quickly with an instrumental precision of ~10 cm s−1.

scholarly journals On N-body simulations of globular cluster streams

2021 ◽  
Vol 504 (1) ◽  
pp. 648-653
Author(s):  
Nilanjan Banik ◽  
Jo Bovy
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Analytical Models ◽  
Numerical Density ◽  
Stellar Streams ◽  
Small Scales ◽  
Order Of Magnitude ◽  
Low Mass ◽  
Stream Density ◽  
Tidal Streams

ABSTRACT Stellar tidal streams are sensitive tracers of the properties of the gravitational potential in which they orbit and detailed observations of their density structure can be used to place stringent constraints on fluctuations in the potential caused by, e.g. the expected populations of dark matter subhaloes in the standard cold dark matter (CDM) paradigm. Simulations of the evolution of stellar streams in live N-body haloes without low-mass dark matter subhaloes, however, indicate that streams exhibit significant perturbations on small scales even in the absence of substructure. Here, we demonstrate, using high-resolution N-body simulations combined with sophisticated semi-analytical and simple analytical models, that the mass resolutions of 104–$10^5\, \rm {M}_{\odot }$ commonly used to perform such simulations cause spurious stream density variations with a similar magnitude on large scales as those expected from a CDM-like subhalo population and an order of magnitude larger on small, yet observable, scales. We estimate that mass resolutions of ${\approx}100\, \rm {M}_{\odot }$ (${\approx}1\, \rm {M}_{\odot }$) are necessary for spurious, numerical density variations to be well below the CDM subhalo expectation on large (small) scales. That streams are sensitive to a simulation’s particle mass down to such small masses indicates that streams are sensitive to dark matter clustering down to these low masses if a significant fraction of the dark matter is clustered or concentrated in this way, for example, in MACHO models with masses of 10–$100\, \rm {M}_{\odot }$.

scholarly journals Improving sensitivity to low-mass dark matter in LUX using a novel electrode background mitigation technique

2021 ◽  
Vol 104 (1) ◽  
Author(s):  
D. S. Akerib ◽  
S. Alsum ◽  
H. M. Araújo ◽  
X. Bai ◽  
J. Balajthy ◽  
...  
Keyword(s):  
Dark Matter ◽  
Low Mass ◽  
Mitigation Technique

scholarly journals Understanding the large inferred Einstein radii of observed low-mass galaxy clusters

2020 ◽  
Vol 494 (4) ◽  
pp. 4706-4712 ◽  
Author(s):  
Andrew Robertson ◽  
Richard Massey ◽  
Vincent Eke
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
Baryonic Matter ◽  
Analysis Method ◽  
Critical Curves ◽  
Hydrodynamical Simulation ◽  
Low Mass ◽  
Main Effects

ABSTRACT We assess a claim that observed galaxy clusters with mass ${\sim}10^{14} \mathrm{\, M_\odot }$ are more centrally concentrated than predicted in lambda cold dark matter (ΛCDM). We generate mock strong gravitational lensing observations, taking the lenses from a cosmological hydrodynamical simulation, and analyse them in the same way as the real Universe. The observed and simulated lensing arcs are consistent with one another, with three main effects responsible for the previously claimed inconsistency. First, galaxy clusters containing baryonic matter have higher central densities than their counterparts simulated with only dark matter. Secondly, a sample of clusters selected because of the presence of pronounced gravitational lensing arcs preferentially finds centrally concentrated clusters with large Einstein radii. Thirdly, lensed arcs are usually straighter than critical curves, and the chosen image analysis method (fitting circles through the arcs) overestimates the Einstein radii. After accounting for these three effects, ΛCDM predicts that galaxy clusters should produce giant lensing arcs that match those in the observed Universe.

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