scholarly journals The first shear measurements from precision weak lensing

2020 ◽  
Vol 499 (4) ◽  
pp. 4591-4604
Author(s):  
Pol Gurri ◽  
Edward N Taylor ◽  
Christopher J Fluke
Keyword(s):  
Statistical Approach ◽  
Velocity Fields ◽  
Circular Motion ◽  
Weak Lensing ◽  
Motion Model ◽  
Average Shear ◽  
End To End ◽  
Kinematic Information ◽  
Individual Galaxy

ABSTRACT We present an end-to-end methodology to measure the effects of weak lensing on individual galaxy–galaxy systems exploiting their kinematic information. Using this methodology, we have measured a shear signal from the velocity fields of 18 weakly lensed galaxies. We selected a sample of systems based only on the properties of the sources, requiring them to be bright (apparent i-band magnitude <17.4) and in the nearby Universe ($z$ < 0.15). We have observed the velocity fields of the sources with WiFeS, an optical IFU on a 2.3 m telescope, and fitted them using a simple circular motion model with an external shear. We have measured an average shear of 〈γ〉 = 0.020 ± 0.008 compared to a predicted 〈γpred〉 = 0.005 obtained using median stellar-to-halo relationships from the literature. While still a statistical approach, our results suggest that this new weak lensing methodology can overcome some of the limitations of traditional stacking-based techniques. We describe in detail all the steps of the methodology and make publicly available all the velocity maps for the weakly lensed sources used in this study.

scholarly journals The velocity fields of elliptical galaxies: constraints on intrinsic shapes

1993 ◽  
Vol 153 ◽  
pp. 433-434
Author(s):  
T. S. Statler ◽  
A. M. Fry
Keyword(s):  
Elliptical Galaxies ◽  
Velocity Fields ◽  
Kinematic Constraint ◽  
Kinematic Information

The problem of determining the intrinsic shapes of elliptical galaxies cannot be solved using photometry alone. Measuring rotation on the apparent major and minor axes adds a kinematic constraint, but does not significantly improve the situation. We find that having two more spectra, at the ±45° position angles, gives enough kinematic information that much tighter limits can be placed on the intrinsic axis ratios than are possible otherwise.

A CAUSALIDADE DO DEUS ARISTOTÉLICO: A PROPÓSITO DA INTERPRETAÇÃO DE ENRICO BERTI A RESPEITO DO PRIMEIRO MOTOR IMÓVEL

2015 ◽  
Vol 41 (130) ◽  
pp. 173
Author(s):  
Kevin L. Flannery
Keyword(s):  
Circular Motion ◽  
Efficient Causality ◽  
Ultimate Cause ◽  
The Subject ◽  
Immovable Object ◽  
End To End ◽  
Celestial Sphere

Em contraposição a Enrico Berti, este artigo defende a interpretação tradicional de que o primeiro motor imóvel é a causa final da primeira esfera celeste. O artigo está dividido em 6 partes: (i) Apresentamos uma síntese da posição de Enrico Berti, tomando-se por base seus artigos a respeito do assunto em 1997 e 2002. (ii) Traz-se à discussão a compreensão que Aristóteles tem a respeito do movimento circular, a partir de duas passagens da física. Para Berti, o movimento da primeira esfera dificulta a compreensão a respeito dela e do primeiro motor imóvel, (iii) Tomamos em consideração Ética Eudêmia I, 8 enquanto afirmação aristotélica de que nenhuma coisa imóvel pode ser "prática", (iv) Enfocando Metafísica XII, 7, observaremos que Berti não levou em conta uma passagem de De sensu et sensibilibus para interpretar este texto da Metafísica, (v) Ao contrário de Berti, veremos que De caelo II 12 se contrapõe à sua posição, (vi) Apresentaremos por fim a conexão entre a causalidade final e causalidade eficiente do primeiro motor imóvel. Com o apêndice, trazemos uma tradução das listas paralelas de De caelo II 12.ABSTRACT: In contraposition to Enrico Berti, this article defends the traditional interpretation of the first unmoved mover is the ultimate cause of the first celestial sphere. The article is divided into 6 parts: (i) present a summary of the Enrico Berti position, taking as a basis Articles on the subject in 1997 and 2002. (ii) brings to the discussion understanding that Aristotle has about the circular motion, from two physical passages. To Berti, the first ball movement difficult to understand about it and the first unmoved mover, (iii) We consider Ethics Eudêmia I, 8 while Aristotelian claim that no immovable object can be "practical", (iv) Focusing on Metaphysics XII, 7, observe that Berti did not take into account a sensu de passing et sensibilibus to interpret this text of Metaphysics, (v) Unlike Berti, we see that de caelo II 12 is opposed to their position, (vi) will present by end to end connection between causality and efficient causality of the first unmoved mover. With the appendix, we present a translation of parallel lists of De caelo II 12.

C. The Continuous Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney
Keyword(s):  
Continuous Spectrum ◽  
Variable Stars ◽  
Velocity Fields ◽  
The Other ◽  
Line Spectrum ◽  
Direct Information ◽  
Thermodynamic Structure ◽  
Diagnostic Interpretation ◽  
Pulsating Variable Stars ◽  
The Continuum

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.

The Interpretation of Line Profiles

1977 ◽  
Vol 36 ◽  
pp. 191-215
Author(s):  
G.B. Rybicki
Keyword(s):  
Magnetic Fields ◽  
Atomic Physics ◽  
Velocity Fields ◽  
Spectral Lines ◽  
Inhomogeneous Structure ◽  
The Sun ◽  
Line Profiles ◽  
Physical Phenomena

Observations of the shapes and intensities of spectral lines provide a bounty of information about the outer layers of the sun. In order to utilize this information, however, one is faced with a seemingly monumental task. The sun’s chromosphere and corona are extremely complex, and the underlying physical phenomena are far from being understood. Velocity fields, magnetic fields, Inhomogeneous structure, hydromagnetic phenomena – these are some of the complications that must be faced. Other uncertainties involve the atomic physics upon which all of the deductions depend.

Surgical management of extracranial carotid artery aneurysms

VASA ◽  
2016 ◽  
Vol 45 (3) ◽  
pp. 223-228 ◽  
Author(s):  
Jan Paweł Skóra ◽  
Jacek Kurcz ◽  
Krzysztof Korta ◽  
Przemysław Szyber ◽  
Tadeusz Andrzej Dorobisz ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Surgical Management ◽  
Minor Stroke ◽  
Stroke Rate ◽  
Extracranial Carotid Artery ◽  
Long Term Follow Up ◽  
End To End ◽  
Dacron Patch ◽  
Major Stroke

Abstract. Background: We present the methods and results of the surgical management of extracranial carotid artery aneurysms (ECCA). Postoperative complications including early and late neurological events were analysed. Correlation between reconstruction techniques and morphology of ECCA was assessed in this retrospective study. Patients and methods: In total, 32 reconstructions of ECCA were performed in 31 symptomatic patients with a mean age of 59.2 (range 33 - 84) years. The causes of ECCA were divided among atherosclerosis (n = 25; 78.1 %), previous carotid endarterectomy with Dacron patch (n = 4; 12.5 %), iatrogenic injury (n = 2; 6.3 %) and infection (n = 1; 3.1 %). In 23 cases, intervention consisted of carotid bypass. Aneurysmectomy with end-to-end suture was performed in 4 cases. Aneurysmal resection with patching was done in 2 cases and aneurysmorrhaphy without patching in another 2 cases. In 1 case, ligature of the internal carotid artery (ICA) was required. Results: Technical success defined as the preservation of ICA patency was achieved in 31 cases (96.9 %). There was one perioperative death due to major stroke (3.1 %). Two cases of minor stroke occurred in the 30-day observation period (6.3 %). Three patients had a transient hypoglossal nerve palsy that subsided spontaneously (9.4 %). At a mean long-term follow-up of 68 months, there were no major or minor ipsilateral strokes or surgery-related deaths reported. In all 30 surviving patients (96.9 %), long-term clinical outcomes were free from ipsilateral neurological symptoms. Conclusions: Open surgery is a relatively safe method in the therapy of ECCA. Surgical repair of ECCAs can be associated with an acceptable major stroke rate and moderate minor stroke rate. Complication-free long-term outcomes can be achieved in as many as 96.9 % of patients. Aneurysmectomy with end-to-end anastomosis or bypass surgery can be implemented during open repair of ECCA.

Central kiloparsec of NGC 1326 observed with SINFONI

2020 ◽  
Vol 638 ◽  
pp. A53
Author(s):  
Nastaran Fazeli ◽  
Gerold Busch ◽  
Andreas Eckart ◽  
Françoise Combes ◽  
Persis Misquitta ◽  
...  
Keyword(s):  
Black Hole ◽  
Galaxy Evolution ◽  
Near Infrared ◽  
Velocity Fields ◽  
Molecular Gas ◽  
Nearby Galaxy ◽  
Stellar Content ◽  
Stellar Rotation ◽  
Supermassive Black Hole ◽  
Integral Field Spectrograph

Gas inflow processes in the vicinity of galactic nuclei play a crucial role in galaxy evolution and supermassive black hole growth. Exploring the central kiloparsec of galaxies is essential to shed more light on this subject. We present near-infrared H- and K-band results of the nuclear region of the nearby galaxy NGC 1326, observed with the integral-field spectrograph SINFONI mounted on the Very Large Telescope. The field of view covers 9″ × 9″ (650 × 650 pc2). Our work is concentrated on excitation conditions, morphology, and stellar content. The nucleus of NGC 1326 was classified as a LINER, however in our data we observed an absence of ionised gas emission in the central r ∼ 3″. We studied the morphology by analysing the distribution of ionised and molecular gas, and thereby detected an elliptically shaped, circum-nuclear star-forming ring at a mean radius of 300 pc. We estimate the starburst regions in the ring to be young with dominating ages of < 10 Myr. The molecular gas distribution also reveals an elongated east to west central structure about 3″ in radius, where gas is excited by slow or mild shock mechanisms. We calculate the ionised gas mass of 8 × 105 M⊙ completely concentrated in the nuclear ring and the warm molecular gas mass of 187 M⊙, from which half is concentrated in the ring and the other half in the elongated central structure. The stellar velocity fields show pure rotation in the plane of the galaxy. The gas velocity fields show similar rotation in the ring, but in the central elongated H2 structure they show much higher amplitudes and indications of further deviation from the stellar rotation in the central 1″ aperture. We suggest that the central 6″ elongated H2 structure might be a fast-rotating central disc. The CO(3–2) emission observations with the Atacama Large Millimeter/submillimeter Array reveal a central 1″ torus. In the central 1″ of the H2 velocity field and residual maps, we find indications for a further decoupled structure closer to a nuclear disc, which could be identified with the torus surrounding the supermassive black hole.

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