Erratum: "Position-angle Statistics of the Brightest Binary Galaxies in Abell Clusters" [A. J. 96, 1534 (1988)]

1989 ◽  
Vol 98 ◽  
pp. 2360
Author(s):  
Mitchell F. Struble
Keyword(s):  
Position Angle ◽  
Abell Clusters ◽  
Binary Galaxies

scholarly journals Alignment of cD-Galaxies with their Surroundings

1990 ◽  
Vol 124 ◽  
pp. 255-260 ◽  
Author(s):  
Eelco van Kampen ◽  
George Rhee
Keyword(s):  
Strong Correlation ◽  
Position Angle ◽  
Alignment Effect ◽  
Parent Cluster ◽  
Abell Clusters ◽  
Cd Galaxies ◽  
Angle Orientation

AbstractFor a sample of 122 rich Abell clusters we find a strong correlation of the position angle (orientation) of the first-ranked galaxy and its parent cluster. This alignment effect is strongest for cD-galaxies. Formation scenarios for cD galaxies, like the merging scenario, must produce such a strong alignment effect. We show some N-body simulations done for this purpose.

scholarly journals Galaxy Orientation in Some Abell Clusters

1999 ◽  
Vol 186 ◽  
pp. 410-410
Author(s):  
W. Godłowski ◽  
F. Baier
Keyword(s):  
Angular Momentum ◽  
Strong Evidence ◽  
Position Angle ◽  
Line Of Sight ◽  
Abell Clusters ◽  
Cluster Area ◽  
Different Parts

We analyze a sample of galaxies in a region of three rich Abell Clusters. The data are taken from the Edinburgh Catalogue of the cluster. First, we divide the whole cluster area into different parts according to the assumed subclusters. Now we can find the position angles of the cluster and subclusters. We find strong evidence that the position angles of galaxies within our clusters are aligned to a large extent. For the cluster A754, position angles of galaxies tend to be perpendicular to the direction of the position angle of the cluster. Consequently, the angular momentum of galaxies are preferentially perpendicular to the cluster plane. For the cluster A14, position angles of galaxies tend to be parallel to the direction of the position angle of the cluster. Consequently, the angular momentum of galaxies are preferentially parallel to the cluster plane. For the cluster A3667 we obtain a more complicated picture suggesting that the alignment of galaxies in this cluster may have a different shape. From the distribution of the positions angles of galaxies we also found evidence for possible subclustering inside the whole cluster. This result is confirmed by the investigation of the distribution of the vectors normal to the galactic planes. Moreover we confirm the existence of a “line of sight” effect, originally found by Godłowski &, Ostrowski (1996) for galaxies belonging to the clusters in the Tully Catalogue (1988), for the clusters in our basic catalog.

Path Tracking Controller Design of Automatic Guided Vehicle Based on Four-Wheeled Omnidirectional Motion Model

2020 ◽  
Vol 17 (2) ◽  
pp. 7996-8010
Author(s):  
X. Wu ◽  
Y. Yang
Keyword(s):  
Control System ◽  
Fuzzy Controller ◽  
Controller Design ◽  
Threshold Value ◽  
Position Angle ◽  
Path Tracking ◽  
Global Coordinate System ◽  
Automatic Guided Vehicle ◽  
Input Variables ◽  
Industrial Pc

This paper presents a new design of omnidirectional automatic guided vehicle based on a hub motor, and proposes a joint controller for path tracking. The proposed controller includes two parts: a fuzzy controller and a multi-step predictive optimal controller. Firstly, based on various steering conditions, the kinematics model of the whole vehicle and the pose (position, angle) model in the global coordinate system are introduced. Secondly, based on the modeling, the joint controller is designed. Lateral deviation and course deviation are used as the input variables of the control system, and the threshold value is switched according to the value of the input variable to realise the correction of the large range of posture deviation. Finally, the joint controller is implemented by using the industrial PC and the self-developed control system based on the Freescale minimum system. Path tracking experiments were made under the straight and circular paths to test the ability of the joint controller for reducing the pose deviation. The experimental results show that the designed guided vehicle has excellent ability to path tracking, which meets the design goals.

ROSATX‐Ray Observations of Abell Clusters with Wide‐Angle Tailed Radio Sources

1997 ◽  
Vol 474 (2) ◽  
pp. 580-597 ◽  
Author(s):  
P. L. Gomez ◽  
J. Pinkney ◽  
J. O. Burns ◽  
Q. Wang ◽  
F. N. Owen ◽  
...  
Keyword(s):  
Radio Sources ◽  
Wide Angle ◽  
Abell Clusters

scholarly journals Abell Clusters as Tracers of Large-Scale Structure: Alignments and Substructure

1988 ◽  
Vol 130 ◽  
pp. 536-536
Author(s):  
G. Rhee ◽  
P. Katgert
Keyword(s):  
Structure Data ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Abell Clusters

Binggeli (A & A, 107, 338, 1982) showed that neighbouring Abell clusters with pair distances less than 30 to 40 h50−1 Mpc show directional correlation. Binggeli's result is based on structure data of 44 Abell clusters (all with zspectr < 0.1). Binggelli's result was questioned by Struble and Peebles (A.J., 90, 582, 1985). They produce a visual estimate of the direction of cluster elongation for 237 clusters. They did not observe reduced probability for small D large Θ pairs.

scholarly journals A High-Contrast Search for Variability in HR 8799bc with VLT-SPHERE

2021 ◽  
Author(s):  
B A Biller ◽  
D Apai ◽  
M Bonnefoy ◽  
S Desidera ◽  
R Gratton ◽  
...  
Keyword(s):  
Position Angle ◽  
High Contrast ◽  
Rule Out

Abstract The planets HR8799bc display nearly identical colours and spectra as variable young exoplanet analogues such as VHS 1256-1257ABb and PSO J318.5-22, and are likely to be similarly variable. Here we present results from a 5-epoch SPHERE IRDIS broadband-H search for variability in these two planets. HR 8799b aperture photometry and HR 8799bc negative simulated planet photometry share similar trends within uncertainties. Satellite spot lightcurves share the same trends as the planet lightcurves in the August 2018 epochs, but diverge in the October 2017 epochs. We consider Δ(mag)b − Δ(mag)c to trace non-shared variations between the two planets, and rule out non-shared variability in Δ(mag)b − Δ(mag)c to the 10-20% level over 4-5 hours. To quantify our sensitivity to variability, we simulate variable lightcurves by inserting and retrieving a suite of simulated planets at similar radii from the star as HR 8799bc, but offset in position angle. For HR 8799b, for periods &lt;10 hours, we are sensitive to variability with amplitude $&gt;5\%$. For HR 8799c, our sensitivity is limited to variability $&gt;25\%$ for similar periods.

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