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On the straight arc in A2390

Kassiola, A. and Kovner, I. and Blandford, R. D. (1992) On the straight arc in A2390. In: Gravitational Lenses. Lecture Notes in Physics. No.406. Springer , Berlin, pp. 318-322. ISBN 978-3-540-55797-5.

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We investigate the long “straight arc” observed in the cluster of galaxies Abell 2390. The arc consists of three segments of comparable optical brightness, and its optical spectrum shows a non-monotonic variation of velocity along its length. In addition to the optical data, recent infrared observations indicate that the longest segment of the arc is much brighter in infrared than the other two. Analytical investigation of the formation of straight arcs shows that single cusps always produce curved images, while fold catastrophes and “beak-to-beak” and “lips” “calamities” can form straight images. On the basis of these results we derive detailed models for the observed features. We argue that it is not possible to reproduce the straight arc without postulating some unseen matter not traced by the cluster. A fold model is consistent with the optical data, but it requires a large and very elongated unseen component, and it is not consistent with the infrared observations. A beak-to-beak model agrees with both infrared and optical data and requires only a small unseen galaxy. Future observations may distinguish between these possibilities.

Item Type:Book Section
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Blandford, R. D.0000-0002-1854-5506
Additional Information:© 1992 Springer-Verlag. We thank R. Ellis and B. Fort for allowing us to quote their data before publication. This research was supported by the United States - Israel Binational Science Foundation grant 88-00461 (AK, IK), the funds granted by the Charles. H. Revson foundation (IK), and the National Science Foundation under grant AST 89-17765 (RB).
Funding AgencyGrant Number
Binational Science Foundation (USA-Israel)UNSPECIFIED
Charles. H. Revson FoundationUNSPECIFIED
NSFAST 89-17765
Subject Keywords:Velocity Dispersion; Critical Line; Fold Model; Traceable Mass; Infrared Observation
Series Name:Lecture Notes in Physics
Issue or Number:406
Record Number:CaltechAUTHORS:20190605-125208871
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96152
Deposited By: Tony Diaz
Deposited On:06 Jun 2019 03:37
Last Modified:16 Nov 2021 17:18

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