Gravitational Lens Models of Arcs in Abell 2218

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view Abstract Citations (10) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Gravitational Lens Models of Arcs in Abell 2218 Saraniti, David W. ; Petrosian, Vahe ; Lynds, Roger Abstract Abell 2218, with redshift z = 0.17, is one of the first clusters in which gravitationally lensed arcs have been found. Abell 2218 contains several arcs, and although none are as large as some of the more studied arcs (Abell 370, Cl 2244-02), they are interesting nonetheless. We present photometric and spectroscopic data of the cluster taken at the NOAO 4 m telescope. We show broadband spectra of some of the more interesting objects in the field. One arc in the cluster is redder than a typical galaxy, which is unusual since most lensed arcs have a bluer color. The spectrum of this arc reveals a redshift of 0.703. There is an almost perfectly circular blue ring surrounding one galaxy. There are several other blue arclets including two, called the twin arcs, that are on either side of two close galaxies. We model the system with a simple mass distribution consisting of the visible galaxies and a diffuse dark matter component. We are able to model the red arc and the twin arcs, but we find that the ring is most likely not a gravitationally lensed image. Combining this with the observed velocity dispersion of galaxies, we set limits on the masses of some of the galaxies and on the parameters describing the distribution of dark matter. We compare the distributions with the X-ray surface brightness variation of the cluster and find that the dark matter component for the lensing models is more compact than the X-ray distribution. We shall discuss this in a future publication. Publication: The Astrophysical Journal Pub Date: February 1996 DOI: 10.1086/176792 Bibcode: 1996ApJ...458...57S Keywords: GALAXIES: CLUSTERS: INDIVIDUAL NAME: ABELL 2218; COSMOLOGY: GRAVITATIONAL LENSING full text sources ADS | data products NED (16) SIMBAD (3)