Broadband photometry of 105 giant arcs: Redshift distribution constraints and implications for giant arc statistics

2011 2011

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Abstract (summary)

We measure the bulk photometric properties of a sample of 105 giant arcs that were identified in systematic searches for galaxy-cluster-scale strong lenses in the Second Red-Sequence Cluster Survey (RCS-2) and the Sloan Digital Sky Survey (SDSS). Using well-established optical broadband color criteria we sort the entire arc sample into redshift bins based on u-g and g-r colors, and for approximately 90% of the full giant arc sample we also measure z-band photometry and r-z colors. This analysis yields broad redshift constraints and linear brightness measurements for the entire sample of arcs, confirming that a majority these objects reside at high redshift, with ∼85% at z > 1, ∼65% at z > 1.4, ∼56% at z ≥ 1.9, and ∼21% at z ≥ 2.7. The arcs have an inferred median redshift of z = 2, in good agreement with a previous determination of the redshift distribution of a smaller sample of much brighter arcs. The agreement between the two measurements suggests that z = 2 is the typical redshift for giant arcs produced by cluster-scale strong lensing, independent of typical brightness of the arcs, and that this observed redshift distribution should therefore provide a good description of samples of lensed arcs over a wide range of arc brightnesses. Both the redshift distribution and linear brightness distribution of giant arcs are direct observables that inform efforts to accurately simulate the statistics of giant arcs as a function of cosmology. Establishing that half of all giant arcs are galaxies at z > 2 contributes significantly toward relieving the tension between past claims of an order of magnitude discrepancy between the number of giant arcs observed and the number expected in a ΔCDM cosmology, but there is considerable evidence to suggest that a discrepancy persists. Additionally, this work confirms that forthcoming large samples of giant arcs will supply the observational community with a large number of strongly lensed galaxies at z > 2. These sources will be significantly magnified and therefore provide an opportunity to investigate the individual properties of intrinsically faint galaxies at much higher signal-to-noise than can be achieved ix for individual sources in the field.

Indexing (details)

0596: Astrophysics
0606: Astronomy
Identifier / keyword
Pure sciences; Cosmology; Gravitational lensing; High-redshift galaxies
Broadband photometry of 105 giant arcs: Redshift distribution constraints and implications for giant arc statistics
Bayliss, Matthew B.
Number of pages
Publication year
Degree date
School code
DAI-B 72/12, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
Gladders, Michael D.
Committee member
Kent, Stephen M.; Kravtsov, Andrey V.; Kron, Richard G.
The University of Chicago
Astronomy and Astrophysics
University location
United States -- Illinois
Source type
Dissertations & Theses
Document type
Dissertation/thesis number
ProQuest document ID
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
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