BROADBAND PHOTOMETRY OF 105 GIANT ARCS: REDSHIFT CONSTRAINTS AND IMPLICATIONS FOR GIANT ARC STATISTICS
We measure the photometric properties of 105 giant arcs that were identified in systematic searches for galaxy-cluster-scale strong lenses in the Second Red-Sequence Cluster Survey and the Sloan Digital Sky Survey. The cluster lenses span 0.2 < z{sub l} < 1.2 in redshift, with a median z-bar{sub l}=0.58. Using broadband color criteria we sort the entire arc sample into redshift bins based on u-g and g-r colors, and also r-z colors for the {approx}90% of arcs that have z-band data. This analysis yields broad redshift constraints with 71{sup +5}{sub -4%} of the arcs at z {>=} 1.0, 64{sup +6}{sub -4%} at z {>=} 1.4, 56{sup +5}{sub -4%} at z {>=} 1.9, and 21{sup +4}{sub -2%} at z {>=} 2.7. The remaining 29{sup +03}{sub -5%} have z < 1. The inferred median redshift is z-bar{sub s}= 2.0{+-}0.1, in good agreement with a previous determination from a smaller sample of brighter arcs (g {approx}< 22.5). This agreement confirms that z{sub s} = 2.0 {+-} 0.1 is the typical redshift for giant arcs with g {approx}< 24 that are produced by cluster-scale strong lenses and that there is no evidence for strong evolution in the redshift distribution of arcs over a wide range of g-band magnitudes (20 {<=} g {<=}24). Establishing that half of all giant arcs are at z {approx}> 2 contributes significantly toward relieving the tension between the number of arcs observed and the number expected in a {Lambda}CDM 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 many magnified galaxies at z {approx}> 2.
- OSTI ID:
- 22004210
- Journal Information:
- Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 744; ISSN ASJOAB; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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