Extinction Curves of Lensing Galaxies out toz= 1

Abstract

We present a survey of the extinction properties of 10 lensing galaxies, in the redshift range z ¼ 0:04Y1:01, using multiply lensed quasars imaged with the ESO VLT in the optical and near-infrared. The multiple images act as ''standard light sources'' shining through different parts of the lensing galaxy, allowing for extinction studies by comparison of pairs of images. We explore the effects of systematics in the extinction curve analysis, including extinction along both lines of sight and microlensing, using theoretical analysis and simulations. In the sample, we see variation in both the amount and type of extinction. Of the 10 systems, seven are consistent with extinction along at least one line of sight. The mean differential extinction for the most extinguished image pair for each lens isĀ(V ) ¼ 0:56 AE 0:04, using Galactic extinction law parameterization. The corresponding meanR V ¼ 2:8 AE 0:4 is consistent with that of the Milky Way at R V ¼ 3:1, where R V ¼ A(V )/E(B À V ). We do not see any strong evidence for evolution of extinction properties with redshift. Of the 10 systems, B1152+199 shows the strongest extinction signal of A(V ) ¼ 2:43 AE 0:09 and is consistent with a Galactic extinction law with R V ¼ 2:1 AE 0:1. Given the similar redshift distribution of SN Ia hosts and lensing galaxies, a large space-based study of multiply imaged quasars would be a useful complement to future dark energy SN Ia surveys, providing independent constraints on the statistical extinction properties of galaxies up to z $ 1. Subject headingg s: dust, extinction -galaxies: ISM -gravitational lensing 1 Based on observations made with ESO Telescopes at the La Silla or Paranal Observatories under program IDs 065.O-0666 and 066.A-0264.

A 5.5-year robotic optical monitoring of Q0957+561: substructure in a non-local cD galaxy

“…Although the strong gravitational lensing scenario produces achromatic and stationary flux ratios of lensed quasars (e.g., Schneider et al 1992;Kochanek et al 2004), actual scenarios are not so simple. Chromatic flux ratios are usually related to differential extinction (e.g., Falco et al 1999;Elíasdóttir et al 2006) or differential microlensing (e.g., Yonehara et al 2008). In addition, time-variable flux ratios are likely due to differential microlensing by stars in lensing galaxies (e.g., Irwin et al 1989;Paraficz et al 2006).…”

Deep optical imaging and spectroscopy of the lens system SDSS J1339+1310

“…7 displays the best fit to a Milky Way-like extinction: p 0 = −0.41, p V = −1.14 and p B = −1.08 mag. From this best fit with χ 2 ∼ 0, we do not infer an unique extinction scenario, but many possible scenarios that are indistinguishable from each other (e.g., Wucknitz et al 2003;McGough et al 2005;Elíasdóttir et al 2006). For example, two physical solutions are (1) E A (B − V) = 1.00, R A (V) = 2.00, E B (B − V) = 0.94, R B (V) = 3.34, and (2) E A (B − V) = 0.60, R A (V) = 3.00, E B (B − V) = 0.54, R B (V) = 5.44.…”

“…The second variant was a power law A(λ) = A(V)[xλ V ] α , with λ V = 0.55 μm and α = 1−2. This can account for extinction in galaxies with types of dust other than those in our own Galaxy (Elíasdóttir et al 2006). For the Galactic extinction, Eq.…”

“…2), and thus, conceivably cross two galactic regions with different dust properties. The general formalism for differential extinction in a pair of lensed images was introduced by several authors (e.g., Falco et al 1999;Wucknitz et al 2003;Elíasdóttir et al 2006), and this is easily applicable to analyse our line-core magnitude differences in Table 2. We assumed a relationship…”

Gravitational lens system SDSS J1339+1310: microlensing factory and time delay

“…Using a standard formalism for the differential extinction of lensed images (e.g. Falco et al 1999;Wucknitz et al 2003;Elíasdóttir et al 2006), we presented two chromaticity laws in equations 2−3 of Paper I, which can be compared with the observed magnitude differences in Table B.1. Although we were able to perfectly fit the Galactic law to the new data for the cores of the Mg ii, C iii] and C iv emissions (χ 2 ∼ 0; see the dotted red line in Fig.…”