KILOPARSEC MASS/LIGHT OFFSETS IN THE GALAXY PAIR-Lyα EMITTER LENS SYSTEM SDSS J1011+0143*

Abstract

We report the discovery of significant mass/light offsets in the strong gravitational lensing system SDSS J1011 +0143. We use the high-resolution Hubble Space Telescope (HST) F555W-and F814W-band imaging and Sloan Digital Sky Survey (SDSS) spectroscopy of this system, which consists of a close galaxy pair with a projected separation of »4.2 kpc at z lens ∼0.331 lensing an Lyα emitter (LAE) at z source =2.701. Comparisons between the mass peaks inferred from lens models and light peaks from HST imaging data reveal significant spatial mass/light offsets as large as 1.72±0.24±0.34kpc in both filter bands. Such large mass/light offsets, not seen in isolated field lens galaxies and relaxed galaxy groups, may be related to the interactions between the two lens galaxies. The detected mass/light offsets can potentially serve as an important test for the self-interacting dark matter model. However, other mechanisms such as dynamical friction on spatially differently distributed dark matter and stars could produce similar offsets. Detailed hydrodynamical simulations of galaxy-galaxy interactions with selfinteracting dark matter could accurately quantify the effects of different mechanisms. The background LAE is found to contain three distinct star-forming knots with characteristic sizes from 116 to 438 pc. It highlights the power of strong gravitational lensing in probing the otherwise too faint and unresolved structures of distance objects below subkiloparsec or even 100 pc scales through its magnification effect.

The Boss Emission-Line Lens Survey. Iv. Smooth Lens Models for the Bells Gallery Sample*

“…Building on our previous works (Bolton et al 2008a;Brownstein et al 2012;Shu et al 2015Shu et al , 2016a, we develop an open source lens modeling tool lfit gui with a graphical user interface (GUI). In this subsection, we use the BELLS GALLERY lenses to demonstrate the settings and functions of lfit gui.…”

“…The empirical point spread function (PSF) was generated by the Tiny Tim tool (Krist 1993). Pixel count errors are rescaled following Shu et al (2015Shu et al ( , 2016a to correct for possible error correlations created by imaging resampling during the data reduction process. The mean pixel count error after the rescaling is ∼ 0.005 electrons per second per pixel 2 .…”

“…Following our previous works (Bolton et al 2008a;Brownstein et al 2012;Shu et al 2015Shu et al , 2016a, the mass distribution of the foreground lens is modeled with the singular isothermal ellipsoid (SIE) model, which has a projected two-dimensional surface mass density profile of…”

The Sloan Lens ACS Survey. XIII. Discovery of 40 New Galaxy-scale Strong Lenses∗

“…For the same consistency reason, we adopt the B-spline fit as the model for the foreground-light distribution following Shu et al (2015). Note that this foreground-subtraction strategy could introduce some systematic uncertainties in the lens and source parameters as discussed in Marshall & Treu (2007) and Shu et al (2016aShu et al ( , 2016b. Following our previous works, we use the singular isothermal ellipsoid (SIE) profile to model the projected lens-mass distribution.…”

SDSS J1640+1932: a spectacular galaxy–quasar strong lens system

“…As discussed in Bolton et al (2006), Marshall et al (2007), and Shu et al (2016a), we fit the foreground light and mass simultaneously in order to reduce the systematic errors. The foreground-light distribution model is combined with the predicted lensed images and convolved with PSF.…”