- ID:
- ivo://CDS.VizieR/J/ApJ/851/48
- Title:
- SLACS. XIII. Galaxy-scale strong lens candidates
- Short Name:
- J/ApJ/851/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the full sample of 118 galaxy-scale strong-lens candidates in the Sloan Lens ACS (SLACS) Survey for the Masses (S4TM) Survey, which are spectroscopically selected from the final data release of the Sloan Digital Sky Survey. Follow-up Hubble Space Telescope (HST) imaging observations confirm that 40 candidates are definite strong lenses with multiple lensed images. The foreground-lens galaxies are found to be early-type galaxies (ETGs) at redshifts 0.06-0.44, and background sources are emission-line galaxies at redshifts 0.22-1.29. As an extension of the SLACS Survey, the S4TM Survey is the first attempt to preferentially search for strong-lens systems with relatively lower lens masses than those in the pre-existing strong-lens samples. By fitting HST data with a singular isothermal ellipsoid model, we find that the total projected mass within the Einstein radius of the S4TM strong-lens sample ranges from 3x10^10^M_{sun}_ to 2x10^11^M_{sun}_. In Shu+ (2015ApJ...803...71S), we have derived the total stellar mass of the S4TM lenses to be 5x10^10^M_{sun}_ to 1x10^12^M_{sun}_. Both the total enclosed mass and stellar mass of the S4TM lenses are on average almost a factor of 2 smaller than those of the SLACS lenses, which also represent the typical mass scales of the current strong-lens samples. The extended mass coverage provided by the S4TM sample can enable a direct test, with the aid of strong lensing, for transitions in scaling relations, kinematic properties, mass structure, and dark-matter content trends of ETGs at intermediate-mass scales as noted in previous studies.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/682/964
- Title:
- Sloan lens ACS survey. V.
- Short Name:
- J/ApJ/682/964
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the definitive data for the full sample of 131 strong gravitational lens candidates observed with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope by the Sloan Lens ACS (SLACS) Survey. All targets were selected for higher redshift emission lines and lower redshift continuum in a single Sloan Digital Sky Survey (SDSS) spectrum.
- ID:
- ivo://CDS.VizieR/J/ApJ/777/97
- Title:
- SL2S galaxy-scale lens sample. III.
- Short Name:
- J/ApJ/777/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Hubble Space Telescope (HST) imaging data and Canada-France-Hawaii Telescope (CFHT) near-infrared ground-based images for the final sample of 56 candidate galaxy-scale lenses uncovered in the CFHT Legacy Survey as part of the Strong Lensing in the Legacy Survey (SL2S) project. The new images are used to perform lens modeling, measure surface photometry, and estimate stellar masses of the deflector early-type galaxies (ETGs). Lens modeling is performed on the HST images (or CFHT when HST is not available) by fitting the spatially extended light distribution of the lensed features assuming a singular isothermal ellipsoid mass profile and by reconstructing the intrinsic source light distribution on a pixelized grid. Based on the analysis of systematic uncertainties and comparison with inference based on different methods, we estimate that our Einstein radii are accurate to ~3%. HST imaging provides a much higher success rate in confirming gravitational lenses and measuring their Einstein radii than CFHT imaging does. Lens modeling with ground-based images, however, when successful, yields Einstein radius measurements that are competitive with space-based images. Information from the lens models is used together with spectroscopic information from companion Paper IV (2013ApJ...777...98S) to classify the systems, resulting in a final sample of 39 confirmed (grade A) lenses and 17 promising candidates (grade B,C).
- ID:
- ivo://CDS.VizieR/J/ApJ/785/144
- Title:
- SL2S galaxy-scale sample of lens candidates
- Short Name:
- J/ApJ/785/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present RINGFINDER, a tool for finding galaxy-scale strong gravitational lenses in multi-band imaging data. By construction, the method is sensitive to configurations involving a massive foreground ETG and a faint, background, blue source. RINGFINDER detects the presence of blue residuals embedded in an otherwise smooth red light distribution by difference imaging in two bands. The method is automated for efficient application to current and future surveys, having originally been designed for the 150 deg^2^ Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). We describe each of the steps of RINGFINDER. We then carry out extensive simulations to assess completeness and purity. For sources with magnification {mu}>4, RINGFINDER reaches 42% (25%) completeness and 29% (86%) purity before (after) visual inspection. The completeness of RINGFINDER is substantially improved in the particular range of Einstein radii 0.8"<=R_Ein_<=2.0" and lensed images brighter than g=22.5, where it can be as high as ~70%. RINGFINDER does not introduce any significant bias in the source or deflector population. We conclude by presenting the final catalog of RINGFINDER CFHTLS galaxy-scale strong lens candidates. Additional information obtained with Hubble Space Telescope and Keck adaptive optics high-resolution imaging, and with Keck and Very Large Telescope spectroscopy, is used to assess the validity of our classification and measure the redshift of the foreground and the background objects. From an initial sample of 640000 ETGs, RINGFINDER returns 2500 candidates, which we further reduce by visual inspection to 330 candidates. We confirm 33 new gravitational lenses from the main sample of candidates, plus an additional 16 systems taken from earlier versions of RINGFINDER. First applications are presented in the Strong Lensing Legacy Survey galaxy-scale lens sample paper series.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A62
- Title:
- Spectra of 13 lensed quasars
- Short Name:
- J/A+A/544/A62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide single-epoch spectroscopic data for a sample of 13 lensed quasars. The sources have bolometric luminosities between 10^44.7-47.4^erg/s and black hole masses 10^7.6-9.8^M_{sun}. These spectra have been used to perform a systematic search for microlensing in the broad line region. The spectra have been deblended using the MCS advanced deconvolution technique. We provide the extracted and flux calibrated spectra, and the 2D deconvolved frames, separating the point-like emission from the extended emission (from the residual sky and from the lensing galaxy).
- ID:
- ivo://CDS.VizieR/J/ApJS/219/29
- Title:
- Spectroscopic redshifts in strong lens fields
- Short Name:
- J/ApJS/219/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the spectroscopic redshift catalog from a wide-field survey of the fields of 28 galaxy-mass strong gravitational lenses. We discuss the acquisition and reduction of the survey data, collected over 40 nights of 6.5m MMT and Magellan time, employing four different multiobject spectrographs. We determine that no biases are introduced by combining data sets obtained with different telescope and spectrograph combinations. Special care is taken to determine redshift uncertainties using repeat observations. The redshift catalog consists of 9768 new and unique galaxy redshifts. 82.4% of the catalog redshifts are between z=0.1 and z=0.7, and the catalog median redshift is z_med_=0.36. The data from this survey will be used to study the lens environments and line-of-sight structures to gain a better understanding of the effects of large-scale structure on lens statistics and lens-derived parameters.
- ID:
- ivo://CDS.VizieR/J/ApJ/641/169
- Title:
- Spectroscopy in lens fields
- Short Name:
- J/ApJ/641/169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from our spectroscopic survey of strong gravitational lens environments. Six of the eight lens galaxies in our sample belong to a poor group of galaxies, three of which are newly discovered here (those associated with BRI 0952-0115, MG 1654+1346, and B2114+022).
- ID:
- ivo://CDS.VizieR/J/ApJS/193/8
- Title:
- Spectroscopy of 26 lensing cluster cores
- Short Name:
- J/ApJS/193/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a spectroscopic program targeting 26 strong-lensing cluster cores that were visually identified in the Sloan Digital Sky Survey (SDSS; Gladders et al. 2011, in prep) and the Second Red-Sequence Cluster Survey (RCS-2; Bayliss et al. 2011, in prep). The 26 galaxy cluster lenses span a redshift range of 0.2<z<0.65, and our spectroscopy reveals 69 unique background sources with redshifts as high as z=5.200. We also identify redshifts for 262 cluster member galaxies and measure the velocity dispersions and dynamical masses for 18 clusters where we have redshifts for N>=10 cluster member galaxies. We account for the expected biases in dynamical masses of strong-lensing-selected clusters as predicted by results from numerical simulations and discuss possible sources of bias in our observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/834/210
- Title:
- Spectroscopy of strong lensing galaxy clusters
- Short Name:
- J/ApJ/834/210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an extensive spectroscopic follow-up campaign of 29 strong lensing (SL) selected galaxy clusters discovered primarily in the Second Red-Sequence Cluster Survey (RCS-2). Our spectroscopic analysis yields redshifts for 52 gravitational arcs present in the core of our galaxy clusters, which correspond to 35 distinct background sources that are clearly distorted by the gravitational potential of these clusters. These lensed galaxies span a wide redshift range of 0.8<=z<=2.9, with a median redshift of z_s_=1.8+/-0.1. We also measure reliable redshifts for 1004 cluster members, allowing us to obtain robust velocity dispersion measurements for 23 of these clusters, which we then use to determine their dynamical masses by using a simulation-based {sigma}_DM_-M_200_ scaling relation. The redshift and mass ranges covered by our SL sample are 0.22<=z<=1.01 and 5x10^13^M_200_/h_70_^-1^M_{sun}_<=1.9x10^15^, respectively. We analyze and quantify some possible effects that might bias our mass estimates, such as the presence of substructure, the region where cluster members are selected for spectroscopic follow-up, the final number of confirmed members, and line-of-sight effects. We find that 10 clusters of our sample with N_mem_>~20 show signs of dynamical substructure. However, the velocity data of only one system is inconsistent with a uni-modal distribution. We therefore assume that the substructures are only marginal and not of comparable size to the clusters themselves. Consequently, our velocity dispersion and mass estimates can be used as priors for SL mass reconstruction studies and also represent an important step toward a better understanding of the properties of the SL galaxy cluster population.
- ID:
- ivo://CDS.VizieR/J/ApJ/850/94
- Title:
- Spectroscopy of the fields of gravitational lenses
- Short Name:
- J/ApJ/850/94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Strong gravitational lensing provides an independent measurement of the Hubble parameter (H_0_). One remaining systematic is a bias from the additional mass due to a galaxy group at the lens redshift or along the sightline. We quantify this bias for more than 20 strong lenses that have well-sampled sightline mass distributions, focusing on the convergence {kappa} and shear {gamma}. In 23% of these fields, a lens group contributes >=1% convergence bias; in 57%, there is a similarly significant line-of-sight group. For the nine time-delay lens systems, H0 is overestimated by 11_-2_^+3^% on average when groups are ignored. In 67% of fields with total {kappa}>=0.01, line-of-sight groups contribute >~2x more convergence than do lens groups, indicating that the lens group is not the only important mass. Lens environment affects the ratio of four (quad) to two (double) image systems; all seven quads have lens groups while only 3 of 10 doubles do, and the highest convergences due to lens groups are in quads. We calibrate the {gamma}-{kappa} relation: log({kappa}_tot_)=(1.94+/-0.34)log({gamma}_tot_)+(1.31+/-0.49) with an rms scatter of 0.34dex. Although shear can be measured directly from lensed images, unlike convergence, it can be a poor predictor of convergence; for 19% of our fields, {kappa} is >~2{gamma}. Thus, accurate cosmology using strong gravitational lenses requires precise measurement and correction for all significant structures in each lens field.
