- ID:
- ivo://CDS.VizieR/J/ApJ/755/31
- Title:
- Compilation of 122 strong gravitational lenses
- Short Name:
- J/ApJ/755/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the redshift distribution of two samples of early-type gravitational lenses, extracted from a larger collection of 122 systems, to constrain the cosmological constant in the {Lambda}CDM model and the parameters of a set of alternative dark energy models (XCDM, Dvali-Gabadadze-Porrati, and Ricci dark energy models), in a spatially flat universe. The likelihood is maximized for {Omega}_{Lambda}_=0.70+/-0.09 when considering the sample excluding the Sloan Lens ACS systems (known to be biased toward large image-separation lenses) and no-evolution, and {Omega}_{Lambda}_=0.81+/-0.05 when limiting to gravitational lenses with image separation {Delta}{theta}>2" and no-evolution. In both cases, results accounting for galaxy evolution are consistent within 1{sigma}. The present test supports the accelerated expansion, by excluding the null hypothesis (i.e., {Omega}_{Lambda}_=0) at more than 4{sigma}, regardless of the chosen sample and assumptions on the galaxy evolution. A comparison between competitive world models is performed by means of the Bayesian information criterion. This shows that the simplest cosmological constant model--that has only one free parameter--is still preferred by the available data on the redshift distribution of gravitational lenses. We perform an analysis of the possible systematic effects, finding that the systematic errors due to sample incompleteness, galaxy evolution, and model uncertainties approximately equal the statistical errors, with present-day data. We find that the largest sources of systemic errors are the dynamical normalization and the high-velocity cutoff factor, followed by the faint-end slope of the velocity dispersion function.
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- ID:
- ivo://CDS.VizieR/J/ApJ/890/148
- Title:
- Concentration-mass relation for XXL clusters
- Short Name:
- J/ApJ/890/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a weak-lensing analysis of X-ray galaxy groups and clusters selected from the XMM-XXL survey using the first-year data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program. Our joint weak-lensing and X-ray analysis focuses on 136 spectroscopically confirmed X-ray-selected systems at 0.031<=z<=1.033 detected in the 25deg^2^ XXL-N region, which largely overlaps with the HSC-XMM field. With high-quality HSC weak-lensing data, we characterize the mass distributions of individual clusters and establish the concentration-mass (c-M) relation for the XXL sample, by accounting for selection bias and statistical effects and marginalizing over the remaining mass calibration uncertainty. We find the mass-trend parameter of the c-M relation to be {beta}=-0.07+/-0.28 and the normalization to be c_200_=4.8+/-1.0(stat)+/-0.8(syst) at M_200_=10^14^h^-1^M_{sun}_ and z=0.3. We find no statistical evidence for redshift evolution. Our weak-lensing results are in excellent agreement with dark-matter-only c-M relations calibrated for recent {Lambda}CDM cosmologies. The level of intrinsic scatter in c200 is constrained as {sigma}(lnc_200_)<24% (99.7% CL), which is smaller than predicted for the full population of {Lambda}CDM halos. This is likely caused in part by the X-ray selection bias in terms of the cool-core or relaxation state. We determine the temperature-mass (T_X_-M_500_) relation for a subset of 105 XXL clusters that have both measured HSC lensing masses and X-ray temperatures. The resulting TX-M500 relation is consistent with the self-similar prediction. Our TX-M500 relation agrees with the XXL DR1 results at group scales but has a slightly steeper mass trend, implying a smaller mass scale in the cluster regime. The overall offset in the TX-M500 relation is at the ~1.5{sigma} level, corresponding to a mean mass offset of 34%+/-20%. We also provide bias-corrected, weak-lensing-calibrated M200 and M500 mass estimates of individual XXL clusters based on their measured X-ray temperatures.
- ID:
- ivo://CDS.VizieR/J/A+A/631/A40
- Title:
- Cosmic Horseshoe (J1148+1930) Ha and OIII spectra
- Short Name:
- J/A+A/631/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed analysis of the inner mass structure of the Cosmic Horseshoe (J1148+1930) strong gravitational lens system observed with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3). In addition to the spectacular Einstein ring, this systems shows a radial arc. We obtained the redshift of the radial arc counter image z_s,r_=1.961+/-0.001 from Gemini observations. To disentangle the dark and luminous matter, we consider three different profiles for the dark matter distribution: a power-law profile, the NFW, and a generalized version of the NFW profile. For the luminous matter distribution, we base it on the observed light distribution that is fitted with three components: a point mass for the central light component resembling an active galactic nucleus, and the remaining two extended light components scaled by a constant M/L. To constrain the model further, we include published velocity dispersion measurements of the lens galaxy and perform a self-consistent lensing and axisymmetric Jeans dynamical modeling. Our model fits well to the observations including the radial arc, independent of the dark matter profile. Depending on the dark matter profile, we get a dark matter fraction between 60% and 70%. With our composite mass model we find that the radial arc helps to constrain the inner dark matter distribution of the Cosmic Horseshoe independently of the dark matter profile.
- ID:
- ivo://CDS.VizieR/J/ApJ/856/68
- Title:
- COSMOS lens candidates with LensFlow
- Short Name:
- J/ApJ/856/68
- Date:
- 08 Mar 2022 14:20:03
- Publisher:
- CDS
- Description:
- In this work, we present our machine learning classification algorithm for identifying strong gravitational lenses from wide-area surveys using convolutional neural networks; LensFlow. We train and test the algorithm using a wide variety of strong gravitational lens configurations from simulations of lensing events. Images are processed through multiple convolutional layers that extract feature maps necessary to assign a lens probability to each image. LensFlow provides a ranking scheme for all sources that could be used to identify potential gravitational lens candidates by significantly reducing the number of images that have to be visually inspected. We apply our algorithm to the HST/ACS i-band observations of the COSMOS field and present our sample of identified lensing candidates. The developed machine learning algorithm is more computationally efficient and complimentary to classical lens identification algorithms and is ideal for discovering such events across wide areas from current and future surveys such as LSST and WFIRST.
- ID:
- ivo://CDS.VizieR/J/ApJS/176/19
- Title:
- COSMOS: strong lens systems
- Short Name:
- J/ApJS/176/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first catalog of 67 strong galaxy-galaxy lens candidates discovered in the 1.64deg^2^ Hubble Space Telescope COSMOS survey. Twenty of these systems display multiple images or strongly curved large arcs. Our initial search is performed by visual inspection of the data and is restricted, for practical considerations, to massive early-type lens galaxies with arcs found at radii smaller than ~5". Simple mass models are constructed for the best lens candidates, and our results are compared to the strong lensing catalogs of the SLACS survey and the CASTLES database. These new strong galaxy-galaxy lensing systems constitute a valuable sample to study the mass distribution of early-type galaxies and their associated dark matter halos.
- ID:
- ivo://CDS.VizieR/J/A+A/454/185
- Title:
- EROS-2 microlensing parameters
- Short Name:
- J/A+A/454/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new EROS-2 measurement of the microlensing optical depth toward the Galactic Bulge. Light curves of 5.6x10^6^ clump-giant stars distributed over 66deg^2^ of the Bulge were monitored during seven Bulge seasons. 120 events were found with apparent amplifications greater than 1.6 and Einstein radius crossing times in the range 5d<t_E_<400d. This is the largest existing sample of clump-giant events and the first to include northern Galactic fields.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1977
- Title:
- FIRST-Optical-VLA survey for lensed radio lobes
- Short Name:
- J/AJ/130/1977
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a survey for gravitationally lensed radio lobes. Lensed lobes are a potentially richer source of information about galaxy mass distributions than lensed point sources, which have been the exclusive focus of other recent surveys. Our approach is to identify radio lobes in the Faint Images of the Radio Sky at Twenty cm (FIRST, Cat. <VIII/71>) catalog and then search optical catalogs for coincident foreground galaxies, which are candidate lensing galaxies. We then obtain higher resolution images of these targets at both optical and radio wavelengths and obtain optical spectra for the most promising candidates. We present maps of several radio lobes that are nearly coincident with galaxies. We have not found any new and unambiguous cases of gravitational lensing. One radio lobe in particular, FOV J0743+1553, has two hot spots that could be multiple images produced by a z=0.19 spiral galaxy, but the lensing interpretation is problematic.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/683
- Title:
- Free-form lensing grid solution for A1689
- Short Name:
- J/MNRAS/446/683
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine Abell 1689 non-parametrically, combining strongly lensed Hubble Space Telescope images and weak distortions from wider field Subaru imaging. Our model incorporates member galaxies to improve the lens solution. By adding luminosity-scaled member galaxy deflections to our smooth grid, we can derive meaningful solutions with sufficient accuracy to permit the identification of our own strongly lensed images, so our model becomes self-consistent. We identify 11 new multiply lensed system candidates and clarify previously ambiguous cases, in the deepest optical and near-infrared data to date from Hubble and Subaru. Our improved spatial resolution brings up new features not seen when the weak and strong lensing effects are used separately, including clumps and filamentary dark matter around the main halo. Our treatment means we can obtain an objective mass ratio between the cluster and galaxy components. We find a typical mass-to-light ratios of M/L_B_=21+/-14 inside the r<1arcmin region. Our model independence means we can objectively evaluate the competitiveness of stacking cluster lenses for defining the geometric lensing-distance-redshift relation in a model-independent way.
- ID:
- ivo://CDS.VizieR/J/ApJ/854/73
- Title:
- Full-data results of HFF: galaxies z~6-9
- Short Name:
- J/ApJ/854/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UV luminosity functions of dropout galaxies at z~6-10 with the complete Hubble Frontier Fields data. We obtain a catalog of ~450 dropout-galaxy candidates (350, 66, and 40 at z~6-7, 8, and 9, respectively), with UV absolute magnitudes that reach ~-14mag, ~2 mag deeper than the Hubble Ultra Deep Field detection limits. We carefully evaluate number densities of the dropout galaxies by Monte Carlo simulations, including all lensing effects such as magnification, distortion, and multiplication of images as well as detection completeness and contamination effects in a self-consistent manner. We find that UV luminosity functions at z~6-8 have steep faint-end slopes, {alpha}~-2, and likely steeper slopes, {alpha}<~-2 at z~9-10. We also find that the evolution of UV luminosity densities shows a non-accelerated decline beyond z~8 in the case of M_trunc_=-15, but an accelerated one in the case of M_trunc_=-17. We examine whether our results are consistent with the Thomson scattering optical depth from the Planck satellite and the ionized hydrogen fraction Q_HII_ at z<~7 based on the standard analytic reionization model. We find that reionization scenarios exist that consistently explain all of the observational measurements with the allowed parameters of f_esc_=0.17_-0.03_^+0.07^ and M_trunc_>-14.0 for log{xi}_ion_/[erg^-1^Hz]=25.34, where f_esc_ is the escape fraction, Mtrunc is the faint limit of the UV luminosity function, and {xi}_ion_ is the conversion factor of the UV luminosity to the ionizing photon emission rate. The length of the reionization period is estimated to be {Delta}z=3.9_-1.6_^+2.0^ (for 0.1<Q_HII_<0.99), consistent with the recent estimate from Planck.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A165
- Title:
- Gaia GraL. III. New lensed systems
- Short Name:
- J/A+A/622/A165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Gaia GraL catalogue of clusters is composed of 2,129,659 clusters consisting of three or four stationary sources from Gaia DR2. Each cluster is assigned a discriminant value, called the extremely randomized trees probability, that reflects its ability to be matched to the image positions and relative magnitudes produced through simulations of gravitational lens systems.
