- ID:
- ivo://CDS.VizieR/J/ApJ/750/168
- Title:
- Redshift survey in the Subaru GTO2deg^2^ field
- Short Name:
- J/ApJ/750/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a dense redshift survey in the foreground of the Subaru GTO2deg^2^ weak-lensing field (centered at 16:04:44+43:11'24 (2000) to assess the completeness and comment on the purity of massive halo identification in the weak-lensing map. The redshift survey (published here) includes 4541 galaxies; 4405 are new redshifts measured with the Hectospec on the MMT. Among the weak-lensing peaks with a signal to noise greater than 4.25, 2/3 correspond to individual massive systems; this result is essentially identical to the Geller et al. (2010ApJ...709..832G) test of the Deep Lens Survey (DLS) field F2. The Subaru map, based on images in substantially better seeing than the DLS, enables detection of less massive halos at fixed redshift as expected. We demonstrate that the procedure adopted by Miyazaki et al. (2002ApJ...580L..97M) for removing some contaminated peaks from the weak-lensing map improves agreement between the lensing map and the redshift survey in the identification of candidate massive systems.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/160/148
- Title:
- RI-band LC of microlensing event OGLE-2018-BLG-1269Lb
- Short Name:
- J/AJ/160/148
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a planet in the microlensing event OGLE-2018-BLG-1269 with a planet-host mass ratio q~6x10^-4^, i.e., 0.6 times smaller than the Jupiter/Sun mass ratio. Combined with the Gaia parallax and proper motion, a strong one-dimensional constraint on the microlens parallax vector allows us to significantly reduce the uncertainties of lens physical parameters. A Bayesian analysis that ignores any information about light from the host yields that the planet is a cold giant (M_2_=0.69_-0.22_^+0.44^M_J_) orbiting a Sun-like star (M_1_=1.13_-0.35_^+0.72^M_{sun}_) at a distance of D_L_=2.56_-0.62_^+0.92^kpc. The projected planet-host separation is a_{perp}_=4.61_-1.17_^+1.70^au. Using Gaia astrometry, we show that the blended light lies <~12mas from the host and therefore must be either the host star or a stellar companion to the host. An isochrone analysis favors the former possibility at >99.6%. The host is therefore a subgiant. For host metallicities in the range of 0.0<=[Fe/H]<=+0.3, the host and planet masses are then in the range of 1.16<=M_1_/M_{sun}_<=1.38 and 0.74<=M_2_/M_J_<=0.89, respectively. Low host metallicities are excluded. The brightness and proximity of the lens make the event a strong candidate for spectroscopic follow-up both to test the microlensing solution and to further characterize the system.
- ID:
- ivo://CDS.VizieR/J/MNRAS/500/859
- Title:
- Ridges in the Dark Energy Survey
- Short Name:
- J/MNRAS/500/859
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cosmic voids and their corresponding redshift-aggregated projections of mass densities, known as troughs, play an important role in our attempt to model the large-scale structure of the Universe. Understanding these structures leads to tests comparing the standard model with alternative cosmologies, constraints on the dark energy equation of state, and provides evidence to differentiate among gravitational theories. In this paper, we extend the subspace-constrained mean shift algorithm, a recently introduced method to estimate density ridges, and apply it to 2D weak-lensing mass density maps from the Dark Energy Survey Y1 data release to identify curvilinear filamentary structures. We compare the obtained ridges with previous approaches to extract trough structure in the same data, and apply curvelets as an alternative wavelet-based method to constrain densities. We then invoke the Wasserstein distance between noisy and noiseless simulations to validate the denoising capabilities of our method. Our results demonstrate the viability of ridge estimation as a precursor for denoising weak lensing quantities to recover the large-scale structure, paving the way for a more versatile and effective search for troughs.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A165
- Title:
- SDSS J1339+1310 light curves and spectra
- Short Name:
- J/A+A/646/A165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We studied the accretion disc structure in the doubly imaged lensed quasar SDSS J1339+1310 using r-band light curves and UV-visible to near-IR spectra from the first 11 observational seasons after its discovery. The 2009-2019 light curves displayed pronounced microlensing variations on different timescales, and this microlensing signal permitted us to constrain the half-light radius of the 1930{AA} continuum-emitting region. Assuming an accretion disc with an axis inclined at 60{deg} to the line of sight, we obtained log(r_1/2_/cm)=15.4_-0.4+^+0.93%. We also estimated the central black hole mass from spectroscopic data. The width of the CIV, MgII, and H{beta} emission lines, and the continuum luminosity at 1350, 3000, and 5100{AA}, led to log(M_BH_/M_{sun}_)=8.6+/-0.4. Thus, hot gas responsible for the 1930{AA} continuum emission is likely orbiting a 4.0x10^8^M_{sun}_ black hole at an r_1/2_ of only a few tens of Schwarzschild radii.
- ID:
- ivo://CDS.VizieR/J/A+A/634/A27
- Title:
- SDSS J1004+4112 spectra
- Short Name:
- J/A+A/634/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new spectroscopic and polarimetric observations of the gravitational lens SDSS J1004+4112 taken with the 6m telescope of the Special Astrophysical Observatory (SAO, Russia). In order to explain the variability that is observed only in the blue wing of the CIV emission line, corresponding to image A, we analyze the spectroscopy and polarimetry of the four images of the lensed system. Spectra of the four images were taken in 2007, 2008, and 2018, and polarization was measured in the period 2014-2017. Additionally, we modeled the microlensing effect in the polarized light, assuming that the source of polarization is the equatorial scattering in the inner part of the torus. We find that a blue enhancement in the CIV line wings affects component A in all three epochs. We also find that the UV continuum of component D was amplified in the period 2007-2008, and that the red wings of CIII] and CIV appear brighter in D than in the other three components. We report significant changes in the polarization parameters of image D, which can be explained by microlensing. Our simulations of microlensing of an equatorial scattering region in the dusty torus can qualitatively explain the observed changes in the polarization degree and angle of image D.We do not detect significant variability in the polarization parameters of the other images (A, B, and C), although the averaged values of the polarization degree and angle are different for the different images. Microlensing of a broad line region model including a compact outflowing component can qualitatively explain the CIV blue wing enhancement (and variation) in component A. However, to confirmed this hypothesis, we need additional spectroscopic observation in future.
- ID:
- ivo://CDS.VizieR/J/A+A/596/A77
- Title:
- SDSS J1339+1310 spectra and light curves
- Short Name:
- J/A+A/596/A77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We spectroscopically re-observed the gravitational lens system SDSS J1339+1310 using OSIRIS on the GTC. We also monitored the r-band variability of the two quasar images (A and B) with the LT over 143 epochs in the period 2009-2016. These new data in both the wavelength and time domains have confirmed that the system is an unusual microlensing factory. The CIV emission line is remarkably microlensed, since the microlensing magnification of B relative to that for A,{mu}_BA_, reaches a value of 1.4 (~0.4mag) for its core. Moreover, the B image shows a red wing enhancement of CIV flux (relative to A), and {mu}_BA_=2 (0.75mag) for the CIV broad-line emission. Regarding the nuclear continuum, we find a chromatic behaviour of {mu}_BA_, which roughly varies from ~5 (1.75mag) at 7000{AA} to ~6 (1.95mag) at 4000{AA}. We also detect significant microlensing variability in the r band, and this includes a number of microlensing events on timescales of 50-100d. Fortunately, the presence of an intrinsic 0.7 mag dip in the light curves of A and B, permitted us to measure the time delay between both quasar images. This delay is {Delta}t_AB_=47^+5^_-6_d (1{sigma} confidence interval; A is leading), in good agreement with predictions of lens models.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A101
- Title:
- SDSS J081830.46+060138.0 spectropolarimetry
- Short Name:
- J/A+A/633/A101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gravitational microlensing is a powerful tool for probing the inner structure of distant quasars. In this context, we have obtained spectropolarimetric observations of the two images of the broad absorption line (BAL) quasar SDSS J081830.46+060138.0 (J0818+0601) at redshift z~~2.35. We first show that J0818+0601 is actually gravitationally lensed, and not a binary quasar. A strong absorption system detected at z=1.0065+/-0.0002 is possibly due to the lensing galaxy. Microlensing is observed in one image and it magnifies the emission lines, the continuum, and the BALs differently. By disentangling the part of the spectrum that is microlensed from the part that is not microlensed, we unveil two sources of continuum that must be spatially separated: a compact one, which is microlensed, and an extended one, which is not microlensed and contributes to two thirds of the total continuum emission. J0818+0601 is the second BAL quasar in which an extended source of rest-frame ultraviolet continuum is found. We also find that the images are differently polarized, suggesting that the two continua might be differently polarized. Our analysis provides constraints on the BAL flow. In particular, we find that the outflow is seen with a nonzero onset velocity, and stratified according to ionization.
- ID:
- ivo://CDS.VizieR/J/ApJ/769/52
- Title:
- SDSS luminous red galaxies concentrations
- Short Name:
- J/ApJ/769/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The best gravitational lenses for detecting distant galaxies are those with the largest mass concentrations and the most advantageous configurations of that mass along the line of sight. Our new method for finding such gravitational telescopes uses optical data to identify projected concentrations of luminous red galaxies (LRGs). LRGs are biased tracers of the underlying mass distribution, so lines of sight with the highest total luminosity in LRGs are likely to contain the largest total mass. We apply this selection technique to the Sloan Digital Sky Survey and identify the 200 fields with the highest total LRG luminosities projected within a 3.5' radius over the redshift range 0.1<=z<=0.7. The redshift and angular distributions of LRGs in these fields trace the concentrations of non-LRG galaxies. These fields are diverse; 22.5% contain one known galaxy cluster and 56.0% contain multiple known clusters previously identified in the literature. Thus, our results confirm that these LRGs trace massive structures and that our selection technique identifies fields with large total masses. These fields contain two to three times higher total LRG luminosities than most known strong-lensing clusters and will be among the best gravitational lensing fields for the purpose of detecting the highest redshift galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/132/999
- Title:
- SDSS quasar lens search
- Short Name:
- J/AJ/132/999
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an algorithm for selecting a uniform sample of gravitationally lensed quasar candidates from low-redshift (0.6<z<2.2) quasars brighter than i=19.1 that have been spectroscopically identified in the Sloan Digital Sky Survey (SDSS). Our algorithm uses morphological and color selections that are intended to identify small- and large-separation lenses, respectively. Our selection algorithm only relies on parameters that the SDSS standard image processing pipeline generates, allowing easy and fast selection of lens candidates. The algorithm has been tested against simulated SDSS images, which adopt distributions of field and quasar parameters taken from the real SDSS data as input. Furthermore, we take differential reddening into account. We find that our selection algorithm is almost complete down to separations of 1" and flux ratios of 10^-0.5^.
- ID:
- ivo://CDS.VizieR/J/AJ/135/496
- Title:
- SDSS quasar lens search. II.
- Short Name:
- J/AJ/135/496
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the first results of our systematic search for strongly lensed quasars using the spectroscopically confirmed quasars in the Sloan Digital Sky Survey (SDSS). Among 46420 quasars from the SDSS Data Release 3 (~4188deg^2^), we select a subsample of 22683 quasars that are located at redshifts between 0.6 and 2.2 and are brighter than the Galactic extinction-corrected i-band magnitude of 19.1. We identify 220 lens candidates from the quasar subsample, for which we conduct extensive and systematic follow-up observations in optical and near-infrared wavebands, in order to construct a complete lensed quasar sample at image separations between 1" and 20" and flux ratios of faint to bright lensed images larger than 10^-0.5^. We construct a statistical sample of 11 lensed quasars. Ten of these are galaxy-scale lenses with small image separations (~1"-2") and one is a large separation (15") system which is produced by a massive cluster of galaxies, representing the first statistical sample of lensed quasars including both galaxy- and cluster-scale lenses. The Data Release 3 spectroscopic quasars contain an additional 11 lensed quasars outside the statistical sample.
