- ID:
- ivo://CDS.VizieR/J/MNRAS/474/3700
- Title:
- Gravitational lens candidates models
- Short Name:
- J/MNRAS/474/3700
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report modelling follow-up of recently discovered gravitational-lens candidates in the Canada France Hawaii Telescope Legacy Survey. Lens modelling was done by a small group of specially interested volunteers from the Space Warps citizen-science community who originally found the candidate lenses. Models are categorized according to seven diagnostics indicating (a) the image morphology and how clear or indistinct it is, (b) whether the mass map and synthetic lensed image appear to be plausible, and (c) how the lens-model mass compares with the stellar mass and the abundance-matched halo mass. The lensing masses range from ~10^11^ to >10^13^M_{sun|_. Preliminary estimates of the stellar masses show a smaller spread in stellar mass (except for two lenses): a factor of a few below or above ~10^11^M_{sun}_. Therefore, we expect the stellar-to-total mass fraction to decline sharply as lensing mass increases. The most massive system with a convincing model is J1434+522 (SW 05). The two low-mass outliers are J0206-095 (SW 19) and J2217+015 (SW 42); if these two are indeed lenses, they probe an interesting regime of very low star formation efficiency. Some improvements to the modelling software (SpaghettiLens), and discussion of strategies regarding scaling to future surveys with more and frequent discoveries, are included.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/131/49
- Title:
- Gravitational lenses among z>=4.0 quasars
- Short Name:
- J/AJ/131/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on i-band snapshot observations of 157 Sloan Digital Sky Survey quasars at 4.0<z<5.4 using the Advanced Camera for Surveys on the Hubble Space Telescope (HST) to search for evidence of gravitational lensing of these sources.
- ID:
- ivo://CDS.VizieR/J/MNRAS/372/1425
- Title:
- Gravitational lensing analysis of Abell 1689
- Short Name:
- J/MNRAS/372/1425
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have derived the mass distribution of galaxy cluster Abell 1689 within 0.3h^-1^_70_Mpc of the cluster centre using its strong lensing (SL) effect on 32 background galaxies, which are mapped in altogether 107 multiple images. The multiple images are based on some from the literature with modifications to both include new and exclude some of the original image systems. The cluster profile is explored further out to ~2.5h^-1^_70_Mpc with weak lensing (WL) shear measurements from the literature. The masses of ~200 cluster galaxies are measured with the Fundamental Plane (FP) in order to model accurately the small-scale mass structure in the cluster. The cluster galaxies are modelled as elliptical truncated isothermal spheres. The scalings of the truncation radii with the velocity dispersions of galaxies are assumed to match those of: (i) field galaxies; and (ii) theoretical expectations for galaxies in dense environments. The dark matter (DM) component of the cluster is described by either non-singular isothermal ellipsoids (NSIE) or elliptical versions of the universal DM profile (elliptical Navarro, Frenk & White, ENFW). To account for substructure in the DM we allow for two DM haloes.
- ID:
- ivo://CDS.VizieR/J/ApJ/736/43
- Title:
- Gravitational lensing flexion in A1689 with an AIM
- Short Name:
- J/ApJ/736/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measuring dark matter substructure within galaxy cluster halos is a fundamental probe of the {Lambda}CDM model of structure formation. Gravitational lensing is a technique for measuring the total mass distribution which is independent of the nature of the gravitating matter, making it a vital tool for studying these dark-matter-dominated objects. We present a new method for measuring weak gravitational lensing flexion fields, the gradients of the lensing shear field, to measure mass distributions on small angular scales. While previously published methods for measuring flexion focus on measuring derived properties of the lensed images, such as shapelet coefficients or surface brightness moments, our method instead fits a mass-sheet transformation invariant Analytic Image Model (AIM) to each galaxy image. This simple parametric model traces the distortion of lensed image isophotes and constrains the flexion fields. We test the AIM method using simulated data images with realistic noise and a variety of unlensed image properties, and show that it successfully reproduces the input flexion fields. We also apply the AIM method for flexion measurement to Hubble Space Telescope observations of A1689 and detect mass structure in the cluster using flexion measured with this method. We also estimate the scatter in the measured flexion fields due to the unlensed shape of the background galaxies and find values consistent with previous estimates.
- ID:
- ivo://CDS.VizieR/J/ApJ/561/106
- Title:
- Gravitational lensing of SN 1997ff
- Short Name:
- J/ApJ/561/106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the effects of gravitational lensing due to intervening galaxies on the recently discovered Type Ia supernova at z~1.7, SN 1997ff, in the Hubble Deep Field North. We find that it is possible to obtain a wide range of magnifications by varying the mass and/or the velocity dispersion normalization of the lensing galaxies. In order to be able to use SN 1997ff to constrain the redshift-distance relation, very detailed modeling of the galaxies to control the systematic effects from lensing is necessary. Thus, we argue that, based on our current limited knowledge of the lensing galaxies, it is difficult to use SN 1997ff to constrain the values of {Omega}_M_ and {Omega}_{Lambda}, or even to place severe limits on gray dust obscuration or luminosity evolution of Type Ia supernovae.
- ID:
- ivo://CDS.VizieR/J/ApJ/600/L155
- Title:
- Gravitational lens in GOODS ACS fields
- Short Name:
- J/ApJ/600/L155
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a systematic search for strong gravitational lenses in the Great Observatories Origins Deep Survey (GOODS) Advanced Camera for Surveys (ACS) data. The search technique involves creating a sample of likely lensing galaxies, which we define as massive early-type galaxies in a redshift range 0.3<z<1.3. The target galaxies are selected by color and magnitude, giving a sample of 1092 galaxies. For each galaxy in the sample, we subtract a smooth description of the galaxy light from the z850-band data. The residuals are examined, along with true-color images created from the B_435_V_606_i_775_ data, for morphologies indicative of strong lensing. We present our six most promising lens candidates as well as our full list of candidates.
- ID:
- ivo://CDS.VizieR/J/ApJ/627/32
- Title:
- Gravitationally lensed arcs in the HST WFPC2 archive
- Short Name:
- J/ApJ/627/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a systematic search for gravitationally lensed arcs in clusters of galaxies located in the Hubble Space Telescope Wide Field and Planetary Camera 2 data archive. By carefully examining the images of 128 clusters we have located 12 candidate radial arcs and 104 tangential arcs, each of whose length-to-width ratio exceeds 7. In addition, 24 other radial arc candidates were identified with a length-to-width ratio of less than 7. Keck spectroscopy of 17 candidate radial arcs suggests that contamination of the radial arc sample from nonlensed objects is ~30%-50%.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/2
- Title:
- Gravitationally lensed quasars
- Short Name:
- J/MNRAS/458/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an imaging observation campaign conducted with the Subaru Telescope adaptive optics system (IRCS+AO188) on 28 gravitationally lensed quasars and candidates (23 doubles, 1 quad, 1 possible triple, and 3 candidates) from the SDSS Quasar Lens Search. We develop a novel modelling technique that fits analytical and hybrid point spread functions (PSFs), while simultaneously measuring the relative astrometry, photometry, as well as the lens galaxy morphology. We account for systematics by simulating the observed systems using separately observed PSF stars. The measured relative astrometry is comparable with that typically achieved with the Hubble Space Telescope, even after marginalizing over the PSF uncertainty. We model for the first time the quasar host galaxies in five systems, without a priori knowledge of the PSF, and show that their luminosities follow the known correlation with the mass of the supermassive black hole. For each system, we obtain mass models far more accurate than those previously published from low-resolution data, and we show that in our sample of lensing galaxies the observed light profile is more elliptical than the mass, for ellipticity >~0.25. We also identify eight doubles for which the sources of external and internal shear are more reliably separated, and should therefore be prioritized in monitoring campaigns aimed at measuring time delays in order to infer the Hubble constant.
- ID:
- ivo://CDS.VizieR/J/ApJ/409/28
- Title:
- Gravitationally Lensed Quasars
- Short Name:
- J/ApJ/409/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Snapshot Survey was a search for cases of gravitational lensing among intrinsically-luminous, high-redshift quasars using the Hubble Space Telescope (HST) Planetary Camera (PC). The accompanying ASCII tables summarize the results of the survey.
- ID:
- ivo://CDS.VizieR/J/ApJ/715/1438
- Title:
- Gravitational-wave bursts with GRBs
- Short Name:
- J/ApJ/715/1438
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for gravitational-wave bursts (GWBs) associated with 137 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments during the fifth LIGO science run and first Virgo science run. The data used in this analysis were collected from 2005 November 4 to 2007 October 1, and most of the GRB triggers were from the Swift satellite. The search uses a coherent network analysis method that takes into account the different locations and orientations of the interferometers at the three LIGO-Virgo sites. We find no evidence for GWB signals associated with this sample of GRBs. Using simulated short-duration (<1s) waveforms, we set upper limits on the amplitude of gravitational waves associated with each GRB. We also place lower bounds on the distance to each GRB under the assumption of a fixed energy emission in gravitational waves, with a median limit of D~12Mpc(E^iso^_GW_/0.01M_{sun}_c^2^)^1/2^ for emission at frequencies around 150Hz, where the LIGO-Virgo detector network has best sensitivity.