- ID:
- ivo://CDS.VizieR/J/A+A/633/A98
- Title:
- Gaia16aye microlensing event photometry
- Short Name:
- J/A+A/633/A98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gaia16aye was a binary microlensing event, the first such event ever discovered in the direction towards the Northern Galactic Disk and one of the first microlensing events detected and alerted by the Gaia space mission. Its light curve exhibited five distinct brightening episodes, reaching up to 11mag, and was covered in great detail with almost 25000 data points gathered by a network of telescopes. We present the photometric and spectroscopic follow-up covering 500 days of the event evolution and search for a possible microlensing model in order to derive the parameters of the lensing binary system. For Gaia16aye event we employed a full Keplerian binary orbit microlensing model combined with the Earth and Gaia motion around the Sun, to reproduce the complex light curve. The photometric data allowed us to solve the microlensing events entirely and to derive the complete and unique set of orbital parameters of the binary lensing system. We also report on the detection of the first ever microlensing space-parallax between the Earth and Gaia located at L2. The binary system properties were derived from microlensing parameters and we found that the system is composed of two main-sequence stars with masses 0.570.05 M and 0.36+/-0.03M_{sun}_ at 780pc, with an orbital period of 2.88 years and eccentricity of 0.30. We also predict the astrometric microlensing signal for this binary lens as it will be seen by Gaia as well as the radial velocity curve. Events like Gaia16aye indicate the potential for the microlensing method to probe the mass function of dark objects, including black holes, in other directions than the Galactic bulge. This case also emphasises the importance of long-term time-domain coordinated observations which can be done with a network of heterogeneous telescopes.
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- ID:
- ivo://CDS.VizieR/J/A+A/657/A17
- Title:
- Gaia 19bld spectroscopic follow-up
- Short Name:
- J/A+A/657/A17
- Date:
- 21 Mar 2022 09:21:49
- Publisher:
- CDS
- Description:
- As the event displayed an increased brightness, spectroscopic follow-up observations were immediately scheduled. Low-resolution spectra (R~500) were obtained using the FLOYDS spectrograph, which is mounted on the Las Cumbres Observatory (LCO) 2-m telescope at Siding Spring Observatory In addition,we used the X-shooter instrument mounted on the ESO Very Large Telescope (VLT) which is a multi-wavelength, medium-resolution spectrograph consisted of three spectroscopic arms allowing for simultaneous observations at three wavelength ranges: UVB (300-559.5nm), VIS (559.5-1024nm), and NIR (1024-2480nm). Spectra used in this publication.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A56
- Title:
- Gaia GraL. II. Known multiply imaged quasars
- Short Name:
- J/A+A/618/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Thanks to its spatial resolution the ESA/Gaia space mission offers a unique opportunity to discover new multiply-imaged quasars and to study the already known lensed systems at sub-milliarcsecond astrometric precisions. Aims : In this paper, we address the detection of the known multiply-imaged quasars from the Gaia Data Release 2 and determine the astrometric and photometric properties of the individually detected images found in the Gaia DR2 catalogue. We have compiled an exhaustive list of quasar gravitational lenses from the literature to search for counterparts in the Gaia Data Release 2. We then analyze the astrometric and photometric properties of these Gaia's detections. To highlight the tremendous potential of Gaia at the sub-milliarcsecond level we finally perform a simple Bayesian modeling of the well-known gravitational lens system HE0435-1223, using Gaia Data Release 2 and HST astrometry. From 478 known multiply imaged quasars, 200 have at least one image found in the Gaia Data Release 2. Among the 41 known quadruply-imaged quasars of the list, 26 have at least one image in the Gaia Data Release 2, 12 of which are fully detected (2MASX J01471020+4630433, HE 0435-1223, SDSS1004+4112, PG1115+080, RXJ1131-1231, 2MASS J11344050-2103230, 2MASS J13102005-1714579, B1422+231, J1606-2333, J1721+8842, WFI2033-4723, WGD2038-4008), 6 have three counterparts, 7 have two and 1 has only one. As expected, the modeling of HE0435-1223 shows that the model parameters are significantly better constrained when using Gaia astrometry compared to HST astrometry, in particular the relative positions of the background quasar source and the centroid of the deflector. The Gaia sub-milliarcsecond astrometry also significantly reduces the parameter correlations. Besides providing an up-to-date list of multiply imaged quasars and their detection in the Gaia DR2, this paper shows that more complex modeling scenarios will certainly benefit from Gaia sub-milliarcsecond astrometry.
- ID:
- ivo://CDS.VizieR/J/MNRAS/467/4220
- Title:
- Galaxies inside 120 arcsec of HE 0435-1223
- Short Name:
- J/MNRAS/467/4220
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on spectroscopy and multiband wide-field observations of the gravitationally lensed quasar HE 0435-1223, we determine the probability distribution function of the external convergence {kappa}_ext_ for this system. We measure the under/overdensity of the line of sight towards the lens system and compare it to the average line of sight throughout the Universe, determined by using the CFHTLenS (The Canada France Hawaii Lensing Survey) as a control field. Aiming to constrain {kappa}_ext_ as tightly as possible, we determine under/overdensities using various combinations of relevant informative weighting schemes for the galaxy counts, such as projected distance to the lens, redshift and stellar mass. We then convert the measured under/overdensities into a {kappa}_ext_ distribution, using ray-tracing through the Millennium Simulation. We explore several limiting magnitudes and apertures, and account for systematic and statistical uncertainties relevant to the quality of the observational data, which we further test through simulations. Our most robust estimate of {kappa}_ext_ has a median value {kappa}^med^_ext_=0.004 and a standard deviation {sigma}_{kappa}_=0.025. The measured {sigma}_{kappa}_ corresponds to 2.5 per cent relative uncertainty on the time delay distance, and hence the Hubble constant H_0_ inferred from this system. The median {kappa}^med^_ext_ value varies by ~0.005 with the adopted aperture radius, limiting magnitude and weighting scheme, as long as the latter incorporates galaxy number counts, the projected distance to the main lens and a prior on the external shear obtained from mass modelling. This corresponds to just ~0.5 per cent systematic impact on H_0_. The availability of a well-constrained {kappa}_ext_ makes HE 0435-1223 a valuable system for measuring cosmological parameters using strong gravitational lens time delays.
- ID:
- ivo://CDS.VizieR/J/ApJ/820/98
- Title:
- Galaxy candidates in the Hubble Frontier Fields
- Short Name:
- J/ApJ/820/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the results of our search for and study of z>~6 galaxy candidates behind the third Frontier Fields (FFs) cluster, MACS J0717.5+3745, and its parallel field, combining data from Hubble and Spitzer. We select 39 candidates using the Lyman break technique, for which the clear non-detection in optical make the extreme mid-z interlopers hypothesis unlikely. We also take benefit from z>~6 samples selected using the previous FF data sets of Abell 2744 and MACS 0416 to improve the constraints on the properties of very high redshift objects. We compute the redshift and the physical properties such emission lines properties, star formation rate, reddening, and stellar mass for all FF objects from their spectral energy distribution using templates including nebular emission lines. We study the relationship between several physical properties and confirm the trend already observed in previous surveys for evolution of star formation rate with galaxy mass and between the size and the UV luminosity of our candidates. The analysis of the evolution of the UV luminosity function with redshift seems more compatible with an evolution of density. Moreover, no robust z>=8.5 object is selected behind the cluster field and few z~9 candidates have been selected in the two previous data sets from this legacy survey, suggesting a strong evolution in the number density of galaxies between z~8 and 9. Thanks to the use of the lensing cluster, we study the evolution of the star formation rate density produced by galaxies with L>0.03 L_{star}_, and confirm the strong decrease observed between z~8 and 9.
- ID:
- ivo://CDS.VizieR/J/MNRAS/455/892
- Title:
- Galaxy cluster concentration-mass relation
- Short Name:
- J/MNRAS/455/892
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Scaling relations of clusters have made them particularly important cosmological probes of structure formation. In this work, we present a comprehensive study of the relation between two profile observables, concentration (cvir) and mass (Mvir). We have collected the largest known sample of measurements from the literature which make use of one or more of the following reconstruction techniques: weak gravitational lensing (WL), strong gravitational lensing (SL), weak+strong lensing (WL+SL), the caustic method (CM), line-of-sight velocity dispersion (LOSVD), and X-ray. We find that the concentration-mass (c-M) relation is highly variable depending upon the reconstruction technique used. We also find concentrations derived from dark matter-only simulations (at approximately Mvir~10^14^M_{sun}_) to be inconsistent with the WL and WL+SL relations at the 1{sigma} level, even after the projection of triaxial haloes is taken into account. However, to fully determine consistency between simulations and observations, a volume-limited sample of clusters is required, as selection effects become increasingly more important in answering this. Interestingly, we also find evidence for a steeper WL+SL relation as compared to WL alone, a result which could perhaps be caused by the varying shape of cluster isodensities, though most likely reflects differences in selection effects caused by these two techniques. Lastly, we compare concentration and mass measurements of individual clusters made using more than one technique, highlighting the magnitude of the potential bias which could exist in such observational samples.
- ID:
- ivo://CDS.VizieR/J/MNRAS/449/4277
- Title:
- GAMA blended spectra catalogue
- Short Name:
- J/MNRAS/449/4277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalogue of blended galaxy spectra from the Galaxy And Mass Assembly (GAMA) survey. These are cases where light from two galaxies are significantly detected in a single GAMA fibre. Galaxy pairs identified from their blended spectrum fall into two principal classes: they are either strong lenses, a passive galaxy lensing an emission-line galaxy; or occulting galaxies, serendipitous overlaps of two galaxies, of any type. Blended spectra can thus be used to reliably identify strong lenses for follow-up observations (high-resolution imaging) and occulting pairs, especially those that are a late-type partly obscuring an early-type galaxy which are of interest for the study of dust content of spiral and irregular galaxies. The GAMA survey setup and its AUTOZ automated redshift determination were used to identify candidate blended galaxy spectra from the cross-correlation peaks. We identify 280 blended spectra with a minimum velocity separation of 600km/s, of which 104 are lens pair candidates, 71 emission-line-passive pairs, 78 are pairs of emission-line galaxies and 27 are pairs of galaxies with passive spectra. We have visually inspected the candidates in the Sloan Digital Sky Survey (SDSS) and Kilo Degree Survey (KiDS) images. Many blended objects are ellipticals with blue fuzz (Ef in our classification). These latter 'Ef' classifications are candidates for possible strong lenses, massive ellipticals with an emission-line galaxy in one or more lensed images. The GAMA lens and occulting galaxy candidate samples are similar in size to those identified in the entire SDSS. This blended spectrum sample stands as a testament of the power of this highly complete, second-largest spectroscopic survey in existence and offers the possibility to expand e.g. strong gravitational lens surveys.
- ID:
- ivo://CDS.VizieR/J/ApJ/811/29
- Title:
- GLASS. IV. Lensing cluster Abell 2744
- Short Name:
- J/ApJ/811/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a strong and weak lensing reconstruction of the massive cluster Abell 2744, the first cluster for which deep Hubble Frontier Fields (HFF) images and spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) are available. By performing a targeted search for emission lines in multiply imaged sources using the GLASS spectra, we obtain five high-confidence spectroscopic redshifts and two tentative ones. We confirm one strongly lensed system by detecting the same emission lines in all three multiple images. We also search for additional line emitters blindly and use the full GLASS spectroscopic catalog to test reliability of photometric redshifts for faint line emitters. We see a reasonable agreement between our photometric and spectroscopic redshift measurements, when including nebular emission in photometric redshift estimations. We introduce a stringent procedure to identify only secure multiple image sets based on colors, morphology, and spectroscopy. By combining 7 multiple image systems with secure spectroscopic redshifts (at 5 distinct redshift planes) with 18 multiple image systems with secure photometric redshifts, we reconstruct the gravitational potential of the cluster pixellated on an adaptive grid, using a total of 72 images. The resulting mass map is compared with a stellar mass map obtained from the deep Spitzer Frontier Fields data to study the relative distribution of stars and dark matter in the cluster. We find that the stellar to total mass ratio varies substantially across the cluster field, suggesting that stars do not trace exactly the total mass in this interacting system. The maps of convergence, shear, and magnification are made available in the standard HFF format.
- ID:
- ivo://CDS.VizieR/J/ApJ/831/182
- Title:
- GLASS. VI. MCS J0416.1-2403 HFF imaging & spectra
- Short Name:
- J/ApJ/831/182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a model using both strong and weak gravitational lensing of the galaxy cluster MACS J0416.1-2403, constrained using spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) and Hubble Frontier Fields (HFF) imaging data. We search for emission lines in known multiply imaged sources in the GLASS spectra, obtaining secure spectroscopic redshifts of 30 multiple images belonging to 15 distinct source galaxies. The GLASS spectra provide the first spectroscopic measurements for five of the source galaxies. The weak lensing signal is acquired from 884 galaxies in the F606W HFF image. By combining the weak lensing constraints with 15 multiple image systems with spectroscopic redshifts and nine multiple image systems with photometric redshifts, we reconstruct the gravitational potential of the cluster on an adaptive grid. The resulting map of total mass density is compared with a map of stellar mass density obtained from the deep Spitzer Frontier Fields imaging data to study the relative distribution of stellar and total mass in the cluster. We find that the projected stellar mass to total mass ratio, f*, varies considerably with the stellar surface mass density. The mean projected stellar mass to total mass ratio is <f*>=0.009+/-0.003 (stat.), but with a systematic error as large as 0.004-0.005, dominated by the choice of the initial mass function. We find agreement with several recent measurements of f* in massive cluster environments. The lensing maps of convergence, shear, and magnification are made available to the broader community in the standard HFF format.
