- ID:
- ivo://CDS.VizieR/J/A+A/610/A53
- Title:
- Strong lensing star-forming galaxies with ALMA
- Short Name:
- J/A+A/610/A53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- According to coevolutionary scenarios, nuclear activity and star formation play relevant roles in the early stages of galaxy formation. We aim at identifying them in high-redshift galaxies by exploiting high-resolution and high-sensitivity X-ray and millimeter-wavelength data to confirm the presence or absence of star formation and nuclear activity and describe their relative roles in shaping the spectral energy distributions and in contributing to the energy budgets of the galaxies. We present the data, model, and analysis in the X-ray and millimeter (mm) bands for two strongly lensed galaxies, SDP.9 (HATLAS J090740.0-004200) and SDP.11 (HATLAS J091043.1-000322), which we selected in the Herschel-ATLAS catalogs for their excess emission in the mid-IR regime at redshift >=1.5. This emission suggests nuclear activity in the early stages of galaxy formation. We observed both of them with Chandra ACIS-S in the X-ray regime and analyzed the high-resolution mm data that are available in the ALMA Science Archive for SDP.9. By combining the information available in mm, optical, and X-ray bands, we reconstructed the source morphology. Both targets were detected in the X-ray, which strongly indicates highly obscured nuclear activity. ALMA observations for SDP.9 for the continuum and CO(6-5) spectral line with high resolution (0.02-arcsec corresponding to ~65pc at the distance of the galaxy) allowed us to estimate the lensed galaxy redshift to a better accuracy than pre-ALMA estimates (1.5753+/-0.0003) and to model the emission of the optical, millimetric, and X-ray band for this galaxy. We demonstrate that the X-ray emission is generated in the nuclear environment, which strongly supports that this object has nuclear activity. On the basis of the X-ray data, we attempt an estimate of the black hole properties in these galaxies. By taking advantage of the lensing magnification, we identify weak nuclear activity associated with high-z galaxies with high star formation rates. This is useful to extend the investigation of the relationship between star formation and nuclear activity to two intrinsically less luminous high-z star-forming galaxies than was possible so far. Given our results for only two objects, they alone cannot constrain the evolutionary models, but provide us with interesting hints and set an observational path toward addressing the role of star formation and nuclear activity in forming galaxies.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/806/185
- Title:
- Strong-lensing systems from 4 surveys
- Short Name:
- J/ApJ/806/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we assemble a catalog of 118 strong gravitational lensing systems from the Sloan Lens ACS Survey (SLACS), BOSS emission-line lens survey (BELLS), Lens Structure and Dynamics (LSD), and Strong Lensing Legacy Survey (SL2S) and use them to constrain the cosmic equation of state. In particular, we consider two cases of dark energy phenomenology: the XCDM model, where dark energy is modeled by a fluid with constant w equation-of-state parameter, and in the Chevalier-Polarski-Linder (CPL) parameterization, where w is allowed to evolve with redshift, w(z)=w_0_+w_1_(z/1+z). We assume spherically symmetric mass distribution in lensing galaxies, but we relax the rigid assumption of the SIS model in favor of a more general power-law index {gamma}, also allowing it to evolve with redshifts {gamma}(z). Our results for the XCDM cosmology show agreement with values (concerning both w and {gamma} parameters) obtained by other authors. We go further and constrain the CPL parameters jointly with {gamma}(z). The resulting confidence regions for the parameters are much better than those obtained with a similar method in the past. They are also showing a trend of being complementary to the Type Ia supernova data. Our analysis demonstrates that strong gravitational lensing systems can be used to probe cosmological parameters like the cosmic equation of state for dark energy. Moreover, they have a potential to judge whether the cosmic equation of state evolved with time or not.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/12
- Title:
- Strong lens models for 37 clusters from SGAS
- Short Name:
- J/ApJS/247/12
- Date:
- 08 Mar 2022 13:45:09
- Publisher:
- CDS
- Description:
- We present strong gravitational lensing models for 37 galaxy clusters from the Sloan Digital Sky Survey Giant Arcs Survey (SGAS). We combine data from multi-band Hubble Space Telescope Wide Field Camera 3 (WFC3) imaging, with ground-based imaging and spectroscopy from Magellan, Gemini, Apache Point Observatory, and the Multiple Mirror Telescope, in order to detect and spectroscopically confirm new multiply imaged lensed background sources behind the clusters. We report spectroscopic or photometric redshifts of sources in these fields, including cluster galaxies and background sources. Based on all available lensing evidence, we construct and present strong-lensing mass models for these galaxy clusters. The clusters span a redshift range of 0.176<z<0.66 with a median redshift of z=0.45, and sample a wide range of dynamical masses, 1.5<M_200_<35x10^14^M_{sun}_, as estimated from their velocity dispersions. As these clusters were selected as lenses primarily owing to a fortuitous alignment with background galaxies that results in giant arcs, they exhibit a wide range in Einstein radii, 1.3"<{theta}_E_<23.1" for a source at z=2, with a median {theta}_E_=10.8".
- ID:
- ivo://CDS.VizieR/J/A+A/631/A91
- Title:
- 2 strongly lensed galaxies MUSE & ALMA datacubes
- Short Name:
- J/A+A/631/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the molecular and ionized gas kinematics of two strongly lensed galaxies at z~1 that lie on the main sequence at this redshift, based on observations from ALMA and MUSE, respectively. We derive the CO and [OII] rotation curves and dispersion profiles of these two galaxies. We find a difference between the observed molecular and ionized gas rotation curves for one of the two galaxies, the Cosmic Snake, for which we obtain a spatial resolution of few hundred parsecs along the major axis. The rotation curve of the molecular gas is steeper than the rotation curve of the ionized gas. In the second galaxy, A521, the molecular and ionized gas rotation curves are consistent, but the spatial resolution is only of few kpc on the major axis. Using simulations, we investigate the effect of the thickness of the gas disk and effective radius on the observed rotation curves and find that a more extended and thicker disk smooths the curve. We also find that the presence of a strongly inclined (>70{deg}) thick disk (>1kpc) can smooth the rotation curve because it degrades the spatial resolution along the line of sight. By building a model using a stellar disk and two gas disks, we reproduce the rotation curves of the Cosmic Snake with a molecular gas disk that is more massive and more radially and vertically concentrated than the ionized gas disk. Finally, we also obtain an intrinsic velocity dispersion in the Cosmic Snake of 18.5+/-7km/s and 19.5+/-6km/s for the molecular and ionized gas, respectively, which is consistent with a molecular disk with a smaller and thinner disk. For A521, the intrinsic velocity dispersion values are 11+/-8km/s and 54+/-11km/s, with a higher value for the ionized gas. This could indicate that the ionized gas disk is thicker and more turbulent in this galaxy. These results highlight the diversity of the kinematics of galaxies at z~1 and the different spatial distribution of the molecular and ionized gas disks. It suggests the presence of thick ionized gas disks at this epoch and that the formation of the molecular gas is limited to the midplane and center of the galaxy in some objects.
- ID:
- ivo://CDS.VizieR/J/MNRAS/477/L70
- Title:
- Strongly lensed quasars in SDSS
- Short Name:
- J/MNRAS/477/L70
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of three quasar lenses in the Sloan Digital Sky Survey, selected using two novel photometry-based selection techniques. The J0941+0518 system, with two point sources separated by 5.46 arcsec on either side of a galaxy, has source and lens redshifts 1.54 and 0.343. Images of J2257+2349 show two point sources separated by 1.67 arcsec on either side of an E/S0 galaxy. The extracted spectra show two images of the same quasar at z_s_=2.10. SDSS J1640+1045 has two quasar spectra at z_s_=1.70 and fits to the SDSS and Pan-STARRS images confirm the presence of a galaxy between the two point sources. We observed 56 photometrically selected lens candidates in this follow-up campaign, confirming three new lenses, re-discovering one known lens, and ruling out 36 candidates, with 16 still inconclusive. This initial campaign demonstrates the power of purely photometric selection techniques in finding lensed quasars.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A36
- Title:
- Subaru H images of UM673
- Short Name:
- J/A+A/566/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed a detailed photometric analysis of the lensed system UM673 (Q0142-100) and an analysis of the tentative lens models. High-resolution adaptive optics images of UM673 taken with the Subaru telescope in the H band were examined. We also analysed the J, H and K-band observational data of UM673 obtained with the 1.3m telescope at the CTIO observatory. We present photometry of quasar components A and B of UM673, the lens, and the nearby bright galaxy using H-band observational data obtained with the Subaru telescope. Based on the CTIO observations of UM673, we also present J- and H-band photometry and estimates of the J, H and K-band flux ratios between the two UM673 components in recent epochs. The near-infrared fluxes of the A and B components of UM673 and their published optical fluxes are analysed to measure extinction properties of the lensing galaxy. We estimate the extinction-corrected flux ratio between components A and B to be about 2.14 mag. We discuss lens models for the UM673 system constrained with the positions of the UM673 components, their flux ratio, and the previously measured time delay.
- ID:
- ivo://CDS.VizieR/J/ApJ/669/714
- Title:
- Subaru weak-lensing survey. I.
- Short Name:
- J/ApJ/669/714
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an ongoing weak-lensing survey conducted with the Subaru Telescope whose initial goal is to locate and study the distribution of shear-selected structures, or halos. Using a Suprime-Cam imaging survey spanning 21.82deg^2^, we present a catalog of 100 candidate halos located from lensing-convergence maps. Our sample is reliably drawn from that subset of our survey area (totaling 16.72deg^2^) uncontaminated by bright stars and edge effects and is limited at a convergence signal-to-noise ratio of 3.69. To validate the sample, detailed spectroscopic measures have been made for 26 candidates using the Subaru multiobject spectrograph, FOCAS. All are confirmed as clusters of galaxies, but two arise as the superposition of multiple clusters viewed along the line of sight. Including data available in the literature and an ongoing Keck spectroscopic campaign, a total of 41 halos now have reliable redshifts.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A148
- Title:
- SuGOHI VI. List up to 2020
- Short Name:
- J/A+A/642/A148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Strong lenses are extremely useful probes of the distribution of matter on galaxy and cluster scales at cosmological distances, but are rare and difficult to find. The number of currently known lenses is on the order of 1000. We wish to use crowdsourcing to carry out a lens search targeting massive galaxies selected from over 442 square degrees of photometric data from the Hyper Suprime-Cam (HSC) survey. We selected from the S16A internal data release of the HSC survey a sample of ~300000 galaxies with photometric redshifts in the range 0.2<zphot<1.2 and photometrically inferred stellar masses logM*>11.2. We crowdsourced lens finding on this sample of galaxies on the Zooniverse platform, as part of the Space Warps project. The sample was complemented by a large set of simulated lenses and visually selected non-lenses, for training purposes. Nearly 6000 citizen volunteers participated in the experiment. In parallel, we used YattaLens an automated lens finding algorithm, to look for lenses in the same sample of galaxies. Based on a statistical analysis of classification data from the volunteers, we selected a sample of the most promising ~1500 candidates which we then visually inspected: half of them turned out to be possible (grade C) lenses or better. Including lenses found by YattaLens or serendipitously noticed in the discussion section of the Space Warps website, we were able to find 14 definite lenses (grade A), 129 probable lenses (grade B) and 581 possible lenses. YattaLens found half the number of lenses discovered via crowdsourcing. Crowdsourcing is able to produce samples of lens candidates with high completeness and purity, compared to currently available automated algorithms. A hybrid approach, in which the visual inspection of samples of lens candidates pre-selected by discovery algorithms and/or coupled to machine learning is crowdsourced, will be a viable option for lens finding in the 2020s with forthcoming wide area surveys such as LSST, Euclid and WFIRST.
- ID:
- ivo://CDS.VizieR/J/ApJS/253/3
- Title:
- Sunyaev-Zel'dovich galaxy clusters surveyed by ACT
- Short Name:
- J/ApJS/253/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 4195 optically confirmed Sunyaev-Zel'dovich (SZ) selected galaxy clusters detected with signal-to-noise ratio >4 in 13211deg^2^ of sky surveyed by the Atacama Cosmology Telescope (ACT). Cluster candidates were selected by applying a multifrequency matched filter to 98 and 150GHz maps constructed from ACT observations obtained from 2008 to 2018 and confirmed using deep, wide-area optical surveys. The clusters span the redshift range 0.04<z<1.91 (median z=0.52). The catalog contains 222 z>1 clusters, and a total of 868 systems are new discoveries. Assuming an SZ signal versus mass-scaling relation calibrated from X-ray observations, the sample has a 90% completeness mass limit of M_500c_>3.8x10^14^M_{sun}_, evaluated at z=0.5, for clusters detected at signal-to-noise ratio >5 in maps filtered at an angular scale of 2.4'. The survey has a large overlap with deep optical weak-lensing surveys that are being used to calibrate the SZ signal mass-scaling relation, such as the Dark Energy Survey (4566deg^2^), the Hyper Suprime-Cam Subaru Strategic Program (469deg^2^), and the Kilo Degree Survey (825deg^2^). We highlight some noteworthy objects in the sample, including potentially projected systems, clusters with strong lensing features, clusters with active central galaxies or star formation, and systems of multiple clusters that may be physically associated. The cluster catalog will be a useful resource for future cosmological analyses and studying the evolution of the intracluster medium and galaxies in massive clusters over the past 10Gyr.
140. SuperCLASS. I.
- ID:
- ivo://CDS.VizieR/J/MNRAS/495/1706
- Title:
- SuperCLASS. I.
- Short Name:
- J/MNRAS/495/1706
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The SuperCLuster Assisted Shear Survey (SuperCLASS) is a legacy programme using the e-MERLIN interferometric array. The aim is to observe the sky at L-band (1.4GHz) to a r.m.s. of 7uJy/beam over an area of 1 square degrees centred on the Abell 981 supercluster. The main scientific objectives of the project are: (i) to detect the effects of weak lensing in the radio in preparation for similar measurements that will be made by the Square Kilometre Array (SKA); (ii) an extinction free census of star formation and AGN activity at z up to 1. In this paper we give an overview of the project including the science goals and multi-wavelength coverage before presenting the first data release. We have analysed around 400 hours of e-MERLIN data which has allowed us to create a DR1 mosaic covering an area ~0.26 square degrees to the full depth. These observations have been supplemented with complementary radio observations from the Karl G. Jansky Very Large Array (VLA) and optical/near infra-red observations taken with the Subaru, Canada-France-Hawaii and Spitzer Telescopes. The main data product is a catalogue of 887 sources detected by the VLA, of which 395 are detected by e-MERLIN and 197 of these are resolved. We have investigated the size, flux and spectral index properties of these sources and find them to be compatible with previous studies. Preliminary photometric redshifts, and an assessment of galaxy shapes measured in the radio data, combined with a radio-optical cross-correlation technique to probe cosmic shear in a supercluster environment, are presented in companion papers.
