- 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.
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- ID:
- ivo://CDS.VizieR/J/ApJ/835/254
- Title:
- GLASS. IX. Structural param. from HFF & GLASS
- Short Name:
- J/ApJ/835/254
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using deep Hubble Frontier Fields imaging and slitless spectroscopy from the Grism Survey from Space, we study 2200 cluster and 1748 field galaxies at 0.2<=z<=0.7 to determine the impact of environment on galaxy size and structure at stellar masses logM_*_/M_{sun}_>7.8, an unprecedented limit at these redshifts. Based on simple assumptions-r_e_=f(M_*_)-we find no significant differences in half-light radii (r_e_) between equal-mass cluster or field systems. More complex analyses --r_e_=f(M_*_,U-V,n,z,{Sigma})-- reveal local density ({Sigma}) to induce only a 7%+/-3% (95% confidence) reduction in r_e_ beyond what can be accounted for by U-V color, Sersic index (n), and redshift (z) effects. Almost any size difference between galaxies in high- and low-density regions is thus attributable to their different distributions in properties other than environment. Indeed, we find a clear color-r_e_ correlation in low-mass passive cluster galaxies (logM_*_/M_{sun}_<9.8) such that bluer systems have larger radii, with the bluest having sizes consistent with equal-mass star-forming galaxies. We take this as evidence that large-r_e_ low-mass passive cluster galaxies are recently acquired systems that have been environmentally quenched without significant structural transformation (e.g., by ram pressure stripping or starvation). Conversely, ~20% of small-r_e_ low-mass passive cluster galaxies appear to have been in place since z>~3. Given the consistency of the small-r_e_ galaxies' stellar surface densities (and even colors) with those of systems more than ten times as massive, our findings suggest that clusters mark places where galaxy evolution is accelerated for an ancient base population spanning most masses, with late-time additions quenched by environment-specific mechanisms mainly restricted to the lowest masses.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/178
- Title:
- GLASS. VII. H{alpha} maps
- Short Name:
- J/ApJ/833/178
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exploiting the slitless spectroscopy taken as part of the Grism Lens-Amplified Survey from Space (GLASS), we present an extended analysis of the spatial distribution of star formation in 76 galaxies in 10 clusters at 0.3<z<0.7. We use 85 foreground and background galaxies in the same redshift range as a field sample. The samples are well matched in stellar mass (10^8^-10^11^M_{sun}_) and star formation rate (0.5-50M_{sun}_/yr). We visually classify galaxies in terms of broad band morphology, H{alpha} morphology, and likely physical process acting on the galaxy. Most H{alpha} emitters have a spiral morphology (41%+/-8% in clusters, 51%+/-8% in the field), followed by mergers/interactions (28%+/-8%, 31%+/-7%, respectively) and early-type galaxies (remarkably as high as 29%+/-8% in clusters and 15%+/-6% in the field). A diversity of H{alpha} morphologies is detected, suggesting a diversity of physical processes. In clusters, 30%+/-8% of the galaxies present a regular morphology, mostly consistent with star formation diffused uniformly across the stellar population (mostly in the disk component, when present). The second most common morphology (28%+/-8%) is asymmetric/jellyfish, consistent with ram-pressure stripping or other non-gravitational processes in 18%+/-8% of the cases. Ram-pressure stripping appears significantly less prominent in the field (2%+/-2%), where the most common morphology/mechanism appears to be consistent with minor gas-rich mergers or clump accretion. This work demonstrates that while environment-specific mechanisms affect galaxy evolution at this redshift, they are diverse and their effects are subtle. A full understanding of this complexity requires larger samples and detailed and spatially resolved physical models.
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJS/180/54
- Title:
- Globular cluster candidates in ACS Virgo survey.
- Short Name:
- J/ApJS/180/54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present catalogs of globular cluster candidates for the 100 galaxies of the Advanced Camera for Surveys Virgo Cluster Survey, a large program to carry out imaging of early-type members of the Virgo Cluster using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. We describe the procedure used to select bona fide globular cluster candidates out of the full list of detections based on model-based clustering methods with the use of expected contamination catalogs constructed using blank field observations and which are customized for each galaxy. We also present the catalogs of expected contaminants for each of our target galaxies. For each detected source we measure its position, magnitudes in the F475W (~Sloan g) and F850LP (~Sloan z) bandpasses, and half-light radii by fitting point-spread function convolved King models to the observed light distribution. These measurements are presented for 20375 sources, of which 12763 are likely to be globular clusters. Finally, we detail the calculation of the aperture corrections adopted for the globular cluster photometry.
- ID:
- ivo://CDS.VizieR/J/AJ/127/24
- Title:
- Globular clusters in 4 cD galaxies
- Short Name:
- J/AJ/127/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used WFPC2 on the Hubble Space Telescope (HST) to obtain F450W and F814W images of four cD galaxies (NGC 541 in Abell 194, NGC 2832 in Abell 779, NGC 4839 in Abell 1656, and NGC 7768 in Abell 2666) in the range 5400km/s<cz<8100km/s. For NGC 541, the HST data are supplemented by ground-based B and I images obtained with FORS1 on the Very Large Telescope.
- ID:
- ivo://CDS.VizieR/J/ApJS/191/254
- Title:
- GMBCG galaxy cluster catalog from SDSS DR7
- Short Name:
- J/ApJS/191/254
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a large catalog of optically selected galaxy clusters from the application of a new Gaussian Mixture Brightest Cluster Galaxy (GMBCG) algorithm to SDSS Data Release 7 data. The algorithm detects clusters by identifying the red-sequence plus brightest cluster galaxy (BCG) feature, which is unique for galaxy clusters and does not exist among field galaxies. Red-sequence clustering in color space is detected using an Error Corrected Gaussian Mixture Model. We run GMBCG on 8240 deg^2^ of photometric data from SDSS DR7 to assemble the largest ever optical galaxy cluster catalog, consisting of over 55,000 rich clusters across the redshift range from 0.1<z<0.55. We present Monte Carlo tests of completeness and purity and perform cross-matching with X-ray clusters and with the maxBCG sample at low redshift. These tests indicate high completeness and purity across the full redshift range for clusters with 15 or more members.
- ID:
- ivo://CDS.VizieR/VII/42A
- Title:
- GMP catalogue: galaxies in the Coma cluster
- Short Name:
- VII/42A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue contains isophotal magnitudes, radii, intensity profiles, ellipticities and (b-r) colours for 6724 galaxies with b26.5 < 21.0 mag in a 26.3 degree square area centered on the Coma cluster. The sample is essentially complete to b26.5 = 20.0, with rms deviations in b26.5, r24.75 and (b-r) all about 0.15mag. The plates used in this investigation were all taken with the Palomar 48-inch Schmidt telescope during good conditions in 1976 May.
- 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.
