- ID:
- ivo://CDS.VizieR/J/ApJ/668/643
- Title:
- Multiply imaged gravitational lens systems
- Short Name:
- J/ApJ/668/643
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a reconstruction of the mass distribution of galaxy cluster Abell 1689 at z=0.18 using detected strong lensing features from deep ACS observations and extensive ground based spectroscopy. Earlier analyses have reported up to 32 multiply imaged systems in this cluster, of which only 3 were spectroscopically confirmed. In this work, we present a parametric strong lensing mass reconstruction using 34 multiply imaged systems of which 24 have newly determined spectroscopic redshifts, which is a major step forward in building a robust mass model. In turn, the new spectroscopic data allows a more secure identification of multiply imaged systems.
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- ID:
- ivo://CDS.VizieR/J/ApJ/761/114
- Title:
- Multi-wavelength study of clusters of galaxies. II.
- Short Name:
- J/ApJ/761/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy clusters provide powerful laboratories for the study of galaxy evolution, particularly the origin of correlations of morphology and star formation rate (SFR) with density. We construct visible to MIR spectral energy distributions of galaxies in eight low-redshift (z<0.3) clusters and use them to measure stellar masses and SFRs as a function of environment. A partial correlation analysis indicates that the SFRs of star-forming galaxies (SFGs) depend strongly on M_*_ (>99% confidence) with no dependence on R/R_200_ or projected local density at fixed mass. A merged sample of galaxies from the five best measured clusters shows <SFR>{prop.to}(R/R_200_)^1.1+/-0.3^ for galaxies with R/R_200_<=0.4. A decline in the fraction of SFGs toward the cluster center contributes most of this effect, but it is accompanied by a reduction in <SFR> for SFGs with R<=0.1R_200_. The increase in the fraction of SFGs toward larger R/R_200_ and the isolation of SFGs with reduced SFRs near the cluster center are consistent with the truncation of star formation by ram-pressure stripping, as is the tendency for more massive SFGs to have higher SFRs. We conclude that stripping is more likely than slower processes to drive the properties of SFGs with R<0.4R_200_ in clusters. We also find that galaxies near the cluster center are more massive than galaxies farther out in the cluster at ~3.5{sigma}, which suggests that dynamical relaxation significantly impacts the distribution of cluster galaxies as the clusters evolve.
- ID:
- ivo://CDS.VizieR/J/A+A/392/795
- Title:
- Multi-wavelength study of 2 galaxy clusters
- Short Name:
- J/A+A/392/795
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from optical, X-ray and radio observations of two X-ray bright (L_X_~10^45^erg/s) galaxy clusters. Abell 1451 is at redshift z=0.1989 and has line-of-sight velocity dispersion {sigma}_V_=1330km/s as measured from 57 cluster galaxies. It has regular X-ray emission without signs of substructure, a Gaussian velocity distribution, lack of a cooling flow region and significant deviations from the observed scaling laws between luminosity, temperature and velocity dispersion, indicating a possible merging shock. There is only one spectroscopically confirmed cluster radio galaxy, which is close to the X-ray peak. 1RXS J131423.6-251521 (for short RXJ1314-25) has z=0.2474 and {sigma}_V_=1100km/s from 37 galaxies. There are two distinct galaxy groups with a projected separation of ~700kpc. The velocity histogram is bi-modal with a redshift-space separation of ~1700km/s, and the X-ray emission is double peaked. Although there are no spectroscopically confirmed cluster radio galaxies, we have identified a plausible relic source candidate.
- ID:
- ivo://CDS.VizieR/J/ApJ/664/777
- Title:
- Multiwavelength study of RX J1117.4+0743
- Short Name:
- J/ApJ/664/777
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiwavelength study of the poor cluster RX J1117.4+0743 ([VMF98] 097) at z=0.485, based on GMOS/Gemini South g' and r' photometry and spectroscopy, and XMM-Newton observations. We examine its nature and surroundings by analyzing the projected galaxy distribution, the galaxy velocity distribution, the weak-lensing mass reconstruction, and the X-ray spectroscopy and imaging.
- ID:
- ivo://CDS.VizieR/J/MNRAS/425/1215
- Title:
- Multiwavelength survey of AGNs
- Short Name:
- J/MNRAS/425/1215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to study the effect of environment on the presence and fuelling of active galactic nuclei (AGNs) in massive galaxy clusters. We explore the use of different AGN detection techniques with the goal of selecting AGN across a broad range of luminosities, AGN/host galaxy flux ratios and obscuration levels. From a sample of 12 galaxy clusters at redshifts 0.5<z<0.9, we identify AGN candidates using optical variability from multi-epoch Hubble Space Telescope imaging, X-ray point sources in Chandra images and mid-infrared (IR) spectral energy distribution power-law fits through the Spitzer Infrared Array Camera channels. We find 178 optical variables, 74 X-ray point sources and 64 IR power-law sources, resulting in an average of ~25 AGN per cluster.
- ID:
- ivo://CDS.VizieR/J/MNRAS/473/663
- Title:
- MUSE and HFFs Photometry of A2744
- Short Name:
- J/MNRAS/473/663
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of Multi Unit Spectroscopic Explorer (MUSE) observations obtained on the massive Frontier Fields (FFs) cluster A2744. This new data set covers the entire multiply imaged region around the cluster core. The combined catalogue consists of 514 spectroscopic redshifts (with 414 new identifications). We use this redshift information to perform a strong-lensing analysis revising multiple images previously found in the deep FF images, and add three new MUSE-detected multiply imaged systems with no obvious Hubble Space Telescope counterpart. The combined strong-lensing constraints include a total of 60 systems producing 188 images altogether, out of which 29 systems and 83 images are spectroscopically confirmed, making A2744 one of the most well-constrained clusters to date. Thanks to the large amount of spectroscopic redshifts, we model the influence of substructures at larger radii, using a parametrization including two cluster-scale components in the cluster core and several group scale in the outskirts. The resulting model accurately reproduces all the spectroscopic multiple systems, reaching an rms of 0.67-arcsec in the image plane. The large number of MUSE spectroscopic redshifts gives us a robust model, which we estimate reduces the systematic uncertainty on the 2D mass distribution by up to ~2.5 times the statistical uncertainty in the cluster core. In addition, from a combination of the parametrization and the set of constraints, we estimate the relative systematic uncertainty to be up to 9 per cent at 200kpc.
- ID:
- ivo://CDS.VizieR/J/ApJ/772/131
- Title:
- Musket Ball Cluster redshift catalog
- Short Name:
- J/ApJ/772/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Merging galaxy clusters have become one of the most important probes of dark matter, providing evidence for dark matter over modified gravity and even constraints on the dark matter self-interaction cross-section. To properly constrain the dark matter cross-section it is necessary to understand the dynamics of the merger, as the inferred cross-section is a function of both the velocity of the collision and the observed time since collision. While the best understanding of merging system dynamics comes from N-body simulations, these are computationally intensive and often explore only a limited volume of the merger phase space allowed by observed parameter uncertainty. Simple analytic models exist but the assumptions of these methods invalidate their results near the collision time, plus error propagation of the highly correlated merger parameters is unfeasible. To address these weaknesses I develop a Monte Carlo method to discern the properties of dissociative mergers and propagate the uncertainty of the measured cluster parameters in an accurate and Bayesian manner. I introduce this method, verify it against an existing hydrodynamic N-body simulation, and apply it to two known dissociative mergers: 1ES 0657-558 (Bullet Cluster) and DLSCL J0916.2+2951 (Musket Ball Cluster).
- ID:
- ivo://CDS.VizieR/J/A+A/571/L4
- Title:
- MWC 349A Halpha lines with 14<n<24 spectra
- Short Name:
- J/A+A/571/L4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The UC-HII region of MWC 349A is the prototype of an ionized wind driven by a massive star surrounded by a disk. Recent high angular resolution observations of the millimeter recombination lines have shown that the disk rotates with a Keplerian law in its outer parts. However, the kinematics of innermost regions in the UC-HII region of MWC 349A is still unknown, in particular the radius where the wind is launched from the disk. We performed hydrogen recombination line observations with the Heterodyne Instrument for the Far Infrared (HIFI) onboard the Herschel Space Observatory to study the kinematics of its innermost regions by studying their spectral features. In addition to the two laser peaks, we report the first detection of two new components that are blueshifted with respect to the laser peaks for all the recombination lines with principal quantum number n<22. These new spectral features originate from the region where the wind is ejected from the disk. We used our 3D non-LTE radiative transfer model for recombination lines (MORELI) to show that these features are consistent with the wind being ejected at a radius of about 24 AU from the star, which supports magnetohydrodynamic wind models.
- ID:
- ivo://CDS.VizieR/J/ApJS/115/1
- Title:
- MX northern Abell cluster redshift survey
- Short Name:
- J/ApJS/115/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results from the COBE satellite show the existence of structure on scales ~ 10% or more of the horizon scale of the universe. Rich clusters of galaxies from the Abell/Abell, Corwin, & Olowin catalogs (Cat. <VII/110>) show evidence of structure on scales of 100h^-1^Mpc and hold the promise of confirming structure on the scale of the COBE results. An impediment to that promise has been that redshift information has been unavailable for a large percentage of these clusters, so knowledge of their three-dimensional distribution has had large uncertainties. We have been working to greatly expand the sample of Abell clusters with reliable redshifts. Our approach in this effort, through the MX Northern Abell Cluster Redshift Survey, has been to measure redshifts of at least 25 galaxies in each of 95 R>=1 Abell cluster fields with m_10_<=16.8 and zero or one previously measured redshift. Of these 95 observed Abell clusters, 88 new cluster redshifts were obtained with an average of nine cluster member galaxy redshifts per field. Two clusters were found to be chance projections of galaxies along the line of sight, while five cluster observations did not provide enough galaxy redshifts to make a positive identification. This work has resulted in a deeper, 98% complete, and more reliable sample of three-dimensional positions of rich Abell clusters in the northern hemisphere. The primary intent of this survey has been to produce a larger and more complete sample of rich Abell clusters that can be used as tracers for large-scale structure. Through analyses with tools such as the two-point correlation function, power spectrum, and velocity dispersions, this sample can be used to constrain theoretical models better for the formation of structure we see in the universe today.
- ID:
- ivo://CDS.VizieR/J/AJ/124/1918
- Title:
- MX northern Abell cluster redshift survey. II.
- Short Name:
- J/AJ/124/1918
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The MX Northern Abell Cluster Survey II is the final stage of a program designed to observe rich Abell clusters with m10<=17.0. We present 1542 new galaxy redshifts within 117 R>=1 Abell cluster fields that have 16.9<=m10<=17.0, 0h<=RA<=24h, -17{deg}<=DE<=90{deg}, and |b|>=30{deg}. Of the 117 clusters observed for the MX Survey II, 105 new cluster redshifts were obtained with an average of eight cluster member galaxy redshifts.
