We observe a system of filaments and clusters around Cl0016+1609 and MACSJ1621.4+3810 using the SITELLE Fourier transform spectrograph at the Canada France Hawaii Telescope. For Cl0016+1609 (z=0.546), the observations span an 11.8 Mpc x 4.3 Mpc region along an eastern filament which covers the main cluster core, as well as two 4.3 Mpc x 4.3 Mpc regions which each cover southern subclumps. For MACSJ1621.4+3810 (z= 0.465), 3.9 Mpc x 3.9 Mpc around the main cluster core is covered. We present the frequency and location of the emission line galaxies, their emission line images, and calculate the star formation rates, specific star formation rates and merger statistics. In Cl0016+1609, we find thirteen [OII]~3727 Angstrom emitting galaxies with star formation rates between 0.2 and 14.0 M$_{\odot}$ yr$^{-1}$. 91$^{+3}_{-10}$% are found in regions with moderate local galaxy density, avoiding the dense cluster cores. These galaxies follow the main filament of the superstructure, and are mostly blue and disky, with several showing close companions and merging morphologies. In MACSJ1621.4+3810, we find ten emission line sources. All are blue (100$^{+0}_{-15}$%), with 40$^{+16}_{-12}$% classified as disky and 60$^{+12}_{-16}$% as merging systems. Eight avoid the cluster core (80$^{+7}_{-17}$%), but two (20$^{+17}_{-7}$%) are found near high density regions, including the brightest cluster galaxy (BCG). These observations push the spectroscopic study of galaxies in filaments beyond z~ 0.3 to z~ 0.5. Their efficient confirmation is paramount to their usefulness as more galaxy surveys come online.
We analyze the relationship between star formation (SF), substructure, and supercluster environment in a sample of 107 nearby galaxy clusters using data from the Sloan Digital Sky Survey. Previous works have investigated the relationships between SF and cluster substructure, and cluster substructure and supercluster environment, but definitive conclusions relating all three of these variables has remained elusive. We find an inverse relationship between cluster SF fraction (f_SF) and supercluster environment density, calculated using the galaxy luminosity density field at a smoothing length of…
High-resolution optical integral field units (IFUs) are rapidly expanding our knowledge of extragalactic emission nebulae in galaxies and galaxy clusters. By studying the spectra of these objects -- which include classic HII regions, supernova remnants, planetary nebulae, and cluster filaments -- we are able to constrain their kinematics (velocity and velocity dispersion). In conjunction with additional tools, such as the BPT diagram, we can further classify emission regions based on strong emission-line flux ratios. LUCI is a simple-to-use python module intended to facilitate the rapid analys…
We present theoretical expectations for infall toward supercluster-scale cosmological filaments, motivated by the Arecibo Pisces-Perseus Supercluster Survey (APPSS) to map the velocity field around the Pisces-Perseus Supercluster (PPS) filament. We use a minimum spanning tree applied to dark matter halos the size of galaxy clusters to identify 236 large filaments within the Millennium simulation. Stacking the filaments along their principal axes, we determine a well-defined, sharp-peaked velocity profile function that can be expressed in terms of the maximum infall rate $V_{\rm max}$ and the d…
The characterization of the internal structure of the superclusters of galaxies (walls, filaments and knots where the clusters are located) is paramount for understanding the formation of the Large Scale Structure and for outlining the environment where galaxies evolved in the last Gyr. (i) To detect the compact regions of high relative density (clusters and rich groups of galaxies); (ii) to map the elongated structures of low relative density (filaments, bridges and tendrils of galaxies); (iii) to characterize the galaxy populations on filaments and study the environmental effects they are su…
We analyse luminosity-weighted ages and metallicity (Z) of galaxies in a continuous range of environments, i.e. clusters, filaments and voids prevalent in the Coma supercluster ($\sim 100 h^{-1}$ Mpc). Specifically, we employ two absorption line indices, H$β$ and $\langle\rm{Fe}\rangle$ as tracers of age and metallicity of galaxies. We find that the stellar-phase metallicity of galaxies declines with increasing age as a function of stellar mass ($M^*$) as well as environment. On the filaments, metallicity of galaxies varies as a function of their distance from the spine of the filament, such t…
The Large-Scale Structure (LSS) of the Universe is a homogeneous network of galaxies separated in dense complexes, the superclusters of galaxies, and almost empty voids. The superclusters are young structures that did not have time to evolve into dynamically relaxed systems through the age of the Universe. Internally, they are very irregular, with dense cores, filaments and peripheral systems of galaxies. We propose a methodology to map the internal structure of superclusters of galaxies using pattern recognition techniques. Our approach allows to: i) identify groups and clusters in the LSS di…
We study the properties, connectivity, and galaxy content of groups and filaments in the low-density region (cocoon) around A2142 supercluster (SClA2142). We traced the SClA2142 cocoon boundaries by the lowest luminosity-density regions that separate SClA2142 from other superclusters. We determined galaxy filaments and groups in the cocoon and analysed the connectivity of groups, the high density core (HDC) of the supercluster, and the whole of the supercluster. We compared the distribution and properties of galaxies with different star-formation properties in the supercluster and in the cocoo…
The Coma supercluster (100 Mpc) offers an unprecedented contiguous range of environments in the nearby Universe. In this paper we present a catalogue of spectroscopically confirmed galaxies in the Coma supercluster detected in the ultraviolet (UV) wavebands. We use the arsenal of UV and optical data for galaxies in the Coma supercluster covering ~ 500 square degrees on the sky to study their photometric and spectroscopic properties as a function of environment at various scales. We identify the different components of the cosmic-web: large-scale filaments and voids using Discrete Persistent St…
We take a close look at the galaxies in the Coma Supercluster and assess the role of the environment (in the form of cluster, group and supercluster filament) in their evolution, in particular examining the role of groups. We characterise the groups according to intrinsic properties such as richness and halo mass, as well as their position in the supercluster and proximity to the two rich clusters, Abell 1656 (Coma) and Abell 1367. We devise a new way of characterising the local environment using a kernel density estimator. We find that apart from the dominant effects of the galaxy mass, the e…
We present results of a blind 21cm HI-line imaging survey of a galaxy overdensity located behind the Milky Way at $\ell,b$ $\approx$ 160 deg, 0.5 deg. The overdensity corresponds to a Zone-of-Avoidance crossing of the Perseus-Pisces Supercluster filament. Although it is known that this filament contains an X-ray galaxy cluster (3C129) hosting two strong radio galaxies, little is known about galaxies associated with this potentially rich cluster because of the high Galactic dust extinction. We mapped a sky area of $\sim$9.6 sq.deg using the Westerbork Synthesis Radio Telescope in a hexagonal mo…
We present a study of the Corona Borealis (CB) supercluster. We determined the high-density cores of the CB and the richest galaxy clusters in them, and studied their dynamical state and galaxy content. We determined filaments in the supercluster to analyse the connectivity of clusters. We compared the mass distribution in the CB with predictions from the spherical collapse model and analysed the acceleration field in the CB. We found that at a radius $R_{\mathrm{30}}$ around clusters in the CB (A2065, A2061, A2089, and Gr2064) (corresponding to the density contrast $Δρ\approx 30$), the galaxy…
We have carried out follow-up spectroscopy on three overdense regions of $g$- and $r$-dropout galaxies in the Canada-France-Hawaii Telescope Legacy Survey Deep Fields, finding two new protoclusters at $z=4.898$, 3.721 and a possible protocluster at $z=3.834$. The $z=3.721$ protocluster overlaps with a previously identified protocluster at $z=3.675$. The redshift separation between these two protoclusters is $Δz=0.05$, which is slightly larger than the size of typical protoclusters. Therefore, if they are not the progenitors of a $>10^{15}\,\mathrm{M_\odot}$ halo, they would grow into closely-l…
High-spectral-resolution Observations of the [S II] Emission-line Doublet in the Filamentary Nebula Surrounding NGC 1275
Université de Montréal（蒙特利尔大学）；Centre de recherche en astrophysique du Québec (CRAQ)（魁北克天体物理研究中心）；Dragonfly Focused Research Organization（Dragonfly专注研究机构）；Leibniz-Institut für Astrophysik Potsdam（波茨坦莱布尼茨天体物理研究所）；Columbia University（哥伦比亚大学）；Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理学中心）；Michigan State University（密歇根州立大学）；Durham University（杜伦大学）；University of Cambridge（剑桥大学）
Superclusters are the largest objects in the Universe, and they provide a unique opportunity to study how galaxy clusters are born at the junction of the cosmic web as well as the distribution of magnetic fields and relativistic particles beyond cluster volume. The field of radio astronomy is going through an exciting and important era of the Square Kilometer Array (SKA). We now have the most sensitive functional radio telescopes, such as the MeerKAT, which offers high angular resolution and sensitivity towards diffuse and faint radio sources. To study the radio environments around supercluste…
Virgo is the nearest galaxy cluster; it is thus ideal for studies of galaxy evolution in dense environments in the local Universe. It is embedded in a complex filamentary network of galaxies and groups, which represents the skeleton of the large scale Laniakea supercluster. Here we assemble a comprehensive catalog of galaxies extending up to ~12 virial radii in projection from Virgo to revisit the Cosmic Web structure around it. This work is the foundation of a series of papers that will investigate the multi-wavelength properties of galaxies in the Cosmic Web around Virgo. We match spectrosco…
We present a 23deg$^2$ weak gravitational lensing survey of the Shapley supercluster core and its surroundings using $gri$ VST images as part of the Shapley Supercluster Survey (ShaSS). This study reveals the overall matter distribution over a region containing 11 clusters at $z{\sim}0.048$ that are all interconnected, as well as several ongoing cluster-cluster interactions. Galaxy shapes have been measured by using the Kaiser-Squires-Broadhurst method for the $g$- and $r$-band images and background galaxies were selected via the $gri$ colour-colour diagram. This technique has allowed us to de…
We report the discovery of DGSAT I, an ultra-diffuse, quenched galaxy located 10.4 degrees in projection from the Andromeda galaxy (M31). This low-surface brightness galaxy (mu_V = 24.8 mag/arcsec), found with a small amateur telescope, appears unresolved in sub-arcsecond archival Subaru/Suprime-Cam images, and hence has been missed by optical surveys relying on resolved star counts, in spite of its relatively large effective radius (R_e(V) = 12 arcsec) and proximity (15 arcmin) to the well-known dwarf spheroidal galaxy And II. Its red color (V-I = 1.0), shallow Sersic index (n_V=0.68), and th…
We investigate the distribution and velocity field of galaxies situated in a band of 100 by 20 degrees centered on M87 and oriented along the Local supercluster plane. Our sample amounts 2158 galaxies with radial velocities less than 2000 km/s. Of them, 1119 galaxies (52%) have distance and peculiar velocity estimates. About 3/4 of early-type galaxies are concentrated within the Virgo cluster core, most of the late-type galaxies in the band locate outside the virial radius. Distribution of gas-rich dwarfs with $M_{\rm H\,I} > M_*$ looks to be insensitive to the Virgo cluster presence. Among 50…
The influence of the Cosmic Web on the properties of dwarf galaxies in the Fornax-Eridanus Supercluster
Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学卡皮坦天文研究所）；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）；Universidad Técnica Federico Santa María（费德里科·圣玛丽亚技术大学）
Cosmic dance in the Shapley Concentration Core II. The uGMRT-MeerKAT view of filaments in the brightest cluster galaxies and tailed radio galaxies in the A3528 cluster complex
本文利用 uGMRT 和 MeerKAT 射电观测结合 eROSITA X 射线数据，研究沙普利超星系团核心 A3528 复合体，发现最亮团星系周围存在谱指数极陡的弥散射电纤维，并提出小型并合可重新加速射电星系等离子体。
We present a large-scale galaxy structure Cl J021734-0513 at z~0.65 discovered in the UKIDSS UDS field, made of ~20 galaxy groups and clusters, spreading over 10 Mpc. We report on a VLT/VIMOS spectroscopic follow-up program that, combined with past spectroscopy, allowed us to confirm four galaxy clusters (M200 ~ 10^14 Msol) and a dozen associated groups and star-forming galaxy overdensities. Two additional filamentary structures at z ~ 0.62 and z ~ 0.69 and foreground and background clusters at 0.6 < z < 0.7 were also confirmed along the line-of-sight. The structure subcomponents are at differ…
The discovery and spectroscopic confirmation of Hyperion, a proto-supercluster at z~2.47, provides an unprecedented opportunity to study distant galaxies in the context of their large-scale environment. We carry out deep narrow-band imaging of a ~1*1 deg^2 region around Hyperion and select 157 Lya emitters (LAEs). The inferred LAE overdensity is delta_g~40 within an effective volume of 30*20*15 cMpc^3, consistent with the fact that Hyperion is composed of multiple protoclusters and will evolve into a super-cluster with a total mass of M_tot ~1.4*10^15 M_sun at z=0. The distribution of LAEs clo…
We present the VIMOS Spectroscopic Survey of a Supercluster in the COSMOS field (VIS3COS) at z~0.84. We use VIMOS high-resolution spectra (GG475 filter) to spectroscopically select 490 galaxies in and around the super-structure and an additional 481 galaxies in the line of sight. We present the redshift distribution, the catalog to be made public and the first results on the properties of individual galaxies and stacked spectra (3500Å<λ<4200Å rest-frame). We probe a wide range of densities and environments (from low-density field to clusters and rich groups). We find a decrease in the median s…
