Find research datasets worth reusing
Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.
4
datasets available to search
ShareScore release 0.9.0
Dataset results
4 results for “cosmic web”
SDSS-IV Cosmic Web Catalog
<p>This repository contains the cosmic web catalog data released in the paper "Cosmic Web Catalog on SDSS-IV Data with SCONCE" (preparing).</p> <p>The catalog is constructed on the SDSS-IV galaxies and quasars (QSO) using our proposed Directional Subspace Constrained Mean Shift (DirSCMS) algorithm. We release both the cosmic filaments and local modes (i.e., local maxima of the estimated galaxy/QSO density field, which serves as candidates of galaxy clusters) within 325 thin redshift slices, each of which spans 20Mpc under the Planck15 cosmology. The entire catalog covers the redshift range from <span class="math-tex">\(z=0\)</span> to <span class="math-tex">\(z=3\)</span>.</p> <p> 1. "<strong>Cosmic_filaments_2D_DirSCMS_new1</strong>": The file contains some discrete realizations of the estimated cosmic filaments in some particular redshift slices. The meaning of each column in the file is described as follows:</p> <ul> <li><strong>RA</strong> -- right ascension.</li> <li><strong>DEC</strong> -- declination.</li> <li><strong>z_low</strong> -- lower limit of the redshift slice.</li> <li><strong>z_high</strong> -- upper limit of the redshift slice.</li> <li><strong>comov_dist_low</strong> -- lower limit of the comoving distance in the redshift slice under the Planck15 cosmology.</li> <li><strong>comov_dist_high</strong> -- upper limit of the comoving distance in the redshift slice under the Planck15 cosmology.</li> <li><strong>bw</strong> -- smoothing bandwidth parameter for the DirSCMS algorithm in the redshift slice.</li> <li><strong>unc_meas</strong> -- uncertainty measure of the filamentary point by the nonparametric bootstrap techinque.</li> <li><strong>density</strong> -- (proportional) estimated galaxy/QSO density value at the filamentary point.</li> <li><strong>grad_Dir1</strong> -- (Riemannian) gradient of the estimated density field (first direction).</li> <li><strong>grad_Dir2</strong> -- (Riemannian) gradient of the estimated density field (second direction).</li> <li><strong>grad_Dir3</strong> -- (Riemannian) gradient of the estimated density field (third direction).</li> <li><strong>knot_label</strong> -- indicator of whether the filamentary point is a knot (i.e., the intersection of several filaments) or not.</li> </ul> <p> 2. "<strong>Cosmic_local_modes_2D_DirMS_unique1</strong>": The file contains some discrete realizations of the estimated local modes in some particular redshift slices. The columns are subsumed by the ones in the cosmic filament file and has been described above.</p> <p><em>Additional notes: We provide both the "csv" and "fits" format for each of the above file.</em></p> <p> </p> <p>Please cite the paper when using the data in this repository.</p> <p>► Pure catalog data:</p> <p>[1] <strong>Cosmic Web Catalog on SDSS-IV Data with SCONCE</strong>. (In preparation)</p> <p>►Methodology:</p> <p>[1] Yikun Zhang, Rafael S. de Souza, and Yen-Chi Chen (2022). <strong>SCONCE: A Cosmic Web Finder for Spherical and Conic Geometries</strong>. <em>arXiv preprint arXiv:2207.07001</em></p> <p>[2] Yikun Zhang and Yen-Chi Chen (2022) <strong>Linear Convergence of the Subspace Constrained Mean Shift Algorithm: From Euclidean to Directional Data</strong>. <em>Information and Inference: A Journal of the IMA</em>, iaac005, <a href="https://doi.org/10.1093/imaiai/iaac005">https://doi.org/10.1093/imaiai/iaac005</a></p> <p>[3] Yikun Zhang and Yen-Chi Chen (2021) <strong>Kernel Smoothing, Mean Shift, and Their Learning Theory with Directional Data</strong>. <em>Journal of Machine Learning Research</em> <strong>22</strong>(154): 1-92.</p>
Analysis of constrained simulations of the Coma cluster and of its surrounding cosmic web
<p>The advent of wide-area spectroscopic galaxy surveys has allowed us to start investigating the properties of the filaments of the cosmic web. How filaments connect to clusters and how these connections impact cluster evolution is a hot topic in astrophysics, of interest for ongoing experiments and future facilities (from both the gas phase perspective, e.g. eROSITA, and the galaxy distribution, e.g. Euclid). The average connectivity (number of connected filaments) of a few observed and simulated clusters has been measured and it has been found that it scales with cluster mass. We applied a cosmic web detection algorithm (DisPerSE) to the Sloan Digital Sky Survey (SDSS) to detect the filaments from the galaxy distribution. We then detected three secure filaments connecting to the Coma cluster. This discovery lead to the developing of a further investigation based on constrained numerical simulations, which allow us to reproduce in detail a portion of the nearby Universe, recreating observed clusters including Coma. We analysed these simulations, with the aim of studying the evolution of the filaments around Coma throughout cosmic history and determining the impact of matter accretion channeled through these structures on the evolution of the Coma cluster. In this talk I will review our previous results and introduce the findings we obtained with the study of our constrained numerical simulations.</p>
Spectroscopy of the Cosmic Web: a view beyond collisional ionisation equilibrium with future X-ray telescopes
<p>This is a special seminar I gave at the Goddard Space Flight Center of NASA about my Ph.D. research at the Leiden University and the Netherlands Institute for Space Research SRON. Here you can download the presentation slides as well as the recording of the seminar. </p> <p> </p> <p>Abstract:</p> <p>In this talk I will focus on the X-ray view of the cosmic web filaments, more specifically the warm-hot intergalactic medium (WHIM). Hitomi kick-started an upcoming era of X-ray microcalorimeters which offer an unprecedented spectral resolution of diffuse sources. Many spectral signatures that could not yet have been studied will become feasible for the detection, and my presentation will focus on two of these spectral effects.</p> <p><br> Firstly, I will discuss how galaxy cluster photons alter the ionization state of nearby WHIM and affect the column densities of e.g. O VI, O VII, C V, or Ne VIII. Secondly,<br> I will discuss the feasibility of detecting the circum- and intergalactic medium in X-ray absorption using the extended intracluster medium as a backlight. For this study we used the cosmological hydrodynamical simulations Hydrangea (based on EAGLE) and we reported the feasibility of the detection of cosmic web filaments in OVII and in OVIII absorption with the microcalorimeter arrays onboard Athena and LEM. Last but not least, I will discuss my contribution to updating the cooling curve in the photoionisation model of the plasma code SPEX, and show the comparison to other plasma codes (MEKAL, APEC, Cloudy) and other atomic databases (CHIANTI, ADAS).</p>
The cosmic web of X-ray active galactic nuclei seen through the eROSITA Final Equatorial Depth Survey (eFEDS)
<p>Which galaxies in the general population turn into active galactic nuclei (AGN) is a keystone of galaxy formation and evolution.</p> <p>Thanks to SRG/eROSITA’s contiguous 140 square degrees pilot survey field, we constructed a large, complete, and unbiased soft<br> X-ray flux-limited AGN sample at low redshift 0.05 < z < 0.55. Two summary statistics, the clustering using spectra from SDSS-V<br> and galaxy-galaxy lensing with imaging from HSC, are measured and interpreted with halo occupation distribution and abundance<br> matching models. Both models successfully account for the observations. We obtain an exceptional complete view of the AGN 12<br> halo occupation distribution. The population of AGN is broadly distributed among halos with a mean mass of 3.9+2.0−2.4 × 10 M⊙ .<br> +0.08. This corresponds to a large-scale halo bias of b(z = 0.34) = 0.99−0.10 . The central occupation has a large transition parameter σlog10 (M) = 1.28 ± 0.2. The satellite occupation distribution is characterized by a shallow slope αsat = 0.73 ± 0.38. We find that AGNs in satellites are rare, with fsat < 20%. Most soft X-ray-selected AGNs are hosted by central galaxies in their dark matter halo. A weak correlation between soft X-ray luminosity and large-scale halo bias is confirmed (3.3σ). We discuss the implications of environmental-dependent AGN triggering. This study paves the way towards fully charting, in the coming decade, the co-evolution of X-ray AGN, their host galaxies, and dark matter haloes by combining eROSITA with SDSS-V, 4MOST, DESI, LSST, and Euclid.</p>
ScienceDex guides
Understand access before you commit
These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.