Misthearthttps://www.youtube.com/watch?v=yDAAlojz8NU
Kurzgesagt alimentando a mis pesadillas
#SpaceIsHard #SpaceIsScary #CosmicVoids #NightmareFuel #Science
YouTube
KillBaitCosmic Voids: Where Dark Energy Dominates and Drives Universe Expansion
📰 Original title: Cosmic voids look empty but they may be tearing the universe apart
🤖 IA: It's clickbait ⚠️
👥 Usuarios: It's clickbait ⚠️
View full AI summary: https://killbait.com/en/cosmic-voids-where-dark-energy-dominates-and-drives-universe-expansion/?redirpost=6098156e-df6d-476b-b6f2-3200710c688c
BoudWhile the holy grail of #InhomogeneousCosmology is to explain #DarkEnergy as an epiphenomenon of the cosmologically recent formation epoch of #CosmicVoids and other #LargeScaleStructure, #YonadavBarryGinat and #PedroGFerreira have gone for a more modest goal: keeping the #CosmologicalConstant but tacking on void formation to get a sort-of #BeyondLCDM inhomogeneous model that better matches #DES and #DESI results [1].
Apparent Dark-Energy Evolution from Cosmic Inhomogeneities
A mildly inhomogeneous universe with a cosmological constant may look like it contains evolving dark energy. We show that could be the case by modelling the inhomogeneities and their effects in three different ways: as clumped matter surrounded by voids, as back-reaction of small-scale structure on the overall expansion of the Universe, and, finally, as a large-scale curvature inhomogeneity. In all of these cases, the propagation of light is affected, and differs from that in a homogeneous and isotropic universe. The net result is that cosmological observables, such as angular diameter and luminosity distances, become distorted. We find, in all three models, that the inclusion of these effects pushes the distance-redshift relation towards closer agreement with recent data from both supernovae Ia from the Dark Energy Survey, and from baryon acoustic oscillations from the Dark Energy Spectroscopic Instrument. The amount of inhomogeneity in these models might not be enough to explain the entirety of the deviation from a cosmological constant, but is found to be of a similar order of magnitude, hinting that these data may be consistent with a universe dominated by a cosmological constant.
Daniel Pomarèdein the #arXiv
DESIVAST: A Catalog of Low-Redshift Voids using Data from the DESI DR1 Bright Galaxy Survey
by Hernan Rincon and co-authors
https://arxiv.org/abs/2411.00148
#Cosmology #Astronomy #Astrophysics #Astrodon #DESI #survey #DESIsurvey #galaxies #catalog #void #voids #cosmicvoids #voidfinder #SDSS #science #STEM #research
DESIVAST: A Catalog of Low-Redshift Voids using Data from the DESI DR1 Bright Galaxy Survey
We present three separate void catalogs created using a volume-limited sample of the DESI Year 1 Bright Galaxy Survey. We use the algorithms VoidFinder and V2 to construct void catalogs out to a redshift of z=0.24. We obtain 1,461 interior voids with VoidFinder, 420 with V2 using REVOLVER pruning, and 295 with V2 using VIDE pruning. Comparing our catalog with an overlapping SDSS void catalog, we find generally consistent void properties but significant differences in the void volume overlap, which we attribute to differences in the galaxy selection and survey masks. These catalogs are suitable for studying the variation in galaxy properties with cosmic environment and for cosmological studies.
in the #arXiv
2D watershed void clustering for probing the cosmic large-scale structure
by Yingxiao Song and co-authors
https://arxiv.org/abs/2410.04898
#Cosmology #universe #voids #cosmicvoids #CosmicWeb #astronomy #astrophysics #astrodon #physics #space #science #research #STEM #watershed #clustering
2D watershed void clustering for probing the cosmic large-scale structure
Cosmic void has been proven to be an effective cosmological probe of the large-scale structure (LSS). However, since voids are usually identified in spectroscopic galaxy surveys, they are generally limited to low number density and redshift. We propose to utilize the clustering of two-dimensional (2D) voids identified using Voronoi tessellation and watershed algorithm without any shape assumption to explore the LSS. We generate mock galaxy and void catalogs for the next-generation Stage IV photometric surveys in $z = 0.8-2.0$ from simulations, develop the 2D void identification method, and construct the theoretical model to fit the 2D watershed void and galaxy angular power spectra. We find that our method can accurately extract the cosmological information, and the constraint accuracies of some cosmological parameters from the 2D watershed void clustering are even comparable to the galaxy angular clustering case, which can be further improved by as large as $\sim30\%$ in the void and galaxy joint constraints. This indicates that the 2D void clustering is a good complement to galaxy angular clustering measurements, especially for the forthcoming Stage IV surveys that detect high-redshift universe.
Cosmography on the cover of Scientific American, with a feature article on cosmic voids
https://scientificamerican.com/issue/sa/2024/01-01/
#cosmology #cosmography #universe #astronomy #astrophysics #astrodon #space #science #research #void #voids #cosmicvoids #sciam #galaxies #cosmicweb
We use #CosmicVoids in [1][2], which in N-body sims are traced by low num-densities of particles => high noise. Full #Maneage controls + fixed seed rng's. We still have intramachine + (higher) intermachine randomness. Statistical upper limits to results OK. But still untraced sources of randomness.
Any clues for remaining randomness [2]?
#Reproducibility #ArXiv_2304_00591 #OpenScience
[1] Frozen record: https://zenodo.org/record/7792910
[2] Live git: https://codeberg.org/mpeper/lensing
Detecting cosmic voids via maps of geometric optics parameters
lensing-e4f7af0.pdf - article in pdf format void_matches*.dat - plain text results files corresponding to Table 3 and Figures 2, 4, 6, 8. lensing-e4f7af0-journal.tar.gz - source package for producing the article pdf, together with the reproducibility package, but without the git history; appropriate for ArXiv lensing-e4f7af0-git.bundle - git source package that can be unbundled with 'git clone lensing-e4f7af0-git.bundle' and used for reproducibility: to download data, do calculations, analyse them, plot them and produce the article pdf software-e4f7af0.tar.gz - this should contain all the software, apart from a minimal POSIX-compatible system and LaTeX packages, needed for compiling and installing the software used in producing this paper lensing-e4f7af0-snapshot.tar.gz - source files of the project; these should be enough, provided that external software packages can be downloaded, to reproduce the full project The authors grant a perpetual, non-exclusive licence to distribute this pdf preprint. All the other materials here are free-licensed, as stated in the individual files and packages.
#CosmicVoids should be detectable via their #GravitationalLensing effects.
Check this starting with a floppy-disk sized source snapshot [1].
#Reproducibility is via the #Maneage template of shell+make files.
Full research paper: [2][3][4][5]
[1] https://zenodo.org/record/7792910/files/lensing-e4f7af0-snapshot.tar.gz
[2] Preprint: https://arxiv.org/abs/2304.00591 #ArXiv_2304_00591
[3] Frozen record: https://zenodo.org/record/7792910
[4] Live git: https://codeberg.org/mpeper/lensing
The force is with us.
A great, unseen force is pushing our galaxy across the cosmos - a paper by Lauren Tousignant writing for the New York Post on the discovery of the Dipole Repeller: https://nypost.com/2017/02/01/a-great-unseen-force-is-pushing-our-galaxy-across-the-cosmos
The research paper published in Nature Astronomy: https://rdcu.be/wqbG
#dipolerepeller #universe #cosmology #cosmography #astronomy #astrophysics #space #science #galaxies #cosmos #physics #scicom #cosmicweb #cosmicvoids #greatattractor #milkyway #galaxy #nature #research #astrodon
A stylized visualization of the Dipole Repeller makes it to the cover of Nature Astronomy
https://web.archive.org/web/20170614103445/http://www.nature.com/natastron/volumes/1/issues/2
#universe #cosmology #cosmography #astronomy #astrophysics #space #science #galaxies #cosmos #physics #bigbangtheory #cosmicweb #cosmicvoids #dipolerepeller #greatattractor #milkyway #galaxy #nature #astrodon
