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The Universe - Superclusters and Voids by Martin Krzywinski
THE ENTIRE UNIVERSE | Put it on your wall. (buy artwork / see all my art)
If you like space, you will love this. The 2017 π Day art imagines the digits of π as a star catalogue with constellations of extinct animals and plants. The work is featured in the article Pi in the Sky at the Scientific American SA Visual blog.
If you like space, you'll love my the 12,000 billion light-year map of clusters, superclusters and voids. Find the biggest nothings in Boötes and Eridanus.The largest map there is shows the location of voids and galaxy superclusters in our visible universe.

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from an undefined
place,
undefined
create (a place)
an account
of us
— Viorica Hrincu

Sometimes when you stare at the void, the void sends you a poem.

Universe—Superclusters and Voids

Universe - Superclusters and Voids / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
The Universe — Superclustesr and Voids. The two supergalactic hemispheres showing Abell clusters (blue), superclusters (magenta) and voids (black) within a distance of 6,000 million light-years from the Milky Way.

The average density of the universe is about `10 \times 10^{-30} \text{ g/cm}^3` or about 6 protons per cubic meter. This should put some perspective in what we mean when we speak about voids as "underdense regions".

references

Before you delve into the background material for the map, calm the nerves and awaken the imagination with these space-themed tunes.

Perfect to listen to while perusing the map ... or the terrain.

1 · Music

2 Wicky by Hooverphonic (Live at Koningin Elisabethzaal 2012)

Space walk by Lemon Jelly

Exploration by Karminsky Experience Inc.

100 Billion Stars by Lux

Journey through the Boötes Void by Scott Lawlor

Ok, now let's get to it.

2 · Combined and parsed catalogues

The individual catalogues of objects (stars, clusters, superclusters, voids) shown on the map are available as a parsed single file.

      n TYPE
  ----- ------------
      2 quasar
   1024 supercluster
   2555 void
   5250 abell
   9096 hr
  18707 zwicky

Each element is represented by a single line and all objects start with the same fields:

TYPE ID CONSTELLATION NAME                  
  radec RA DEC                               
  lb GALACTIC_LONG GALACTGIC_LAT              
  sglb SUPERGALACTIC_LONG SUPERGALACTIC_LAT  
  z REDSHIFT d DISTANCE(Mly)                

For some objects the NAME is blank ("-").

In addition to these fields, each object type has additional information.

Abell cluters have the number of galaxies in them (N) and the IDs of the superclusters to which they belong listed.

abell ... count N mscc/sscc ID1,ID2,...

Superclusters have the number of galaxies in them (N), their size (SIZE) and the two constellation of the supercluster's Abell's clusters (same as CONSTELLATION if the supercluster's Abell clusters are all in the same constellation).

supercluster ... count N size SIZE(Mly) con_compound CON_COMPOUND

Voids have their size void ... size SIZE

The stars, taken from the Yale Catalogue of Bright Stars, do not have a distance or redshift but have a magnitude

hr ... mag MAGNITUDE

3 · Individual catalogues

These are the individual catalogues from Vizier used in the map and to create the single parsed file above.

3.1 · Stars

V/50 Bright Star Catalogue, 5th Revised Ed., Hoffleit+, 1991

3.2 · Abell clsuters

VII/110A Rich Clusters of Galaxies, Abell+, 1989

VII/4A Abell and Zwicky Clusters of Galaxies, Abell+, 1974

3.3 · Abell redshifts

VII/56 Redshifts for Abell Clusters, Sarazin+, 1982

J/APJ/365/66 Redshifts of a sample of distant Abell clusters, Huchra+, 1990

VII/165A Measured Redshifts of Abell Clusters of Galaxies, Andernach, 1991

VII/177 Redshifts and Velocity Dispersions for Abell Clusters, Struble+, 1991

J/APJS/96/343 Redshifts of rich clusters of galaxies, Quintana+, 1995

J/A+A/310/8 The ESO Nearby Abell Cluster Survey I., Katgert+, 1996

J/A+A/310/31 The ESO Nearby Abell Cluster Survey. II., Mazure+, 1996

J/APJS/126/1 Abell clusters photometry, Quintana+, 2000

J/AJ/126/119 Optical and radio data for rich Abell clusters, Rizza+, 2003

3.4 · Zwicky clusters

VII/190 Zwicky Galaxy Catalog, Zwicky+, 1968

J/PASP/111/438 Updated Zwicky catalog (UZC), Falco+, 1999

3.5 · Superclusters

J/MNRAS/445/4073 Two catalogues of superclusters, Chow-Martinez+, 2014

3.6 · Voids

J/APJ/744/82 Catalog of cosmic voids from the SDSS-DR7, Varela+, 2012

J/MNRAS/440/1248 SDSS DR7 voids and superclusters, Nadathur+, 2014

J/APJ/835/161 A cosmic void catalog of SDSS DR12 BOSS galaxies, Mao+, 2017

3.7 · Constellations

VI/42 Identification of a Constellation From Position, Roman, 1987

4 · Literature and online references

Good places to start your exploration of the Universe.

4.1 · Stars

Hoffleit, D. & Warren, Jr., W.H. The Bright Star Catalog, 5th Revised Edition (Preliminary Version) (1991)

4.2 · Constellations

Roman N.G. Identification of a constellation from a position Publications of the Astronomical Society of the Pacific 99 695–699 (1987)

Constellation list

To determine constellation shapes, I originally started with a list by Marc van der Sluys

BSC (Yale Catalogue of Bright Stars) constellation edges by Marc van der Sluys

However, many of these constellations were not the asterisms sanctioned by the IAU. I therefore corrected all the constellation shapes by manually examining the IAU map and cross-referencing the stars to the Yale Catalogue of Bright Stars. Ugh.

IAU Constellation shapes as edges between BSC stars (Yale Catalogue of Bright Stars) by Martin Krzywinski

For more details about the constellations see my IAU Constellation Shape Resources.

4.3 · Clusters

Abell clusters [Wikipedia]

Abell, G.O. The distribution of rich clusters of galaxies. A catalog of 2712 rich clusters found on the National Geographic Society Palomar Observatory Sky Survey The Astrophysical Journal Supplement Series 3 211–88 (1958)

LC 1101: supergiant elliptical galaxy [Wikipedia]

Abell 2029 galaxy cluster [Wikipedia]

4.4 · Superclusters

The universe within 2 billion light years. by Richard Powell

4.5 · Voids

Finelli F. et al. Supervoids in the WISE–2MASS catalogue imprinting cold spots in the cosmic microwave background Monthly Notices of the Royal Astronomical Society 455 (2016)

Kopylov A.I. & Kopylova F.G. Search for streaming motion of galaxy clusters around the Giant Void Astronomy and Astrophysics 382 389–396 (2002)

Linder U. et al. The structure of supervoids. I. Void hierarchy in the Northern Local Supervoid. Astronomy and Astrophysics 329–347 (1995)

El-Ad H. & Piran T. Voids in the large-scale structure The Astrophysical Journal 491 421–435 (1997)

List of voids [Wikipedia]

Giant void [Wikipedia]

Boötes void [Wikipedia]

Northern local supervoid [Wikipedia]

Southern local supervoid [Wikipedia]

Eridanus supervoid (CMBR Cold spot) [Wikipedia]

4.6 · Quasars

J1120+0641 [Wikipedia]

Mortlock D.J. et al A luminous quasar at a redshift of z = 7.085 474 616–619 (2011)

Bañados E. et al An 800-million-solar-mass black hole in a significantly neutral universe at a redshift of 7.5 Nature 553 (2018)

J1342+0928 [Wikipedia]

4.7 · Coordinate systems

Celestial coordinate system [Wikipedia]

NASA/IPAC Extragalactic Database: Coordinate Transformation & Galactic Extinction Calculator

RA DEC flexible converter by Jan Skowron

4.8 · Redshift

How far out in the universe can we see? by Harald Lang

Redshift and distance calculator by Edward Wright

Wright, E.L. The Publications of the Astronomical Society of the Pacific 118 1711–1715 (2006)

Loeb, A. Long-term future of extragalactic astronomy Physical Review D 65 047301.1–047301.4 (2002)

Bennett, C.L. et al The 1% Concordance Hubble Constant Astrophysical Journal 794 (2014)

news + thoughts

How Analyzing Cosmic Nothing Might Explain Everything

Thu 18-01-2024

Huge empty areas of the universe called voids could help solve the greatest mysteries in the cosmos.

My graphic accompanying How Analyzing Cosmic Nothing Might Explain Everything in the January 2024 issue of Scientific American depicts the entire Universe in a two-page spread — full of nothing.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
How Analyzing Cosmic Nothing Might Explain Everything. Text by Michael Lemonick (editor), art direction by Jen Christiansen (Senior Graphics Editor), source: SDSS

The graphic uses the latest data from SDSS 12 and is an update to my Superclusters and Voids poster.

Michael Lemonick (editor) explains on the graphic:

“Regions of relatively empty space called cosmic voids are everywhere in the universe, and scientists believe studying their size, shape and spread across the cosmos could help them understand dark matter, dark energy and other big mysteries.

To use voids in this way, astronomers must map these regions in detail—a project that is just beginning.

Shown here are voids discovered by the Sloan Digital Sky Survey (SDSS), along with a selection of 16 previously named voids. Scientists expect voids to be evenly distributed throughout space—the lack of voids in some regions on the globe simply reflects SDSS’s sky coverage.”

voids

Sofia Contarini, Alice Pisani, Nico Hamaus, Federico Marulli Lauro Moscardini & Marco Baldi (2023) Cosmological Constraints from the BOSS DR12 Void Size Function Astrophysical Journal 953:46.

Nico Hamaus, Alice Pisani, Jin-Ah Choi, Guilhem Lavaux, Benjamin D. Wandelt & Jochen Weller (2020) Journal of Cosmology and Astroparticle Physics 2020:023.

Sloan Digital Sky Survey Data Release 12

constellation figures

Alan MacRobert (Sky & Telescope), Paulina Rowicka/Martin Krzywinski (revisions & Microscopium)

stars

Hoffleit & Warren Jr. (1991) The Bright Star Catalog, 5th Revised Edition (Preliminary Version).

cosmology

H0 = 67.4 km/(Mpc·s), Ωm = 0.315, Ωv = 0.685. Planck collaboration Planck 2018 results. VI. Cosmological parameters (2018).

Error in predictor variables

Tue 02-01-2024

It is the mark of an educated mind to rest satisfied with the degree of precision that the nature of the subject admits and not to seek exactness where only an approximation is possible. —Aristotle

In regression, the predictors are (typically) assumed to have known values that are measured without error.

Practically, however, predictors are often measured with error. This has a profound (but predictable) effect on the estimates of relationships among variables – the so-called “error in variables” problem.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Error in predictor variables. (read)

Error in measuring the predictors is often ignored. In this column, we discuss when ignoring this error is harmless and when it can lead to large bias that can leads us to miss important effects.

Altman, N. & Krzywinski, M. (2024) Points of significance: Error in predictor variables. Nat. Methods 20.

Background reading

Altman, N. & Krzywinski, M. (2015) Points of significance: Simple linear regression. Nat. Methods 12:999–1000.

Lever, J., Krzywinski, M. & Altman, N. (2016) Points of significance: Logistic regression. Nat. Methods 13:541–542 (2016).

Das, K., Krzywinski, M. & Altman, N. (2019) Points of significance: Quantile regression. Nat. Methods 16:451–452.

Convolutional neural networks

Tue 02-01-2024

Nature uses only the longest threads to weave her patterns, so that each small piece of her fabric reveals the organization of the entire tapestry. – Richard Feynman

Following up on our Neural network primer column, this month we explore a different kind of network architecture: a convolutional network.

The convolutional network replaces the hidden layer of a fully connected network (FCN) with one or more filters (a kind of neuron that looks at the input within a narrow window).

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Convolutional neural networks. (read)

Even through convolutional networks have far fewer neurons that an FCN, they can perform substantially better for certain kinds of problems, such as sequence motif detection.

Derry, A., Krzywinski, M & Altman, N. (2023) Points of significance: Convolutional neural networks. Nature Methods 20:1269–1270.

Background reading

Derry, A., Krzywinski, M. & Altman, N. (2023) Points of significance: Neural network primer. Nature Methods 20:165–167.

Lever, J., Krzywinski, M. & Altman, N. (2016) Points of significance: Logistic regression. Nature Methods 13:541–542.

Neural network primer

Tue 10-01-2023

Nature is often hidden, sometimes overcome, seldom extinguished. —Francis Bacon

In the first of a series of columns about neural networks, we introduce them with an intuitive approach that draws from our discussion about logistic regression.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Neural network primer. (read)

Simple neural networks are just a chain of linear regressions. And, although neural network models can get very complicated, their essence can be understood in terms of relatively basic principles.

We show how neural network components (neurons) can be arranged in the network and discuss the ideas of hidden layers. Using a simple data set we show how even a 3-neuron neural network can already model relatively complicated data patterns.

Derry, A., Krzywinski, M & Altman, N. (2023) Points of significance: Neural network primer. Nature Methods 20:165–167.

Background reading

Lever, J., Krzywinski, M. & Altman, N. (2016) Points of significance: Logistic regression. Nature Methods 13:541–542.

Cell Genomics cover

Mon 16-01-2023

Our cover on the 11 January 2023 Cell Genomics issue depicts the process of determining the parent-of-origin using differential methylation of alleles at imprinted regions (iDMRs) is imagined as a circuit.

Designed in collaboration with with Carlos Urzua.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Our Cell Genomics cover depicts parent-of-origin assignment as a circuit (volume 3, issue 1, 11 January 2023). (more)

Akbari, V. et al. Parent-of-origin detection and chromosome-scale haplotyping using long-read DNA methylation sequencing and Strand-seq (2023) Cell Genomics 3(1).

Browse my gallery of cover designs.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
A catalogue of my journal and magazine cover designs. (more)

Science Advances cover

Thu 05-01-2023

My cover design on the 6 January 2023 Science Advances issue depicts DNA sequencing read translation in high-dimensional space. The image showss 672 bases of sequencing barcodes generated by three different single-cell RNA sequencing platforms were encoded as oriented triangles on the faces of three 7-dimensional cubes.

More details about the design.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
My Science Advances cover that encodes sequence onto hypercubes (volume 9, issue 1, 6 January 2023). (more)

Kijima, Y. et al. A universal sequencing read interpreter (2023) Science Advances 9.

Browse my gallery of cover designs.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
A catalogue of my journal and magazine cover designs. (more)
Martin Krzywinski | contact | Canada's Michael Smith Genome Sciences CentreBC Cancer Research CenterBC CancerPHSA
Google whack “vicissitudinal corporealization”
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