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— Viorica Hrincu
Sometimes when you stare at the void, the void sends you a poem.
Universe—Superclusters and Voids
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
contents
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.
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.
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
These are the individual catalogues from Vizier used in the map and to create the single parsed file above.
V/50 Bright Star Catalogue, 5th Revised Ed., Hoffleit+, 1991
VII/110A Rich Clusters of Galaxies, Abell+, 1989
VII/4A Abell and Zwicky Clusters of Galaxies, Abell+, 1974
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
VII/190 Zwicky Galaxy Catalog, Zwicky+, 1968
J/PASP/111/438 Updated Zwicky catalog (UZC), Falco+, 1999
J/MNRAS/445/4073 Two catalogues of superclusters, Chow-Martinez+, 2014
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
VI/42 Identification of a Constellation From Position, Roman, 1987
Good places to start your exploration of the Universe.
Hoffleit, D. & Warren, Jr., W.H. The Bright Star Catalog, 5th Revised Edition (Preliminary Version) (1991)
Roman N.G. Identification of a constellation from a position Publications of the Astronomical Society of the Pacific 99 695–699 (1987)
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.
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]
The universe within 2 billion light years. by Richard Powell
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]
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]
Celestial coordinate system [Wikipedia]
NASA/IPAC Extragalactic Database: Coordinate Transformation & Galactic Extinction Calculator
RA DEC flexible converter by Jan Skowron
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)
Convolutional neural networks
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).
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:.
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
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.
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
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.
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.
Science Advances cover
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.
Kijima, Y. et al. A universal sequencing read interpreter (2023) Science Advances 9.
Browse my gallery of cover designs.
Regression modeling of time-to-event data with censoring
If you sit on the sofa for your entire life, you’re running a higher risk of getting heart disease and cancer. —Alex Honnold, American rock climber
In a follow-up to our Survival analysis — time-to-event data and censoring article, we look at how regression can be used to account for additional risk factors in survival analysis.
We explore accelerated failure time regression (AFTR) and the Cox Proportional Hazards model (Cox PH).
Dey, T., Lipsitz, S.R., Cooper, Z., Trinh, Q., Krzywinski, M & Altman, N. (2022) Points of significance: Regression modeling of time-to-event data with censoring. Nature Methods 19:1513–1515.
Music video for Max Cooper's Ascent
My 5-dimensional animation sets the visual stage for Max Cooper's Ascent from the album Unspoken Words. I have previously collaborated with Max on telling a story about infinity for his Yearning for the Infinite album.
I provide a walkthrough the video, describe the animation system I created to generate the frames, and show you all the keyframes
The video recently premiered on YouTube.
Renders of the full scene are available as NFTs.