Feel the vibe, feel the terror, feel the painMad about you, orchestrally.more quotes

DNA on 10th — street art, wayfinding and font

# data visualization + art

If you like space, you'll love my 2017 Pi Day art which imagines the digits as a star catalogue. Meet the Quagga and Aurochs—the Constellations in this sky are extinct animals and plants.

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— Viorica Hrincu

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

# Universe—Superclusters and Voids

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".

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.

# 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.

# 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 ("-").

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

$hr ... mag MAGNITUDE$

# Individual catalogues

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

#### Stars

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

#### Abell clusters

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

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

#### 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

#### Zwicky clusters

VII/190 Zwicky Galaxy Catalog, Zwicky+, 1968

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

#### Superclusters

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

#### 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

#### Constellations

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

# Literature and online references

Good places to start your exploration of the Universe.

#### Stars

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

#### Constellations

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.

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

#### 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]

#### Superclusters

The universe within 2 billion light years. by Richard Powell

#### 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]

#### 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]

#### Coordinate systems

Celestial coordinate system [Wikipedia]

RA DEC flexible converter by Jan Skowron

#### 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)

VIEW ALL

# Quantile regression

Sat 01-06-2019
Quantile regression robustly estimates the typical and extreme values of a response.

Quantile regression explores the effect of one or more predictors on quantiles of the response. It can answer questions such as "What is the weight of 90% of individuals of a given height?"

Nature Methods Points of Significance column: Quantile regression. (read)

Unlike in traditional mean regression methods, no assumptions about the distribution of the response are required, which makes it practical, robust and amenable to skewed distributions.

Quantile regression is also very useful when extremes are interesting or when the response variance varies with the predictors.

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

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

# Analyzing outliers: Robust methods to the rescue

Sat 30-03-2019
Robust regression generates more reliable estimates by detecting and downweighting outliers.

Outliers can degrade the fit of linear regression models when the estimation is performed using the ordinary least squares. The impact of outliers can be mitigated with methods that provide robust inference and greater reliability in the presence of anomalous values.

Nature Methods Points of Significance column: Analyzing outliers: Robust methods to the rescue. (read)

We discuss MM-estimation and show how it can be used to keep your fitting sane and reliable.

Greco, L., Luta, G., Krzywinski, M. & Altman, N. (2019) Points of significance: Analyzing outliers: Robust methods to the rescue. Nature Methods 16:275–276.

Altman, N. & Krzywinski, M. (2016) Points of significance: Analyzing outliers: Influential or nuisance. Nature Methods 13:281–282.

# Two-level factorial experiments

Fri 22-03-2019
To find which experimental factors have an effect, simultaneously examine the difference between the high and low levels of each.

Two-level factorial experiments, in which all combinations of multiple factor levels are used, efficiently estimate factor effects and detect interactions—desirable statistical qualities that can provide deep insight into a system.

They offer two benefits over the widely used one-factor-at-a-time (OFAT) experiments: efficiency and ability to detect interactions.

Nature Methods Points of Significance column: Two-level factorial experiments. (read)

Since the number of factor combinations can quickly increase, one approach is to model only some of the factorial effects using empirically-validated assumptions of effect sparsity and effect hierarchy. Effect sparsity tells us that in factorial experiments most of the factorial terms are likely to be unimportant. Effect hierarchy tells us that low-order terms (e.g. main effects) tend to be larger than higher-order terms (e.g. two-factor or three-factor interactions).

Smucker, B., Krzywinski, M. & Altman, N. (2019) Points of significance: Two-level factorial experiments Nature Methods 16:211–212.

Krzywinski, M. & Altman, N. (2014) Points of significance: Designing comparative experiments.. Nature Methods 11:597–598.

# Happy 2019 $\pi$ Day—Digits, internationally

Tue 12-03-2019

Celebrate $\pi$ Day (March 14th) and set out on an exploration explore accents unknown (to you)!

This year is purely typographical, with something for everyone. Hundreds of digits and hundreds of languages.

A special kids' edition merges math with color and fat fonts.

116 digits in 64 languages. (details)
223 digits in 102 languages. (details)

Check out art from previous years: 2013 $\pi$ Day and 2014 $\pi$ Day, 2015 $\pi$ Day, 2016 $\pi$ Day, 2017 $\pi$ Day and 2018 $\pi$ Day.

# Tree of Emotional Life

Sun 17-02-2019

One moment you're $:)$ and the next you're $:-.$

Make sense of it all with my Tree of Emotional life—a hierarchical account of how we feel.

A section of the Tree of Emotional Life.

# Find and snap to colors in an image

Sat 29-12-2018

One of my color tools, the $colorsnap$ application snaps colors in an image to a set of reference colors and reports their proportion.

Below is Times Square rendered using the colors of the MTA subway lines.

Colors used by the New York MTA subway lines.

Times Square in New York City.
Times Square in New York City rendered using colors of the MTA subway lines.
Granger rainbow snapped to subway lines colors from four cities. (zoom)